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Li 2 O–ZnO–B 2 O 3 -WO 3 (LZBW) sealing glasses for Si substrates were prepared and the effect of WO 3 on the structure, thermal properties, and sintering behaviour was investigated. As the WO 3 increases from 0 to 12 mol%, the glass transition temperature and softening temperature reach the lowest values of 448 °C and 479 °C, respectively, at which time the glass network has the lowest degree of polymerization. The thermal expansion coefficient increases from 6.959 × 10−6/°C to 8.476 × 10−6/°C with increasing WO 3 contents. It is verified that the introduction of WO 3 can effectively improve the conductivity. The sealing property of the glasses was evaluated by the wetting angle of the glasses after co-sintering with Si substrate for 10 min at 860 °C, and the 25Li 2 O-7ZnO-2.7Bi 2 O 3 -1.3P 2 O 5 -55B 2 O 3 -9WO 3 glass had the minimum wetting angle of 34.07°. The excellent thermal properties, conductivity, and wetting behaviour of the LZBW glasses make it a potential material as a binder material for positive silver pastes. [ABSTRACT FROM AUTHOR]

Borosilicate glass-ceramics are promising materials for sealing applications in solid oxide fuel cells (SOFC). This work synthesized glass and glass-ceramics of the 18CaO–27SrO–10B 2 O 3 –45SiO 2 composition containing 0, 2, and 4% TiO 2 (mol) by conventional melting/quenching and characterized by structural and thermal techniques. The 11B-NMR and 29Si-NMR spectra indicate no significant change in the relative concentration of the tetrahedral (B-IV) and trigonal (B-III) boron populations of all glasses, with the presence of Q2, Q3, and Q4 species. The crystalline phases of CaSiO 3 , SrB 2 Si 2 O 8, and Sr 2 SiO 4 precipitated in all the compositions. The thermal expansion coefficients of the glasses and corresponding glass-ceramics are compatible with those of the other stack components, and their glass transition temperatures are below the operating temperature of SOFCs (≈ 800–950 °C), thus can provide a hermetic seal. The sintering temperature of the T2 and T4 glasses is lower than 1000 °C, an essential characteristic for their application. However, the T4 glass exhibited even better sintering characteristics, making it a potential candidate for sealing. [ABSTRACT FROM AUTHOR]

· Study of lead germanate glasses by neutron diffraction, RMC, DSC and Raman analysis. · Density increases while Tg and atomic number density decrease with an increase in PbO mol%. · Ge-O co-ordination essentially tetrahedral and in the range: 3.9 to 4.2(1). · Small amount of GeO 3 and GeO 5 but no GeO 6 units in glass structure. · Pb-O co-ordination decreases from 4.0 to 3.1(1) with increase in PbO mol%. The effects of PbO concentration on the density, thermal and structural properties of xPbO–(100-x)GeO 2 (x = 20 to 55 mol%) glasses were studied. Density of glasses increases linearly from 5.043 to 6.981(5) g·cm−3, while the glass transition temperature decreases drastically from 467 °C to 359 °C on increasing PbO concentration from 20 to 55 mol%. Neutron diffraction studies found that Ge-O co-ordination is in the range: 3.9–4.2(1), and there is a very weak germanate co-ordination anomaly at PbO concentration of 40 and 50 mol%. GeO 4 are the dominant structural units with a small quantity of GeO 3 and GeO 5 but very little GeO 6 in the glass network. Pb-O and O O co-ordination decreases with an increase in PbO mol% and are in the range of: 4.0–3.1(1) and 6.3–5.4(1) respectively. Raman studies indicate a decrease in Pb-O co-ordination with increase in PbO mol%, in good agreement with the neutron diffraction findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel blend of aromatic nitrile-based resin named PAB was prepared. • PAB was prepared by collaborative design of structure and blending strategy. • PAB resin demonstrated low melting point and high curing activity. • The cured PAB resin exhibited excellent thermal and thermomechanical properties. The contradiction between processability and thermal properties has been limiting the development of high-performance thermoset resins, especially aromatic nitrile resins (AN). A new AN resin blend of 2-(3-(3,4-dicyanophenoxy)phenyl)-1H-imidazole-4,5dicarbonitrile (PNDCI) and 4-(4-aminophenoxy) phthalonitrile (APN) named PAB based on Brønsted acid-base blending strategy and introduction of asymmetric structure was designed and prepared in this paper. A series of characterizations showed that the PAB has not only excellent processability with a diminished melting point (118°C), wider processing window (90°C), and high curing reactivity, but that the cured PAB resins (C-PAB) also possessed high glass transition temperature (477°C), excellent long-term thermo-oxidative stability, thermomechanical properties and dimensional stability. The present design strategy of blending resins provides PAB as a good reference material for achieving a good balance between processability and high-temperature resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The three novel quinoxaline-based PAEs have been successfully prepared. • PAE films exhibit ultra-low D k (2.45–2.87) and D f (0.0019–0.0057) at high frequency. • PAEs show excellent hydrophobic, solubility and thermal properties. With the rapid growth of 5G communication technology, low-dielectric materials can decrease the loss of the signal during transmission. Hence, there is an urgent need to develop high-performance materials with low dielectric constant (D k) and dielectric loss (D f) at high frequency. In this study, we propose a strategy that combines bulk rigid quinoxaline structure and low polarizability trifluoromethyl group to prepare poly (aryl ether)s (PAEs) with low D k and D f at high frequencies. The effect of methyl substituents on the properties of PAEs was focuses on investigated. Accordingly, three difluoro-monomers containing quinoxaline structures were designed and prepared and novel quinoxaline-based PAEs with different numbers of methyl substituents were synthesized by nucleophilic condensation reactions with the bisphenol monomer hexafluorobisphenol A (BP6F). Test results that the resultant PAEs exhibited excellent thermal and solubility properties, with 5 % thermal decomposition temperatures (T d5%) in the range of 500−515 °C and glass transition temperatures (T g) reaching 225 °C. Furthermore, these PAE films show outstanding optical transparency, with cut-off wavelengths of 398−400 nm and above 87 % transmission at 800 nm. Most importantly, the novel PAE films possess ultra-low D k and D f , with the lowest values reaching 2.45 and 0.0024 at 10 GHz and maintain low water absorption (0.53–0.63 %). The excellent properties of novel quinoxaline-based PAEs provide its application potential in the field of high-frequency communications. [ABSTRACT FROM AUTHOR]

• Electron-donating substituent increased the polymerization activity of benzoxazine. • Electron-withdrawing substituent increased the heat resistance of polybenzoxazine. • Impacts of meta-substituents on thermal stability of polybenzoxazines were complex. The molecular structure of benzoxazine is closely related to its polymerization activity and the properties of its polymer. In this work, benzoxazines were successfully synthesized from phenol, paraformaldehyde and meta-substituted anilines. Their polymerization behaviors were discussed by non-isothermal differential scanning calorimetry (DSC). Moreover, the thermal properties of corresponding polybenzoxazines were evaluated using DSC and thermogravimetric analysis. The results showed that the electron-withdrawing substituent increased the polymerization temperature while the electron-donating substituent lowered the polymerization temperature. The glass transition temperature decreased for polybenzoxazine with electron-donating substituent but elevated for polybenzoxazine with electron-withdrawing substituent. Besides, the thermal stability and thermal degradation mechanism of polybenzoxazine were significantly affected by the substituent. This work supplied further insight in the structure-property relationship of benzoxazine resin. [Display omitted] [ABSTRACT FROM AUTHOR]

• Quaternary chalcogenide glassy systems have been prepared by melt quenching method. • Compositional dependence of various thermal parameters has been studied by deploying DSC analysis. • The Meyer-Neldel rule is used to explain AC conduction mechanism. • Mott's and Greaves VRH model is used to investigate DC conduction mechanism. • Electrical conduction relaxation has been analyzed by using Pan and Ghosh model. Tunability of thermal, and electrical characteristics of Sb x Se 50-x Sn 20 Te 30 (x = 2, 4, 6, and 8 at. %) bulk glass systems with varying doping concentrations are the major objective of this study. The melt quenching technique has been employed to synthesize the samples. Various thermal parameters have been inspected by using DSC measurements. The effect of Sb addition on the glass transition temperature (T g), crystallization temperature (T c), peak crystallization temperature (T p), and melting temperature (T m) have been observed from DSC thermograms. The dependence of Tg, Tc, Tp, and Tm on the heating rate has been measured. The thermal analysis is performed under non-isothermal conditions at heating rates of 5, 10, 15, and 20 K/min. The activation energies for the glass transition temperature are estimated by using the Kissinger method and are found to decrease from (211.21-168.85) KJ.mol−1. Thermal stability and glass forming ability for all glassy compositions have been examined in terms of Hruby's parameter. In addition, electrical conductivity mechanisms over vast temperature and frequency ranges are analyzed. The DC conductivity mechanism has been analyzed by deploying Mott and Greaves's variable range hopping model, while the AC conductivity mechanism has been analyzed by deploying the modified correlated barrier hopping model. AC conductivity scaling property has been examined by using the Pan and Ghosh model. The influence of Sb addition has been observed as the DC and AC conductivity increases with the increase of doping concentration. [ABSTRACT FROM AUTHOR]

Phosphate glasses containing Gd3+ ions as ultraviolet (UV) type B light emitters are of interest for applications in phototherapy lamps for treating skin diseases. The composition-structure-property relation in this type of glass systems is thus of interest from fundamental and applied perspectives. In this work, Gd3+-containing glasses were prepared by melting with 50P 2 O 5 -(50 – x)BaO- x Gd 2 O 3 (x = 0, 1, 2, 3, 4, 5 mol %) nominal compositions, and studied comprehensively by X-ray diffraction (XRD), densitometry, Raman spectroscopy, differential scanning calorimetry (DSC), dilatometry, optical absorption, and photoluminescence (PL) spectroscopy with emission dynamics appraisal. XRD supported the amorphous nature of the glasses, whereas the densities of the Gd3+-containing glasses were found to increase with Gd 2 O 3 content. The Raman spectra evolution was indicative of glass depolymerization being induced by Gd3+ ions. DSC results showed that the glass transition temperatures increased with Gd3+ concentration while the glasses exhibited decreased susceptibility for crystallization. Dilatometry ultimately revealed a steady decrease in the coefficient of thermal expansion for the Gd3+-containing glasses indicating tighter networks were realized. The PL evaluation showed that the UVB emission intensity at 312 nm increased linearly with Gd3+ concentration, even though the 6P 7/2 state lifetime reached a maximum for 2 mol % Gd 2 O 3. The PL intensities finally showed strong linear correlations with the thermal parameters linked to the structural evolution thus supporting the interconnection between the properties. [Display omitted] • Composition-structure-property relation studied in melt-quenched UV-emitting phosphate glasses containing Gd3+. • Characterizations by XRD, density, Raman spectroscopy, DSC, dilatometry, optical absorption, and PL spectroscopy. • Glass depolymerization induced by Gd 2 O 3 replacing BaO indicated by Raman spectroscopy. • Gd3+ ions increase glass transition and softening temperatures while decreasing thermal expansion. • PL intensity increase up to 5 mol% Gd 2 O 3 correlated with thermal parameters. [ABSTRACT FROM AUTHOR]

In order to prepare thermoplastic polyimide (PI) resins with good comprehensive performances, the modification of thermoplastic polyetherimides (PEIs) by 1,4-bis(2,3-dicarboxyphenoxy)-2- tert -butylbenzene dianhydride (3,3′-TBHQDA) was systematically investigated. The PEI-a-x and PEI-b-x series of polyetherimides were synthesized by chemical imidization of the diamine monomer m -phenylenediamine (m -PDA) with different contents of 1,4-bis(3,4-dicarboxyphenoxy)-2- tert -butylbenzene dianhydride (4,4′-TBHQDA) and 3,3′-TBHQDA or 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (4,4′-BPADA) and 3,3′-TBHQDA. These PEIs had glass transition temperatures (T g s) in the range of 217–264 °C, low melt viscosities of 79–2367 Pa s, good transmittances of 87–88 % at 450 nm, and displayed good mechanical properties with tensile modulus of 2.8–3.2 GPa, tensile strengths of 89.6–118.4 MPa, and elongations at break of 3.9–6.4 %. The introduction of 3,3′-TBHQDA successfully improved thermal properties and melt processability of the PEIs. Among them, PEI-a-50 and PEI-b-50 displayed better comprehensive performances in PEI-a-x and PEI-b-x series, respectively, with moderate T g s (256 and 249 °C, respectively), extremely low melt viscosities (161 and 297 Pa s at 400 °C, respectively), high transmittances at 450 nm (87 %), and good mechanical properties (tensile modulus of 3.1 and 2.8 GPa, tensile strengths of 105.6 and 106.3 MPa, respectively). [Display omitted] • The modification of PEIs based on 4,4′-TBHQDA and 4,4′-BPADA by 3,3′-TBHQDA. • The heat resistance and melt processability of PEIs were modified by 3,3′-TBHQDA. • The PEI-a-50 and PEI-b-50 showed T g s of 256 and 249 °C, respectively. • The PEI-a-50 and PEI-b-50 had melt viscosities of 161 and 297 Pa s, respectively. [ABSTRACT FROM AUTHOR]

• Impacts of alkaline earth and zinc cations on performances in Al-rich aluminosilicate glasses were unraveled. • Ca2+, Sr2+, and Ba2+cations in peraluminous aluminosilicate glasses mainly act as balancers for charged AlO 4 tetrahedra. • Similarities and differences of roles acted by Mg2+ and Zn2+ cations in peraluminous aluminosilicate glasses were identified. Here, the substitution of divalent cations is used as a strategy to tune the thermal and mechanical properties of aluminosilicate glasses. Following the successive substitution of R in 7RO·14MgO·28Al 2 O 3 ·51SiO 2 glasses (R= Mg, Ca, Sr, Ba, Zn), the nonlinear evolution in performances occurs, including glass transition temperature (T g), thermal stability (Δ T), fragility index (m), hardness (H V), crack resistance (C R), elastic modulus (E and G), and Poisson's ratio (ν). Specifically, although similar in ionic radius, replacement of Mg with Zn in present glasses results in clear differences in properties, such as a drop of 26 K in T g , 5.9 GPa in E , 9.5 in m , and an enhancement of 11 K in Δ T. Based on Raman spectra, 27Al and 29Si NMR Spectra, we revealed the chemical and atomic-scale structural origin of the nonlinear evolution in performances following the substitution of divalent cations in peraluminous aluminosilicate glasses. [ABSTRACT FROM AUTHOR]

Most polymers used in coatings are thermosetting resins because of their good adhension, protective capability, thermal and mechanical properties. Prepolymerization is a common procedure in the application of thermosetting resins, in order to adapt the specific processing condition, processing equipment or to achieve desired performance. However, the effects of prepolymerization on the curing behavior, chemical structure and properties of the resultant resins haven't been systematically studied. Among various thermosetting resins used as coatings, benzoxazine is a relatively new member, but it is being intensively studied due to its good processability, adhesive strength, low water absorption, as well as good anticorrosive property. Hence, in this work, 1,3-benzoxazine, a kind of high-performance thermosetting resin, was used as an example to probe the influence of prepolymerization. The chemical structure variation was characterized, the curing activity and the rheological behavior were investigated, and the thermal, mechanical and dielectric properties of the resultant polymers were also studied. It was found that the content of benzoxazine groups decreased while the molecular weight and the melt viscosity increased with prelonged prepolymerization time, which may release more active phenolic hydroxyls that could promote the curing of benzoxazine, but also caused worse molecular moveability. The glass transition temperature, initial decomposition temperature and char yield of most polymers decreased consequently, with few exceptions. However, the mechanical property was improved, as suggested by higher tensile strength and elongation at break value after prepolymerization. [Display omitted] • 1,3-benzoxazine was used as an example to probe the influence of prepolymerization; • Prepolymerization led to consumption of functional groups, increased molecular weight and higher melt viscosity; • Prepolymerization led to lower crosslinking density; • Prepolymerization led to lower glass transition temperature; • Prepolymerization led to higher mechanical strength. [ABSTRACT FROM AUTHOR]

• Strict controlled segment length and alternate sequence. • P(AMMO-ab-EG) exhibit excellent flexibility and thermal properties. • Fine controlled segment lengths enable high crystallinity but lower T g value. The flexibility of high energy polymers is hindered by bulky and polar high energy groups, resulting in reduced mechanical properties. In this paper, poly(3-azidomethyl-3-methyloxetane-glycol) (P(AMMO-ab-EG)) with an alternating block structure was synthesized and characterized. Diethylene glycol and triethylene glycol are used to improve flexibility, which length in this polymer structure is tightly controlled. (P(AMMO-ab-EG)) exhibits good flexibility, suitable viscosity and good thermal stability. It was found that P(AMMO-ab-DEG) exhibited a lower glass transition temperature but higher viscosity and better temperature viscosity sensitivity than P(AMMO-ab-TEG). These results demonstrate that fine tuning of the block length has a greater effect on T g than on viscosity. This finding is of great significance to prepare energetic polymers with good processing properties and lower T g value. Al, the prepared (P(AMMO-ab-EG) has excellent compatibility with NG (nitroglycerine) and NP (bis(2,2-dinitropropyl)acetal and bis(2,2- dinitropropyl)formal). [Display omitted] [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a promising, sustainable alternative to conventional petroleum-based polymers, but its mechanical and thermal properties limit its applications. This study introduces bamboo powders (BP) and montmorillonite clay particles (MMT) into the PLA matrix to prepare novel bio-based polymer hybrid composites using a unique combination of weight percentages of BP and MMT without chemical solvents through a stir casting process under optimised input parameters followed by compression moulding. Polymer hybrid composites were fabricated with different weight combinations, and their mechanical, morphological, and thermal properties were analysed. Tensile, flexural, and impact tests were performed to examine the mechanical performance, while thermogravimetric analysis and differential scanning calorimetry were used to assess thermal stability and characteristics. Microscopy observations showed a strong interaction between the bamboo, clay, and PLA matrix. The results revealed that the maximum tensile strength and modulus increased by 26.1 % and 40.8 %, respectively, with 10 wt% BP and 4 wt% clay content. Impact strength increased by 48 % with 15 wt% BP and 4 wt% clay content. Moreover, the thermal decomposition temperature, glass transition temperature (T g), crystallisation temperature (T c), and melting temperature (T m) of the hybrid composites improved considerably with 10 wt% BP and 4 wt% clay content, increasing by 4 °C, 2 °C, and 8 °C, respectively. Based on the findings of this study, the controlled processing parameters were optimised to fabricate the bio-based composite with significantly improved mechanical and thermal properties. These properties make the composite suitable for various automotive and structural applications. [Display omitted] • Polymer hybrid composites made by stir casting without solvents show enhanced mechanical properties. • Good interaction has been identified between matrix and reinforcement. • Bamboo and clay particles enhanced the mechanical performance of the composite. • Clay particles influence the thermal stability of the composite. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) recycling has been carried out by various methods, e.g., mechanical recycling, chemical recycling, and energy recovery method. In this study, chemical recycling of PET was carried out by aminolysis using ethanolamine and converted into bis(2-hydroxyethyl) terephthalamide (BHETA). We have studied the effective polymeric catalysis of the aminolytic depolymerization of waste polyethylene terephthalate (PET) using sulfated polyborate producing a broad range of crystalline terephthalamides. The reaction was performed by varying the PET: ethanolamine ratio, reaction time and catalyst. Recycled PET bottles, film, and fibres were used for conversion. A yield of 95 % was obtained for PET: ethanolamine ratio of 1:4 (w/w), with 4 h reaction time, at 160 o C with sulfated polyborate as a catalyst. BHETA was characterized with FTIR, 1H,13C NMR, and DSC analysis. BHETA further gets reacted with dimer acid along with Ethylenediamine (EDA) at different molar ratios which produces polyesteramide (PEA) based hot melt adhesive (HMA). Thermal, mechanical, and rheological tests are performed and compared with traditional HMA. The effect on the properties of the hot melt adhesive, such as mechanical properties: tensile strength, shore D hardness, elongation at break; thermal properties: glass transition temperature (Tg), melting temperature (Tm), the heat of crystallization (Hc), crystallization temperature (Tc); adhesion properties: lap shear strength (LSS) and T-peel strength (TPS); rheological properties and degree of crystallinity were investigated. It was observed that the mechanical and thermal properties are increased by optimizing the concentration of BHETA. These HMA materials may have the capacity of being eco-friendly and have high adhesion properties. [ABSTRACT FROM AUTHOR]

A study of the thermal and mechanical properties, as well as the molecular chain orientation of sulfur-vulcanized hydrogenated nitrile-butadiene rubber (HNBR) with acrylonitrile (ACN) content of 34 and 36 wt% and different crosslink density is presented. The objective is to establish the relationships between structural changes during stretching and the tensile and elastic behavior of HNBR having different chain microstructure. The (vulcanized) HNBR samples are amorphous at room temperature with glass transition temperatures that increase with increasing ACN content and crosslink density. The samples do not exhibit strain-induced crystallization. Stretching at room temperature only induces orientation of the amorphous segments along the stretching direction, which contributes to improved tensile strength, strain-hardening, and toughness, while preserving excellent elastic recovery of the rubbers. Precise correlations are established between the degree of orientation of the amorphous chain and the deformation in the framework of the affine deformation model of rubber elasticity. [Display omitted] • The structure and physical properties of hydrogenated nitrile-butadiene rubbers are investigated. • The relationships between strain-induced orientation and tensile and elastomeric behavior are established. • The ultimate tensile strength of vulcanized samples is associated to the degree of orientation of the amorphous phase achieved at high deformations before breaking. • The amorphous phase orientation contributes to improved toughness, strain-hardening and excellent elastic recovery. [ABSTRACT FROM AUTHOR]

Two series of aluminum lead borate glasses, (Al 2 O 3) y (PbO) 35- y (B 2 O 3) 65 and (Al 2 O 3) y (PbO) 70- y (B 2 O 3) 30 , were prepared and effect of PbO → Al 2 O 3 substitution on their structure and thermal properties was studied. The semi-quantitative analysis of the Raman spectroscopy data was used to structural interpretation of glass transition behavior in the Al 2 O 3 -doped lead borate glasses. The mechanisms of structural reorganization of glassy network under PbO → Al 2 O 3 substitution were found to differ for the studied series although Al3+ ions are incorporated in the glass network, mainly, in form of AlO 4 units in the both cases. The formation of AlO 4 tetrahedra is accompanied by transformation of various isolated borate anions into finite-sized metaborate chains as well as the conversion of four-fold coordinated [BØ 3 O−]− species with one non-bridging oxygen atom into fully polymerized [BØ 4 ]− tetrahedra in the (Al 2 O 3) y (PbO) 70- y (B 2 O 3) 30 glasses. In the series of glasses with high concentration of B 2 O 3 , B[4] → B[3] transformation including the shift of [BØ 4 ]− ↔ BØ 2 O− equilibrium toward the right side is the main process of structural reorganization caused by PbO → Al 2 O 3 substitution. In this case, the change in the network connectivity is determined by competition between increasing the amount of Al-O-B bonds against the background of decreasing the amount of B-O-B bonds between borate structural species. In the B-poor series, the glass transition temperature increased with Al 2 O 3 from 280 to 360 °C, and the crystallization peak onset occurs at 340 and 380 °C for the glasses with the 0 and 3 mol.% Al 2 O 3 contents, respectively (higher aluminum oxide contents already prevent crystallization). In the B-rich series, T g increases with the Al 2 O 3 content from 430 to 490 °C, and the crystallization occurs at 560 °C only for the Al 2 O 3 -free glass. The structural relaxation behavior in the glass transition rage was described in terms of the Tool-Narayanaswamy-Moynihan model. The activation energy for the relaxation movements was found to be non-monotonous in case of both compositional series. [ABSTRACT FROM AUTHOR]

The aim of this study was to produce new nanocomposites with antimicrobial, antioxidant and anticancer properties that can be used in biomedical research based on carboxymethyl cellulose (NaCMC) biopolymer. First, poly(2-oxo-2-(pentafluorophenoxy)ethyl-2-methylprop-2-enoate) (PPFMA) was synthesized and characterized by FTIR and NMR techniques. It was then blended with NaCMC by in situ/hydrothermal method to produce a semi-synthetic functional material. Changes in the FTIR data of the blend and the single Tg value from DSC confirmed the compatibility of the blend. To enhance the thermal and biological properties of the NaCMC-PPFMA blend, biosynthesized Ag-ZnONPs were hydrothermally incorporated into the blend at different weight ratios. The prepared materials were characterized by SEM, EDX, TEM, XRD and FTIR. The thermal stability of the materials was determined by thermogravimetric analysis (TGA), and glass transition temperatures (Tg) was determined by differential scanning calorimeter (DSC). The oxidant, antioxidant, antimicrobial, and cytotoxic properties of PPFMA, Ag-ZnONPs, PPFMA-NaCMC blend, and nanocomposites were investigated in detail. The total oxidant state (TOS) value of the NaCMC-PPFMA blend, which was 0.72 μmol equivalent H 2 O 2 /L, increased to 7.2–10.4 μmol equivalent H 2 O 2 /L with the addition of Ag-ZnONPs. Ag-ZnONPs decreased total antioxidant state (TAS) levels of the nanocomposites while increasing their oxidant activity. Therefore, an increase in the antimicrobial activity of the nanocomposites was observed. Adding Ag-ZnONPs to the NaCMC-PPFMA blend increased the thermal stability by 22 °C and the Tg value by 9 °C. Finally, the potential of Ag-ZnONPs containing nanocomposites in wound healing therapies was examined. The findings suggest that nanocomposites prepared by incorporating Ag-ZnONPs into the semi-synthetic NaCMC-PPFMA blend can be a source of bio-safe raw materials and can be used as potential wound healers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based copolyesters involving 2,6-pyridine structure with isosorbide as a second diol were synthesized. • Incorporation of isosorbide enhanced thermal properties of the pyridine-based polyesters. • Isosorbide significantly improved the mechanical properties of the pyridine-based polyesters. • The copolyesters showed high gas barrier properties. Driven by sustainable development and low-carbon policies, many high-performance bio-based polyesters are produced. Our previous work uncovered the high barrier but low thermal and mechanical properties of a renewable 2,6-pyridinedicarboxylic-based polyester. In this article, the copolymerization with isosorbide as a second diol is considered to ameliorate these properties. The chemical structures of copolyesters and the successful introduction of isosorbide were confirmed by FT-IR and 1H NMR. The 1H NMR spectra also allowed the calculation of isosorbide ratio in polymers. GPC revealed a decrease in molar masses with the increase of isosorbide ratio. Contact angle and water/gas permeation measurements disclosed an increase in hydrophilicity and water/gas permeability with the introduction of isosorbide. TGA and DSC analyses demonstrated an enhancement in thermal stability: 8 mol% of isosorbide to the total diol ratio increased the 5 % weight loss temperature (T 5%) by 9 °C, the maximum weight loss temperature (T max) by 8 °C and the glass transition temperature (T g) by 6 °C. DSC investigation showed that the incorporation of isosorbide significantly influenced the crystallization properties, particularly from the melt, by decreasing the crystallinity. XRD patterns indicated the presence of similar crystallization units in these polyesters. Tensile test revealed that incorporating 8 mol% of isosorbide greatly improved the mechanical properties by doubling Young's modulus and tripling the strength at break. Such enhancement in thermal and mechanical properties is important for high gas barrier food packaging applications of these polyesters. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrogenated nitrile butadiene rubber (HNBR) has been widely used in petrochemical, aerospace, and other fields for its excellent properties. In this study, molecular dynamics methods were employed to construct molecular models of HNBR and hydrogenated carboxyl butadiene rubber (HXNBR). It was found that the introduction of carboxyl groups significantly enhanced the mechanical properties of the material, whereas the glass transition temperature of the material increased by 9.96% and the thermal conductivity decreased by 17.3%. Subsequently, the grafted hydrogenated carboxylated nitrile butadiene rubber (HXNBR-Rx) model and the HXNBR-Rx/Fe bilayer adsorption model, which incorporate grafting modifications with of C 5 H 11 OH, C 10 H 21 OH, C 15 H 31 OH, C 20 H 41 OH and C 25 H 51 OH, were constructed. In comparison between their thermal properties and the adsorption properties on the metal walls, we revealed that as the number of grafted side chain carbon atoms increased, both the mechanical properties and the glass transition temperature of the material showed a trend of first decreasing and then increasing, while the thermal conductivity of the material first increased and then decreased. Furthermore, the effect of grafting on the material properties was analyzed at the molecular level in terms of free volume fraction, interfacial interaction energy, and relative atomic concentration. The simulation results can provide some theoretical guidance for optimizing the thermal properties of HNBR materials and the adsorption capacity of the metal walls while maintaining their oil resistance and mechanical properties. [ABSTRACT FROM AUTHOR]

The preparation of biobased benzoxazine resin with low melting point and low curing temperature has important significance for environmental sustainable development and practical application in industrial field. In this paper, biobased benzoxazine monomer HA-fa was synthesized from p-hydroxybenzyl alcohol, paraformaldehyde and furfurylamine, and H-fa were prepared by Mannich reaction of hordenine with paraformaldehyde and furfurylamine. The two benzoxazine organic molecules showed different thermodynamic behaviors. HA-fa and H-fa were liquid at room temperature. The viscosity of HA-fa and H-fa at room temperature (25 °C) were 1.683 Pa/s and 0.602 Pa/s, and the curing peak temperature was 220 °C and 208 °C, respectively, both organic molecules showed excellent processability. Then poly(HA-fa) and poly(H-fa) were prepared by two organic molecules through thermal curing procedure. The comprehensive properties of two benzoxazine resins were investigated. The glass transition temperature (T g) of poly(H-fa) is 223 °C, while the T g of poly(HA-fa) has two peak temperatures, 225 °C and 281 °C, respectively. This may be due to the existence of two different crosslinking networks in the resin, which leads to the phase separation of the resin, thus reflecting two T g. Meanwhile, the initial thermal decomposition temperatures T di of poly(HA-fa) and poly(H-fa) were 330 °C and 331 °C, respectively, showing excellent thermal stability of the newly prepared resin. In addition, poly(HA-fa) and poly(H-fa) have both high storage modulus (3174 MPa and 2608 MPa, respectively, measured at 25 °C) and good flexural strength (121 ± 2.7 MPa and 96 ± 3.6 MPa). Among the two resins, poly(HA-fa) showed more excellent comprehensive properties, which may be based on the joint action of resin multi-crosslinking sites and hydrogen bond crosslinking network. Two benzoxazine monomers have low viscosity at room temperature, they also have low curing temperature, both monomers showed excellent processability. [Display omitted] • Two benzoxazine monomers have low viscosity at room temperature, both monomers showed excellent processability. • Results demonstrate that poly(HA-fa) and poly(H-fa) showed excellent comprehensive properties. • The nature behind these attractive performances of poly(HA-fa) and poly(H-fa) was intensively investigated. [ABSTRACT FROM AUTHOR]

• Novel poly(phthalazinone thioether sulfone/ketone)s were prepared. • These polymers possess good solubilities and excellent thermal stabilities. • These polymers have potential application prospects in many fields. A novel series of poly(phthalazinone thioether sulfone/ketone)s were prepared by nucleophilic substitution of 4-(4′-thiolphenyl) phthalazinone with different di-halogen monomers. The achieved copolymers can dissolve in common organic solvents such as N,N -dimethylacetamide, N -methylpyrrolidone and chloroform at room temperature. The chemical structures of the copolymers were characterized by FT-IR and NMR, and their thermal properties were investigated by TGA and DSC. The results demonstrated that they have good thermal stability with the glass transition temperatures ＞208 °C and the 5 % weight loss temperatures in the range of 490–504 °C. [ABSTRACT FROM AUTHOR]

• Vulcanized Eucommia ulmoides gum modified asphalt made from natural plant materials was created. • The optimal preparation parameters of vulcanized Eucommia ulmoides gum modified asphalt were determined. • Clarified the relationship between the dosage of Eucommia ulmoides gum and the optimal dosage of sulfur. • The modification mechanism of vulcanized Eucommia ulmoides gum modified asphalt is clarified from the microstructure. • The combustion products of vulcanized Eucommia ulmoides gum modified asphalt were clarified. In this study, a vulcanized Eucommia ulmoides gum modified asphalt (VEUGMA) was prepared using a natural plant-based renewable rubber Eucommia ulmoides gum (EUG) as the matrix. The preparation process and microstructural and thermal properties of VEUGMA were investigated. The results showed that the optimum shearing time for preparing VEUGMA was 45 min, and the optimum development time was 120 min. Moreover, the EUG dosage follows a monotonically decreasing linear relationship with the optimum sulfur dosage. The VEUGMA exhibited a preferable corrugated network structure, and the vulcanization process of EUG in asphalt can be divided into three stages: slight crosslinking, deep crosslinking, and supreme crosslinking. The X-ray diffraction pattern displayed that only new diffraction peaks of ZnO appeared in the VEUGMA, and the EUG and asphalt exhibited better compatibility under the action of vulcanization aids. After EUG was vulcanized in asphalt, the aromatic ring hydrogen in the asphalt was replaced by aliphatic chains. The VEUGMA exhibited a lower glass transition temperature that suggests a better low-temperature crack resistance. Two maximum decomposition temperatures were noted in the thermal decomposition process of VEUGMA. Moreover, the main gases released were CO 2 , CO, CH 4 , SO 2 , NO 2 , and NO; of which, CO 2 and CO exhibited the highest content, whereas the inferior emissions of SO 2 , NO 2 , and NO, can be ignored. The VEUGMA can effectively reduce the release of CO 2 and CO but has no significant effect on the release of CH 4. Further, VEUGMA demonstrated a smaller storage modulus (E'), loss modulus (E"), and loss factor (tanδ), which suggested better flexibility at low temperatures. Therefore, this work demonstrated the preferable modification effect achieved by adding 3.5 wt% EUG and 6 phr (parts per hundred parts of resin) sulfur to the matrix asphalt. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple way is proposed to realize 4D printing of benzoxazine. • Copolymerization with epoxy enhances the toughness of the material. • The 4D printing thermoset has higher T g and tensile strength than reported ones. • The 4D printing structure has shape memory property. Benzoxazine is employed in an increasing number of domains due to its exceptional thermal stability, but it is difficult to apply for 4D printing due to its high brittleness and lack of photo-curable groups. Herein, dual-cure DIW 4D printing inks (BZs) consisting mainly of a commercial benzoxazine and a synthesized diglycidyl ether bisphenol A monoacrylate (DGEBAMA) were formed. In the dual-cure ink, photo-curable groups were cross-linked to rapidly prototype complex structures. After thermal curing, 4D-printing structures with isotropic properties were obtained. The ether bonds provided by the copolymerization of epoxy groups and oxazine rings and the soft segment of DGEBAMA increased the material's toughness. The highest overall performance was obtained by BZ50, which displayed higher glass transition temperature (188 °C), tensile strength (92.13 MPa), elongation at break (9.34 %), and good shape-memory ability. This work provides a straightforward method for enabling the 4D printing of benzoxazine/epoxy-based materials with good toughness, excellent thermal properties, and shape-memory abilities, expanding the potential application of benzoxazine/epoxy-based materials in advanced fields. [ABSTRACT FROM AUTHOR]

• Three polyzwitterions (PZIs) were synthesized based on the sulfobetaine moiety. • LiCl salt, added in molar ratios, affects the PZI structure and thermal properties. • Salt ions disrupt dipolar crosslinks of PZI side groups increasing chain mobility. • Ratchet drying method in DSC/TMDSC removes surface and molecularly bound water. • With added salt the PZI heat capacity increment of unconfined liquid is reached. Thermal and structural properties of polyzwitterions (PZI)s comprising the sulfobetaine moiety were studied as a function of LiCl addition and variations in monomer chemistry. The polyzwitterions chosen for this study are: poly(sulfobetaine methacrylate), PSBMA; poly(sulfobetaine acrylate), PSBA; and, poly(ethyl sulfobetaine methacrylate), PESBMA. When LiCl salt is added, the Li+and Cl− ions disrupt the dipole-dipole electrostatic interaction of the PZI side groups. Fourier transform infrared spectroscopy shows that the vibrational frequencies of the symmetric and asymmetric S = O bonds increase as LiCl content increases. Structural studies by wide angle X-ray scattering show that all the PZIs are amorphous, and the average interatomic spacing, d, increases in the order: d PSBA (= 0.456±0.006nm) < d PSBMA (= 0.474±0.015nm) < d PESBMA (= 0.493±0.011nm). Upon the addition of LiCl, d -spacing for a given PZI decreases as LiCl content increases. Thermogravimetry showed that PZIs had degradation onset temperatures T d ∼ 300°C. As LiCl content increases, the onset temperature of degradation decreases suggesting that the disruption of dipole-dipole crosslinks destabilizes the polymer. All the PZIs are hydrophilic and hygroscopic, and a drying procedure was developed so that well-defined glass-to-liquid transitions could be observed in the dry solid state. PZIs without LiCl have glass transition temperatures, T g , increasing in the order: T g , PSBA (= 200±1°C) < T g , PESBMA (= 204±1°C) < T g , PSBMA (= 237±1°C). As the LiCl content increases, T g decreases, and the liquid state heat capacity increases, in all PZIs. The specific heat capacity increment at T g was studied for PSBA as a function of LiCl content. In PSBA, the heat capacity increment reached a maximum for molar ZI:LiCl content at and above 1:1, and its value agreed well with predictions based on an empirical bead model of polymers. Thermal data on the dry state of PZI-LiCl complexes suggest an analogy between electrostatically crosslinked, fully amorphous PZIs and semicrystalline polymers. The dipolar crosslinks confine the molecular motion of PZIs just as crystal domains confine the molecular motion of the amorphous phase in semicrystalline polymers. [Display omitted] [ABSTRACT FROM AUTHOR]

• Films of PVA/PEO blend incorporated with CrBr2 were prepared and characterized. • The change in the structure of PVA/PEO-CrBr2 was studied by different techniques. • The addition of CrBr2 into the PVA/PEO blend resulted in an increase in conductivity. • The dielectric values in the frequency range increased as the increase of CrBr2. Films of the PVA/PEO polymer blend incorporated by CrBr 2 were prepared using the casting method. Several characterization tools were used to study the PVA/PEO CrBr 2 samples. Adding CrBr 2 to the PVA/PEO significantly affects the structure, optical and thermal behaviour of the samples. The X-ray diffraction peaks suggest that the pure PEO/PVA blend is semi-crystalline. Still, the presence of CrBr 2 reduces the intensity of these peaks, indicating interactions between the polymer blend and filler. The appearance of the main peaks of CrBr 2 confirms that the complexation between the PVA/PEO and CrBr 2 leads to decreased crystallinity and increased amorphous phase. The UV-Visible data indicate that adding CrBr 2 reduces the energy band gap transitions due to the presence of defects and increasing disorder in the samples, creating localized energy states that can lead to energy level overlaps and a reduction of the energy gap. The DSC thermograms show that adding CrBr 2 results in higher glass transition and melting temperatures, indicating improved thermal properties and enhanced thermal stability due to intermolecular interactions between CrBr 2 and the PVA/PEO blend. The Coats-Redfern method was used to estimate ΔS*, ΔH*, and ΔG* in TGA measurements. These thermal parameters suggest that the presence of CrBr 2 affects the thermal degradation mechanism. The values of ΔS*, ΔH*, and ΔG* decrease irregularly with increasing CrBr 2 , indicating that adding CrBr 2 alters the thermal degradation mechanism of the PVA/PEO blend. The dielectric constant and the dielectric loss of the samples decrease with frequency No relaxation peaks observed in the dielectric curves indicate non-Debye behavior. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites (PNCs) films based on Polyvinylidene fluoride co-hexafluoropropylene (PVDF-HFP), Polyvinylpyrrolidone (PVP), and Ag/ZnO nanoparticles have been prepared using solution casting technique. Investigation of prepared films has been created using various experimental techniques. These prepared films were characterized by XRD, FTIR, UV–visible, and DSC/TGA analysis to study their structural, optical, and thermal properties. The Enhanced amorphous nature of PVDF-HFP/PVP blend film due to doping has been identified from X-ray diffraction analysis. The FTIR spectra confirmed the complexation between the Ag and ZnO ions and the host polymer in terms of changes in intensity and certain band positions. The UV–visible analysis showed that the optical band gap (direct and indirect band gap) of the pristine polymeric blend change significantly with the concentration of dopant Ag/ZnO NPs, and these effects are more noticeable at the higher loading. Variation in glass transition temperature (Tg) and melting temperature (Tm) of PVDF-HFP/PVP-Ag/ZnO PNCs system having various concentration of Ag/ZnO NPs were observed by DSC analysis. The Tg of the composite has been found to be decreasing with increase in the content of Ag/ZnO NPs revealing the ordered arrangement of nanoparticles in the blend. The excellent thermal stability of the blend nanocomposite compared to pure PVDF-HFP/PVP blend and its improvement with the loading of Ag/ZnO NPs has been proved by TGA. From all the characterization results, Ag/ZnO-doped PVDF-HFP/PVP polymer blend exhibits better properties which are more suitable for electrochemical devices. • The PVDF-HFP/PVP-Ag/ZnO nanocomposites films were prepared. • XRD and FTIR have been performed. • The structural and optical properties of the polymer nanocomposites films have been explored. • The thermal properties showed that all nanocomposites films exhibited improved as compared to pure blend. [ABSTRACT FROM AUTHOR]

• Low defect phthalonitrile (PN) resin was prepared by powder hot isostatic pressing. • Strength and toughness of PN were significantly improved through POSS modification. • The organic/inorganic network constructed by POSS enhanced the thermal stability of PN. The high melting point of high-temperature resistant phthalonitrile resin is often prone to defects in traditional hot melt manufacturing. And its high cross-linking density leads to poor toughness of the resin. In this work, we report for the first time a novel densifying processing, powder hot isostatic pressing (PHIP), for phthalonitrile resin with low defect and high mechanical performance. The bending strength and impact strength of the pure phthalonitrile resin (PBAPN) by PHIP reached to 108.5 MPa and 9.1 kJ·m−2, respectively, increasing by 186.3% and 405.6% than PBAPN by hot melt method. The epoxycyclohexyl polyhedral oligomeric silsesquioxane (EP-POSS) with excellent heat resistance was used to achieve synchronous improvement of thermal and mechanical properties of phthalonitrile resin. The bending strength and impact strength of the phthalonitrile resin containing 1 wt% POSS (PBAPNPOSS-1) further increased to 120.1 MPa and 13.0 kJ·m−2. In addition, the glass transition temperature of PBAPNPOSS-5 increased by 40 °C compared with PBAPN. [ABSTRACT FROM AUTHOR]

Loosening and infection are the main reasons for revision surgery in total hip arthroplasty (THA). Removing partially detached cemented implant components during revision surgery remains challenging and poses the risk of periprosthetic bone damage. A promising approach for a gentler removal of partially detached prostheses involves softening the PMMA-based bone cement by heating it above its glass transition temperature (T G), thus loosening the implant-cement bond. It is assumed that the T G of PMMA-based bone cement decreases in-vivo due to the gradual absorption of body fluid. Reliable data on T G are essential to develop a heat-based method for removing cemented implant components during revision surgery. The effect of water absorption was investigated in-vitro by ageing PMMA-based bone cement samples for different periods up to 56 days in both Ringer's solution (37 °C) and air (37 °C and 30% humidity). Subsequently, the T G and Vicat softening temperatures of the samples were determined by differential scanning calorimetry and Vicat tests, respectively, according to prescribed methods. Over the entire ageing period, i.e. comparing one day of ageing in air and 56 days in Ringer's solution, the Vicat softening temperature dropped by 16 °C, while the T G dropped by 10 °C for Palacos® R PMMA-based bone cement. Water absorption over time correlated significantly with the Vicat softening temperature until saturation of the PMMA-based bone cement was reached. Based on the T G and Vicat softening temperature measurements, it can be assumed that in body-aged bone cement, an optimal softening can be achieved within a temperature range of 85 °C–93 °C to loosen the bond between the PMMA-based bone cement mantle and the prosthesis stem. These findings may pave the way for a gentler removal of the implant in revision THA. [Display omitted] • Ageing of PMMA-based bone cement in body-like medium lowers its softening temperature. • The decrease in this temperature correlates with water absorption to saturation. • Softening of PMMA-based bone cement aged in the body can occur between 85 and 93 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fully biobased polyesters based on isoidide were synthesized and characterized. • The molecular weight of the polyesters was enhanced by SSPC. • Adding small amounts of aliphatic diol as comonomer did not inhibit crystallization. • Poly(isoidide furanoates) are a promising class of high-performance polyesters. A fully biobased high-performance polyester was prepared by the sequential melt polymerization and solid-state post-condensation of the symmetrical 1,4:3,6-dianhydrohexitol isoidide and dimethyl 2,5-furandicarboxylate (FDME). The thermal properties of the resulting poly(isoidide furanoate) were well within the "high-performance" range with a glass transition- and melting temperature of approx. 165 and 280 °C, respectively. Since such a high melting temperature does not allow for conventional melt processing without thermal degradation of the polymer, various C2-C4 diol comonomers were incorporated in an attempt to create semi-crystalline co-polyesters with a high-glass-transition-temperature and sufficiently low melting point. It was found that semi-crystalline co-polyesters could be obtained with either low (3–5 mol%) or high (80–95 mol%) isoidide contents. All semi-crystalline co-polyesters with low diol comonomer contents (≤20 mol%) had still glass transition temperatures ≥ 118 °C despite having low molecular weights. Co-polyesters with a high diol comonomer content had lower melting points than the PiIF homopolymer, as well as a significantly lower glass transition temperature. The molecular weight of the PiIF homopolymer and a semicrystalline poly(ethylene-co-isoidide furanoate) co-polyester could be significantly enhanced by solid-state post-condensation. Thus, poly(isoidide furanoates) are an interesting class of new fully biobased polyesters that has potential in high-performance applications. [ABSTRACT FROM AUTHOR]

Poly(L -lactide) (PLA) is the most important biobased polymer and is widely used in various fields. However, its application is still greatly limited by the distinct disadvantage such as poor thermal resistance. In this study, in order to improve the thermal properties, crosslinked PLA with high crystallinity (44 %) and high gel content (91 %) is prepared by the UV irradiation of its semicrystalline films by the loading of certain photoinitiators and curing agents. The structure and properties of the obtained films are systematically investigated with NMR, DSC, DMA, TG and WAXD. It is found that the crosslinking of the semicrystalline PLA film is more difficult than that of the amorphous in the absence of crosslinker. However, the combinations of 2phr photoinitiator such as 4,4′-dichloro benzophenone (DCB) and 2 phr crosslinker of 1,3,5-triallylisocyanurate (TAIC) can effectively trigger the crosslinking and high gel content up to 91 % can be achieved. Corresponding to the high density crosslinking, an increase of the glass transition temperature from 66.6 °C to 75.5 °C is observed for crystallized PLA, indicating an obvious improvement in thermal resistance. More interestingly, it is found that this crosslinked PLA with high crystallinity and high gel content still possesses high crystallizability. [Display omitted] • The combination of photoinitiator and curing agents is efficient to promote the crosslinking of crystallized PLA. • PLA with high crystallinity (44 %) and high gel content (91 %) was prepared by UV irradiation. • The resulting PLA films presents improved thermal resistance and good crystallizability. [ABSTRACT FROM AUTHOR]

High performance composites not only pursue high strength, light weight, but also need to have multifunctional characteristics. To further improve curing efficiency and mechanical properties of phthalonitrile resin (PN75) and give full play to its excellent thermal and dielectric properties, mica as reinforcement was introduced into PN75 to form particle-filled resin (Mica/PN75) and CFRP (Mica/PN75/CF) composites. The introduction of mica reduced the curing temperature of PN75 and improved the curing efficiency. The thermal stability of resin and composites was further improved. The bending strength of the two groups of mica reinforced resin increased by 44.87% and 55.97%, and the dielectric constant decreased from 3.3 to 2.7 and 2.5, respectively. The bending strength of the composites was increased by up to 19.9%, and the glass transition temperature of composites was increased by up to 26 °C after reinforcement. The multidirectional reinforcement of PN75 by mica was studied and analyzed in this work. [Display omitted] • Mica was used for the first time to particle reinforce phthalonitrile resin. • Powder blending was used to complete the mixing of inorganic particlesand phthalonitrilephtha resins. • The structure of reinforced resin is more stable, the bending toughness and dielectric property are greatly improved. • The reinforced composites have better thermal stability and improved toughness. [ABSTRACT FROM AUTHOR]

Two high heat resistance resins, low dielectric constant and low dielectric loss biobased benzoxazine reins were prepared and the nature behind these attractive performances was intensively investigated. [Display omitted] High heat resistance, low dielectric constant and low dielectric loss benzoxazine resin is of great significance to the practical application of information industry. In this article, two biobased benzoxazine monomers HA-dea and H-dea were prepared by mannich reaction using p-hydroxybenzyl alcohol and hordenine as phenol sources and 1,10-diaminodecane as amine sources. The two benzoxazine monomers showed different thermodynamic behaviors. The melting point of HA-dea was 77.5 °C, while H-dea was liquid at room temperature, the viscosity of H-dea at room temperature (25 °C) was 5.517 Pa/s. The curing peak temperatures of the two monomers were 217 and 193 °C, respectively. Both monomers showed excellent processability. Two benzoxazine resins poly(HA-dea) and poly(H-dea) were prepared through thermal curing procedure, and the comprehensive properties of two benzoxazine resins were investigated. The glass transition temperatures (T g) of poly(HA-dea) and poly(H-dea) were 267 °C and 233 °C, respectively, showing excellent heat resistance of the newly prepared resin. Moreover, poly(HA-dea) and poly(H-dea) have both high storage modulus (3341 MPa and 3124 MPa, respectively, measured at 25 °C) and good flexural strength (109 ± 3.6 MPa and 101 ± 3.8 MPa). Moreover, the resins poly(HA-dea) and poly(H-dea) also have low dielectric constant and dielectric loss at 1 MHz, the dielectric constants are 2.78 and 2.56, respectively, and dielectric losses are 0.018 and 0.016, respectively. Among the two resins, poly(HA-dea) exhibits more excellent heat resistance, which may be based on the multi-crosslinking sites and hydrogen bond crosslinking networks. [ABSTRACT FROM AUTHOR]

All-Cellulose Composites (ACCs) with cellulose derivatives have been neglected in the composite industry due to their high brittleness, low impact strength, and flowability. Epoxidized vegetable oils are well-known plasticizers for several polymers and composites but have never been exploited on the production of ACCs. The present work investigates the potential of an epoxidized linseed oil (ELO) as a cost-effective additive to enhance the properties and processability of ACCs made with cellulose acetate butyrate (CAB) and micronized Eucalyptus pulp fibers. The thermo-mechanical characterization of the composites, obtained by melt-mixing, revealed that ELO significantly decreases the glass transition temperature (Tg) of the obtained composites without compromising their thermal stability. Moreover, an 84-fold improvement was achieved on the melt flow rate (MFR) with 30 wt% ELO, and growing amounts of this additive caused an augment on the elongation and flexural strains at break. High loads of ELO resulted also on a substantial improvement of the impact strength, with values raising from 5.3 ± 0.9 kJ.m−2 up to 29.5 ± 1.7 kJ.m−2. Furthermore, this eco-friendly plasticizer also led to higher water uptake values, as well as higher biodegradation rates than the non-plasticized ACCs. Therefore, these results evince a remarkable improvement on the ACCs processability, performance, and biodegradation upon addition of a bio-based and cost-effective plasticizer. [Display omitted] • All-Cellulose Composites of cellulose acetate butyrate with micronized fibers. • Non-plasticized composites are brittle, have low impact strength and flowability. • An epoxidized linseed oil was effectively employed as a green plasticizer. • The epoxidized oil improves the processability and melt flow rate of the composites. • The mechanical properties of the composites were enhanced with the epoxidized oil. [ABSTRACT FROM AUTHOR]

A facile approach to incorporate an intramolecular 6-membered ring hydrogen bond into a benzoxazine monomer containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) moiety has been developed, leading to a novel monobenzoxazine, ODOPB-pa. This monobenzoxazine was successfully synthesized via a Mannich condensation from 2-(6-oxido-6 H -dibenz-[ c , e ][1,2]oxaphosphorin-1,4-dihydroxy phenylene (ODOPB), propargylamine and paraformaldehyde. The newly obtained ODOPB-pa possesses a relatively lower polymerization temperature than most commercialized benzoxazine resins. In addition, the intramolecular 6-membered ring hydrogen bond is identified as an essential feature in its polymerization behavior. The cured product, poly(ODOPB-pa) , exhibits high thermal stability with a 5% weight loss temperature of 327 °C, and good flame retardant properties with a heat release capacity value of 119 Jg−1 K−1 and a total heat release value of 41 kJg−1. Moreover, ODOPB-pa was also applied to mix in different amounts (5, 10, 15 and 20 wt%) with a tri-functional benzoxazine bearing propargyl group, TH-pa. Notably, it has been demonstrated that the TH-pa/ODOPB-pa blend derived thermoset with 10 wt% ODOPB-pa exhibits the best thermal and flame retardant properties in consideration of the high glass transition temperature (312 °C) and very low heat release capacity value (56.5 Jg−1 K−1). These combined advantages highlight the potential of intramolecular 6-membered ring hydrogen bond-containing ODOPB-based benzoxazine in the producing of high-performance thermosetting systems. [Display omitted] • A novel phosphaphenanthrene-based benzoxazine (ODOPB-pa) has been synthesized. • The intramolecular hydrogen bond in ODOPB-pa has been investigated. • The performance of a tri-functional benzoxazine can be enhanced by blending with ODOPB-pa. • The thermoset blends show excellent thermal and flame retardant properties. [ABSTRACT FROM AUTHOR]

In this study, gelatin (GE) was composited with chitosan films (CH) and chitosan films incorporated with curcumin nanoemulsion (CH-CNE) through blending and layer-by-layer (LbL) assembly in order to overcome the physical limitations of the chitosan and its incorporated films. Furthermore, the distinctive effects of blending and LbL assembly on the physicochemical parameters of the composite films were assessed. The composite LbL films incorporated with GE exhibited improvement of water vapor barrier, tensile strength, solubility, which contributed to the enhanced antioxidant activity from the single components. By contrast, the composite films of the blending method exhibited greater elongation at break and increased swelling degree. Additionally, the films containing the nanoemulsion exhibited reduced light transmission and increased opacity. The thermal properties indicating the thermal stability and compatibility interactions of the composite films were examined by the glass transition temperature (T g). Results revealed that the distinctive behavior of the T g was affected by the compositing method. The LbL films exhibited substantially increased T g , indicating enhanced thermal stability. The results indicated that the composited films formed via the LbL assembly attained better physicochemical properties and thermal stability, implying higher compatible film than the blending. • Limitations of chitosan film (CH) were improved by compositing with gelatin. • Antioxidant activities were improved by incorporating curcumin nanoemulsion (CurNE). • Blended films exhibited increased elongation values and swelling degree. • LbL films exhibited a higher water vapor barrier, tensile strength, and solubility. • LbL method increased the antioxidant activity of chitosan incorporated with CurNE. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyphenylsulfide (PPS)/carbon nanotube (CNT) composites were blended. • The dispersion states of CNTs in PPS were evaluated using Raman spectroscopy. • Thermal behaviour and Vickers hardness were related to the dispersion of CNTs. • The uniform dispersion of CNTs provided a further hardness effect to the composites. Polyphenylene sulphide (PPS)/carbon nanotube (CNT) composite materials (combining PPS and multi-walled CNTs modified with carboxyl groups) were blended using two methods: (1) solution mixing with 1-chloronaphthalene and (2) melt blending. The dispersion states of CNTs in PPS prepared by the two methods were evaluated using Raman spectroscopic mapping. The effect of the dispersibility of CNTs on the physical properties of the composite materials was evaluated by measuring their thermal behaviour and Vickers hardness. Raman spectroscopic mapping revealed that the dispersion states of CNTs in composites obtained via the solution mixing method were more uniform than in those obtained via melt blending methods. This improved uniformity in the dispersion states of CNTs in the solution mixing method can be attributed to the prior dispersion of CNTs in the solution. Additionally, thermal properties such as the crystallisation and glass transition temperatures, and mechanical properties such as the Vickers hardness of the solution-mixed composite material were higher than those of the melt-blended composite. These results indicate that the uniform dispersion of CNTs increases the contact area between PPS and CNTs, which causes an increase in the crystallisation temperature and a further hardness effect. [ABSTRACT FROM AUTHOR]

With the development of alternate electrical power system and the improvement of voltage level, the operation conditions faced by epoxy resin (ER) insulation materials are becoming more and more complex. The traditional ER materials have been difficult to meet the increasingly stringent requirements. In this paper, the thermal and mechanical properties of DGEBA/TDE-85/MTHPA blend system were studied by molecular dynamics (MD) simulation and experiment. The results show that the addition of TDE-85 can significantly improve the thermal and mechanical properties, and the comprehensive improvement effect is the best when the molar ratio of DGEBA and TDE-85 is about 8:2. The experimental results are consistent with the simulation results. Further analysis of the micro-parameters of the monomer and the cross-linking network found that the torsional energy barrier of TDE-85 is higher than DGEBA. And the compatibility of the two ER is better when the ratio is 8:2. In addition, TDE-85 can introduce high-stability Y-nodes into the system, making the cross-linked network more stable, which has a significant effect on improving the thermal and mechanical properties. The research provide a reference for the blending modification of high-performance ER for high-voltage insulation. [Display omitted] • TDE-85 can introduce the Y-nodes of elevated stability into the epoxy resin crosslinking system. • TDE-85 has the potential to substantially enhance the thermal and mechanical characteristics of epoxy resin. • The most optimal improvement effect was observed when the molar ratio of DGEBA to TDE-85 was 8:2. [ABSTRACT FROM AUTHOR]

Rigid polyimide foams (PIFs) were successfully fabricated through thermal foaming of polyester ammonium salt precursors (PEASs) with the addition of a pararosaniline base (PA) as a crosslinker. These foams exhibited good mechanical properties and thermal resistance. The construction of crosslinked structure derived from PA could improve melt viscosity and provide cell walls with sufficient strength to prevent shrinkage, which was conducive to elevating compressive properties. PIF BMP -2 (i.e., repeating unit was 2) exhibited optimal compressive strength of 1.76 and 1.25 MPa at room temperature (RT) and 200 °C, which were increased by 6.6 and 7.9 times compared to PIF BM (0.17 MPa (RT) and 0.11 MPa (200 °C)). Furthermore, a relationship between compressive strength and density was established, showing that the compressive strength is proportional to 2.34 and 2.13 powers of density at RT and 200 °C, respectively. Moreover, PIFs owned excellent thermal properties, the 5% weight loss temperature was higher than 458.9 °C in a nitrogen (N 2) atmosphere, and the glass transition temperature was up to 291.3 °C. Additionally, the thermal conductivities of the rigid polyimide foams (PIFs) ranged from 0.058 to 0.094 W m−1 K−1, which makes them highly suitable for potential applications in the fabrication of high-temperature resistant multifunctional composites, particularly in aerospace, defense, and transportation industries. [Display omitted] • Rigid polyimide foams were fabricated with pararosaniline base as a crosslinker. • Crosslinked structure could significantly improve mechanical properties of fabricated foams. • Relationship between PI chains and properties was investigated. [ABSTRACT FROM AUTHOR]

In this study, poly(2-(3,5-dichloroanilino)-2-oxoethyl 2-methylprop-2-enoate) (PDCOEMA), a new synthetic polymer based on methacrylate, was synthesized and characterized. The blend of PDCOEMA with chitosan (CS) was prepared by the hydrothermal method and the DSC technique confirmed its formation. It was observed that PDCOEMA increased the thermal stability and glass transition temperature (Tg) of CS. The Tg value of the PDCOEMA-CS blend was increased at about 7 °C with the highest ZnO NPs contribution rate. PDCOEMA-CS/ZnO nanocomposites were prepared by adding ZnO NPs produced by biosynthesis at different weight ratios to the PDCOEMA-CS blend by hydrothermal method. When the thermal stability of nanocomposites determined by TGA was examined, it was observed that it increased significantly compared to CS. While the initial decomposition temperature of CS was 270 °C, this value increased to 293 °C after blending with DCOEMA, and to 317 °C with the addition of 7 % ZnO NPs. Antimicrobial, anticancer, cytotoxic, antioxidant, and wound healing properties of PDCOEMA, CS, PDCOEMA-CS blend, and nanocomposites were determined. According to the obtained results, it was observed that nanocomposites containing 5 % and 7 % ZnO NPs showed good anticancer activity against A549 cells at a dose of 10 μg/mL. The results show that the produced nanocomposites can contribute to developing CS-based materials. [ABSTRACT FROM AUTHOR]

This work reports the effect of a reactive extrusion (REX) process on polylactide (PLA) based formulations plasticized with dibutyl itaconate (DBI). As DBI contains a carbon-carbon double bond, it is suitable for reactive extrusion. REX was carried out in a co-rotating twin extruder with the addition of two different organic peroxides. The main aim of using REX during the blending of the DBI plasticizer with PLA is to improve the interaction between them so the obtained final properties of the formulations could be improved. Plasticization process allowed to improve the ductile properties of PLA, by using REX, an improvement on the tensile strength was obtained with a no remarkable change in ductility. The thermal characterization also revealed that the glass transition temperature T g was reduced for all formulations including DBI. REX with DBI provided a slight increase in T g and this effect was also evident in thermomechanical properties. Regarding the thermal degradation behaviour, the plasticizer reduced the onset degradation and the maximum degradation rate, while a slight improvement on thermal stability was observed by using REX with organic peroxides. Finally, plasticizer migration in water was observed in conventional extruded PLA/DBI formulations, while REX provided improved behaviour against migration. • Plasticization process allowed to improve the ductile properties of PLA. • Reactive extrusion (REX) improved the tensile strength was obtained with a no remarkable change in ductility. • Thermal degradation behaviour was improved by using REX with organic peroxides. • Plasticizer migration was improved REX provided improved behaviour against migration. [ABSTRACT FROM AUTHOR]

Smart dielectrics with self-adaptive capabilities can exhibit desirable electric field-grading performance as the applied electric field exceeds a critical value. However, the conventional approaches to such dielectrics need heavy doping rate, which will not only increase the interface thermal resistance and limit the improvement of thermal conductivity, but also severely sacrifice the mechanical property. In this contribution, a new type of electric field-grading co-continuous phase composite (EP/SiC cf) composed of epoxy resin and SiC ceramic foam was prepared to realize tunable nonlinear conductive performance, while simultaneously improving thermal and mechanical properties. Results show that there is no percolation threshold for all EP/SiC cf composites. The volume loadings of EP/SiC cf composites range from 8.7 vol% to 15.6 vol%, while the nonlinear coefficient subjected to potential barrier height increases from 2.1 to 4.5 and the switching field tuned by barrier width decreases from 1008 V/mm to 686 V/mm. The EP/SiC cf40 still exhibits sharp thermal conductivity enhancement of about 1000% and glass transition temperature enhancement of 10.8 °C. The surface temperature fluctuation over time during heating and cooling has illustrated the prospective application of thermal management capability. In addition, the dynamic mechanical analysis reveals that all EP/SiC cf composites have the significantly improved storage modulus and crosslinking density ascribed to the intact SiC skeleton. The novel co-continuous phase composite provides a new approach for global enhancement of smart dielectric composites in potential applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The nanoparticles of glycidoxy propyl POSS (GPOSS) and alumina microparticles were added into a two-part epoxy adhesive. The filler dispersion in adhesive samples were characterized by EDXA and SEM micrographs indicating weaker dispersion for the highly loaded alumina and/or GPOSS filled compositions. Comparing with neat epoxy resin, DSC thermograms revealed lower heat of cure and higher onset cure temperatures in all compositions. The highest glass transition temperature (T g) was obtained for the composition containing 10 wt% alumina microparticles and 20 wt% GPOSS, which was about 44 °C higher than that of the neat epoxy. The thermal stability of this composition was improved up to 7 °C based on the first decomposition peak temperature in a TGA test. However, the highest char yield obtained from the TGA test was recorded for a composition containing 20 wt% alumina microparticles and 10 wt% GPOSS. Adhesive lap shear strength values showed a maximum of 13.2 MPa (>40% than epoxy) for the composition containing 10 wt% alumina microparticles and 10 wt% GPOSS. The improvement in adhesive thermal stability was further verified by the results of adhesive strength retention after heat aging at 200 °C for 24 h. It can be concluded that the simultaneous incorporation of GPOSS and alumina in an epoxy results in noticeable improvements in T g , thermal stability and adhesion strength, mainly due to improved interfacial interactions between GPOSS and alumina particles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biologically relevant 50P 2 O 5 -30CaO-(20 – x)Na 2 O- x Fe 2 O 3 (x = 0.1, 1, 5, 10 mol%) glasses synthesized. • Characterized by density, FT-IR, Raman, DSC, and dilatometry. • Structural and thermal properties suggested to be guided by P–O–Fe(III) bond formation. Bio-relevant glasses with 50P 2 O 5 -30CaO-(20 – x)Na 2 O- x Fe 2 O 3 (x = 0.1, 1, 5, 10 mol%) compositions were prepared by melting and studied by densitometry, Fourier transform-infrared (FT-IR) spectroscopy, Raman scattering, differential scanning calorimetry (DSC), and dilatometry. The densities of the glasses increased linearly with Fe 2 O 3 replacing Na 2 O. The FT-IR and Raman spectroscopy evaluation indicated that increasing Fe 2 O 3 concentration modifies the glass structure via depolymerization effect, likely in connection with P–O–Fe(III) bond formation. The thermal evaluation showed a trend of increase in the glass transition and softening temperatures, whereas the coefficient of thermal expansion decreased with increasing Fe 2 O 3 in agreement with a glass strengthening effect induced by iron(III). [ABSTRACT FROM AUTHOR]

Preparing biobased thermosetting resins with high mechanical properties and superior heat resistance is an important issue for the sustainable development and applications of high performance resins. Herein, a novel biobased allyl compound (DBB) with aryl propargyl ether groups was synthesized from renewable honokiol, which was then used to copolymerize with 4,4′-bismaleimidodiphenylmethane (BDM) to develop new biobased resins (BDM/DBB). The effects of the molar ratio of BDM to DBB on the thermal and mechanical properties were studied. Results show that all BDM/DBB resins possess both high thermal and mechanical properties. Specifically, their glass transition temperatures (T g > 440 °C) and storage moduli (> 1.3 GPa at 400 °C) are higher than those of biobased allyl compounds modified BDM resins reported so far (SCI database); moreover, their initial thermal decomposition temperatures are about 448 °C and flexural strengths range from 106 to 117 MPa. These excellent comprehensive performances are attributed to the unique crosslinked network resulted from the complex curing mechanism of BDM/DBB, which including the copolymerization between imide groups and allyl groups as well as the additional thermal crosslinking of aryl propargyl ether. This work provides a sustainable and facile strategy to construct high performance biobased resins. [Display omitted] • New biobased allyl compound with aryl propargyl ether group (DBB) was synthesized. • New resins (BDM/DBB) through copolymerizing bismaleimide with DBB were prepared. • BDM/DBB resins have extremely high glass transition temperatures over 440 °C. • BDM/DBB resins also have high mechanical properties. • Structure-property relationship of BDM/DBB resins was studied. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two series of cardo polyimides with high T g s and high transparency were prepared. • A new method to prepare PIs with alicyclic diamine to avoid salt formation was provided. • The DMPF base polyimide PI-IIa displayed high thermal properties with T g of 350 ℃ and high transparency with transmittance of 86% at 400 nm. Two series of transparent cardo polyimides (PIs) derived from bisphenol fluorenes and 1,4-bis(4-fluorophthalimide)cyclohexanes (BFCH) with different ratios of trans- and cis - 1,4-diaminocyclohexane were prepared via aromatic nucleophilic substitution. These PIs exhibited high glass transition temperatures (T g s) of 271–352 °C, 5% weight loss temperatures (T d 5%) of 400–433 °C in nitrogen, mechanical properties of tensile strengths of 62–107 MPa, tensile moduli of 3.0–4.4 GPa and elongations at break of 1.7–4.5% and great solubility in a variety of organic solvents. These PI films appeared excellent optical transparency, which displayed the cut-off wavelengths from 323 to 355 nm and high transmittance at 450 nm with more than 85 %. The steric effects of different substituent groups on bisphenol fluorene and different ratios of trans / cis configuration were also investigated. [ABSTRACT FROM AUTHOR]

• Long-term heat exposure above critical temperature can induce continuous degeneration of thermal insulation property for Fe-based amorphous coating, revealing an importance of kinetic effect. • The coupling effect of microstructure transformation and structural sintering is disclosed, leading to a particular insight into the degeneration mechanism. • The low atomic diffusivity of amorphous phase retards the progress including crystallization transition, grain growth and pore healing, resulting in a sluggish degeneration of thermal insulation property. Fe-based amorphous coatings have been proposed to perform a promising thermal barrier application, however, the uncertain degeneration of properties induced by thermal stimulation is significantly concerned owing to their metastable nature. Herein, Fe 57 Cr 15 Nb 4 B 20 Si 4 amorphous coating with a low thermal conductivity was employed to investigate the degeneration of thermal insulation property and related mechanisms during long-term heat exposure. Excellent stability can be defined for the amorphous coating when annealed below glass transition temperature, despite a slight increase of thermal conductivity induced by structural relaxation. Extraordinary increase of thermal conductivity is found when prolonged annealing time at a critical temperature of 600 °C. The sluggish structural sintering dominates thermal conductivity to increase, whereas the effect of precipitated ultrafine nanocrystals is little. The cooperation of grain coarsening and structural sintering leads to a dramatical increase of thermal conductivity at the initial stage of 850 °C annealing, while the relatively low increase of thermal conductivity with prolonged duration is ascribed to the further grain growth. The obtained results demonstrate a comprehensive understanding on the thermal evolution of Fe-based amorphous coatings and form a basis for future works aiming to shed further light on the degeneration of related metallic coatings at high temperatures. [ABSTRACT FROM AUTHOR]

The correlation between the thermal transport properties and microstructure features of amorphous coatings is crucial for reliable thermal insulation applications. In this work, an Fe 48 Cr 15 Mo 14 C 15 B 6 Y 2 amorphous coating prepared by high-velocity oxygen-fuel spraying (HVOF) was employed to reveal this relationship under long-term heating. From the combined effects of the amorphous phase and unique coating structure, the proposed coating exhibits an extremely low thermal conductivity of 1.92 W/(m∙K), granting a significant potential for being as metal-based thermal barrier coatings. Isothermal annealing experiments below the glass transition temperature demonstrate that the thermal insulation property can maintain stability with prolonged annealing time, despite a slight degradation relative to the as-sprayed coating which is ascribed to structural relaxation. Although nearly full crystallization can be slowly induced by annealing at the critical temperature of 600 °C, the thermal conductivity displays a distinct two-stage variation with annealing time, which is primarily attributed to the sluggish sintering of the coating structure. Moreover, grain growth and rapid structural sintering result in a drastic degradation of thermal insulation in the early stage of annealing at 850 °C, whereas grain growth upon prolonged annealing governs further variation of thermal conductivity. The results of this study not only provide important insights into the degeneration mechanism of thermal insulation of Fe-based amorphous coating, but also present an inspiration for exploring the degeneration mechanism of the most metallic coatings serving at high temperatures. • The Fe-based amorphous coating exhibits an extremely low thermal conductivity of κ = 1.92 W/(m∙K). • The degeneration mechanism of thermal insulation property of Fe-based amorphous coating is disclosed. • The low atomic diffusivity retards the bridge-connection of interlamellar pores, resulting in a sluggish sintering kinetics. [ABSTRACT FROM AUTHOR]

Benefiting from its superior thermal and mechanical properties, the stereocomplex crystal (SC) of PLLA/PDLA is catching increasing interest. In this work, a systematic investigation was performed to reveal the effect of solid-state stretching on the formation of SC during annealing. Results show that as the stretching temperature was close to the glass transition temperature (T s = 60 °C), the polymer chains orientation was increased gradually with draw ratio (λ). As a result, the crystallization induction time (t 0) was shortened, the growth rate (G r) of SC was enlarged, and the crystallinity of SC (X SC) was elevated as a result of orientation-induced crystallization. Whereas, the saturation of t 0 , G r , and X SC appeared quickly when λ reached 2.7, although the orientation of polymer chains continued to increase. The reason is that in addition to orientation, strong phase separation between PLLA and PDLA was also triggered therein. The phase separation prohibited greatly the crystallization of SC due to a long time would be needed for PLLA or PDLA chains to diffuse to a distance close enough to activate the hydrogen-bonding interaction, which is the prerequisite of SC crystallization. When the stretching temperature was elevated to 75 °C, the phase separation became much weaker. So X SC was higher compared to that of the blend stretched at 60 °C to the same λ. Moreover, in the annealing temperature from 180 °C–190 °C, t 0 was much smaller for the blend stretched at 75 °C since the crystallization of SC in this temperature range is a diffusion-controlled process. [Display omitted] • Strong orientation of polymer chains and phase separation are induced by solid-state stretching. • Orientation of polymer chains and phase separation exhibit a competition effect on the crystallization of SC. • The more intense phase separation at lower stretching temperature gives rise to a longer crystallization. induction time [ABSTRACT FROM AUTHOR]

Cassava starch (CS) and chitosan (CH) are biopolymers used alone or blended (CS/CH) to produce films, thanks to their excellent film-forming properties. Their main physical properties have been characterized, but their physical and water state have not yet been studied. The objective of this research was to study the water and macromolecular physical state of CS, CH and CS/CH films by DSC and dielectric properties, after sorption isotherms determinations. Biopolymers and obtained films were also analyzed by SEM, FTIR, X-ray diffraction and gas permeability. Dielectric properties of active films containing pitanga leaves hydroethanolic extract were also analyzed. All films presented type II sorption isotherms. Glass transition temperature of films decreased with the increase of moisture content (X w) following the Gordon and Taylor model. The dielectric constant behaves depending of the monolayer moisture content (X m): increased linearly as a function of X w when X w > X m. For X w ≤ X m , the dielectric constant remained constant. An exponential relationship between α-relaxation and Tg was calculated. • Cassava starch and chitosan produces homogenous and high gas barrier films. • Films moisture content (X w) varied with water activity according to the GAB model. • Films glass transition temperature varied with X w following the Gordon & Taylor model. • Dielectric constant increased linearly with X w for above the water monolayer. • α-relaxation reduced exponentially as a function of glass transition temperature. [ABSTRACT FROM AUTHOR]

• New TiO 2 -LaO 3/2 -HfO 2 glass has been prepared by aerodynamic levitation method to research the effect of HfO 2 on optical, thermal and mechanical properties. • Hafnium oxide can increase the refractive index n d up to 2.324. • Hafnium oxide has a higher melting point than lanthanum oxide, but its incorporation reduces glass transition temperature T g and onset crystallization temperature T x. • TiO 2 -LaO 3/2 -HfO 2 glass performs strong mechanical properties with hardness of 9.058 Gpa. 70.21TiO 2 -(29.79-x)LaO 3/2 -xHfO 2 (x=0, 1.5, 3, 4.5, 6) glasses were fabricated by aerodynamic levitation technique. XRD shows the amorphous state of these synthesized glasses. DSC indicates that the glass transition temperature (T g) and onset crystallization temperature (T x) decreases while ΔT (=T x - T g) decreases and then increases with the increase of HfO 2. Density increases from 4.931 to 5.147 gcm−3 with the addition of HfO 2 , while hardness increases from 8.587 to 9.058 GPa. Raman spectra indicate that the maximum phonon energy is 720 cm−1. The transmittance region of glasses is wide from 386nm to 6.5 μm, and the largest transmittance can reach 72%. Furthermore, Abbe number decreases from 17.797 to 16.969 with the addition of HfO 2 , which is attributed to the increase in the inherent absorption wavelength (λ 0). Finally, the refractive index increases from 2.293 to 2.324 with the addition of HfO 2 , which is attributed to the increase in oxygen packing density (OPD), decrease in molar volume (V m). The reason for the relatively small increase in the refractive index is that the oxygen polarizability has a certain decrease, which offsets a part of the effects of V m and OPD. These results are useful for designing new optical glass with excellent properties. [Display omitted] [ABSTRACT FROM AUTHOR]