二元乙丙橡胶的环氧官能化及其增韧尼龙6的研究

在双螺杆挤出机中制备了环氧官能化的二元乙丙橡胶(gEPR) ,采用红外光谱工作曲线法测量了EPR的接枝率.将环氧官能化的EPR与尼龙6 (Nylon- 6 )熔融共混,并对共混体系的相形态、断裂形貌、增韧机理、力学性能进行了研究.结果表明,gEPR的环氧官能团与Nylon- 6的端羧基和(或)端氨基发生了化学反应生成Nylon -6 co EPR共聚物,该共聚物作为界面改性剂降低了Nylon -6与EPR之间的界面张力,使EPR在Nylon -6基体中均匀、稳定地分散,而且随着EPR接枝率的增加,EPR的粒径尺寸逐渐减小.断面形貌观察发现,与Nylon -6 EPR体系相比,Nyon -6 gEPR共混体系呈现明显的韧性断裂特征.通过对Nylon -6 gEPR共混体系缺口冲击形变区的研究得出EPR增韧Nylon -6的机理是橡胶粒子的空洞化和塑料基体的剪切屈服.力学性能测试表明gEPR的引入显著提高了Nylon -6的缺口冲击强度.

TOUGHENING OF NYLON-6 WITH EPOXY-FUNCTIONALIZED ETHYLENE PROPYLENE RUBBER

Epoxy-functionalized ethylene propylene rubber (gEPR) was prepared in a corotating twin-screw extruder.The degree of grafting of EPR was determined by FTIR measurements.The phase structure,fracture morp hology,toughening mechanism and mechanical properties of Nylon-6/gEPR blend s were studied in detail.The results show that the epoxy groups of gEPR can re act with the carboxyl and (or) amine groups of Nylon-6 and form Nylon-6-co -EPR copoymer,which can act as compatibilizer to decrease the interfacial ten sion between Nylon-6 and EPR,and result in a more uniform dispersion of EPR in t he Nylon-6 matrix.At the same time,the particle size of EPR decreases with the increase of the grafting degree of EPR. SEM observation of fracture surfaces in dicates that Nylon-6/gEPR blends exhibit fractures of ductile mode,and fro m the SEM analysis of deformation zones it can be concluded that the cavitation of rubber particles and shear yielding of matrix are the main toughe ning mechanism.Mechanical tests also show that the addition of gEPR into Nyl on- 6 matrix improves the Izod notched impact strength of Nylon-6 significantly.