聚乳酸的热性能研究

Study on Thermal Properties of Poly(lactic acid)

通过差示扫描量热仪对聚乳酸的热性能进行了表征研究。聚乳酸的玻璃化转变温度(T)g与丙交酯组成相关,随着L-丙交酯(质量分数)由50%提高到100%,聚合物的Tg从48.03℃跃升至62.18℃。在玻璃化转变区域,Δc_P值在一个很窄的范围内[0.571～0.602 J(/g·℃)],单体组成对其影响不大。当D-丙交酯的含量高于20%时,聚合物为无定形态,无结晶熔融温度(T_m)。当D-丙交酯含量小于10%时,聚合物有一定程度的结晶,T_m随着L-丙交酯含量的增加而升高,焓的变化趋势与T_m相同。

The thermal properties of poly(lactic acid)(PLA)were characterized by differential scanning calorimetry(DSC).The results showed that the glass transition temperature(Tg)of PLA was correlated with the composition of lactide.With the increase of L-lactide content from 50%to 100%,the Tg of PLA jumped from 48.03℃to 62.18℃.In the glass transition region,the value of△cP was in a very narrow range of 0.571-0.602 J/(g·℃),and the monomer composition had little effect on it.When the content of D-lactide was higher than 20%,the polymer was amorphous and had no crystallization melting temperature(Tm).When the content of L-lactide was less than 10%,the polymer crystallized to a certain extent,and the melting temperature increased with the increase of L-lactide content.The change trend of enthalpy was the same as that of Tm.