Polyarylene ether nitriles (PENs)/TiO2 nanocomposite has been successfully synthesized through the sol–gel process; the films were characterized by FTIR, XPS, SEM and TG. The dielectric properties of the films were also measured to find that the dielectric constant of nanocomposite films increases linearly with the TiO2 weight content and reaches 6.21 at a 20 wt.% TiO2 content. The nanocomposite films have favorable mechanical and thermal properties and are not sacrificing dielectric breakdown strength compared to that of pristine polymer. © 2004 Elsevier B.V. All rights reserved.

Poly (D, L-lactide) (PDLLA) degraded at processing temperature under air and nitrogen. A random chain scission model was established and used to determine the activation energy Ea, and FT-IR, 1H and 13C NMR were used to elucidate the degradation behavior under different atmospheres. Results showed that there were two to three stages. The 1st stage was dominated by the oligomers containing carboxylic acid groups and hydroxyl groups, during which oxygen and nitrogen had little effect on the degradation, thus they share similar Ea. When the oligomers were consumed over or evaporated, the 2nd stage began, and oxygen had a promoting effect on the thermo-oxidation process, resulting in the great decrease in Ea. The third stage of PDLLA was observed when it degraded under nitrogen over 200

A new kind of aliphatic polyetheresteramide copolymers (PEEAs) based on E-caprolactone, 11-aminoundecanoic acid, and poly (ethylene glycol) (PEG) were synthesized by melt polycondensation. The thermal and hydrolytic degradation behaviour of these copolymers was studied using FTIR, 1H-NMR, and TGA. PEG content, thickness of the test sample, and pH of degradation medium have great effect on degradation rate. The degradation rate increased with PEG content and pH, but decreased with thickness of the test sample.

Hydrolytically degradable PET/PEG block copolymer was synthesized by the macromolecular transesterification method from PET and PEG. Non-isothermal crystallization behavior of the copolymers was investigated by differential scanning calorimetry (DSC). Water absorption and in vitro degradation behaviour of these copolymers were studied in detail. When hydrophilic PEG was incorporated into the PET chain, water absorption increased. With the increase in PEG concentration, the degradation rate increased accordingly. PEG molecular weight has different effects on PET/PEG copolymers’ degradation rate. © 2003 Elsevier Ltd. All rights reserved.

Phenolphthalein-modified polyarylene ether nitrile copolymers were synthesized by nucleophilic substitution reaction of 2,6-difluorobenzonitrile (DFBN) with varying molar ratios of phenolphthalein (PP) and hydroquinone (HQ). The copolymers were chemically and physically characterized to have good thermal and mechanical properties. PP content of the copolymers has influence on glass transition temperature (Tg) as well as decomposition temperature (Tid). Coats–Redfern method was applied to study the thermal decomposition kinetics of the copolymers to predict the lifespan under thermal aging process of the copolymers, the results show that the lifespan increases with increasing PP content. © 2005 Elsevier B.V. All rights reserved.