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.

Degradable polyesteramide fibres were processed by melt-spinning. Tensile properties of as-spun and hot-drawn fibres were also investigated. After drawing, the overall crystallinity and the melting temperature of the copolymer increased. As a result, the tensile strength of the fibre increased, and the elongation at break decreased. The morphology of the surface and fracture cross section were studied by SEM. During alkaline degradation, the tensile strength and the elongation at break both decreased.

A new kind of polyesteramide copolymer based on e-caprolactone and 11-aminoundecanoic acid has been synthesized by melt polycondensation. The copolymers were characterized by FTIR, 1H-NMR, DSC, and WAXD. With the increase in aminoundecanoic acid content, the melting temperature, heat of fusion, and Td, 50% increased accordingly. The thermal degradation of the P (CL/AU) x/y copolymers was studied using FTIR, and TG During thermal degradation, the ester bond decomposes at lower temperature, then the amide bond decomposes at higher temperature.

Factors influencing the in vitro release of bovine serum albumin (BSA) from poly(butylcyanoacrylate) (PBCA) nanocapsules, such as the pH value, BSA loading, the polymeric nanocapsule walls and protein molecular weight, were investigated in detail. The BSA release rate was affected by the degradation rate of the polymeric wall and protein loading. For low molecular weight proteins, the initial burst release was faster than that of high molecular weigh proteins and got to equilibrium quickly. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis results showed that BSA encapsulated within PBCA nanocapsules did not suffer covalent aggregation or fragmentation during the initial days of in vitro incubation. For nanocapsules prepared by interfacial polymerization in waterinoil microemulsions, these findings were useful as a foundation for the development of nanocapsules with desired properties.

In this work, a new kind of aliphatic polyesteramide (PEA) copolymer based on €-caprolactone and 6-aminocaproic acid was synthesized by the melt polycondensation method. Biodegradable PEA fibers were processed by the meltspinning method. 1H-NMR, FTIR, SEM, and tensile testing were used to characterize the degradation of PEA fibers in concentrated alkaline solution. The PEA fiber undergoes surface erosion in such concentrated alkaline solutions.