Search

Bioactive glasses (BG) containing silicon, phosphorous, and boron have emerged as promising materials for bone tissue engineering. Modifying ions play a multifaceted role in BGs, influencing their structure, properties, and biological activity that depends on their size, charge, and coordination chemistry. This study investigates the addition of sodium borate (Na 2 B 4 O 7) to the 58S BG and the mixed alkali effect (MAE) resulting from incorporating Na and B ions into the CaO–SiO 2 –P 2 O 5 system. In specific concentrations, Na+ and Ca2+ ions function as network modifiers, introducing structural disruptions and generating defects that impact the glass transition temperature (T g), crystallization temperature (T c), hardness, and sintering characteristics. The physicochemical characterization of BGs confirms the incorporation of Na and B structures. Furthermore, the Na and B doped glass sample with a [Na/Si] ratio of 0.045 exhibits favorable properties for promoting cell attachment, including forming a hydroxyapatite (HAp) layer over the surface, thereby accelerating human placental mesenchymal stem cells (hPMSCs) proliferation. The findings demonstrate the potential of Na 2 B 4 O 7 incorporation in BG for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

A range of new fluorine‐containing copolyarylates were successfully produced through interfacial polymerization using hexafluorobisphenol A (BPAF) featuring a symmetric trifluoromethyl group structure, bisphenol B (BPB), and two acyl chloride monomers as raw materials. The results indicated that the synthesized amorphous copolyarylates exhibited good solubility, with number average molecular weights (Mn) of 19,000–44,000 g/mol, weight average molecular weights (Mw) of 66,000–159,000 g/mol, and intrinsic viscosities of 0.66–1.19 dL/g. The thermal stability of copolyarylates increased with the increase of BPAF monomer content (0~100%), which was manifested by the linear increase of glass transition temperature (Tg) from 201.6 to 237.1°C, and the increase of 5% thermogravimetric weight loss temperature (T5%) from 474.1 to 491.5°C. The tensile strength of copolyarylates ranged from 52.63 to 59.93 MPa, the tensile modulus ranged from 1102.08 to 1502.84 MPa, and the elongation at break ranged from 32.0 to 75.5%. In addition, the copolyarylates had good dielectric properties with a dielectric constant of 2.58–3.75 at 107 Hz and a dielectric loss tangent of 0.021–0.028. [ABSTRACT FROM AUTHOR]

Highlights The bonding interface of carbon‐fiber‐reinforced polymer (CFRP)‐reinforced steel structure is a weak part, and nanomaterial‐modified adhesives are expected to improve its comprehensive performance. This paper investigates the micro‐modification mechanisms of nanomaterials on epoxy resin adhesives using molecular dynamics simulation method. It explores how the functionalized nano SiO2 and carbon nanotubes affects the thermal and mechanical properties of the epoxy resin adhesive. The models established using Materials Studio software include the pure epoxy resin adhesive model (EP) with varying degrees of crosslinking, the functionalized nano‐SiO2‐modified epoxy resin adhesive model (EP + SiO2/OH), the single‐walled carbon nanotube‐modified epoxy resin adhesive model (EP + SWNT), and the synergistic enhancements model of the epoxy resin adhesive with nano‐SiO2 and carbon nanotubes (EP + SWNT + SiO2/OH). Based on the aforementioned models, the Forcite module is used to calculate the free volume, glass transition temperature and mechanical properties of the adhesive. The results show that the degree of crosslinking effects significantly the mechanical performance of epoxy resin adhesive. A high degree of crosslinking restricts the movement of the molecular chain, enhancing the strength of the epoxy resin adhesive. Furthermore, the trend of the mechanical and thermal properties of the four models remains constant with the rise of temperature, and the properties decrease most significantly in the range of the glass transition temperature. Moreover, the epoxy resin adhesive doped with nanomaterials exhibits varying degrees of enhancement in mechanical and thermal properties. The epoxy resin adhesive reinforced with functionalized nano‐SiO2 and carbon nanotubes exhibits better properties compared to those with a single nanomaterial. The micro‐modification mechanism is revealed for nanomaterial modified epoxy resin adhesive. The degree of crosslinking effects significantly the mechanical performance of epoxy resin adhesive. The epoxy resin adhesive doped with nanomaterials exhibits varying degrees of enhancement in mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

Nylon nanocomposites were prepared by in‐situ ring‐opening polymerization to overcome the problem of poor properties due to the uneven dispersion of the nanoparticles by the traditional melt blending. This high‐performance polyamide 6 (PA6) nanocomposites with high dispersion and strong interface was prepared by grafting PA6 onto the surface of cellulose nanocrystals (CNC). The micromorphology, mechanical, crystalline and thermal properties of the composites were also investigated. Firstly, the hydroxyl group on the surface of CNC reacted with the para isocyanate of toluene diisocyanate (TDI), and the remaining ortho isocyanate was blocked by caprolactam to prepare CNC grafted with caprolactam (CNC‐g‐CL). Then CNC‐g‐CL was used as an activator to prepare cellulose nanocrystal grafted with polyamide 6 (CNC‐g‐PA6) composites by the ring‐opening polymerization of caprolactam on the CNC. The effects of different reaction temperatures, solvent amounts and molar ratios on the grafting rate of CNC‐g‐CL were investigated. The results showed that the highest grafting rate of CNC‐g‐CL with 66.7% was achieved at a reaction temperature of 45°C, 0.1 g/mL CNC in toluene, and a molar ratio of 6 for TDI/CNC. Further, different CNC‐g‐PA6 composites prepared from different CNC content and activator content were explored. For CNC‐g‐PA6 composites, CNC was uniformly dispersed in the PA6 matrix and had a good compatibility with the matrix. CNC exhibited significant reinforcement in the composites with a tensile strength of up to 108 MPa. In addition, the glass transition temperature of CNC‐g‐PA6 was increased to 92°C, which significantly improved the heat resistance of the new composites. Highlights: Effects of reaction condition of CNC and TDI on DSTDI and DSCL were studied.Effects of CNC and activator content on CNC‐g‐PA6 properties were studied.CNC is uniformly dispersed in PA6 with average particle size less than 1 micron.The nylon matrix was significantly strengthened by the addition of CNC.The addition of CNC significantly improved the heat resistance of the composites. [ABSTRACT FROM AUTHOR]

Allyl ether naphthol resin (ANPF) was synthesized by introducing 1,5‐dihydroxynaphthalene and 2,7‐dihydroxynaphthalene into phenolic resin and was copolymerized with 4,4′‐bismaleimidodiphenylmethane resin (BDM) to obtain allyl ether naphthol‐modified bismaleimide resins (15‐ANPF‐BDM and 27‐ANPF‐BDM). The resulting thermal stability and glass transition temperature (Tg) were explored by thermogravimetric and dynamic mechanical analyses. The char yield of 15‐ANPF‐BDM at a temperature of 800°C was 46.0%. Additionally, the Tg of 15‐ANPF‐BDM was measured as 311°C, which is an increase of 44°C compared to that of c. The mechanical properties of the ANPF‐BDM/quartz fiber (Qf) composites were also investigated. The results reveal that ANPF‐BDM/Qf composites exhibit similar mechanical strength to APF‐BDM/Qf composites at room temperature. In addition, the mechanical properties of the ANPF‐BDM/ Qf composites demonstrated significant improvement in mechanical properties retained significantly improved at 200°C, with a 68% flexural strength retention and a 96% interlaminar shear retention of 15‐ANPF‐BDM/Qf composites. Thus, ANPF‐BDM/Qf composites exhibit outstanding mechanical properties at 200°C. [ABSTRACT FROM AUTHOR]

To improve the comprehensive properties of polybutylene furandicarboxylate (PBF), 2,5‐furandicarboxylic acid (2,5‐FDCA), and aliphatic chain diol 1,8‐octanediol and 1,4‐butanediol were used as monomers to synthesize a series of bio‐based polybutylene glycol‐octanediol 2,5‐furandicarboxylate (PBOF). The results showed that the chemical composition of PBOF could be controlled through the molar ratio of monomers. Compared with PBF, as the proportion of octanediol segments gradually increased, PBOF could gradually transform from semi‐crystalline thermoplastic to amorphous form, and the glass transition temperature (Tg) gradually decreased. The crystallization ability reduced but a part of the crystal area was still retained. The copolyesters still has a decomposition temperature above 370°C, indicating excellent thermal stability. The introduction of the octanediol segment significantly improved the tensile mechanical properties and flexibility of the POBF copolyester. These meet the requirements for the preparation of bio‐based engineering plastics. The water absorption rate of PBOF showed that it may have certain degradable potential. PBOF copolyesters have potential application prospects in bio‐based medical plastics and biodegradable packaging polymer materials after copolymerization modification. [ABSTRACT FROM AUTHOR]

The study primarily focuses on the in situ synthesis of polystyrene (PS) and copper oxide (CuO) nanocomposites. An extensive analysis was conducted on the optical, thermal, mechanical, and electrical properties of PS with different CuO concentrations. The effective inclusion of CuO into PS was characterized by Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, filed emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), differential scanning calorimetric analysis (DSC) and thermal gravimetric analysis (TGA). The reinforcement of CuO into the PS was established through FTIR. The optical bandgap energy deduced from UV–visible spectra decreases with CuO addition, whereas the refractive index rises significantly with the addition of CuO nanoparticles up to 7 mass%. The XRD analysis revealed the amorphous to crystalline transformation of PS with the homogeneous dispersion of nanoparticles. The SEM–EDX analysis revealed the uniform distribution of CuO nanofillers in the PS matrix. The CuO addition considerably increased the glass transition temperature and thermal stability of PS. The tensile strength, impact resistance and hardness of nanocomposite were significantly increased with the loading of CuO in the polymer matrix. The AC conductivity and dielectric constant of the PS was improved with the addition of CuO nanoparticles. The effect of temperature on conductivity, activation energy, and pre-exponential factor was determined using the universal power law and the Arrhenius equation. The highest electrical and mechanical properties were observed for 7 mass% nanocomposite. The synthesized PS/CuO nanocomposites with excellent optical characteristics, thermal stability, electrical conductivity, dielectric constant and mechanical strength can be used in supercapacitors and flexible nano-electronic devices. [ABSTRACT FROM AUTHOR]

Thermoset-based polymer composites containing functional fillers are promising materials for a variety of applications, such as in the aerospace and medical fields. However, the resin viscosity is often unsuitably high and thus impedes a successful filler dispersion in the matrix. This challenge can be overcome by incorporating suitable low-viscosity modifiers into the prepolymer. While modifiers can aptly influence the prepolymer rheology, they can also affect the prepolymer curing behavior and the mechanical and thermal properties of the resulting matrix material. Therefore, this study investigates the effects that a commercial-grade low-viscosity additive (butyl glycidyl ether) has on a common epoxy polymer system (diglycidyl ether of bisphenol-A epoxy with a methylene dianiline curative). The weight percentage of the modifier inside the epoxy was varied from 0 to 20%. The rheological properties and cure kinetics of the resulting materials were investigated. The prepolymer viscosity decreased by 97% with 20 wt% modifier content at room temperature. Upon curing, 20 wt% modifier addition reduced the exothermic peak temperature by 12% and prolonged the time to reach the peak by 60%. For cured material samples, physical and thermo-mechanical properties were characterized. A moderate reduction in glass transition temperature and an increase in elastic modulus was observed with 20 wt% modifier content (in the order of 10%). Based on these findings, the selected material system is seen as an expedient base for material design due to the ease of processing and material availability. The present study thus provides guidance to researchers developing polymer composites requiring reduced prepolymer viscosity for successful functional filler addition. [ABSTRACT FROM AUTHOR]

Borophosphosilicate glasses with varying sodium ion concentrations were investigated for their, structural, thermal, and electrical properties. All the obtained glasses were transparent except the glass with the highest sodium content, which exhibited translucency due to inhomogeneities. Increasing sodium content led to reduced boron and silicon content while maintaining a constant B/Si ratio, indicating progressive depolymerization of the glass network. Confocal microscopy, scanning electron microscopy, and atomic force microscopy showed homogeneous and granular structure for samples with lower sodium content, but higher sodium content resulted in visible agglomeration/nanocrystallization. X-ray diffractograms showed amorphous nature for most samples, with samples doped with the highest concentrations of Na 2 O showing several broad reflections suggesting nanoscale crystallinity. Fourier-transform infrared spectroscopy revealed shifts in dominant bands with increasing sodium content, indicating depolymerization of the borate network. An observed decrease in glass transition temperature and thermal stability with increasing sodium content was attributed to depolymerization and formation of non-bridging oxygens. Impedance spectroscopy revealed two relaxation processes associated with the transport of Na+ ions through two different regions. DC conductivity and activation energy predominantly increased with the sodium ion content at high temperatures. [ABSTRACT FROM AUTHOR]

Filler components play a crucial role as thermo‐mechanical reinforcement to the epoxy‐based solder mask, ensuring effective insulation and passivation. This study investigates the impact of different inorganic filler types (talc, silica (SiO2), boron nitride (BN) and barium sulfate (BaSO4)) and loadings (5 and 15 wt%) on the tensile and thermal properties of the epoxy composites. The composites were blended, cast and thermally cured. Of these composites, only 15 wt% SiO2/epoxy composite exhibits notable increments in both tensile strength and modulus, surpassing unfilled epoxy by 11.65% and 31.9%, respectively. It also displays the highest elongation at break, supported by small particle size, high specific surface area and minimal void volume fraction. For thermal tests, the addition of all fillers increases the storage modulus in both glassy and rubbery regions, especially 15 wt% talc/epoxy composite with 30.09% increment at 25 °C. Additionally, all fillers raise the glass transition temperature (Tg), notably improving it by 9 °C in the 15 wt% BN/epoxy composite. Moreover, their inclusion generally enhances the onset decomposition temperature (Tonset) and reduces weight loss during decomposition. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Bismaleimide (BMI) resins is widely used in the aerospace field because of its excellent properties, but its poor toughness limits the possibility of its application in a wider range of fields. Therefore, a novel bio‐compound, 4‐(allyloxy)‐3‐methoxy‐N‐(3‐(triethoxysilyl)propyl)benzamide (AMTPM), was designed and synthesized from renewable vanillin, which has Schiff‐base structure, silico‐oxygen bond structure, and allyl structure. The chemical structure of AMTPM has been characterized and validated by Fourier transform infrared (FTIR) and hydrogen nuclear magnetic resonance (1H NMR). It was found that the addition of AMTPM can effectively promote the curing behavior of BD resins (BMI and diallyl bisphenol A (DBA) was mixed and cured at the ratio of 1:0.87, named BD resins). AMTPM can affect the thermal stability and improve the mechanical properties of BD‐AMTPM resins (BD resins modified by AMTPM in different addition), and the detailed discussion was conducted. With the increase of AMTPM content, the thermal stability of BD‐AMTPM resins was deteriorated while the residual weight percentage at 800°C (Yc) was increased. When the content of AMTPM reached 12 wt%, the results showed that Yc achieved the values at a magnitude of 37.57%. Meanwhile, the glass transition temperature (Tg) achieved 320°C. Among the BD‐AMTPM resins system, the BD‐6 wt% AMTPM has the best toughness and mechanical properties. The impact strength was increased by 29.2%, the tensile strength was increased by 22.1% and the elongation at break was increased by 44%. The fracture morphology of BD‐AMTPM resins was also studied by scanning electron microscopy (SEM) to support the mechanical experimental conclusions. This study provides a more environmentally friendly and convenient modifier, which is of great significance for expanding the application of bismaleimide resin. Highlights: A bio‐based modifying agent (AMTPM) was designed and successfully synthesized.AMTPM has both Si‐O and Schiff‐base structures.AMTPM can effectively improve the toughness of BD‐AMTPM resins through impact and tensile tests. [ABSTRACT FROM AUTHOR]

Levoglucosenone (LGO), a renewable compound obtained from cellulose biomass, has been utilized to prepare novel monomers bearing alkene functional groups. These monomer derivatives of LGO were subsequently cured via ultraviolet (UV)‐initiated radical thiol‐ene “click” chemistry with commercially available multifunctional thiols to obtain colourless, optically transparent cross‐linked thermosets. The monomers prepared in this work are unique due to utilising the internal double bond of the LGO ring during polymerization as part of the cross‐linked network. The thermal and mechanical properties along with the degradation of thermosets containing both ether and ester linkages within the LGO monomers were studied. These thermosets had tensile strengths of 1.3–3.3 MPa, glass transition temperatures between 23.2 and 27.2 °C, and good thermal stability of up to 300 °C. [ABSTRACT FROM AUTHOR]

Highlights In this electronic era, there is a demand to switch from conventional polymers to conducting biopolymers. We developed conducting biopolymer nanocomposites of cashew gum (CG) and polypyrrole (PPy) with zinc oxide (ZnO) nanofillers [CG/PPy/ZnO] via in‐situ oxidative polymerization using a sustainable solvent. These nanocomposites were characterized using Fourier‐transform infrared spectroscopy (FTIR), UV–visible spectroscopy, field emission scanning electron microscope (FE‐SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The FTIR signal at 855 cm−1 confirms the successful inclusion of ZnO nanofillers into the biopolymer. UV–vis absorption of the blend nanocomposite increases with the nanoparticle doses. Among the various blend nanocomposites, the least bandgap energy was observed for 7 wt% ZnO loading. FE‐SEM revealed homogeneous dispersion of ZnO nanofillers in the CG/PPy blend at 7 wt% ZnO. TGA and DSC demonstrated that the CG/PPy/ZnO nanocomposites have better thermal stability and glass transition temperature than the pure polymer blend, indicating enhanced thermal properties. The CG/PPy/7 wt% ZnO showed the highest conductivity, 4.62 times greater than the pristine blend at 100 Hz. Dielectric constant, activation energy, AC conductivity and dielectric loss measurements demonstrated that the nanocomposites outperformed the pure polymer blend. Complex impedance analysis revealed increased impedance with rising temperature. Overall, CG/PPy/ZnO nanocomposites exhibit superior optical, morphological, thermal, electrical, and dielectric properties, making them promising for energy storage and optoelectronic applications. Ecofriendly synthesis of CG/PPy/ZnO nanocomposites Enhancement in optical, structural, and thermal properties of CG/PPy/ZnO Dielectric properties and temperature‐dependent AC conductivity are summarized. Blend nanocomposite shows higher AC conductivity and dielectric constant CG/PPy/ZnO nanocomposites are suitable for energy storage applications [ABSTRACT FROM AUTHOR]

Epoxy resins, known for their excellent properties, are widely used thermosetting resins, but their tendency towards brittle fracture limits their applications. This study addresses this issue by preparing graphene oxide via the Hummer method, modifying it with hyperbranched polyamide ester, and reducing it with hydrazine hydrate to obtain functionalized graphene. This functionalized graphene improves compatibility with epoxy resin. Using a novel two-phase extraction method, different ratios of functionalized graphene/epoxy composites were prepared and tested for mechanical properties and thermal stability. The results showed significant improvements: the tensile strength of composites with 0.1 wt% functionalized graphene increased by 77% over pure epoxy resin, flexural strength by 56%, and glass transition temperature by 50°C. These enhancements, attributed to the improved compatibility between graphene and epoxy resin, demonstrate the potential of functionalized graphene to mitigate the brittleness of epoxy resins, expanding their application potential. [ABSTRACT FROM AUTHOR]

Difunctional glycidyl azide polymer (GAP) is an energetic binder promising for propellant formulations. The multifunctional fluorine‐containing GAP has been synthesized to enhance its mechanical properties. This work outlined multifunctional GAP partially grafted with 1,2,3‐triazole‐5‐(α‐hydroxyl)‐fluorinated polyether (GAP‐g‐3F) synthesized by thermal and catalyst‐free azide‐alkyne cycloaddition reaction, in which the azide groups were from GAP and electron‐deficient alkynes from β‐propargyl‐α‐hydroxyl poly (tri‐fluoropropane glycidyl ether) (PHP3F). PHP3F was synthesized via the typical cationic ring‐opening polymerization of 2‐((2,2,2‐trifluoroethoxy) methyl) oxirane and propargyl alcohol as the initiator. The chemical structures, molecular weight, and thermal properties were characterized by FTIR, NMR, GPC, DSC, and TGA, respectively. HNMR results showed that 8 % of total azide groups in GAP were grafted. GAP‐g‐3F had a slightly higher glass transition temperature than that of GAP. The results of TGA showed that GAP‐g‐3F had suitable thermal decomposition resistance up to 200 °C. The thermal properties, mechanical properties, cross‐linking network structures, and microstructures of the polyurethane networks cured with hexamethylene diisocyanate trimer as a crosslinking agent were determined and compared by TGA, universal tensile test, swelling measurement, and SEM, respectively. The initial decomposition temperature of GAP‐g‐3F‐based polyurethane networks (GAP‐g‐3F‐PU) was around 220 °C, thus meeting the requirements for propellants. In addition, GAP‐g‐3F‐PU exhibited superior mechanical properties, showing an almost twelvefold increase in tensile strength to 16.9 MPa compared with difunctional GAP‐PU with 1.4 MPa tensile strength. The results of the swelling measurement revealed that the GAP‐g‐3F‐PU sample showed a higher crosslinking density in comparison to the GAP‐PU sample. SEM results indicated that the multifunctional fluorine‐containing GAP could enhance compatibility between the soft and hard segments of polyurethanes, leading to a decrease in their separation degree. This finding showed that the synthesis of a multifunctional GAP partially grafted with fluorinated polyether via a triazole ring may be a promising solution to decrease the separation degree increase of PUs, thereby improving the mechanical properties. [ABSTRACT FROM AUTHOR]

Although significant efforts have been undertaken to explore the toughening of epoxy resins, it remains challenges to establish a simple and effective toughening technique which does not compromise its strength, thermal stability and processing performance. In this paper, toluene‐diisocyanate‐trimer (TDI‐T) was utilized to manufacture a novel epoxy‐terminated dendritic modifier TDI‐T glycol diglycidyl ether (TDI‐T GLDE). When the addition of TDI‐T GLDE reaches 20% of the resin mass, the tensile strength, tensile elongation, compressive strength and impact strength were increased by 28.1%, 75%, 24.8%, and 138.0% respectively, compared to E‐51. The thermal properties of the samples have been improved, including an increased glass transition temperature (Tg) from 68.2 to 73.2°C, as well as an increase in the initial decomposition temperature from 240.6 to 257.7°C. The toughening mechanism of TDI‐T GLDE was studied through a combination of mechanical performance tests, thermal performance tests, and resin fracture surface morphology analysis. [ABSTRACT FROM AUTHOR]

Polylactic Acid (PLA) comes from renewable resources, has a reasonable biodegradability rate, and is used in biomedical, food packaging, textiles, and agricultural applications. PLA offers high mechanical strength and the ability to compost, similar to polyethylene terephthalate (PET) and nylon. However, the brittleness of PLA has always limited its usage. Therefore, bio-based plasticizers in the biopolymer matrices can increase flexibility (elasticity), durability, and workability. This study aims to determine the optimal blending ratio for the PLA blended with epoxidized waste cooking oil (EWCO) to enhance the mechanical and thermal properties of PLA/EWCO. The mechanical strength test consists of the hardness test (N/mm2), flexural strength (MPa), and impact energy (kJ/m2) adopted to evaluate the plasticizing characteristics. The thermal stability analysis involves glass transition temperature (Tg) (°C), cold-crystallization temperature (Tcc) (°C) and melting temperature (Tm) (°C). The blending ratio is 97.5PLA/2.5EWCO, 95PLA/5EWCO, 92.5PLA/7.5EWCO and 90PLA/10EWCO. As a result, 97.5:2.5 of PLA/EWCO reduces intermolecular interactions by stimulating more free volume in biopolymer chains' mobility and enhancing the flexibility and elasticity of the PLA blends. Ultimately, the brittleness of PLA decreased with increasing EWCO bio-based plasticizer. [ABSTRACT FROM AUTHOR]

Highlights The homogeneous dispersion of multi‐walled carbon nanotubes (MWCNTs) in a polymer matrix significantly affects the overall properties of composites. In this study, MWCNTs/epoxy (EP) composites were prepared using DeoxyriboNucleic acid (DNA) as a dispersant. The MWCNTs were uniformly dispersed in a phenalkamine curing agent and crosslinked with an epoxy resin matrix. The non‐covalent functionalization of DNA‐dispersed MWCNTs was confirmed by characterizing both the pristine and DNA‐modified MWCNTs. Additionally, the dispersion state and stability of MWCNTs in the curing agent solution were evaluated. Tensile strength and single‐lap‐shear (SLS) were employed to assess the mechanical properties of the composites. The results indicated that the DNA‐dispersed MWCNTs composites exhibited superior strength and toughness, with tensile and shear strengths of 46.81 and 19.64 MPa, respectively, at optimal ratios. These values represent increases of 68.38% and 50.96% compared to pure EP. Dynamic mechanical thermal analysis (DMTA) revealed that the energy storage modulus of DNA‐dispersed MWCNTs/EP composites increased to 2722 MPa, a 24.7% enhancement over pure EP. Furthermore, the thermal properties of the composites were thoroughly investigated. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that the initial decomposition temperature of the DNA‐assisted dispersed composites rose to 330°C. The macromolecular relaxation of the EP materials occurred at higher temperatures, leading to an increased glass transition temperature. DNA was used to disperse MWCNTs in phenalkamine curing agent. MWCNTs/EP composites were made by crosslinking DNA‐dispersed MWCNTs with epoxy resin. DNA‐dispersed MWCNTs boosted tensile and lap shear strength. Thermal properties improved due to DNA‐dispersed MWCNTs, and increased the energy storage modulus of the composite. [ABSTRACT FROM AUTHOR]

This study explores how the size and hybridisation of graphene nanoplatelets (GNPs) affect the properties of graphene nanoplatelet-filled natural rubber (NR) nanocomposites (GNP-filled NR). Results demonstrate notable enhancements in the thermal properties and electrical conductivity of NR with the addition of GNPs. However, mechanical properties experienced partial enhancement, showing increased modulus by up to 200% and hardness by up to 50%, alongside decreased tensile strength by up to 60% and elongation by up to 70%. The comparative analysis highlights the superior mechanical and thermal properties associated with smaller GNPs. These smaller particles enhanced mechanical properties such as modulus at 100% strain and Shore A hardness, increased the glass transition temperature by up to 10%, and reduced thermal degradation rates by up to 30% due to their superior dispersion and interfacial bonding with NR. Larger GNPs exhibited a 1000% increase in electrical conductivity at 10 × 106 Hz due to increased surface area and network formation due to reduced dispersion. Notably, hybrid GNPs contributed significantly to overall property enhancements compared to the single filler system, with up to 80% higher tensile strength, up to 30% higher elongation at break, up to 20% higher glass transition temperature, lower degradation rate at high temperature, attributed to improved dispersion of GNPs and interfacial adhesion with NR. This study highlights the substantial influence of GNP sizes on the performance of NR nanocomposites and the significant effects of hybridisation, providing valuable insights for optimising material properties for advanced applications. [ABSTRACT FROM AUTHOR]

To study the service performance of polymer bilayer sheets, this experimental study focuses on the thermal and mechanical characterization of sheets composed of two polymer layers (named ABS/PMMA), an Acrylonitrile–Butadiene–Styrene layer and a 15% Poly(Methyl Methacrylate) layer. These sheets are used in many industrial components subjected to thermal and mechanical strain. The studied bilayer sheets were obtained by a co-extrusion process. Thermal properties were measured through Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Mechanical behavior was determined via uniaxial tensile tests at various temperatures less than the glass transition temperature and using two strain rates of 3.33 × 10−4 s−1 and 1.66 × 10−2 s−1. Furthermore, the viscoelastic properties are determined via Dynamic Mechanical Analysis (DMA) using two frequencies. The findings revealed substantial ABS/PMMA bilayer thermal stability. The obtained glass transition temperature of this bilayer was 111 °C. Its viscoelastic behavior was described by determining the storage and loss modulus. Furthermore, the influence of temperature and strain rate parameters on the tensile behavior of the ABS/PMMA bilayer was also determined showing high dependence of mechanical behavior on these two parameters. This bilayer exhibits brittleness at room temperature and high total strain exceeding 62% at 90 °C. [ABSTRACT FROM AUTHOR]

A novel diphenyl monomer, dimethyl 2,2'-(((ethane-1,2-diylbis(oxy))bis(4-acetyl-3,1-phenylene))bis(oxy))diacetate (EDPD), was synthesized from methyl 2-(4-acetyl-3-hydroxyphenoxy)acetate (MAHA), a 2,4-dihydroxyacetophenonederivative, and combined with 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or p-phenylenedimethanolto afford a series of biodegradable polyesters via melt polymerization. The polyesters were characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The weight-average molecular weight (Mw) of the polyesters varied from 3.2–4.4 × 104 g/mol, the glass transition temperature (Tg) from 52 to 80 °C, and the 5% decomposition temperature (Td,5%) was in the 334–362 °C range. All the samples exhibited high yield strength (53–68 MPa) and elongation at break (230–330%) values, comparable with poly(ethylene terephthalate) (PET), owing to their aromatic character. Degradability testing of the polyesters in soil yielded mass losses reaching up to 7% after 32 weeks. In ecotoxicity testing, earthworms had a survival rate of more than 80% after 14 d of incubation, indicating relatively low toxicity. Overall, the good thermal and mechanical properties, biodegradability and low ecotoxicity of the polyesters make them promising materials for packaging applications, in replacement for PET, thereby promoting carbon neutrality and sustainable development. [ABSTRACT FROM AUTHOR]

In this study, the effect of boric acid (H3BO3) on fiber-reinforced layered composites was investigated. Glass fiber-reinforced epoxy composites were used, and the effects of boric acid on thermal and mechanical properties were investigated. For this purpose, composite plates were manufactured by adding boric acid (BA) to the epoxy in different ratios (0, 0.5, 1, and 1.5% by weight). Tensile tests, compression tests, and shear tests were performed to determine the mechanical properties of these plates, and DSC, TGA, and DMA analyses were performed to determine their thermal properties. SEM and EDS analyses were performed on the specimens to examine their morphologies. Furthermore, examinations were conducted on how BA affected the specimens' failure behavior. In the study, it was found that, except for the compressive strength, the mechanical properties were improved by the added BA. The highest tensile strength, shear strength, modulus of elasticity, shear modulus, and Poisson's ratio were obtained from 0.5% BA-added specimens and were 24.78%, 8.75%, 25.13%, 11.24%, and 12.5% higher than the values obtained from 0% BA-added specimens, respectively. The highest loss and storage modulus were obtained from 0% and 0.5% BA-added specimens, respectively. The specimens' glass transition temperatures were decreased by the addition of BA; the specimen with a 1% addition of BA had the lowest value. Furthermore, interlayer delamination and fiber/matrix failure were observed in all BA-added specimens. [ABSTRACT FROM AUTHOR]

The melt quenching technique was used to prepare tellurite glasses with compositions 70TeO2–20BaO–10WO3 (BT:W glass), 70TeO2–20BaO–10Y2O3 (BT:Y glass), 70TeO2–20BaO–10SrO (BT:Sr glass) and 70TeO2–20BaO–10Li2O (BT:Li glass). The impact of modifying ions Ba2+, W6+, Y3+, Sr2+, and Li+ on structural, physical, thermal and mechanical properties of the prepared glasses has been explored by using XRD, DTA, and FTIR spectroscopic techniques. XRD analysis conformed that the prepared glasses are amorphous and homogeneous in nature. The FTIR spectra revealed the presence of TeO4 trigonal bipyramids, TeO3 trigonal pyramids and NBOs in the network of BT:Y, BT:Sr and BT:Li glasses. Meanwhile, the structure of BT:W glass is composed of TeO4, TeO3, WO4 and WO6 units, which are connected to each other through W–O–Te linkages. The glass transition temperature and thermal stability increased in the order BT:W glass > BT:Y glass > BT:Sr glass > BT:Li glass. These results were compared to those of binary 80TeO2–20BaO glass (BT) and pure TeO2 glass. Changes in the thermal properties have been analyzed and predicted by correlating them with the calculated molar volume, ratio of packing density to mean atomic volume, dissociation energy per unit volume, field strength of the modifying ions, average single bond strength, and elastic moduli. The R-squared values of the regression lines can be improved if the effect of all structural groups as well as the uncertainty inherent in experimental measurements are taken into account. The highest thermal stability and glass transition temperature of BT:W glass making it a good candidate for shielding material in the fields of medical, industrial, and nuclear applications. [ABSTRACT FROM AUTHOR]

Context: Traditional conductive adhesives based on epoxy resin system often encounter problems such as high brittleness and low heat resistance. Therefore, it is particularly important to improve the thermal and mechanical properties of the conductive adhesive. In this study, the effects of SWCNT-Ag and SWCNT fillers on the thermal properties of DGEBA/DETA/Ag conductive adhesive system were studied by using molecular dynamics to construct different cross-linking models. The final results show that the addition of SWCNT and SWCNT-Ag can significantly improve the thermal properties of the conductive adhesive. However, the nanosilver particles on the surface of SWCNT-Ag act as a bridge for the connection between SWCNT and Ag in the conductive adhesive. Therefore, SWCNT-Ag has a more positive impact on the thermal properties of DGEBA/DETA/Ag conductive adhesive system. Methods: In this paper, the influence of SWCNT-Ag on the thermal properties of traditional DGEBA/DETA/Ag conductive adhesive system was studied by using Materials Studio software. The volume shrinkage, glass transition temperature, thermal expansion coefficient, and thermal conductivity of the material were calculated based on COMPASS force field. The thermal conductivity is calculated by using reverse non-equilibrium molecular dynamics method. Finally, it is found that SWCNT-Ag has a positive effect on the thermal properties of the conductive adhesive system by comparing several groups of calculation data. [ABSTRACT FROM AUTHOR]

A novel epoxy resin, DPHP, was synthesized from diphenolic acid, which contains biobased levulinic acid, with triethylphosphite, to improve the flame retardancy of bisphenol‐A diglycidyl ether (BADGE) epoxy. Curing experiments were conducted using isophorone diamine as a curing agent for BADGE and DPHP mixtures. Variations in cure kinetics, mechanical properties, and flame retardancy were evaluated across different DPHP contents. The introduction of phosphorus functional groups into DPHP affected the polarization of epoxide CO bonds, resulting in reduced apparent activation energy for epoxy curing reactions. However, the higher epoxy equivalent weight of DPHP compared with that of BADGE led to a decrease in the tensile strength and the glass transition temperature of the cured material with increasing DPHP content. A significant increase in char yield for combustion of the epoxy blend was observed, ranging from 8.3% at 0 wt% DPHP to 20.1% at 50 wt% DPHP. Additionally, cone calorimeter measurements showed significant reductions in heat release rate and total heat release, leading to a decrease in fire spread from 1.07 MJm−2 s−1 at 0 wt% DPHP to 0.43 MJm−2 s−1 at 50 wt% DPHP. These results show that the flame retardancy of the cured material improved significantly as the DPHP content increased. [ABSTRACT FROM AUTHOR]

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]

Two organo‐soluble polyimide (PI) resins were prepared from a tricyclic fluoro‐containing dianhydride 9,9‐bis(trifluoromethyl)xanthene‐2,3,6,7‐tetracarboxylic dianhydride (6FCDA) and aromatic diamine of 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (BDAF) for PI‐IIa and 1,3‐bis(3‐aminophenoxy)benzene (133APB) for PI‐IIb, respectively. For comparison, two analogous PIs were prepared from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and the same diamines to afford PI‐Ia (6FDA‐BDAF) and PI‐Ib (6FDA‐133APB), respectively. Incorporation of the rigid and planar xanthene units in the 6FCDA‐PIs obviously decreased the solubility of the resins in organic solvents. Flexible and tough PI films were fabricated from the PI solutions in N,N‐dimethylacetamide (DMAc). The PI films derived from the rigid and planar 6FCDA dianhydride exhibited obviously enhance thermal stability, and high‐temperature dimensional stability. For example, PI‐IIa (6FCDA‐BDAF) showed the glass transition temperature (Tg) and coefficient of linear thermal expansion (CTE) values of 311.5°C and 50.5 × 10−6/K, respectively, which were all superior to those of the PI‐Ia counterpart (Tg = 264.6°C; CTE = 55.4 × 10−6/K). In addition, the 6FCDA‐PI films maintained the intrinsically excellent optical transparency of the fluoro‐containing PI films and showed the comparable optical properties to those of the 6FDA‐PI films. As for the properties highly related to the space applications, all the PI films exhibited low solar absorptivity (α) values of 0.18–0.20 and the good thermal emissivity (ε) values in the range of 0.68–0.70. PI‐Ia (6FDA‐BDAF) and PI‐IIa (6FCDA‐BDAF) films showed the similar atomic oxygen erosion behaviors with the standard Kapton® type of PI film derived from pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA). [ABSTRACT FROM AUTHOR]

Biodegradable films are considered an alternative to petroleum‐based plastics to solve environmental problems. In this study, potato flour films are prepared with dispersions at pH 3, 5, 7, 9, and 11. The film‐forming dispersion at pH 7 shows the highest apparent viscosity. Dispersions at alkaline conditions show a reduction in particle size, resulting in a smooth film surface. Films at alkaline conditions present a yellow appearance and have the lower transmittance. The film at pH 5 has the highest retrogradation enthalpy and glass transition temperature, while its moisture content and solubility are the lowest. The water contact angle increases from 33.33° to 93.67° with the increase in pH. However, pH has no significant effect on the water vapor permeability. The tensile strength and elongation at break increase slightly with the increase in pH. Overall, pH modifies the properties of potato flour films. Film with appropriate performance can be selected based on actual needs, such as the use of packaging materials for food preservation. [ABSTRACT FROM AUTHOR]

The preparation of 0.58 Li2S + 0.315 SiS2 + 0.105 LiPO3 glass, and the impacts of polysulfide and P1P defect structure impurities on the glass transition temperature (Tg), crystallization temperature (Tc), working range (ΔT≡ Tc ‐ Tg), fragility index, and the Raman spectra were evaluated using statistical analysis. In this study, 33 samples of this glass composition were synthesized through melt‐quenching. Thermal analysis was conducted to determine the glass transition temperature, crystallization temperature, working range, and fragility index through differential scanning calorimetry. The quantity of the impurities described above was determined through Raman spectroscopy peak analysis. Elemental sulfur was doped into a glass to quantify the wt% sulfur content in the glasses. Linear regression analysis was conducted to determine the impact of polysulfide impurities and P1P defect impurities on the thermal properties. Polysulfide impurities were found to decrease the Tg at rate of nearly 12°C per 1 wt% increase in sulfur concentration. The sulfur concentration does not have a statistically significant impact on the other properties (α = 0.05). The P1P defect structure appears to decrease the resistance to crystallization of the glass by measurably decreasing the working range of the glasses, but further study is necessary to fully quantify and determine this. [ABSTRACT FROM AUTHOR]

The promotion of different properties of polymers has become a substantial worldwide objective for different counterparts in industry and academia. In this work, different loadings of multi walled carbon nanotubes (MWCNTs) were employed to reinforce acrylonitrile butadiene styrene (ABS) to prepare polymer nanocomposites. The employed loadings by solution blending approach were (0.1, 0.5, 1.0, and 5.0) wt. %. FTIR and XRD were utilized to investigate the chemical interaction and crystal structure; respectively. The morphological investigation performed by scanning electron microscopy (SEM) showed the nature of the neat polymer, the dimensions and orientations of the nanotubes, and the good dispersion of the nanotubes within the polymer for the loadings up to 1.0 wt. %. As a result of this good dispersion, thermal properties represented by thermal degradation temperature (Td) and glass transition temperature (Tg) were improved. Furthermore, Young's modulus and tensile strength for the nanocomposite of 1.0 wt. % were enhanced by 87% and 46%, respectively as compared to the neat polymer. [ABSTRACT FROM AUTHOR]

Elevating the heat resistance of the highly transparent cyclic block copolymer (CBC) is of great significance for the synthesis of high-performance polymers. In this study, a novel bimetallic NixPd/NCNT@MFN catalyst was prepared and applied in the hydrogenation of α-methylstyrene-butadiene-styrene (α-SBS) ternary block copolymer. Ni2Pd/NCNT@MFN exhibited excellent catalytic performance, and after 8 h of reaction, a new fully hydrogenated polymer, α-CBC, was obtained. The hydrogenation of the butadiene segment in α-SBS became more difficult as the length of the segment increased. The presence of α-methyl resulted in the highest adsorption-activation energy for the α-methylstyrene monomer unit, leading to a longer hydrogenation time with increasing length of this segment. Furthermore, the introduction of α-methylstyrene not only increased the glass transition temperature of the styrene and α-methylstyrene (S) segments in α-SBS, but also increased the glass transition temperature of α-CBC even more after hydrogenation. This conclusion provides valuable theoretical guidance for the synthesis of high-heat-resistant α-CBC polymers. [ABSTRACT FROM AUTHOR]

Silicone resins are widely used in various fields because of their excellent high thermal stability. To improve their comprehensive performances, many organic resins have been used for modification of silicone resins. In this article, silicone resins containing phthalonitrile groups were synthesized by the reaction of the silicone resin containing amino groups and 4-(2-oxiranylmethoxy)-1,2-benzenedicarbonitrile. The structures of phthalonitrile-modified silicone resins were characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H-NMR). The curing process was characterized by differential scanning calorimetry and FT-IR. Thermogravimetric analysis results showed that the cured modified silicone resins had good thermal stabilities. Dynamic mechanical analysis indicated that they owned high glass transition temperature, suggesting that silicone resins containing phthalonitrile groups have high-temperature resistance. [ABSTRACT FROM AUTHOR]

This research aims to highlight the importance of diverse forms of graphitic carbon nitride (g-C3N4) as strengthening elements in epoxy composites. It explores the influence of three different forms of g-C3N4 and their concentrations on the mechanical properties of the epoxy composites. Various characterization techniques, such as scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR), were utilized to comprehend the effects of g-C3N4 morphology and particle size on the physical and chemical characteristics of epoxy resin. Mechanical properties, such as tensile strength, strain, modulus, and fracture toughness, were determined for the composite samples. SEM analysis was performed to examine crack morphology in samples with different reinforcements. Findings indicate that optimal mechanical properties were achieved with a 0.5 wt% bulk g-C3N4 filler, enhancing tensile strength by 14%. SEM micrographs of fracture surfaces revealed a transition from brittle to rough morphology, suggesting increased toughness in the composites. While the TGA results showed no significant impact on degradation temperature, dynamic mechanical analysis demonstrated a 17% increase in glass transition temperature. Furthermore, the improvement in thermal breakdown up to 600 °C was attributed to reinforced covalent bonds between carbon and nitrogen, supported by FTIR results. [ABSTRACT FROM AUTHOR]

Biochar (BC) is a by-product rich in carbon, from the pyrolysis of biomass, and therefore, it has great appeal to be used in several applications. In the present work, the use of biochar from poultry litter waste (PLW) as a filler for composites with epoxy resin is evaluated regarding its performance in the thermal, mechanical and dynamic mechanical properties. The BC was produced from the pyrolysis of the PLW, and the composites were produced from concentrations of 2.5, 5.0 and 10.0 wt% of BC, in relation to the epoxy resin mass. The composites were characterized in terms of micrography (MEV), infrared spectroscopy with Fourier transform (FTIR), thermogravimetric analysis (TGA), mechanical properties (tension and impact) and dynamic mechanical analysis (DMA). From the dynamic mechanical point of view, there was a considerable increase in parameters such as storage modulus at both glassy (≈ 23%) and rubbery regions (≈ 43%) and loss modulus (≈ 32%). However, a decrease at the glass transition temperature, in loss modulus, (≈ 19 °C) was reported, comparing the neat epoxy with those composites with 10 wt% of BC. This behavior was mainly related to the poor dispersion of BC into the composites, especially those with 10 wt% of reinforcement. [ABSTRACT FROM AUTHOR]

A new thermally stable chromophore exhibiting the intense blue fluorescence with the high quantum yield of 91%, 4-(4-(9H-carbazol-9-yl)phenyl)-2,6-bis-(4-N,N-diphenyl-aminophenyl)pyridine, was synthesized in a high yield via the three-component reaction of 4-(N,N-dimethylamino)acetophenone, 4-(9H-carbazol-9-yl)benzaldehyde, and ammonium acetate. [ABSTRACT FROM AUTHOR]

The present research article demonstrates the dispersion of boehmite (BHM) nanoparticles into sericin (SER) from silk industry waste with polyvinyl alcohol (PVA) to enhance the optical, mechanical, thermal and electrical characteristics of PVA/SER blend nanocomposites prepared by a simple green synthesis. Techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV visible spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out for the characterization of the prepared composites. XRD revealed the increased crystallinity of the polymer blend by the reinforcement of BHM. The existence of intermolecular interactions in the blend composite was confirmed by FTIR and UV spectroscopy. The optical bandgap energy of the biopolymer blend decreases with the inclusion of BHM. The SEM and HR-TEM confirmed the homogeneous dispersion of BHM in the blend at 5 wt% loading. The glass transition temperature and thermal stability of the blend nanocomposites were significantly improved by the inclusion of BHM was deduced from DSC and TGA. The dielectric constant and AC conductivity were remarkably increased with the reinforcement of nanoparticles. The activation energy obtained from AC conductivity decreased with temperature. The mechanical properties of the blend nanocomposites (hardness, tensile strength and Young's modulus) were greatly increased in presence of BHM. The 5 wt% sample has the highest tensile strength, Young's modulus, dielectric constant, AC conductivity and optical properties, allowing it to be used to make optoelectronic devices with better charge-storing capacity and flexible-type electrochemical gadgets. [ABSTRACT FROM AUTHOR]

This study prepared six different ice creams to investigate the effect of yeast protein (YP) on their sensory, rheological, thermal properties and fat destabilisation. Results indicated that YP could improve sensory quality, flow and viscoelastic properties. The thermal property was also positively influenced by YP with a significant decrease in frozen water percentage and an increase in glass transition temperature (P < 0.05). Additionally, the particle size and confocal laser scanning microscopy results illustrated that YP could moderately promote the fat aggregate percentage and size. Overall, YP could serve as a fat replacer to produce reduced‐fat ice cream. [ABSTRACT FROM AUTHOR]

Polymer biocompositions of poly(3-hydroxybutyrate) (P3HB) and linear polyurethanes (PU) with aromatic rings were produced by melt-blending at different P3HB/PU weight ratios (100/0, 95/5, 90/10, and 85/15). Polyurethanes have been prepared with 4,4′-diphenylmethane diisocyanate and polyethylene glycols with molar masses of 400 g/mol (PU400), 1000g/mol (PU1000), and 1500 g/mol (PU1500). The compatibility and morphology of the obtained polymer blends were determined by infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The effect of the polyurethane content in the biocompositions on their thermal stability and mechanical properties was investigated and compared with those of the native P3HB. It was shown that increasing the PU content in P3HB-PU compositions to 10 wt.% leads to an improvement in the mentioned properties. The obtained results demonstrated that the thermal stability and mechanical properties of P3HB were improved, particularly in terms of increasing the degradation temperature, reducing hardness, and increasing impact strength. The best thermal and mechanical properties were shown by the P3HB-PU polymer compositions containing 10 wt.% of polyurethane modifiers, especially PU1000, which was also confirmed by the morphology analysis of these biocompositions. The presence of polyurethanes in the resulting polymer biocomposites decreases their glass transition temperatures, i.e., makes the materials more flexible. The resulting polymer biocompositions have suitable mechanical properties and thermal properties within the processing conditions for the predicted application as biodegradable, short-lived products for agriculture. [ABSTRACT FROM AUTHOR]

Cyanate ester (PT‐30) resin possesses exceptional thermal and mechanical properties, including high heat distortion temperature, high glass transition temperature (Tg), and outstanding mechanical characteristics. Conversely, the Tg of the homopolymer of tris(2‐hydroxyethyl)isocyanurate triacrylate (T‐acrylate) surpasses that of other acrylates. The combination of PT‐30 and T‐acrylate results in the formation of an interpenetrating polymer network (IPN) through a dual curing mechanism. Furthermore, the combination of these two polymers enables the tuning of rheology for shear thinning behavior for Ink Extrusion 3D printing technology by adjusting the amount of photoinitiator and rheological modifier. Here, 3D printable ink was formulated using PT‐30, T‐acrylate with a higher Tg, a photoinitiator, and a powdered rheological additive. The printed structures underwent a dual‐curing process involving exposure to UV light and thermal curing. Thermomechanical properties of the printed samples were characterized using dynamic mechanical analysis, thermogravimetric analysis, and tensile testing. The successful formation of an IPN structure through the polymerization of T‐acrylate and PT‐30 was observed, resulting in improved mechanical properties and an elevated Tg. The Fourier transform infrared spectroscopy analysis verified the formation of cross‐linked samples. Overall, this study demonstrates the feasibility of Ink Extrusion 3D printing, using a cyanate ester resin and tris(2‐hydroxyethyl)isocyanurate triacrylate with a dual‐curing mechanism. The enhanced mechanical properties at elevated temperatures (~80% retention of room temperature tensile strength at 200°C for sample with 70/30 wt%) and high Tg of 349 ± 3°C for printed structures shown in this study make them suitable for high‐performance structural applications in industries such as aerospace, defense, and microelectronics. [ABSTRACT FROM AUTHOR]

The metal cross-linking fluorinated polyacrylate colloid has a high cross-linking density, high transparency, high heat resistance and hydrophobicity. In this paper, the metal cross-linking fluorinated polyacrylate colloid is synthesized via the semi-continuous seeded emulsion polymerization technology, which uses the self-made magnesium acrylate, calcium acrylate and zinc acrylate as metal crosslinker and dodecafluoroheptyl methacrylate as a fluorine monomer. In this study, the ablation effect of the metal ions is weakened by the increased amount of environmentally friendly and polymerizable anion emulsifier DNS-86. The demulsification phenomenon of emulsion is successfully overcome through destroying the double layer structure of micelles or colloid particles by polyvalent metal ions. The colloidal particle size is smaller and the particle size distribution of the colloid is more uniform. Colloidal film has a good hydrophobicity and the glass transition temperature and the thermal decomposition temperature are high. [ABSTRACT FROM AUTHOR]

This study aims to develop sustainable, renewable and biodegradable biocomposite films from environmentally friendly materials. For this purpose, completely biodegradable polymer composites were prepared by mixing polylactic acid (PLA) with a new source, quince peel (QP), by solvent casting method, and their structural, mechanical and thermal properties were examined. The tensile strengths of the composites prepared using QP in proportions varying between 5% (P5Q) and 30% (P30Q) by weight vary between 21.13 ± 0.80 and 12.01 ± 0.10 MPa, and their elongations at break vary between 11.33 ± 0.38 and 4.08 ± 1.06 %. As the QP contribution increased, the tensile strength and breaking elongation of these composites generally decreased, while the elastic modulus also increased. Among these composites, whose elastic modulus varies between 1040.00 ± 140.01 and 811.33 ± 13.31 MPa, it was determined that the elastic modulus (1040.00 ± 140.01 MPa) of the 20% QP added composite (P20Q) was higher than the others. When the thermal analysis of PLA/QP films were examined, it was observed that the glass transition temperatures (Tg) were between 58.54 and 51.45°C and the melting temperatures (Tm) were between 167.71 and 164.28°C, and these temperatures generally decreased with increasing QP doping. When the T50 values, which represent the temperature at which 50% of the composite materials decompose, were examined, it was found that the QP-added ones were higher than the pure composites. While this value was 317.96°C in pure PLA composite, T50 values varied between 327.92 and 340.80°C depending on the varying QP ratios. According to the XRD results performed to evaluate the crystalline properties of PLA composites containing quince bark, the crystallinity of pure PLA was determined as 19.5% and the crystallinity of composites containing 5, 10, 20 and 30 wt % QP additives was determined as 19.3, 18.3, 16.4 and 14.6%, respectively. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) have gained interest recently due to their biodegradability and versatility. In particular, the chemical compositions of medium‐chain‐length (mcl)‐PHAs are highly diverse, comprising different monomers containing 6–14 carbon atoms. This review summarizes different feedstocks and fermentation strategies to enhance mcl‐PHA production and briefly discusses the downstream processing. This review also provides comprehensive details on analytical tools for determining the composition and properties of mcl‐PHA. Moreover, this study provides novel information by statistically analyzing the data collected from several reports on mcl‐PHA to determine the optimal fermentation parameters (specific growth rate, PHA productivity, and PHA yield from various structurally related and unrelated substrates), mcl‐PHA composition, molecular weight (MW), and thermal and mechanical properties, in addition to other relevant statistical values. The analysis revealed that the median PHA productivity observed in the fed‐batch feeding strategy was 0.4 g L−1 h−1, which is eight times higher than that obtained from batch feeding (0.05 g L−1 h−1). Furthermore, 3‐hydroxyoctanoate and ‐decanoate were the primary monomers incorporated into mcl‐PHA. The investigation also determined the median glass transition temperature (−43°C) and melting temperature (47°C), which indicated that mcl‐PHA is a flexible amorphous polymer at room temperature with a median MW of 104 kDa. However, information on the monomer composition or heterogeneity and the associated physical and mechanical data of mcl‐PHAs is inadequate. Based on their mechanical values, the mcl‐PHAs can be classified as semi‐crystalline polymers (median crystallinity 23%) with rubber‐like properties and a median elongation at break of 385%. However, due to the limited mechanical data available for mcl‐PHAs with known monomer composition, identifying suitable processing tools and applications to develop mcl‐PHAs further is challenging. [ABSTRACT FROM AUTHOR]

Functional cyclophosphazenes have proven to be effective modifiers of polymer materials, significantly improving their performance properties, such as adhesive characteristics, mechanical strength, thermal stability, fire resistance, etc. In this study, 4-(β-carboxyethenyl)phenoxy-phenoxycyclotriphosphazenes (CPPP) were obtained by the condensation of 4-formylphenoxy-phenoxycyclotriphosphazene with malonic acid. Its structure was studied using 31P, 1H, and 13C NMR spectroscopy and MALDI-TOF mass spectrometry, and the thermal properties were determined by DSC and TGA methods. Molecular modeling using the MM2 method showed that CPPPs are nanosized with diameters of spheres described around the molecules in the range of 1.34–1.93 nm, which allows them to be classified as nanosized structures. The epoxy resin DER-331 was cured with CPPP, and the conversion of epoxy groups was assessed using IR spectroscopy. Using optical interferometry, it was shown that CPPPs are well compatible with epoxy resin in the temperature range from 80 to 130 °C. It was established that the cured epoxy composition was fire resistant, as it successfully passed the UL-94 vertical combustion test due to the formation of porous coke during the combustion process and also had high heat resistance and thermal stability (decomposition onset temperature about 300 °C, glass transition temperature 230 °C). The composition has low water absorption, high resistance to fresh and salt water, fire resistance, and adhesive strength to steel and aluminum (11 ± 0.2 MPa), which makes it promising for use as an adhesive composition for gluing parts in the shipbuilding and automotive industries, the aviation industry, and radio electronics. [ABSTRACT FROM AUTHOR]

Physical parameters are necessary to determine the suitability of the chalcogenide materials for specific applications. The present study reports the physical characteristics of the multicomponent GeTe2-x(SeSb)x (x = 0, 0.2, 0.4, 0.6) chalcogenide glasses synthesised by the melt-quench technique. The differential scanning calorimetric (DSC) technique has been used at separate heating rates β = 5, 10, 15, 20 °C / min. XRD and SEM–EDX studies have been carried out for structural and morphological analyses. The average coordination number and constraints of the compound have been calculated which indicates that the composition forms a glassy system. Lone pair electrons present in the composition have been evaluated. R parameter has a value greater than 1, indicating that the composition has sufficient chalcogen, chalcogen–chalcogen and heteropolar bonds. The overall bond energy of the compound has been calculated using the chemical bonding approach to understand the fine-structure properties of the compound. Cohesive energy has been observed to increase with composition. Thermal stability, glass transition temperature and glass forming ability of the compound have been calculated using different relations like Saad and Poulin relation, Dieztal relation, Hurby parameter (Hr) and reduced glass transition temperature (Trg) and studied theoretically to examine the thermal stability of the composition that shows that the prepared samples are suitable for data storage. [ABSTRACT FROM AUTHOR]

This study presents a novel approach to modifying copolymers with active azide end-groups through click chemistry, specifically targeting the incorporation of cysteine amino acid. The synthesis commenced with the reaction between cysteine amino acid and propargyl amine, yielding the alkyne-terminated amino acid Boc-Cys(Bnz)-PA compound. Through the click chemistry methodology, the copolymer with active azide ends was modified with alkyne-terminated Cys-PA. Thermal characterization of the copolymers was performed via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC measurements revealed an increase in glass transition temperature (Tg) from 65 °C to 83 °C upon the modification with cysteine, indicating enhanced thermal stability. However, TGA data suggested a decrease in thermal stability as evidenced by lower initial degradation temperatures for the modified copolymer compared to the unmodified counterpart.The degradation activation energies of the copolymers were estimated using the Flynn-Wall-Ozawa method across various conversion ranges, demonstrating higher thermal degradation activation energy for the modified copolymer compared to the unmodified one. Dielectric behavior analysis conducted at room temperature over a frequency range from 100 Hz to 20 kHz revealed a decreasing trend in dielectric constant and dielectric loss values with increasing frequency for all copolymer structures. The alternating current (AC) conductivities at 30 kHz were calculated as 1.84 × 10−7 S cm−1, and 4.75 × 10−7 S cm−1 for P(VBCl-co-VBN3 0.77) and (P(VBCl-co-(VBN3-click-Cys)0.77), respectively, indicating a frequency-dependent conductivity enhancement with increasing frequency. Overall, the results suggest that these polymeric materials, containing amino acid structures, hold promise as dielectric materials for low-frequency and low-voltage devices such as sensors, owing to their tunable thermal and dielectric properties achieved through click chemistry modification. [ABSTRACT FROM AUTHOR]

This study reports the fabrication of quartz fabric reinforced phthalonitrile composite possessing good thermal and wave-transmitting properties. Phthalonitrile-terminated oligomer PN-SF curing behavior was investigated using differential scanning calorimetry (DSC) and dynamic rheological analysis (DRA), revealing a good processability pre-curing temperature of only 175°C. The thermoset exhibited the 5% loss temperature about 462°C, and after the temperature rising to 400°C and 400°C/2 h aging, the weight loss was only 10%, indicating that the resulting thermoset possessed outstanding thermal property. Moreover, the resulting thermosets possessed extremely high glass transition temperature (Tg) about 420°C. Besides, the quartz fabric/phthalonitrile composite possessed extremely excellent mechaical properties. Importantly, the transmission efficiencies can reach 87% at a certain frequency at the incident angle of 0°∼35°, indicating its well waving-transmitting performance. Meanwhile, the composite exhibited stable and relatively low dielectric constant and dielectric loss at the range of 12∼18 GHz. This study can serve as a basis for rapid evaluation of the high heat resistance and waving-transmitting phthalonitrile resin-based composite in various application environments. [ABSTRACT FROM AUTHOR]

A fundamental understanding of crystallization behavior is essential for the processing of both virgin and recycled polymers. This research delves into the crystallization characteristics and non‐isothermal crystallization kinetics of recycled polyethylene terephthalate (rPET) and its blends with poly butylene terephthalate (PBT), which have been modified using epoxy‐based multifunctional chain extenders (CE). The preparation of rPET/PBT blends involved a twin‐screw extruder, with varying weight ratios and different CE concentrations. Differential scanning calorimetry was employed to perform crystallization analysis on the samples. The results underscore the profound impact of blend composition on the thermal characteristics of the system, with CE exerting only a marginal influence. The glass transition temperatures (Tg) of the two polymers were measured at 49 and 79°C. During blending, the Tg values demonstrated variations relative to the proportions but did not adhere to the Fox equation. Furthermore, PBT was found to enhance the crystallization tendencies of rPET, resulting in an increase in relative crystallinity from 11% to 36%. Notably, the crystallization rate of PBT at 0.40 min−1 exceeded that of rPET at 0.36 min−1. PBT minimally affected the crystallization rate constant of rPET‐dominant blends, while rPET significantly reduced the crystallization rate in PBT‐dominant blends. [ABSTRACT FROM AUTHOR]

To expedite the valorisation of lignin as a sustainable component in materials applications, rapid and generally available analytical methods are essential to overcome the bottleneck of lignin characterisation. Where features of a lignin's chemical structure have previously been found to be predicted by Partial Least Squares (PLS) regression models built on Infrared (IR) data, we now show for the first time that this approach can be extended to prediction of the glass transition temperature (Tg), a key physicochemical property. This methodology is shown to be convenient and more robust for prediction of Tg than prediction through empirically derived relationships (e. g., Flory‐Fox). The chemometric analysis provided root mean squared errors of prediction (RMSEP) as low as 10.0 °C for a botanically, and a process‐diverse set of lignins, and 6.2 °C for kraft‐only samples. The PLS models could separately predict both the Tg as well as the degree of allylation (%allyl) for allylated lignin fractions, which were all derived from a single lignin source. The models performed exceptionally well, delivering RMSEP of 6.1 °C, and 5.4 %, respectively, despite the conflicting influences of increasing molecular weight and %allyl on Tg. Finally, the method provided accurate determinations of %allyl with RMSEP of 5.2 %. [ABSTRACT FROM AUTHOR]

This research study focused on the effect of adding boric acid to epoxy resin in order to obtain a composite material with improved properties and performance. To this end, a fine powder of boric acid (H3BO3) was introduced into epoxy resin in different amounts, i.e., 0.5 g, 1.0 g, and 1.5 g. As the matrix of the epoxy composites, styrene-modified epoxy resin based on bisphenol A (BPA) (Epidian 53) was used. It was cross-linked with two types of curing agents, i.e., an amine (ET) and a polyamide (PAC). The mechanical properties of the obtained epoxy composites (in terms of compressive strength, compressive modulus, and compressive strain) were determined at room temperature in order to assess the effect of the addition of boron acid and of the type of curing agent employed to cure the epoxy on these characteristics. Calorimetric measurements were made to highlight any changes in the glass transition temperature (Tg) as a result of the addition of boric acid to epoxy resin. Finally, flammability tests were performed on both Epidian 53/PAC and Epidian 53/ET epoxy composites to analyze their fire behavior and consequently establish the effectiveness of the selected additive as a flame retardant. [ABSTRACT FROM AUTHOR]

The long-term operation of motors induces substantial alterations in the surface conductivity and nonlinear coefficient of anti-corona paint, diminishing its efficacy and jeopardizing the longevity of large motors. Hence, the development of high-performance anti-corona paint holds paramount importance in ensuring motor safety. In this study, we integrate two nano-fillers, namely silicon carbide (SiC) and organic montmorillonite (O-MMT), into a composite matrix comprising micron silicon carbide and epoxy resin (SiC/EP). Subsequently, three distinct types of anti-corona paint are formulated: SiC/EP, Nano-SiC/EP, and O-MMT/SiC/EP. Remarkably, O-MMT/SiC/EP exhibits a glass transition temperature about 25 °C higher than that of SiC/EP, underscoring its superior thermal properties. Moreover, the introduction of nano-fillers markedly augments the surface conductivity of the anti-corona paint. Aging tests, conducted across varying temperatures, unveil a notable reduction in the fluctuation range of surface conductivity post-aging. Initially, the nonlinear coefficients exhibit a declining trend, succeeded by an ascending trajectory. The O-MMT/SiC/EP composite displays a maximum nonlinearity coefficient of 1.465 and a minimum of 1.382. Furthermore, the incorporation of nanofillers amplifies the dielectric thermal stability of epoxy resin composites, with O-MMT/SiC/EP showcasing the pinnacle of thermal endurance. Overall, our findings elucidate the efficacy of nano-fillers in enhancing the performance and longevity of anti-corona paint, particularly highlighting the exceptional attributes of the O-MMT/SiC/EP composite in bolstering motor safety through improved thermal stability and electrical properties. [ABSTRACT FROM AUTHOR]