Poly(vinyl alcohol) (PVA), fully or partially hydrolyzed, was reacted with D,L-lactic acid and glycolic acid in different conditions to synthesize polymers with pendant lactate and glycolate groups. Various degrees of grafting were obtained. 1 Hand 13 C-NMR analysis as well as thermal and mechanical methods were used to characterize the polymers. Such grafts lead to polymers with lower glass transition temperature, therefor enhancing the polymers solubility in cold water (10°C) and improving flexibility and elasticity as well as tear resistance.

In this study, we have prepared predominantly syndiotactic poly([R,S]‐β‐hydroxybutyrate) using different distannoxane catalyst systems (1‐hydroxy‐3‐chlorotetrabutyldistannoxane, 1‐ethoxy‐3‐chlorotetrabutyldistannoxane, 1,3‐dichlorotetrabutyldistannoxane, and dibutyltin oxide). Copolymers poly([R,S]‐β‐hydroxybutyrate‐co‐ϵ‐caprolactone), P(BL‐co‐CL), and poly([R,S]‐β‐hydroxybutyrate‐co‐δ‐valerolactone), P(BL‐co‐VL), have also been synthetized from the ring‐opening copolymerization of (R,S)‐β‐BL with ϵ‐caprolactone (CL) and δ‐valerolactone (VL) using hydroxy‐ and ethoxydistannoxanes catalysts. The enzymatic degradability of these polymers was studied in aerobic medium. The objective of this work was to determine the influence of the tacticity and crystallinity of the corresponding polymers on their degree of aerobic biodegradation and on their initial degradation rate. It was shown that the degradation rate value measured for bacterial PHB 100% (R) was the highest and the degree of aerobic biodegradation reached around 94% after 36 days. A percentage of final biodegradation of about 35% was obtained for predominantly syndiotactic PHB. This result is agreement with the calculated result obtained from triads sequences. The influence of crystallinity on the initial degradation rate was observed for the copolymers P(BL‐co‐CL) and P(BL‐co‐VL) of various feed ratios. All these, copolymers, synthetized from distannoxane catalysts, exhibit a high degree of biodegradation of around 75–88%. © 2002 Society of Chemical Industry

Copolymers of racemic β‐butyrolactone (β‐BL) with ε‐caprolactone (ε‐CL) (P(BL‐co‐CL)) and δ‐valerolactone (δ‐VL) (P(BL‐co‐VL)) were prepared by ring‐opening polymerization reactions using the commercial aluminoxane catalyst tetraisobutyldialuminoxane (TIBAO). The yields, molecular weights, compositions and crystallinities were determined for both copolymers by gel permeation chromatography (GPC), nuclear magnetic resonance (1H NMR) spectroscopy and differential scanning calorimetry (DSC). A detailed study by 13C NMR spectroscopy has been made to determine monomer diad sequence distributions. These results and those of reactivity ratios indicate that the co‐polymers may consist of compatible blocks of BL units and VL units of variable size. © 1998 SCI.

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Poly(vinyl alcohol) (PVA) prepared by full hydrolysis of poly(vinyl acetate) was etherified with propylene oxide and epichlorohydrin. The reaction was done in water with sulfuric acid or sodium hydroxide. Previously, model reactions were carried out on propan-2-ol, pentan-3-ol, and pentan-2,4-diol in order to make the NMR characterization of grafted PVA easier. The new materials were also characterized by DSC and mechanical tests. A determination of their solubility in cold water was done as well. Generally, the prepared polymers showed excellent solubility in water at 10°C and a very low glass-transition temperature. Consequently, the properties of tension, elongation, elasticity, and resistance were improved.