【摘要】 采用显微傅立叶转换红外光谱技术研究了mLLDPE/EVA共混物的非等温结晶过程。通过采集150℃～67℃连续降温过程的显微红外光谱数据,运用在等压条件下的van′tHoff关系式推导计算特征基团在降温结晶过程中起点和终点振动的两种能态吸光度比值的变化和振动能态转变的表观焓变。对比DSC分析结果来看,结晶过程中观察到的两个放热峰分别对应着mLLDPE和EVA的富集区。而从计算得到的各种特征基团在两个放热峰处表观焓变的数据可知,共混物中亚甲基的弯曲振动的表观焓变数值最大,表明在结晶过程中,亚甲基的弯曲振动方式对mLLDPE和EVA分子链段向各自富集区迁移和规整排列贡献最大。更多还原

【Abstract】 Thermal spectra of mLLDPE/EVA blends were collected at 150 ℃~67 ℃ by FT-IR micro-spectroscopy. Conformational apparent enthalpy differences ΔH in the crystallization process have been calculated by van′t Hoff equation at constant pressure and plotted with temperature. Compared with DSC analysis, two exothermal peaks were examined during the crystallization process, corresponding to mLLDPE and EVA centralized regions respectively. In comparison with the values of apparent enthalpy ΔH, it can be seen that the bending vibration of methylene groups make prominent contribution to the regular arrangement of chain segments in the crystallizing process.更多还原