反式1,4-聚丁二烯的非等温结晶动力学研究

Nonisothermal Crystallization Kinetics of Trans 1,4-Polybutadiene

采用Nd(P507)3 LiBu AlEt3和AlEt3 VCl3两种催化剂体系分别合成了两种分子量与反式1,4单元结构含量不同的反式1,4 聚丁二烯样品(TPBD)。用DSC方法不仅研究了两样品六方相晶体的非等温结晶过程,同时还对单斜相结晶的非等温动力学过程进行了研究。Avrami方程分析显示,在低结晶度下TPBD六方相和单斜相的结晶生长过程呈现热成核的三维球晶生长。研究表明:虽然Ozawa方程在较低温度下能描述TPBD的六方相结构的实验数据,但不能完全描述在较高温度下六方相及单斜相非等温结晶过程,而用莫志深等建议的方程则能很好地描述TPBD六方相和单斜相非等温结晶过程。由Kissinger方程得到TPBD六方相和单斜相结晶的平均结晶活化能分别为-165.8kJ/mol和-220.5kJ/mol。

Two samples of Trans 1,4-Polybutadiene with different molecular weight , trans 1,4 unit content were synthesized using Nd(P507)3-LiBu-AlEt_3和AlEt_3-VCl_3 catalyst systems, respectively. Nonisothermal crystallization of hexagonal structure and the nonisothermal transition from hexagonal to monoclinic structures were carried out by DSC. The avrami equation analysis indicates that the primary crystallizations of hexagonal structure and monoclinic structure at low crystallization degree correspond to three dimension spherutic growth with thermal nucleation. The Ozawa equation cannot completely describe the nonisothermal crystallization of hexagonal and monoclinic structures except the nonisothermal crystallization of hexagonal structure at lower crystallization temperature. The equation suggested by Mo et al can well describe the nonisothermal crystallization of hexagonal and monoclinic structures. The average crystallization activation energies of hexagonal and monoclinic structures of trans 1,4-polybutadiene were obtained by Kissinger equation to be -165.8 kJ/mol, -220.5 kJ/mol, respectively.