作　　者： ; ; ; ; ;

机构地区： 郑州大学材料科学与工程学院

出　　处： 《材料导报》 2010年第16期29-34,共6页

摘　　要： 利用示差扫描量热仪(DSC)研究了3种不同分子量的聚己内酯(PCL)在-20～50℃等温结晶所得晶体在不同升温速率下的熔融现象。分别讨论了PCL晶体熔点(Tm)的等温结晶温度(Tc)依赖性和升温速率依赖性,根据Tm与升温速率的关系外推得到不同Tc时形成的晶体在零升温速率下的Tm。通过Tm随Tc变化的趋势确定出PCL结晶的高温区,根据Hoffoman-Weeks方法外推得3种分子量的伸展链片晶的平衡熔点(Tm0(MW))。通过PCL晶体结构参数和分子量可估算得到3种分子量的PCL伸展链片晶的厚度(lex),以1/lex与Tm0(MW)作图,可外推得PCL的平衡熔点(Tm0(∞))。利用小角X射线散射(SAXS)测定了不同Tc时形成的PCL晶体的长周期,根据广角衍射信息计算得到其体积结晶度(vc),而后分别求出不同Tc时的晶区厚度(Lc),通过Gibbs-Thomson关系式对1/Lc与Tm作图,外推至1/Lc=0,即求得PCL的平衡熔点(Tm0(∞))。用上述2种方法求得的Tm0(∞)相当接近,均为74℃左右。 The melting of three samples of poly（ε-eaprolactone） （PCL） isothermally crystallized at -20-50℃ with different molecular weight（MW） is investigated using differential scanning calorimetry（DSC）. The effects on the melting point（Tin ） of PCL crystals caused by the heating rate of DSC are studied, and the true Tms are extrapolated using the relationship between Tm and the heating rate of DSC. The high temperature of PCL crystalline from the changes between Tm and To. The equilibrium melting points of different MW of PCL（Tm^0 （MW）） are obtained according Hoffman-Weeks method. The long distance of PCL at different Tc is measured by SAXS and the relative crystallinity is calculated using the wide-angle diffraction peak area, which define the length of crystalline area. Moreover, the equilibrium melting point of different MW of PCL（ Tm^0 （∞）, is extrapolated using Gibbs-Thomson method, which is measured by the relation of Tm^0 （∞） and the extended chain length of different MW PCL. These results obtained by the two different methods are consistent with each other, and Tm^0 （∞）≈74℃.

关 键 词： 聚己内酯 升温速率 晶区厚度 平衡熔点

领　　域： [理学] [理学]