壳-核结构增韧剂超高增韧非晶共聚酯的形貌和形态

研究了马来酸酐接枝的壳核结构增韧剂 (TPEg)对非晶热塑共聚酯 (PETG)的增韧和增强效果 ,并与马来酸酐接枝的纯橡胶类增韧剂 (POEg)作了对比 .TPEg对PETG具有显著的增韧效果 ,当TPEg含量由 5%增加到 1 0 %时 ,共混物就可以发生由脆性到超高韧性的快速转变 .而POEg虽然也可以使PETG发生由脆性到韧性的快速转变 ,但转变是在较高的增韧剂含量下发生的 ,这意味着共混物的抗张强度和模量损失更多 .利用扫描电镜观察、分析了随增韧剂含量的增加 ,共混物的形貌、形态的演化过程 .共混物的缺口冲击韧性与其形貌、形态之间存在很好的对应关系 .

IMPACT FRACTURE MORPHOLOGY OF COPOLYESTER TOUGHENED WITH A MALEITED CORE-SHELL IMPACT MODIFIER

A maleited impact modifier (TPEg) with polyethylene\|octene rubber shell and semi\|crystalline polymer core was used to toughen non\|crystalline copolyester (PETG) resin.TPEg has a significant toughening effect on PETG.A sharp transition from brittle to super\|tough states for PETG/TPEg blends occurred when the TPEg content was up to 10%.Although the maleited polyethylene\|octene rubber (POEg) also results in a brittletough transition, this transition takes place at a higher POEg content indicating that the loss of thensile strength and modulus of PETG blends in more serious. The effects of TPEg on impact toughness of PETG blends are well reflected from their evolution processes of topography and morphology formed during the impact fracture testing. The impact fractured surface of PETG blend with 5 wt% TPEg exhibits a very small area of its slow crack growth region and feather\|like markings in its fast crack growth region under low magnification, indicating a brittle appearance. Whereas the impact fractured surface of PETG blend with 10wt% TPEg exhibits a very large area of its slow crack growth region and some parabola\|like markings in its fast crack growth region under low magnification.Moreover,an extensive shear yielding of matrix can be seen both in the slow and the fast crack growth regions of the PETG/TPEg(90/10) blend under high magnification. It may dissipate a significant amount of impact energy,thereby responsible for the super toughness.