tailieunhanh - Ung thư polyester phân hủy sinh học trong dược phẩm và môi trường

Tham khảo tài liệu 'ung thư polyester phân hủy sinh học trong dược phẩm và môi trường', tài liệu phổ thông, sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Mac coma lecu tar Hu 4d Con ulninkiíLĩùit 117 Macromol. Rapid Commun. 21 117-132 2000 Review Numerous biodegradable polymers have been developed in the last two decades. In terms of application biodegradable polymers are classified into three groups medical ecological and dual application while in terms of origin they are divided into two groups natural and synthetic. This review article will outline classification requirements applications physical properties biodegradability and degradation mechanisms of representative biodegradable polymers that have already been commercialized or are under investigation. Among the biodegrad- able polymers recent developments of aliphatic poly- Polarizing optical photomicrograph of a PLLA film annealed esters especially polylactides and poly lactic acid s will at 140 C after melting at 200 C be mainly described in the last part. Biodegradable polyesters for medical and ecological applications Yoshito Ikada 1 Hideto Tsuji1 1 Suzuka University of Medical Science 1001-1 Kishioka-cho Suzuka Mie 510-0293 Japan 2 Department of Ecological Engineering Faculty of Engineering Toyohashi University of Technology Tempaku-cho Toyohashi Aichi 441-8580 Japan tsuji@ Received June 9 1999 revised August 19 1999 1. Introduction Polymer degradation takes place mostly through scission of the main chains or side-chains of polymer molecules induced by their thermal activation oxidation photolysis radiolysis or hydrolysis. Some polymers undergo degradation in biological environments when living cells or microorganisms are present around the polymers. Such environments include soils seas rivers and lakes on the earth as well as the body of human beings and ani-rnals118 . In this article biodegradable polymers are defined as those which are degraded in these biological environments not through thermal oxidation photolysis or radiolysis but through enzymatic or non-enzymatic hydrolysis. In a strict sense such polymers that require enzymes of .