L. H. Tagle

Glass transition temperature-molecular weight relation for poly(hexamethylene perchloroterephthalamide)

SummaryIn order to determine the Tg variation with the molecular weight, several fractions of poly (hexamethylene perchloroterephthalamide) were studied. The Tg-molecular weight relationship was established to determine the Tg∞and K values of Fox-Flory relationship.

Polymer conformation and viscometric behaviour: 6. Synthesis, characterization and chain flexibility of (phenyl methacrylate-co-menthyl methacrylate) copolymers

SummaryPhenyl methacrylate-co-Menthyl methacrylate copolymers of different compositions were synthetized by radical polymerization in benzene at 298°K. Copolymers from three different compositions were fractionated by solubility. Number average molecular weights ¯Mn were obtained by osmometric measurements. The Mark-Houwink-Sakurada (MHS) equations were established in benzene at 298°K and the unperturbed dimensions determined by using the Stockmayer-Fixman extrapolation. From these results, the rigidity parameter σ was determined. The results show that the rigidity of the copolymers increase when the menthyl methacrylate content increase, and this is discussed in terms of specific interactions between the different units of the chain. The influence of the nature of the side group and their steric hindrance to rotation is also discussed.

Thermal Degradation Studies of Poly (Amide-Ester)s

Abstract The thermal behaviour of poly(amide-ester)s with the amide group in the side chain was studied. Polymers were sinthesized from the diphenol-amides N-(2,6-dichloro-4-nitrophenyl)-2, 2-bis(4-hydroxyphenyl)-propanamide, N-(2, 6-dichloro-4-nitrophenyl)-3,3-bis(4-hydroxyphenyl)-butanamide, and N-(2,6-dichloro-4-nitrophenyl)-4, 4-bis(4-hydroxyphenyl)-pentanamide and terephthaloyl chloride, isophthaloyl chloride and adipoyl chloride under phase-transfer conditions using several phase-transfer catalysts. The thermal decomposition temperature was influenced by both, the nature of the diacid and the length of the side chain, those derived from terephthaloyl chloride being more stable than those derived from isophthaloyl chloride and adipoyl chloride. All polymers degrade in a single-step process and the kinetics parameters were determined using the Arrhenius relationship and a computer program.

Glass transition temperature ― molecular weight relation of a poly(amide-imide)

SummarySeveral fractions of a poly(amide-imide), prepared from 3,4-dicarboxy-4′-chloroformyl biphenyl anhydride and 4,4′-methylene dianiline, were studied in order to determine the Tg∞ and K values of Fox-Flory relationship.