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Poly(ethylene terephthalate)/copoly(succinic anhydride/ethylene oxide) copolymers, (PET/PES copolymers) were synthesized by the transreaction between PET and PES and characterized with GPC, ¹H NMR, and DSC. Most of the copolymers obtained were random copolymers. The films cast of these copolymers were transparent. The thermal, mechanical properties, and biodegradability of the copolymers obtained were studied with respect to the composition and lengths of aliphatic and aromatic units in the copolymers. In the copolymers having high PET content, the melting points, due to the PET segment, were observed by DSC measurement, although the fusion heats of the copolymers were small. The enzymatic hydrolyzability by a lipase from Rhizopus arrhizus and biodegradability by activated sludge of the copolymers decreased with an increase in PET content. When the length of succinic acid unit in the copolymer was below 2, the hydrolyzability of the copolymers decreased considerably. The tensile strengths of the cast films prepared from the copolymers synthesized by the transreaction increased with an increase in PET content, whereas, the elongations at break decreased. Their tensile strengths were half, and the elongations were double compared to those of PET homopolymer film. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4478–4489, 2000

Four triethylene glycol derivatives, which have different end substituents, quinolyl and ortho-substituted phenyl groups, were synthesized in good yields.The proton NMR spectrum of these compounds and their complexes with alkali and ammonium ions was measured to show that these compounds exhibit complexation specificity for sodium ion. On complexation, these acyclic polyethers are considered to wrap adequately themselves around sodium ion like a pseudocyclic species.

Abstract: Biodegradable polyesters were synthesized by ring-opening copolymerization of gamma-butyrolactone (BL) and its derivatives withl-lactide (LLA). Although tetraphenyl tin was the main catalyst used, other organometallic catalysts were used as well.1H and13C NMR spectra showed that poly(BL-co-LLA)s were statistical and that their number-average molecular weights were as high as 7×104. The maximum BL content obtained from copolymerization BL/LLA was around 17%. TheT m andT g values of the copolymers showed a gradual depression with an increase in BL content. NoT m was obtained for the copolymers containing more than 13 mol% BL. The biodegradability of the copolyesters was evaluated by enzymatic hydrolysis and nonenzymatic hydrolysis tests. The enzymatic hydrolysis was carried out at 37°C for 24 h using lipases fromRhizopus arrhizus andR. delemar. Hydrolyses by both lipases showed that an increase in BL content of the copolymer resulted in enhanced biodegradability. Nonenzymatic accelerated hydrolysis of copolymers at 70°C was found to increase proportionally to their exposure time. The hydrolysis rate of these copolymers was considerably faster than that of PLLA. The higher hydrolyzability was recorded for the BL-rich copolymers. The copolymerization of gamma-methyl-gamma-butyrolactone (MBL) or gamma-ethyl-gamma-butyrolactone (EBL) with LLA resulted in relatively LA-rich copolymers.

A polymer-bond cyclic N-hydroxy amide has been prepared by reaction of aminomethylated copoly(styrene–2% divinylbenzene) with 1-hydroxy-5-oxo-3-pyrrolidinecarboxylic acid using dicyclohexylcarbodiimide (DCC) as a condensing agent. Several N-blocked α-amino acids have been loaded on this resin by use of DCC. The amino acid resin can be utilized for peptide synthesis. Repetitive usage of the resin in the form of esters and facile synthesis of a biologically active pentapeptide, Leu5-enkephalin, show the usefulness of the polymer-bound 1-hydroxy-2-pyrrolidinone.