苯丙二酸钙改性生物可降解聚L-乳酸材料的性能研究

Study on the performances of biodegradable poly(L-lactic acid) modified using calcium phenylmalonate

为进一步认识半结晶型聚合物性能与结构的关系,以苯丙二酸钙作为聚L-乳酸的结晶促进剂,借助差示扫描量热仪、热失重分析仪、熔融指数仪和透光仪考察其改性聚L-乳酸材料的结晶行为、熔融行为、热稳定性、流动性以及透光性等物理性能。非等温结晶测试结果显示,苯丙二酸钙可显著加速聚L-乳酸的结晶过程,其中5%的苯丙二酸钙可使聚L-乳酸具有最大的非等温结晶焓,且结晶可以在更高温度下发生;同时降温速率以及非等温结晶方式都会对聚L-乳酸的非等温结晶过程产生显著影响。不同条件下熔融行为的差异进一步证实了苯丙二酸钙对聚L-乳酸的结晶促进作用,另外熔融行为也依赖于结晶温度。相关测试进一步表明,苯丙二酸钙会降低聚L-乳酸的热稳定性和透光性,但会大幅提高聚L-乳酸的加工流动性。

In order to further understand the relationship between performances and structure of semicrystalline polymers,calcium phenylmalonate (CaPA) was used to act as a crystallization accelerator for poly( L- lactic acid)(PLLA),and the influence of CaPA on the crystallization behavior,melting behavior,thermal stability,fluidity,and optical property of PLLA was investigated through differential scanning calorimetry,thermogravimetric analysis,melt index instrument,and light transmittance meter.The results from non-isothermal crystallization showed that the addition of CaPA could promoted significantly the crystallization of PLLA,upon the cooling of 1 ℃/min,5% CaPA made the PLLA have the maximum non-isothermal crystallization enthalpy,and the crystallization also occurred at higher temperature.Meantime,the non-isothermal crystallization behavior was affected by cooling rate and crystallization mode.The melting behavior under different conditions further confirmed the crystallization promoting effect of CaPA for PLLA ,in addition,the melting behavior of PLLA/CaPA also depended on the crystallization temperature.The relevant measurements further indicated the introduction of CaPA decreased the thermal stability and light transmittance of PLLA,but CaPA could remarkly improve the fluidity of PLLA.