环氧化三元乙丙橡胶对PBT/GF复合材料非等温结晶动力学的影响

Influence of Epoxidized Ethylene Propylene Diene Rubber on Nonisothermal Crystallization Kinetics of PBT/GF Composite

以叔丁基过氧化氢(t-BuOOH)作氧化剂,三氧化钼(MoO3)作催化剂,成功制备了环氧化三元乙丙橡胶(eEPDM),并用其对聚对苯二甲酸丁二醇酯/玻璃纤维(PBT/GF)进行改性。采用差示扫描量热仪(DSC)分析了PBT/GF/eEPDM的非等温结晶行为,利用莫志深方程研究了eEPDM对PBT/GF复合材料非等温结晶动力学的影响。结果表明,在PBT/GF中添加eEPDM可提高PBT组分的非等温结晶速率,结晶活化能结果进一步证实了这一结论。通过扫描电子显微镜(SEM)观察PBT/GF/eEPDM的微观形貌,发现各相间的界面黏结性能良好,并对试样的力学性能进行了测试。

Poly(butylene terephthalate)(PBT),a semicrystalline polymer belonging to polyester family,is widely used in engineering applications due to its versatile combination of mechanical and thermal properties,chemical resistance,and high rates of crystallization.The physical and mechanical properties of the product are directly related to the microstructure,which is determined by the extent of crystallization and influenced by the nonisothermal conditions set forth during practical processing.Therefore,the nonisothermal crystallization kinetics can be used to clarify the crystallization behavior and provide a theoretical basis for the formation of crystals.In this paper,the epoxidized ethylene propylene diene rubber(eEPDM)was first successfully prepared by the epoxidation of ethylene propylene diene rubber(EPDM)using t-butyl hydroperoxide as an oxidant and molybdenum oxide as a catalyst.The prepared rubber was characterized by Fourier transform infrared spectroscopy(FT-IR)and 1H-nuclear magnetic resonance(1H-NMR).Then the PBT/Glass fiber(GF)/eEPDM composites with different eEPDM contents were prepared in a twin-screw extruder.The influence of eEPDM on the nonisothermal crystallization kinetics of PBT/GF was investigated using differential scanning calorimetry(DSC).The phase structure of PBT/GF/eEPDM was observed by scanning electron microscopy(SEM).Analysis of the crystallization data by Mozhishen model revealed that the presence of eEPDM could accelerate the nonisothermal crystallization rate of PBT in PBT/GF/eEPDM.The result was further proved by the effective activation energy calculated by Friedman method.The observation of SEM demonstrated that the interface performance was excellent among PBT,GF and eEPDM phases.Meanwhile,the mechanical properties of the specimens were evaluated.