| 摘要 |
While polyesters of organic hydroxy acids, and their derivatives, are an important group of potentially biologically degradable polymers, due to the fact that the ester bond is hydrolytically cleavable, they possess some weak mechanical properties as thermoplastic resins and bearing in mind certain applications, especially with regard to the properties which apply to their thermoplastic processing. According to this method, it is possible, by using a two stage reaction and a coupling monomer, to produce polyurethane copolymers from lactic acid and an organic hydroxyacid which contains a long, flexible hydrocarbon chain or a corresponding lactone, such as ε caprolactone, which copolymers are found, when the preparation parameters have been correctly chosen, to be unexpectedly strong, tough and/or rubber-like materials. Mixing, in liquid phase, a copolyester urethane according to the invention with biologically degradable polymers which are otherwise brittle has resulted in substantially better impact-resisting materials being obtained.
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