【摘要】 通过聚苯乙烯大分子单体与乙烯、丙烯共聚得到的乙丙橡胶（EPR）为主干、聚苯乙烯（PS）为支链的接枝共聚物EPR-g-PS,在无化学交联的情况下,模压样品具有与三元乙丙硫化胶可比拟的强度(PS=37.5％,M_300％=113公斤/厘米²,抗张强度=198公斤/厘米²,伸长率=705％)。聚苯乙烯含量、平均支链数目和成型条件是影响接枝共聚物力学性能的主要因素。聚苯乙烯微区除了以热塑交联网络起到物理交联作用外,在应力作用下本身还发生非弹性形变,起到补强填料的作用,使EPR-g-PS表现出热塑弹性体的性质。更多还原

【Abstract】 Without chemical crosslinking, the graft copolymer EPR-g-PS of ethylene-propylene (EPR) backbone with polystyrene (PS) branches possesses mechanical properties comparable with those of vulcanized EP terpolymers. A tensile strength of 198 kg/cm2, 300% modulus of 113 kg/cm2, and an elongation at break of 705% were achieved with the sample containing 37.5% PS (molded speciment). The tensile strength of specimens (cast film) is higher than that of Kennedy’s EPR-g-PS prepared by cationic grafting reaction. PS-content in the copolymers and average number of branches per molecule are main factors affecting the mechanical properties of EPR-g-PS. Highly dispersed microdomains, formed by PS branches, act as a thermoplastic network and energy-absorbing "reinforcing filler", actually undergoing deformation under stress, and are responsible for the thermoplastic elastomeric properties of EPR-g-PS.更多还原