Margaretha Söderqvist Lindblad

Biodegradable Polymers from Renewable Sources. New Hemicellulose‐Based Hydrogels

Communication: Hemicellulose/poly(2-hydroxyethyl methacrylate) (PHEMA)-based hydrogels were prepared by the radical polymerization of HEMA with hemicellulose purposely modified with well-defined amounts of methacrylic functions using a redox initiator system. Oligomeric hydrosolube hemicelluloses produced from spruce chips were used for modification studies. The chemical modification of hemicellulose was performed with 2-[(1-imidazolyl)formyloxy]ethyl methacrylate as a modifying agent and triethylamine as the catalyst. The kinetics of the modification reaction was monitored by means of H-1 NMR spectroscopy. The resulting hydrogels obtained after a 30 min reaction were homogeneous, elastic, and transparent materials.

Polymers from Renewable Resources

From the point of view of making novel polymers with inherent environment-favorable properties such as renewability and degradability, a series of interesting monomers are found in the metabolisms and cycles of nature. This review presents and discusses a number of aliphatic polyesters which show interesting applications as biomedical materials and degradable packages. Available from nature are amino acids, microbial metabolites from the conversion of glucose and other monosaccharides (e.g., acetic acid, acetone, 2,3-butanediol, butyric acid, isopropanol, propionic acid), lactic acid, ethanol and fatty acids. A series of biodegradable polymers with different properties and different potential industrial uses were made starting with succinic acid and/or 1,3-propanediol. There were two routes for making the polyester-based materials; the direct ring-opening polymerization of lactones (cyclic esters) synthesized from 1,3-propanediol, and the chain-extension of α,ω-dihydroxy-terminated oligomeric polyesters produced by thermal polycondensation of 1,3-propanediol and succinic acid (oligo(propylene succinate)s).

New biodegradable polymers from renewable sources. High molecular weight poly(ester carbonate)s from succinic acid and 1,3‐propanediol

High molecular weight poly(ester carbonate)s have been prepared by a two-step chain-extension reaction performed on oligomeric alpha,omega-dihydroxy-terminated poly(1,3-propylene succinate) in turn obtained by thermal polycondensation of excess 1,3-propanediol with succinic acid. The new polymers have a biodegradable backbone and derive from renewable sources. Therefore, they have a potential as environment-friendly materials.

New biodegradable polymers from renewable sources - segmented copolyesters of poly(1,3-propanediol succinate) and poly(ethylene glycol).

New high-molecular-weight hydrophobic/hydrophilic segmented copolymers of poly(ester-ether-carbonate) structure, containing poly(1,3-propylene succinate) (SP) and poly(ethylene glycol) (PEG) segments in the main chain, were synthesized and characterized. These copolymers were obtained by a two-step chain-extension reaction performed by the thermal polycondensation of αω-dihydroxy-oligo(1,3-propylene succinate) with PEG1000 and PEG2000, respectively. The molecular structure of all the synthesized materials was characterized by 1H-NMR, by SEC for molecular weights, and by DSC for thermal properties. The molecular characterizations were in agreement with the proposed structures. Solubility and swellability tests indicated that the introduction of hydrophilic PEG segments into the high molecular weight poly(1,3-propylene succinate)s imparted amphiphilic character to the new materials. This is expected to influence the biocompatibility and biodegradability of these materials. The new polymers, besides having a degradable backbone, were derived from the monomers, 1,3-propanediol and succinic acid, which are both obtainable from renewable sources. Therefore, they have a potential as environmental friendly materials.