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To enhance mechanical, adhesive, and thermal properties of Room Temperature Vulcanized (RTV) silicone rubber, a silicon-containing polyurethane/epoxy resin modifier (ESiPU) was developed. A three-phase system of polyurethane/epoxy resin/silicone rubber was prepared through blending, modification, and co-curing. FT-IR and 1H-NMR were employed to characterize the chemical structure of ESiPU. Microscopic analysis revealed improved compatibility between modified epoxy resin and silicone rubber. Mechanical testing showed significant enhancements in tensile strength, elongation at break, and adhesive strength, with RTV-20phr exhibiting increases of 236, 266, and 259%, respectively. Thermogravimetric analysis indicated higher initial decomposition temperature compared to pure RTV. At the same time, the char residue at 800 °C increased to 8.67%. TG-IR analysis demonstrated ESiPU's ability to delay thermal degradation. Contact angle test confirmed improved hydrophobicity. Overall, the developed silicone rubber system exhibits promising mechanical and thermal properties, suggesting potential for aerospace heat protection applications. [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]

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]

In addition to being bio-degradable, cellulose nanocrystals (CNC) provide high mechanical strength to polymer composites. They exhibit outstanding properties like high strength-to-weight ratio, abundant surface functional groups and sustainability. In this study, we prepared nanocomposites of poly (ethylene-co-methyl acrylate) (EMA) and CNC using the melt-mixing technique. The mechanical properties of EMA were improved after adding CNC to it. The ultimate tensile stress and maximum elongation increased from 6 MPa and 860% (for pristine EMA) to 9.5 MPa and 1090% (for 2 wt.% EMA/CNC composite). Thermal properties of the EMA/CNC composites were analyzed by using DSC and TGA analysis. The dispersion of CNC in the composite was analyzed by SEM and XRD analyses. The EMA/CNC composites showed interesting birefringence properties on analysis via polarized optical microscopy (POM). The POM analysis indicated that the CNC in composites aligns themselves in the direction of applied stress, enhancing the mechanical strength of nanocomposites. Biodegradation of the bio-composite was also studied via soil-burial test. [ABSTRACT FROM AUTHOR]

The polyimides were prepared by pyromellitic dianhydride (PMDA) or 4,4'-(4,4'-Isopropylidenediphenoxy)diphthalic anhydride (BPADA) as dianhydride monomer and 1,4-bis(4-aminophenoxy)benzene(TPE-Q) or 1,3-bis(4-aminophenoxy)benzene(TPE-R) as diamine monomer. The polyimides were well characterized by FT-IR, thermogravimetric analysis, dynamic thermomechanical analysis, dielectric measurement and tensile test. The flexibility of polyimide molecular chain was judged by the comparison of molecular volumes, molecular length and conformation transition energy through molecular simulations. [ABSTRACT FROM AUTHOR]

A series of polyurethane acrylate UV curing films (FPUA) were designed and prepared from three different hard segment structure, hard segment content and NCO/OH molar ratio via prepolymer process from polytetramethylene ether glycol(PTMEG), diisocyanate and polycaprolactone modified acrylate (FM1D). And the influence of structural parameters on the cured films' mechanical properties was studied; Besides, its thermal properties was characterized by Dynamic Thermomechanical Analysis (DMA) and Thermo Gravimetric Analyzer (TGA). Among these three hard segment structures, hexamethylene diisocyanate (HMDI) -based cured films have the best mechanical properties. The modulus and tensile strength of the cured films increases along with the increase of hard segment content, whereas the elongation at break of the cured films decreases since the rising of the NCO/OH molar ratio. Indeed, with hard segment content at 48.6% and NCO/OH molar ratio at 1.06, the UV cured films (exhibits the best performance)with tensile strength up to 50.5 MPa, and break elongation upto238%. DMA and TGA data showed that the low-temperature glass transition temperature of UV-cured films is around −50 °C, and the fastest thermal degradation temperature is 355 °C, showing good resistance to high and low temperatures. [ABSTRACT FROM AUTHOR]

Schiff bases and their conjugated oligo(azomethine)s have been synthesized via condensation and oxidative polycondensation of o-anisidine (OA) with 2-hydroxy-1-naphthaldehyde (2-HNA) and p-anisidine (PA) with 4-hydroxy benzaldehyde (4-HBA), respectively. The oxidative polycondensation reaction conditions of 1-[(2-methoxyphenylimino)methyl]naphthalen-2-ol (1,2-MPIMN) and 4-[(4-methoxyphenylimino)methyl]phenol (4,4-MPIMP) were studied by oxidants such as air and aqueous solutions of H2O2 and NaOCl in different concentrations in an aqueous alkaline medium between 50 °C and 90 °C at different reaction times. The structures of polymers were confirmed by FT-IR, UV-Vis and 1H-13C-NMR measurements. The molecular weights and surface morphologies of oligomers were determined by size exclusion chromatography (SEC) and scanning electron microscopy (SEM), respectively. Electrochemical and thermal features of compounds were studied using UV-Vis spectroscopies, cycling voltammetry (CV), and TG-DTA. The mass losses values ​​of the 1,2-MPIMN, oligo(1,2-MPIMN), 4,4-MPIMP, and oligo(4,4-MPIMP) were calculated from the thermogravimetric curves as 98.00%, 53.52%, 69.00%, and 58.70%, respectively, at 1000 °C. The HOMO, LUMO levels, electrochemical (E'g), and optical band gap energies (Eg) values of the compounds were calculated from CV and UV-Vis data. The E'g values of 1,2-MPIMN, oligo(1,2-MPIMN), 4,4-MPIMP, and oligo(4,4-MPIMP) were found to be 2.64, 1.54, 2.31, and 2.16 eV, respectively. The electrical properties of monomers and oligomers were determined at room temperature. [ABSTRACT FROM AUTHOR]

Epoxy-functionalized cyclotriphosphazene compounds were designed and synthesized from nucleophilic substitution reactions of hexachlorocyclotriphosphazene. The synthesized compounds were purified and their structures were characterized using spectroscopic techniques. The prepared compounds were then used as part of a commercial powder epoxy resin formulation with varying feed ratios. Thermal analysis results showed that the addition of the epoxy-functionalized phosphazenes improved the thermal stability and thus flame retardancy of the final coatings. The epoxy-functionalized phosphazene derivatives developed in this study can become a potential candidate for fire- and heat-resistant powder coating applications with more safety and performance. [ABSTRACT FROM AUTHOR]

This work focused on optical, thermal stability and temperature-dependent electrical properties of chlorinated natural rubber (Cl-NR)/zinc ferrite (ZnFe2O4) nanocomposites. The insertion of ZnFe2O4 into Cl-NR showed a decrease in bandgap energy was revealed by UV spectroscopy. The thermal stability of rubber nanocomposites increased with an increase in the content of nanoparticles. The AC conductivity, dielectric constant and dielectric loss tangent of the nanocomposites were higher than the parent polymer and these properties increased with an increase in temperature and frequencies. The non-ohmic type of AC conductivity proves the dynamic relaxation process of typical semiconducting materials. The activation energy calculated from AC conductivity decreases with the temperature. The semi-circular arc obtained from Cole-Cole plot proved the temperature enhanced conductivity of the nanocomposites. The DC conductivity increased with the increase in content of nanoparticles and the changes in conductivity were correlated with different theoretical approaches such as Scarisbrick, Bueche and McCullough model. The experimental conductivity of nanocomposites was in good agreement with the McCullough model indicating the interfacial interaction developed in rubber nanocomposites. The enhanced optical properties, dielectric constant, thermal stability and electrical conductivity of Cl-NR/ZnFe2O4 systems enable the fabrication of highly-durable flexible electronic devices, actuators, super-capacitors and elastomeric pressure sensors. [ABSTRACT FROM AUTHOR]

Cardanol, a byproduct of the cashew processing industry, has been widely studied feeedstock for sustainable monomers and polymers. In this article, the Atom Transfer Radical Polymerization (ATRP) of three radically polymerizable monomers, namely, cardanyl acrylate (CA), hydrogenated cardanyl acrylate (PA) and hydrogenated cardanyl methacrylate (PMA), was studied. The monomers as well as the polymers were structurally characterized and studied by differential scanning calorimetry (DSC) to understad their thermal behavior. The PA monomer showed melting (Tm) at 35 °C and crsytallization (Tc) at −3.27 °C. The synthesized polymer shows Tm of 16.5 °C and the Tc increased to 7.2 °C. In PMA monomer, the Tm was observed at 15.21 °C and Tc at −11 °C and the correponding values for the polymer decreasing to 1 °C and −18 °C, respectively. The coressponding transitions of CA monomer and its polymer were broad and less defined. The homopoymerization of CA and PMA yielded good conversions but the PA polymer yield was low under identical conditions, probably due to the higher monomer crystallinity of PA. The effect of different ATRP ligands, viz, pentamethyldiethylenetriamine (PMDETA) and bipyridine (dNbpy), on the conversion, molecular weight and polydispersity was also investigated. [ABSTRACT FROM AUTHOR]

Spacecrafts circling in low earth orbit suffer from highly reactive atomic oxygen (AO). To shield AO from erosion, a series of polyimide (PI) copolymer containing α,ω'-Aminopropyl poly(dimethyl siloxane)PDMS(Mn = 860 g mol−1), Octa(aminophenyl) silsesquioxanes (OAPS) were successful prepared by a two-step copolymerization. By controlling the amount of dianhydride, the different chain length block dianhydride capped poly (amic acid siloxane) (PAAS) was obtained. Then, the PAAS was reacted with OAPS which contains polyhedral oligomeric silsesquioxane (POSS) and surrounds eight amine groups to give the copolymers film with heat imidization. The effects of the different chain length block of the copolymers on the morphology and structure were investigated using field emission scanning electron microscopy (SEM) and FTIR, respectively. DSC, DMA, TGA and TMA were using to determine the thermal properties of the copolymer films. A poly(imide siloxane) copolymer with POSS nanocomposites show the best atomic oxygen (AO) resistance with the lowest erosion yield of 0.37 × 10−24 cm3 atoms−1. The results indicate that the copolymer films are capable of providing protection against atomic oxygen (AO) attack and may find wide usage in aerospace. [ABSTRACT FROM AUTHOR]

Two types of structurally different benzoxazines (BF-abn and BZ-abn) have been developed using bisphenol-F and bisphenol-Z with 4-aminobenzonitrile and paraformaldehyde through Mannich condensation reaction under an appropriate experimental conditions. Molecular structure of benzoxazine was confirmed by FTIR and 1H-NMR spectral analyses. Cure behavior and thermal stability were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively. The results from DSC analysis indicated that these benzoxazines exhibit marginally lower polymerization temperature than that of conventional benzoxazines. Further, the curing behavior of both benzoxazine samples were studied at two different heating rates viz. 10 °C/min and 20 °C/min to ascertain their heat releasing properties. The formation of polybenzoxazine was confirmed by FTIR analysis after the thermal curing through the cleavage of benzoxazine ring and subsequently led to the formation of three dimensional cross-linked network structure. Results from TGA infers that among the benzoxazines studied, poly(BF-abn) possess better thermal stability than that of poly(BZ-abn). Further, the values of LOI calculated using char yield obtained at 850 °C from TGA for poly(BF-abn) and poly(BZ-abn) are 41% and 30% respectively. The values of water contact angle obtained for poly(BF-abn) and poly(BZ-abn) are 138° and 140° respectively. Both benzoxazine samples exhibit an excellent hydrophobic behavior. [ABSTRACT FROM AUTHOR]

In this work, a highly flexible bio-silica reinforced poly (benzoxazine-co-epoxy) hybrid composites have been developed using renewable cardanol based benzoxazine (C-aee), commercially available bisphenol-F epoxy (EP) and functionalized bio-silica (BS). Sustainable C-aee was synthesized with cardanol (C), aminoethoxyethanol (aee), and paraformaldehyde through Mannich condensation reaction. The structure of C-aee monomer was characterized with FT-IR and 1HNMR techniques. Bio-silica (BS) was synthesized from rice husk and functionalized with 3-mercaptopropyl trimethoxysilane (3-MPTMS). Later, the hybrid PC-aee-co-EP/BS composites was prepared with various weight percentages (0, 1, 3, and 5%) of BS reinforced into PC-aee-co-EP. The curing performance of C-aee, C-aee + EP and thermal properties of PC-aee-co-EP/BS composites was characterized using DSC and TGA. Data acquired from thermal studies confirmed that the bio-silica reinforced hybrid composite show improved thermal properties and flame-resistance properties with good flexibility. Hence, the developed PC-aee-co-EP/BS composites are potential material for various applications including marine coating, aerospace, and microelectronics. [ABSTRACT FROM AUTHOR]

Starch was extracted from potato (Solanum tuberosum) cultivated in Nepal. The yield of starch of different sorts of the species S. tuberosum was compared with each other. Extracted starch (E St.) Kufre Sindure was characterized and compared with commercial starch (Com St.) by the Fourier transform infrared spectroscopy (FTIR). The properties of extracted starch were evaluated by measuring ash content, moisture content and amylose content. A series of butylene adipate-co-terephthalate (PBAT)/TPS blend of varying concentration (5%, 10%, 20% and 30%) were prepared using citric acid (compatibilizer) and glycerol as plasticizer, respectively, via solution casting method. The physical and chemical properties of resulting blends were characterized by FTIR and X-ray photoelectron spectroscopy (XPS). The FTIR results proved the esterification reaction between PBAT, thermoplastic starch (TPS) and citric acid in blends. Morphology of the PBAT/TPS film was studied through scanning electron microscopy (SEM) and XPS analysis. Microindentation measurements revealed improvement in mechanical properties of PBAT with the loading of starch. Thermogravimetric analysis (TGA) showed decrease in the thermal stability of PBAT/TPS blend. Degradation behavior of blend showed that rate of degradation was increased with increase of starch content. [ABSTRACT FROM AUTHOR]

In this work, an amino-terminated polyether (ATP) was synthesized and used for the functionalization of GO to obtain an amino-terminal polyether-functionalized graphene oxide (FGO). The structure of FGO was characterized by FTIR, Raman, XPS, XRD, AFM, SEM and TGA. And then the FGO was incorporated into waterborne epoxy resin (WEP) to prepare FGO/WEP composites. The SEM results revealed that such amino-terminal polyether functionalization can significantly improve the interfacial interaction between GO and the WEP matrix. The tensile test showed that the Young's modulus and tensile strength of FGO/WEP composites were much higher than that of WEP and GO/WEP composites. In particular, the 0.1 wt% FGO/WEP nanocomposite exhibited increases of 56% and 83% in tensile strength and Young's modulus as compared to WEP. In addition, the initial thermal decomposition temperature (Td) of the 0.1 wt% FGO/WEP composite was increased by 42 °C compared with pure WEP. Furthermore, the FGO/WEP composites showed lower water absorption and higher water contact angles, indicated that the addition of FGO can significantly improve the hydrophobicity of WEP. [ABSTRACT FROM AUTHOR]

In this article, we reported a new strategy to synthesize of isosorbide-based copolycarbonates with good flexibility and tunable thermal property via one-pot direct melt polycondensation of isosorbide (ISB), dimethyl carbonate (DMC) and 1,4-benzenedimethanol (BDM). The effect of different feed ratio on the chemical structure, molecular weight, thermal and mechanical property of copolycarbonates was in-depth studied. A series of metal ion-containing compounds as catalysts were used, and the copolycarbonates was synthesized with weight average molecular weight (Mw) of 80,300 and dispersity index below 1.78 by sodium tert-butoxide catalyst, and the reaction time was shorted to only 3.5 h with the ISB conversion up to 99.0%. Meanwhile, the Tg values realized controllable and tunable from 69 to 164 °C by varying the ratio of two diol monomers, and the influence of the structure of carbonyl carbon in repeating units of copolycarbonates on the thermal properties were demonstrated. Moreover, the results of dynamic mechanical analysis (DMA) implied that the flexibility of copolycarbonates was increased with increasing BDM content, and the results of scratch resistance and melting index of the copolycarbonates provided enormous prospect for the industrial application. Synopsis: A green synthetic pathway for high molecular weight and flexible isosorbide-based copolycarbonate was developed via one-pot melt polycondensation of isosorbide, dimethyl carbonate and 1,4-benzenedimethanol. [ABSTRACT FROM AUTHOR]

The first example of the usefulness of titanium (IV) butoxide, as initiators for open air in-situ intercalative polymerization of ε-caprolactone (ε-CL) in the presence of organoclay is herein reported. The bionanocomposites based on poly(ε-caprolactone) (PCL) were prepared by in-situ Ring Opening Polymerization (ROP) of ε-caprolactone in the presence of different organomodified montmorillonite clay (ODA-MMT) loading (1, 3 and wt%). Structural, thermal and mechanical characterizations of the resulting bionanocomposites were investigated. The presence of the nanoclay increased PCL crystallinity, melting temperature and thermal stability, whereas some decrease in Tg was observed. TEM analyses confirmed the good dispersion of ODA-MMT with 1 and 3 wt% content into the PCL polymer as already asserted by XRD diffraction. Finally, the Young's modulus of the PCL nanocomposites was higher compared to the neat PCL, while a decrease of stress and strain at break for materials with different filler content was observed. [ABSTRACT FROM AUTHOR]

We have explored the sulfonic-functionalized graphene oxides (S-GOs) as an efficient conductive reinforcement to enhance the dielectric permittivity and electromagnetic interference (EMI) shielding effectiveness of the polyethersulfone (PES). The S-GOs having numerous terminal -SO3− groups not only promote the homogeneous dispersion for achieving the low percolation threshold, but also induce strong H-bonding and dipole–dipole interactions at the interfaces. As-prepared S-GO nanosheets showed uniform dispersion in PES matrix with strong adhesion with the polymer matrix via non-bonding interactions. The remarkable enhancement of dielectric permittivity of PES upon inclusion of S-GOs could be attributed to the interfacial polarization effect and microcapacitor model. As-prepared nanocomposites exhibited low conductive percolation threshold. The well-wrapped graphene nanosheets by thin PES layer prevented direct contact of graphene nanosheets and consequently decreased the dielectric loss by suppressing the current leakage. The PES/S-GO nanocomposites exhibited significant improvement in thermal stability with high char yield in N2 atmosphere compared to pure PES. A high EMI shielding effectiveness of 23.5 dB was achieved for the nanocomposite film with 5 wt% graphene loading, which might be originated from the development of conductive network at higher graphene loading. Overall, the as-prepared PES/S-GO hybrid nanocomposite could be used in DC and radiofrequency electronics. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of pendant methyl fluorinated polyimides (5a–f) derived from fluorinated diamine monomer, 2′-methyl-1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (2) and several aromatic dianhydrides (3a–f) is described. The synthesis of new fluorinated diamine (2) and the precursor fluorinated dinitro compound (1) are also discussed. The presence of trifluoromethyl group in the backbone of the fluorinated polyimide exhibited better optical transparency, organic solubility, dielectric constant, moisture adsorption and maintained mechanical and thermal properties than trifluoromethyl-free analogs (5′a–f). The highly fluorinated polyimides 5f via chemical imidization exhibited the best organic solubility, highest optical properties (b* cutoff wavelength = 367 nm). In addition, the highly fluorinated polyimide via thermal imidization also displayed relative lower dielectric constants (3.06 at 1 MHz) and moisture adsorption (0.16%) than most fluorinated polyimides. The t-butyl and phenyl substituted fluorinate diamine analogs and their fluorinated polyimides were also compared and discussed on thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

Epoxy resin containing active hydroxymethyl group, 5-hydroxymethyl resorcinol diglycidyl ether, was synthesized to produce 5-hydroxymethyl resorcinol diglycidyl ether-terminated polyurethane (ETPU1000). The synthesized epoxy resin is a small monomer molecule, and no polymer is produced during the synthesis process. A monomer contains one hydroxyl group, and more flexible polyurethane segments can be introduced into the main chain when synthesizing the epoxy-terminated polyurethane. The synthesis process of ETPU1000 was investigated by FT-IR spectroscopy. The disappearance of NCO peak in the FT-IR spectrum showed that diisocyanate has completely reacted to form ETPU1000. Then, a series of epoxy cured systems were prepared by changing the mass ratio of ETPU1000 and the diglycidyl ether of bisphenol A (DGEBA), and cured with 4,4'-diaminodiphenyl methane (DDM). The effect of the content of ETPU1000 on the thermal properties, mechanical properties and fracture morphology of epoxy cured systems were investigated. The results showed that when the DGEBA/ETPU1000 blends with 75 wt% ETPU1000, impact strength of the cured systems reached 29.6 kJ·m−2, which significantly increased by 176.6% compared to that of neat epoxy. Scanning electron microscopy (SEM) was used to observe the fracture surfaces of cured DGEBA/ETPU1000 blends, which showed obvious ductile fracture characteristics. [ABSTRACT FROM AUTHOR]

The graphene-based additives containing polyethyleneimine (PEI) or hydroxyapatite (HAP) were synthesized and their effects on the flame retardancy, thermal, mechanical properties of polyvinyl alcohol (PVA) matrix were evaluated. Thermogravimetric analysis studies (TGA) and Scanning electron microscope (SEM) images were indicated that PEI and HAP have a strong influence on the fire behavior of the composites which might be explained by the forming of a uniform and compact char during combustion. The presence of nitrogen in PEI and phosphorus in HAP which are generated nonflammable gases and phosphoric radicals, respectively at combustion conditions could represent a significant role in the catalytic char residue formation, heat transfer limitation and then diminish or even stop the combustion reactions. The char yields of the 5 wt% PVA/GO-PEI nanocomposites were increased up to 22 folds without any significant change in mechanical properties; Moreover, the char yield of PVA/GO-HAP nanocomposites was more than pure PVA (24 folds) because of its thermal stability at high temperature. All these data demonstrated that not only did PVA/GO-PEI keep the mechanical properties nearly the same as in pure PVA but also improved flame retardancy. But, the PVA/GO-HAP has great potential as flame retardants between all obtained composites. [ABSTRACT FROM AUTHOR]

To examine the reinforcing effects of isocyanated graphene oxide (NCO-GO) on a waterborne polyurethane matrix, the surface of GO was respectively modified by isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) and toluene diisocyanates (TDI) and then confirmed by FT-IR, Raman, TGA, XRD, TEM, AFM and SEM-EDS. The dispersity behavior between different NCO-GO and polymer was evaluated by FESEM and XRD. The nanocomposites' chemical structure, emulsion morphology, hydrophobicity, thermal and mechanical properties were investigated by FT-IR, TEM, TGA, tensile testing machine and water contact angle test, respectively. It was shown that these properties of nanocomposites including tensile strength, initial thermal degradation and hydrophobicity were increased by the incorporation of NCO-GO, in which, particularly, the tensile stress and initial degradation temperature were respectively increased from 13.32 to 18.80 Mpa and 249 to 288 °C after the addition of TDI-GO. These superior reinforcing effects were attributed to the two-dimensional structure of NCO-GO as well as the good interfacial adhesion between the NCO-GO and WPU matrix. [ABSTRACT FROM AUTHOR]

A series of thermoplastic poly(butylene-co-hydroquinone bis(2-hydroxyethyl)ether terephthalates) (PBHT), with different molar ratios of hydroquinone bis(2-hydroxyethyl)ether (HQEE)/1,4-butanediol 9/91, 18/82 and 27/73, were synthesized via melt polycondensation. The compositions, thermodynamics and crystallization properties of the obtained copolyesters were characterized in detail by 1H NMR, differential scanning calorimeters (DSC), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). These results showed that the PBHTs were successfully synthesized, and the incorporation of the HQEE group significantly improved thermal properties of the polymers. However, HQEE did not change the crystal structure of PBT. The Tm values of the copolymers decreased (from 208 °C to 174 °C) with increasing content of HQEE segments, on the contrary, Tg values increased (from 37 °C to 43 °C). The temperatures for 5% weight loss did not decrease and appeared at a range of 373–377 °C. [ABSTRACT FROM AUTHOR]

We report the preparation and enhanced thermal and mechanical properties of poly (vinylidine diflouride) (PVDF) nanocomposites reinforced by few-layer graphene flakes which are produced by the direct liquid-phase exfoliation of pristine graphite. Graphene flakes are found to homogeneously disperse in PVDF, reduce the bubble defects and thus the porosity of PVDF, and change PVDF's crystallinity. Thermogravimetric analysis indicates that graphene can accelerate the fracture of hydrogen bond connecting PVDF and N-Methyl pyrrolidone molecules. 1.5 wt% graphene loading leads to around 20 °C enhancement in the melting temperature of PVDF. The mechanical properties like Young's modulus (EIT), yield stress (σy), and hardness (H) of the nanocomposites are investigated by nanoindentation technique. A 1.0 wt% loading of graphene is found to increase EIT, σy, and H of PVDF by ∼337%, ∼102%, and ∼228%, respectively. Few-layer graphene was produced by liquid-phase exfoliation. Graphene were added to PVDF to enhance thermal and mechanical properties of polymer. Mechanical properties of PVDF/graphene composite films were investigated by nanoindentation. [ABSTRACT FROM AUTHOR]

Benzoxazine monomers namely 1,1-bis (3-methyl-4-hydroxyphenyl)cyclohexane benzoxazine (CBDDM) and bis(4-maleimidophenyl) triphenylphosphine oxide benzoxazine (BMPBBAPPPO) were synthesized and blended with bismaleimide (BMPM) to improve thermal properties of polybenzoxazine. The benzoxazine- bismaleimide (Bz-BMI) hybrid polymer matrices were prepared via in-situ polymerization and their thermal and morphological properties were studied. The chemical reaction of benzoxazines with the bismaleimide was carried out thermally and the resulting product was analyzed by FT-IR spectra. The glass transition temperature, curing behavior, thermal stability, char yield and flame resistance of the hybrid polymer matrices were analyzed using DSC and TGA. The homogeneous structure of the hybrid polymer matrices was determined by SEM and visual observations. Data obtained from thermal studies infer that these hybrid materials possess high thermal stability which can be used as adhesives, sealants, coating and matrices for high performance automobile and microelectronic applications. [ABSTRACT FROM AUTHOR]

The phenolic epoxy resin (F51) was siliconized by KH550 and the product was named as FKS. A hydroxyl-terminated polydimethylsiloxane (HTPDMS) which was modified with FKS was prepared. The siliconization reaction ensured a segment of siloxane on the side chain of F51. FT-IR and 1H-NMR were employed to confirm the chemical structure of FKS. Morphology observations revealed that the enhancement of mechanical properties of the silicone rubber systems can be attributed to good compatibility between FKS and silicone rubber matrix. Thermogravimetric analysis showed that the residual yield at 800 °C of silicone rubber composites increased significantly when compared with that of neat HTPDMS. The mechanical properties demonstrated that tensile strength and elongation at break of silicone rubber system increased distinctly after modification, especially when 30 phr siliconized F51 were added to the silicone rubber. Shear strength was improved gradually with the addition of FKS. These above observations emphasize the vital effect of FKS on the behavior of modified HTPDMS. [ABSTRACT FROM AUTHOR]

Two liquid crystalline epoxies containing biphenyl ether and aromatic ester mesogenic units, oxybis(4,1-phenylene)bis(4-(oxiran-2-ylmethoxy)benzoate)(LCE1) and oxybis(4,1-phenylene) bis(4-(4-(oxiran-2-yl)butoxy)benzoate)(LCE2), were synthesized and characterized. Subsequently, the epoxy monomers were cured with diaminodiphenylsulfone (DDS). From DSC, XRD and POM results, monomers did not show liquid crystalline phase while the cured samples exhibited nematic phase. The cured samples showed good mechanical properties with strength of 99.1MPa and excellent thermal stabilities with high glass transition temperature up to 168.0 °C, 5% weight loss temperature at 343 °C and high char yield of 24.5% at 800 °C. The relationship between thermal conductivity and network structure was discussed in this work. Due to the introduction of mesogenic units into epoxy networks, the cured resins showed high thermal conductivity as high as 0.292 W/(m*K), more than 1.5times higher than conventional epoxy resins. By introducing alumina (Al2O3) into LCE1/DDS cured system, composites of LCE1/DDS/Al2O3 with the highest thermal conductivity of 1.61 W/(m*K) was obtained with the content of 80 wt% while that of diglycidyl ether of bisphenol A (DGEBA, E51) epoxy resin/DDS/Al2O3 was 1.10 W/(m*K). The as-prepared epoxy resins showed high glass transition temperature and excellent thermal stabilities, indicating the potential of application in microelectronics. [ABSTRACT FROM AUTHOR]

The effect of incorporating sorbic acid (SA), an echo-friendly curing agent, and silica or carbon black (CB) filler, as well as gamma irradiation on the physico-chemical, mechanical and thermal properties of ethylene propylene diene monomer rubber (EPDM) was investigated. The results indicated that the developed composites revealed improvement in the studied parameters over the untreated samples. Filler incorporation into rubber matrix has been proven a key factor in enhancing the swelling resistance, tensile strength and thermal properties of the fabricated composites. The improvement in tensile strength and modulus was attributed to better interfacial bonding via SA. Alternatively, a comparison was established between the performance of the white and black fillers. The utmost mechanical performance was reported for the incorporated ratios 10 phr SA and 40 phr white filler into a 50 kGy irradiated composite. Meanwhile, the incorporation of CB yielded better thermally stable composites than those filled with silica at similar conditions. [ABSTRACT FROM AUTHOR]

Three bisphenols containing cardo perhydrocumyl cyclohexylidene group, namely; 1,1-bis(4-hydroxyphenyl)-4-perhydrocumylcyclohexane, 1,1-bis(4-hydroxy-3-methylphenyl)-4-perhydrocumylcyclohexane and 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-4-perhydrocumylcyclohexane were synthesized starting from p-cumyl phenol. Each of these bisphenols was polycondensed with both terephthaloyl chloride and isophthaloyl chloride by phase transfer-catalyzed interfacial polymerization to obtain a series of new aromatic polyesters. Inherent viscosities and number average molecular weights of polyesters were in the range 0.51-0.64 dL/g and 17390-41430 g/mol, respectively which indicated the formation of reasonably high molecular weight polymers. The detailed NMR studies revealed that axial and equatorial identity of the phenyl rings of bisphenols was retained in polyesters resulting in constitutional isomerism. Polyesters containing perhydrocumyl cyclohexylidene groups showed excellent solubility in organic solvents viz, chloroform, dichloromethane, 1,1,2,2-tetrachloroethane and tetrahydrofuran. The self-standing films of polyesters could be cast from their chloroform solution. The 10% weight loss temperatures and glass transition temperatures of polyesters were in the range 453–485 °C and 201–267 °C, respectively demonstrating their excellent thermal characteristics. The gas permeability study of polyesters was carried out for He, H2 and N2 by variable-volume method. An improvement in permeability and decrease in selectivity was observed due to symmetric methyl substituents while reverse trend was observed in case of polyesters with asymmetric methyl substituents. [ABSTRACT FROM AUTHOR]

Three new classes of the amino acid based biodegradable (AABB) polymers were synthesized via step growth polymerization of bis-azlactones and amino acid based diamine-diesters with activated fatty diester and alkylenediamine: a) poly(ester amide)s (PEAs) were obtained by polymerization of bis-azlactones with diamine-diesters, b) hydrophobically modified co-poly(ester amide)s (co-PEAs) were synthesized by copolymerization of activated fatty diacid diester and bis-azlactones with diamine-diesters, and c) poly(ester amide-co-amide)s (PEA-co-PAs) were obtained by copolymerization of alkylene diamine and diamine-diesters with bis-azlactones. The new poly(ester amide)s showed relatively low-molecular-weights (Mw within 2,800-19,600 Da, GPC in DMF), whereas the new co-poly(ester amide)s and poly(ester amide-co-amide)s exhibited high-molecular-weights (Mw within 40-100 kDa) leading to good mechanical properties. Incorporation of the bis-azlactone fragments into the poly(ester amide)s backbone increased hydrophobicity and thermal stability, whereas incorporation of diamine-diester units into the backbone of the bis-azlactone based polyamides rendered them biodegradable. Synthesized AABB polymers are potential candidates for constructing resorbable surgical and pharmaceutical devices. [ABSTRACT FROM AUTHOR]

Dendrimer (G-0.5 and G0 PAMAM) and derivative of G-0.5 PAMAM (Hydroxy substituted PAMAM, hereafter called PAMOL) were synthesized using different catalyst such as KF/Al2O3, 15-Crown-ether, Aliqate-336, 15-Crown-ether & Aliqate-336, K2CO3, and Lipase. Products were characterized by IR, NMR and GCMS analysis. The yield of the product was calculated for each reaction and it was found that lipase from Candida antarctica acts as the best catalyst for the reactions with maximum yield 95% and 78% for PAMAM and PAMOL respectively. The structure of PAMAM and PAMOL were optimized by Density Functional Theory at B3LYP/6-311++ G (d,p) and CAM-B3LYP/6-311++G(d,p) level of theory using Gaussian 09 to check the consistency of the results. The thermodynamic properties of the compounds such as thermal energy, enthalpy and Gibbs free energy were determined and reported. The global reactivity descriptors such as chemical potential (μ), hardness (η) and electrophilicity index (ω) were also calculated to characterize the reactive stability of the molecules. [ABSTRACT FROM AUTHOR]

Three wholly, semi aromatic and aliphatic-aromatic polyimides containing bis(phenoxy) naphthalene, bis[(phenoxy) phenyl] propane and bis(phenoxy-methyl) cyclohexane segments by the two-step procedure from 2, 7-bis(4-aminophenoxy) naphthalene (BAPON), 2, 2-bis[4-(4-aminophenoxy)phenyl]propane (BAPOP), 1, 4-bis (4-aminophenoxy methyl) cyclohexane (BAPMC) as a diamine and 4,4′-carbonyldiphthalic anhydride (CDPA) were prepared. The first step of this procedure including ring-opening polyaddition in a polar solvent to give poly(amic-acid)s, second step containing cyclodehydration reaction to form polyimides. Synthesized monomer and polyimides were characterized by FT-IR, 1H NMR spectroscopy and elemental analyses (CHN) that obtained results gave the most powerful evidence. The polyimide synthesized from BAPON was characterized as semi-crystalline, whereas the other polyimides showed amorphous patterns by the x-ray diffraction studies. The inherent viscosity was ranging between 0.87-1.01 dL/g. Tensile strength, initial moduli, and elongation at break of the polyimide films ranged from 88-117 MPa, 1.98-2.32 GPa, and 5-8%, respectively. Thermogravimetric analysis in nitrogen atmosphere shows that these polymers having good stability, so 10% weight will be lost in the range of 500-630°C. The point of polyimide with BAPMC segment, is “adding of good thermal stability and processability” lower moisture absorption and dielectric constant (0.75% and 2.90). [ABSTRACT FROM AUTHOR]

A series of new polyamides containing tetraphenyl thiophene having pendant phenyl moiety with heterocyclic quinoxaline unit were synthesized by using the solution polycondensation method of novel diamine monomer V with isopthaloyl chloride (IPC) and terpthaloyl chloride (TPC) in various mole proportions. These novel polymers were characterized by FT-IR, solubility, inherent viscosity, thermal analysis and X-ray diffraction studies. Inherent viscosities of these polymers were in the range 0.66 to 1.44 dL/g indicating moderate to high molecular weight built-up. These polymers exhibited solubility in various solvents such as DMAc, NMP, pyridine, m-cresol etc. X-ray diffraction pattern of polymers showed that introduction of pendant phenyl moiety would disturb the chain regularity and packing, leading to amorphous nature. Thermal analysis by TGA and DSC showed excellent thermal stability of polymers. The structure -property correlation among these polyamides were studied, in view of these polymer's potential applications as processable high temperature resistance materials. [ABSTRACT FROM AUTHOR]

Statistical copolymers of N-vinylpyrrolidone (NVP) with benzyl methacrylate (BzMA) were prepared by Reversible Addition-Fragmentation chain Transfer Polymerization (RAFT), employing three different xanthates as RAFT agents: [(O-ethylxanthyl)methyl]benzene, [1-(O-ethylxanthyl)ethyl]benzene and O-ethyl S-(phthalimidylmethyl) xanthate. The reactivity ratios were estimated using the Fineman-Ross, inverted Fineman-Ross, Kelen-Tüdos and extended Kelen-Tüdos linear graphical methods, as well as the computer program COPOINT. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length. All the methods are in agreement that the probability for the incorporation of BzMA units is much greater than for that of NVP units. The glass-transition temperature (Tg) values of the copolymers were measured by Differential Scanning Calorimetry and examined by means of several theoretical equations, allowing for the prediction of theseTg values. Subsequently, a systematic and detailed investigation of the thermal degradation of these copolymers compared with that of the respective homopolymers, was carried out by Thermogravimetric Analysis, within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies. As expected, the thermal stability of the copolymers is influenced by the structure of the substituents of the thiocarbonylthio end groups due to the RAFT agents. [ABSTRACT FROM PUBLISHER]

In this paper, two novel bismaleimide resins based on 9, 9-bis[4-(4-maleimidophenoxy) phenyl] fluorene (PFBMI), 9, 9-bis[4-(4-maleimidophenoxy)-3-methylphenyl]fluorene (MFBMI), and 2, 2’-diallyl bisphenol A (DABPA) were prepared. Their curing mechanism and curing kinetic were carefully investigated by Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The thermal mechanical properties of the composites based on these BMI resins and the glass cloth were obtained by Dynamic mechanical analysis (DMA), displaying that the novel resins whoseTgwere 296°C and 289°C had excellent thermal performance. In addition, Thermogravimetric analysis (TGA) results showed that both the cured PD and MD resins possessed good thermal stability, and theirT5%were all higher than 410°C. [ABSTRACT FROM PUBLISHER]

In order to obtain pristine polyimides with high barrier properties, pyromellitic dianhydride (PMDA) and 9H-fluorene-2,7-diamine (FDA) containing rigid planar fluorene moieties were used to prepare polyimide (FPI) via a conventional two-step polymerization process in this paper. The synthesized polyimide shows good barrier properties, with oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) low to 1.01 cm3m−2day−1and 2.35 g m−2day−1, respectively. The effect of rigid planar structure in main chain on the barrier properties of polyimide was studied by means of wide angle X-ray diffractograms (WAXD), molecular dynamics simulations and positron annihilation lifetime spectroscopy (PALS), which was rarely reported before. The results reveal that the good barrier properties of FPI are mainly due to the high crystallinity, high chain rigidity and low free volume, which are resulted from the rigid planar structure. Additionally, the polyimide exhibits excellent thermal and dimensional stability with 5 wt% loss temperature of 519°C, glass transition temperature of 370°C and coefficient of thermal expansion (CTE) of 5.72 ppm/K. The good gas barrier and thermostability endow the polyimide with promising potential in flexible electronics encapsulation applications. [ABSTRACT FROM AUTHOR]

This review article is based on the recent trends and development of biobased polyurethane (PU) adhesives from vegetable oil. A detail discussion has been reported about the PU adhesive starting from petroleum based to biobased source. Special attention has been given towards the utilization of castor oil based PU in adhesive technology, due to the wide range of castor oil among all vegetable oil. The appreciable adhesion, mechanical, thermal properties of vegetable oil based PU adhesives were compared with petroleum based PU adhesive, which were utilized to meet the specific application in adhesion industry. [ABSTRACT FROM AUTHOR]

In this study, a series of poly(ϵ-caprolactone) (PCL)/clay bionanocomposites were prepared viain situring opening polymerization (ROP) of ϵ-caprolactone catalyzed by titanium butoxide. The natural Moroccan clay beidellite (BDT), used as nanocharge, was organomodified with cetyltrimethylammonium bromide, CTA, to obtain the organically modified 3CTA-BDT (3 = CTA/BDT equivalent feed ratio). Characteristics of the final nanocomposites are investigated by FTIR, SEC, XRD, SEM, TGA, DSC, optical tensiometry, thermal conductivity and water vapor sorption analysis. The intercalated/exfoliated morphologies, revealed by XRD and SEM analyses, confirm uniform dispersion of the nanoclay within the PCL matrix. Thermal stability of all the nanocomposites is improved by the addition of 3CTA-BDT clay compared to pure PCL polymer. The DSC data show that the addition of 3CTA-BDT particles promotes an increase in the disorder of the crystalline phase, which reduces the crystallinity degree. The hydrophobicity of Polymer/clay compatibility was analyzed by studying surface polarity degree of samples by contact angle measurements. Thermal conductivity and water vapor sorption was also discussed. The permeability (P), the sorption coefficient (S) and the diffusion coefficient (D), showed a significant decrease with increasing 3CTA-BDT loading. [ABSTRACT FROM PUBLISHER]

New cyclopentylidene ring-containing diamino-diesters, 1,1-bis(3-aminobenzoyloxy phenyl) cyclopentane, was prepared through reaction of cyclopentanone with two moles of phenol to yield 1,1-bis (4-hydroxy phenyl) cyclopentane (BHPP) (I), the resulting diol (I) on reaction with 3-nitrobenzoyl chloride in N,N-dimethyl acetamide (DMAc) and triethyl amine yield 1,1-bis(3-nitrobenzoyloxy phenyl) cyclopentane (II) which on finally reduced by catalytic hydrogenation in presence of 10% Pd/C in DMAc and stirred at room temperature under a 4 kg/cm2hydrogen pressure yields 1,1-bis(3-aminobenzoyloxy phenyl) cyclopentane (III) (m-BABPP). The structure of novel m-diester-diamine was confirmed by FT-IR,1H-NMR and13C-NMR. A series of new m-poly (ester-amide)s and co-poly(ester-amide)s were synthesized by using the solution polycondensation method of novel diamine (III) with IPC and TPC in various mole proportion. These novel polymers were characterized by FTIR spectroscopy, solubility, inherent viscosity and thermal analysis and XRD studies. Inherent viscosities of these polymers were in the range 0.30 to 0.46 dL/g indicating moderate molecular weight built-up. These polymers exhibited excellent solubility in various polar aprotic solvents such as NMP, Pyridine. These polymers were partially soluble in DMSO, DMAc, DMF etc. X-Ray diffraction pattern of polymers showed that introduction of cardo moiety containing ester linkage would disturb the chain regularity and packing, leading to amorphous nature. Thermal analysis by TGA showed excellent thermal stability of polymers. The structure -property correlation among these poly(ester-amide)s were studied, in view of these polymer's potential applications as processable high temperature resistance materials. [ABSTRACT FROM AUTHOR]

A new aromatic based monomer 2-phenoxy-2-phenylethyl acrylate (PPEA) was synthesized. Copolymers of PPEA with 2-phenylethyl acrylate (PEA) were prepared by free radical polymerization. The reactivity ratios were estimated using various graphical methods. Structural parameters of the copolymers were obtained by calculating the dyad monomer sequence fractions and the mean sequence length. Optical properties of polymers such as refractive indices and UV-Visible absorption were investigated. The glass transition temperature and thermal degradation behavior of the copolymers were studied. Combined with the RI, transparency and thermal properties, prepared copolymers hold great promise as materials for intraocular lens applications. [ABSTRACT FROM PUBLISHER]

Two novel bismaleimide monomers based on fluorene cardo moiety and ester bonds, namely 9, 9-bis[4-(4-maleimidobenzoate) phenyl]fluorene (PEFBMI) and 9,9-bis[4-(4-maleimidobenzoate)-3-methylphenyl]fluorene (MEFBMI) were designed and synthesized. Their structures were confirmed by FTIR,1H-NMR,13C-NMR spectroscopy and Elemental analysis. Both monomers obtained have excellent solubility in some organic solvents with low boiling point, including acetone, chloroform and dichloromethane. The curing process of the monomers were investigated by DSC, displaying that the melting point of the monomers were 157.1°C and 193.6°C respectively, and all processing windows exceed 30°C. DMA results showed the glass transition temperature of the cured PEFBMI/glass cloth composite was higher than 390°C while that of the cured PEFBMI composite was 349.2°C. TGA results indicated that the cured BMI resins have good thermal stability and their 5% weight loss temperatures were both higher than 410°C. [ABSTRACT FROM PUBLISHER]

The effect of butyl acrylate (BA), divinyl benzene (DVB) and vinyltrimethoxysilane (TMVS) on the thermal properties of poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid) was investigated. Glass transition temperature (Tg), melting temperature (Tm) and specific heat capacity of the copolymers were investigated using Differential Scanning Calorimetry. Thermal stability of the copolymers which is associated with the degradation temperature (Td) was studied by Thermogravimetric Analysis. Polyacrylates withTgranges between -19°Cand 19°C were obtained. With the incorporation of >7 wt% of DVB, theTgof the copolymer increases from about −17°C to −10°C even though they have not undergone UV irradiation. Gel content results prove that crosslinking has occurred in the copolymers. With increasing amount of TMVS from 0 wt% to 7 wt%, theTmof the copolymers prepared at acidic pH is about 40-60°C higher than that at the alkaline pH. However, the addition of TMVS gives no significant effect to theTgandTdof the copolymer films. The thermal stability of the copolymer has improved with increasing amount of BA and DVB, with DVB being more effective. The highestTdof 425°C with 8% of DVB has been obtained. Consequently, a polyacrylate copolymer with aTgof about −13°C, aTmof 170 °C and aTdof about 424°C has been successfully synthesized. Hence, the soft polyacrylate with its relatively highTmandTdcould serve as a superb material especially to be applied in the areas that require high melting temperature and good thermal stability. [ABSTRACT FROM PUBLISHER]

The cellulose acetate-grafted-poly(glycidyl methacrylate) copolymers were synthesized successfully by free radical polymerization. The resulting copolymer was characterized by proton nuclear magnetic resonance (1H-NMR), solid-state13C-NMR, Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The crystallization behavior, thermal properties, specific particle surface area, moisture sorption behavior of the modified cellulose acetate were investigated by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) method and Dynamic Vapor Sorption (DVS) instrument. It was found that the poly(glycidyl methacrylate) (PGMA) grafting was effective in improving the water adsorption of cellulose acetate (CA) changing the specific surface area, and reducing theTgof copolymers. [ABSTRACT FROM PUBLISHER]

A series of polyesteramides (PEAs) differing in their amide/ester ratio, within a range of molar composition from 90/10 to 10/90, have been synthesized by a direct melt polycondensation of 1,4-butanediol, adipic acid and β-alanine. Their structure was fully characterized by FTIR and NMR spectroscopy. The resulting copolymers are amorphous, they are thermally stable to temperatures up to 330°C, and present increasing glass transition temperatures at increasing amide content. [ABSTRACT FROM AUTHOR]

In this study, the thermal behavior of polyacenaphthylene (PAcN) and partially modified polyacenaphthylene with Cl, Br, and H2PO3groups, both under air and nitrogen atmosphere, have been investigated. The influence of the molecular weight, the heating rate, and the introduced substituent have been studied. Thermogravimetric Analysis combined with Fourier Transform Infrared Spectroscopy was used to determine the thermal stabilities and the degradation mechanism. All polyacenaphthylene samples degrade through a depolymerisation process under a nitrogen atmosphere, whereas in air, elimination and thermo-oxidation reactions take place. [ABSTRACT FROM AUTHOR]

1,3,5,7,9,11,13-heptaphenyl-15-vinyl cage half siloxane (Phenyl-Vinyl-POSS) was synthesized via the corner capping reaction of incompletely condensed silsesquioxane, [(C6H5)7Si7O9(OH)3], with trichlorovinylsilane. The chemical structure of Phenyl-Vinyl-POSS was characterized by FT-IR,1H-NMR, mass spectrometry and elemental analysis. Phenyl-Vinyl-POSS/ATC silicone rubber organic-inorganic hybrid materials were prepared by hydrosilylation between Phenyl-Vinyl-POSS and addition-type curable (ATC) silicone rubber with karstedt platinum catalyst. These hybrid materials were characterized through SEM, IR, XRD, TGA, DSC and tensile test. The results indicate that Phenyl-Vinyl-POSS is successfully incorporated into silicone rubber matrix by chemical bonding. Both mechanical properties and thermal properties of Phenyl-Vinyl-POSS/ATC silicone rubber hybrid materials have been improved compared to neat silicone rubber. The hardness of Phenyl-Vinyl-POSS/ATC silicone rubber hybrid materials increases from 18A to 28A, tensile strength increases from 0.2 MPa to 0.64 MPa, and the elongation at break increases from 14.12% to 184.39% when Phenyl-Vinyl-POSS content is up to 10 wt%. Meanwhile, temperature with 5% decomposition of modified ATC silicone rubber increases from 344.1°C to 360.4°C. [ABSTRACT FROM AUTHOR]