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Thermal Degradation Temperature (thermal + degradation_temperature)
Selected AbstractsThermal and dynamic mechanical properties of organic,inorganic hybrid composites of itaconate-containing poly(butylene succinate) and methacrylate-substituted polysilsesquioxaneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008Takenori Sakuma Abstract Itaconate-unit-containing poly(butylene succinate) (PBSI) was synthesized by the reaction of 1,4-butanediol, succinic acid, and itaconic acid in a molar ratio of 2.0 : 1.0 : 1.0, and the obtained PBSI was reacted with methacryl-group-substituted polysilsesquioxane (ME-PSQ) in the presence of benzoyl peroxide (BPO) at 130°C to produce PBSI/ME-PSQ hybrid composites. The thermal and dynamic mechanical properties of the PBSI/ME-PSQ hybrid composites were investigated in comparison with those of PBSI cured at 130°C in the presence of BPO. As a result, the hybrid composites showed a much higher thermal degradation temperature and storage modulus in the rubbery state than the cured PBSI (C-PBSI). The thermal degradation temperature and storage modulus of the hybrid composites increased with increasing ME-PSQ content. The glass-transition temperature, measured by dynamic mechanical analysis of the hybrid composites, somewhat increased with increasing ME-PSQ content. However, the glass-transition temperatures of all the hybrid composites were lower than that of C-PBSI. Although the IR absorption peak related to CC groups was not detected for C-PBSI, some olefinic absorption peaks remained for all the hybrid composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Nonaqueous synthesis of nanosilica in epoxy resin matrix and thermal properties of their cured nanocompositesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2006Tzong-Ming Lee Abstract Nonaqueous synthesis of nanosilica in diglycidyl ether of bisphenol-A epoxy (DGEBA) resin has been successfully achieved in this study by reacting tetraethoxysilane (TEOS) directly with DGEBA epoxy matrix, at 80 °C for 4 h under the catalysis of boron trifluoride monoethylamine (BF3MEA). BF3MEA was proved to be an effective catalyst for the formation of nanosilica in DGEBA epoxy under thermal heating process. FTIR and 29Si NMR spectra have been used to characterize the structures of nanosilica obtained from this direct thermal synthetic process. The morphology of the nanosilica synthesized in epoxy matrix has also been analyzed by TEM and SEM studies. The effects of both the concentration of BF3MEA catalyst and amount of TEOS on the diameters of nanosilica in the DGEBA epoxy resin have been discussed in this study. From the DSC analysis, it was found that the nanosilica containing epoxy exhibited the same curing profile as pure epoxy resin, during the curing reaction with 4,4,-diaminodiphenysulfone (DDS). The thermal-cured epoxy,nanosilica composites from 40% of TEOS exhibited high glass transition temperature of 221 °C, which was almost 50 °C higher than that of pure DGEBA,DDS,BF3MEA-cured resin network. Almost 60 °C increase in thermal degradation temperature has been observed during the TGA of the DDS-cured epoxy,nanosilica composites containing 40% of TEOS. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 757,768, 2006 [source] High molecular weight monodisperse polystyrene microspheres prepared by dispersion polymerization, using a novel bifunctional macromonomerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2005Hyejun Jung Abstract A novel bifunctional vinyl-terminated polyurethane macromonomer was applied to the dispersion polymerization of styrene in ethanol. Monodisperse polystyrene (PS) microspheres were successfully obtained above 15 wt % of macromonomer relative to styrene. The steep slope from the reduction of the average particle size reveals that the macromonomer can efficiently stabilize higher surface area of the particles when compared with a conventional stabilizer, poly(N -vinylpyrrolidone). The stable and monodisperse PS microspheres having the weight-average diameter of 1.2 ,m and a good uniformity of 1.01 were obtained with 20 wt % polyurethane macromonomer. The grafting ratio of the PS calculated from 1H NMR spectra linearly increased up to 0.048 with 20 wt % of the macromonomer. In addition, the high molecular weights (501,300 g/mol) of PS with increased glass transition and enhanced thermal degradation temperature were obtained. Thus, these results suggest that the bifunctional vinyl-terminated polyurethane macromonomer acts as a reactive stabilizer, which gives polyurethane-grafted PS with a high molecular weight. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3566,3573, 2005 [source] Effects of synthesis conditions on crystal morphological structures and thermal degradation behavior of hydrotalcites and flame retardant and mechanical properties of EVA/hydrotalcite blendsPOLYMER COMPOSITES, Issue 2 2007Longchao Du The effects of synthesis methods and reaction conditions on the crystal morphological structures and thermal degradation behavior of hydrotalcites have been studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), particle size analysis (PSA), and differential thermal analysis (DTA). The flame retardant and mechanical properties of ethylene,vinyl acetate (EVA) blends with the corresponding hydrotalcites have been estimated by limiting oxygen index (LOI), UL-94, and mechanical measurements. The results from the XRD, TEM, and PSA demonstrate that the hydrotalcites synthesized by ultrasound method have larger crystal sizes and particle size distribution than those by mechanical stirring method. Higher reaction temperature, longer dripping time, and lower solution concentration can increase the crystal and particle sizes of ultrasound-synthesized hydrotalcites, whereas the longer ultrasound aging time can increase the crystal sizes and decrease the particle sizes of hydrotalcites because of the smashing conglomeration. The DTA data give a positive evidence that the hydrotalcite samples prepared by mechanical stirring method with longer alkaline dripping time have higher thermal degradation temperature than those by ultrasound method, since the ultrasound-synthesized hydrotalcites have more lattice defects than stirring-prepared hydrotalcites. The data from LOI, UL-94, and mechanical tests show that the ultrasonic-synthesized hydrotalcites have better flame retardant properties, whereas the stirring-synthesized hydrotalcites have better tensile strength in the EVA/hydrotalcite blends. POLYM. COMPOS., 28:131,138, 2007. © 2007 Society of Plastics Engineers [source] A novel organic rectorite modified bismaleimide/diallylbisphenol A systemPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11 2009Li Yuan Abstract 4,4,-Bismaleimidodiphenylmethane (BMIPM)/O,O,-diallylbisphenol A (BA) system was modified by organic rectorite (OREC) to develop a novel BMI/BA/OREC nanocomposite. The effect of OREC on the viscosity and reactivity of BMIPM/BA system was investigated. The mechanical properties of BMIPM/BA/OREC composites such as the flexural and impact strength were evaluated. The morphology of cured BMIPM/BA/OREC systems was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The hot water resistance of BMIPM/BA/OREC systems was discussed. The thermal property of BMIPM/BA/OREC systems was investigated using thermogravimetric analysis (TGA). The dynamic mechanical properties of BMIPM/BA/OREC systems were also measured. Results show that the addition of OREC has a significant influence on the reactivity of the BMIPM/BA system. Proper content of OREC can improve the flexural strength, impact strength, and hot water resistance of a BMIPM/BA system. The addition of OREC cannot decrease the thermal degradation temperature of cured BMIPM/BA system with a slight sacrifice of the glass transition temperature (Tg). Copyright © 2008 John Wiley & Sons, Ltd. [source] Recycled PCB flour reinforced linear low-density polyethylene composites enhanced by water cross-linking reactionASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2009Chen-Feng Kuan Abstract Recycled printed circuit board (PCB) flour reinforced linear low-density polyethylene (LLDPE) composites were prepared successfully. Water cross-linking technique was adopted to improve the physical characteristics of the composites. Composites were compounded using a twin-screw extruder and treated with a coupling agent (vinyltrimethoxysilane, VTMOS) and a compatibilizer (polyolefin elastomer grafted with melaic acid, POE-g-MA). They were then moisture-cross-linked in hot water. The composite that was cross-linked in water exhibited better mechanical properties than the noncross-linked composite because of strong chemical bonding between the filler and the polyolefin matrix. When the PCB flour content reaches 60 wt% following 4 h of water cross-linking, the tensile strength and the flexural strength are increased by 18.8% (12.8,15.2 MPa) and 13.2% (21.9,24.8 MPa) respectively. Scanning electron microscopy (SEM) images of the fracture surfaces of water cross-linked composites indicated that good interfacial strength existed between the filler and the polyolefin matrix. Thermal analyses of water cross-linked composites indicated that the thermal degradation temperature and the heat deflection temperature (HDT) of the composite increased with the increasing of water cross-linking time. The HDT of the composite rose from 55.8 to 83 °C. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||