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Initial Decomposition Temperature (initial + decomposition_temperature)
Selected AbstractsPreparation of novel polyindene/polyoxymethylene blends and investigation of their propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Tenzile Zilhan Cabuk Abstract In this study, the conducting homopolymer of indene was synthesized by a chemical polymerization method in a nonaqueous medium, and polyindene (PIn)/polyoxymethylene (POM) blends were prepared. The physical, chemical, thermal, and spectral properties of the synthesized homopolymer and their blends were investigated. The conductivities of PIn and the PIn/POM blends were measured with a four-probe technique. The conductivity of PIn was determined as 1.16 × 10,5 S/cm, whereas the conductivities of the PIn/POM blends were determined to be in the range 3.16 × 10,6 to 9.8 × 10,6 S/cm. From Gouy scale magnetic susceptibility measurements, we found that PIn and the PIn/POM blends had polaron natures. The amount of Fe (milligrams per gram) in the PIn and PIn/POM structures were determined by inductively coupled plasma,optic emission spectrometry. Fourier transform infrared spectra were taken to analyze the structural properties of PIn and the PIn/POM blends. The thermal properties of PIn and PIn/POM blends were investigated with thermogravimetric analysis and differential scanning calorimetry analyses, and we found that they showed adequate thermal stability. According to the initial decomposition temperature among the blends, the blend including 16% PIn had the highest decomposition temperature with 244°C. The morphological structures of the PIn, POM, and blends were clarified with scanning electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Morphology, mechanical properties, and thermal stability of poly(L -lactic acid)/poly(butylene succinate- co -adipate)/silicon dioxide compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Ruyin Wang Abstract Poly(butylene succinate- co -adipate) (PBSA) and two types of SiO2 (hydrophilic or hydrophobic) were used to modify poly(L -lactic acid) (PLLA). The mechanical properties, rheological and thermal behavior, phase morphology, and thermal stability of PLLA/PBSA/SiO2 composites were investigated. The impact strength, flexural strength, and modulus of PLLA/PBSA blends increased after the addition of hydrophobic SiO2 without decreasing the elongation at break, and the elongation at break monotonically decreased with increasing hydrophilic SiO2 content. The melt elasticity and viscosity of the PLLA/PBSA blend increased with the addition of SiO2. The hydrophilic SiO2 was encapsulated by the dispersed PBSA phase in the composites, which led to the formation of a core,shell structure, whereas the hydrophobic SiO2 was more uniformly dispersed and mainly located in the PLLA matrix, which was desirable for the optimum reinforcement of the PLLA/PBSA blend. The thermogravimetric analysis results show that the addition of the two types of SiO2 increased the initial decomposition temperature and activation energy and consequently retarded the thermal degradation of PLLA/PBSA. The retardation of degradation was prominent with the addition of hydrophobic SiO2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Thermal and mechanical properties of diglycidylether of bisphenol A/ trimethylolpropane triglycidylether epoxy blends cured with benzylpyrazinium saltsPOLYMER INTERNATIONAL, Issue 5 2002Soo-Jin Park Abstract The effect of blend composition on thermal stability and mechanical properties of diglycidylether of bisphenol A (DGEBA)/trimethylolpropane triglycidylether (TMP) epoxy blends cured with benzylpyrazinium salts (N -benzylpyrazinium hexafluoroantimonate, BPH) as a thermal latent catalyst was investigated. The thermal stability, characterized by the initial decomposition temperature, temperature of maximum rate of weight loss, integral procedural decomposition temperature, and activation energy for decomposition, increase in DGEBA-rich compositions. This could be due to the long repeat unit and stable aromatic ring in the DGEBA. The mechanical properties are also discussed in terms of the fracture toughness (KIC), flexural and impact tests for the blend composition studied. The addition of TMP into DGEBA gives systematic improvements in fracture toughness, which results from the increase in aliphatic and flexible chain segments of TMP. © 2002 Society of Chemical Industry [source] Catalysis of intumescent flame retardancy of polypropylene by metallic compounds,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2003Menachem Lewin Abstract Divalent and multivalent metallic compounds catalyze the flame retardancy performance of intumescent systems based on ammonium polyphosphate (APP) and pentaerythritol (petol) in poly(propylene) (PP). The catalytic effect is shown by increases in the oxygen index (OI) and UL-94 ratings. The effect is exerted by small concentrations of the metallic compounds in the range of 0.1,2.5 wt% of the compositions. The effect increases with the concentration of the catalyst until a maximum is reached. At higher concentrations of the catalyst a decrease in the flame retardancy parameters is observed, accompanied in several cases by a degradation and discoloration of the composition. The catalyst replaces melamine in intumescent systems. Catalytic effectiveness is defined and calculated for a number of compounds. Thermogravimetric parameters, such as initial decomposition temperature, temperature of the transition point and residue-after-transitions (RAT) change in parallel with the catalytic effect of the metal compound concentration. Metal compounds investigated include oxides, acetates, acetyl acetonates, borates and sulfates of Mn, Zn, Mg, Al, Ca, Ba,,V, Co, Ni, Cu, Mo, Zr, and Cr. Mechanistic considerations on the activity of the catalysts are presented. Copyright © 2003 John Wiley & Sons, Ltd. [source] Novel amorphous perfluorocopolymeric system: Copolymers of perfluoro-2-methylene-1,3-dioxolane derivativesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2006Yu Yang Abstract Perfluorotetrahydro-2-methylene-furo[3,4- d][1,3]dioxole (monomer I) and perfluoro-2-methylene-4-methoxymethyl-1,3-dioxolane (monomer II) are soluble in perfluorinated or partially fluorinated solvents and readily polymerize in solution or in bulk when initiated by a free-radical initiator, perfluorodibenzoyl peroxide. The copolymerization parameters have been determined with in situ19F NMR measurements. The copolymerization reactivity ratios are rI = 1.80 and rII = 0.80 in 1,1,2-trichlorotrifluoroethane at 41 °C and rI = 0.97 and rII = 0.85 for the bulk polymerization. These data show that this copolymerization pair has a good copolymerization tendency and yields nearly ideal random copolymers. The copolymers have only one glass-transition temperature from 101 to 168 °C, depending on the copolymer compositions. Melting endotherms have not been observed in their differential scanning calorimetry traces, and this indicates that all the copolymers with different compositions are completely amorphous. These copolymers are thermally stable (the initial decomposition temperatures are higher than 350 °C under an N2 atmosphere) and have low refractive indices and high optical transparency from UV to near-infrared. Copolymer films prepared by casting were flexible and tough. These properties make the copolymers ideal candidates as optical and electrical materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1613,1618, 2006 [source] Aromatic polybenzoxazoles containing ether,sulfone linkagesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2001Sheng-Huei Hsiao Abstract A series of poly(o -hydroxy amide)s having both ether and sulfone linkages in the main chain were synthesized via the low-temperature solution polycondensation of 4,4,-[sulfonylbis(1,4-phenylene)dioxy]dibenzoyl chloride and 4,4,-[sulfonylbis(2,6-dimethyl-1,4-phenylene)dioxy]dibenzoyl chloride with three bis(o -aminophenol)s including 4,4,-diamino-3,3,-dihydroxybiphenyl, 3,3,-diamino-4,4,-dihydroxybiphenyl, and 2,2-bis(3-diamino-4-hydroxyphenyl)hexafluoropropane. Subsequent thermal cyclodehydration of the poly(o -hydroxy amide)s afforded polyethersulfone benzoxazoles. Most of the poly(o -hydroxy amide)s were soluble in polar organic solvents such as N -methyl-2-pyrrolidone; however, the polybenzoxazoles without the hexafluoroisopropylidene group were organic-insoluble. The polybenzoxazoles exhibited glass-transition temperatures (Tg) in the range of 219,282 °C by DSC and softening temperatures (Ts) of 242,320 °C by thermomechanical analysis. Thermogravimetric analyses indicated that most polybenzoxazoles were stable up to 450 °C in air or nitrogen. The 10% weight loss temperatures were recorded in the ranges of 474,593 °C in air and 478,643 °C in nitrogen. The methyl-substituted polybenzoxazoles had higher Tg's but lower Ts's and initial decomposition temperatures compared with the corresponding unsubstituted polybenzoxazoles. For a comparative purpose, the synthesis and characterization of a series of sulfonyl polybenzoxazoles without the ether group that derived from 4,4,-sulfonyldibenzoyl chloride and bis(o -aminophenol)s were also reported. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2262,2270, 2001 [source] The influence of chain-ends on the thermal and rheological properties of some 40/60 PES/PEES copolymersPOLYMER ENGINEERING & SCIENCE, Issue 8 2009Lorenzo Abate Four random, differently ended (Cl, NH2, OH, and COO,), polyethersulfone/polyetherethersulfone (PES/PEES) copolymers were studied to investigate the influence of chain ends on thermal and rheological behaviors. The number average molar mass (Mn , 9500 g·mol,1) and the PES/PEES ratio (40/60) of all copolymers investigated were checked by 1H NMR spectra. Thermal degradations were carried out in the scanning mode and initial decomposition temperatures (Ti) and activation energy values of degradation (Ea) were obtained. Glass transition temperature (Tg) was determined by differential scanning calorimetry and complex viscosity (,*) by rheological measurements in isothermal heating conditions (T = 270°C). All parameters determined were largely affected by copolymer chain ends and decreased according to the same order, OH > NH2 > Cl > COO,. The results were discussed and interpreted. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] | ||||||||||