分散相对高分子合金增韧及脆/韧转变的影响

发生脆／韧转变的合金材料，其刚性体分散相ＣＰＰ在基质形成的静水应力的作用下沿拉抻方向发生了塑性形变。分散相无论是刚性体还是弹性体，在基质形成的静水压应力的作用下均可通过形变吸收能量使合金材料增韧；同时分散相也可作为应力集中剂引发基质产生银纹和屈服剪切带，使合金材料增韧，脆／韧转变过程提前，当分散相模量较时，后一种作用为主。随着分散相模量的增加，前一种作用的影响逐渐增加，并最终转变成为主导作用。

EFFECTS OF DISPERSED PHASE ON TOUGHENING AND BRITTLE-TOUGH TRANSITION IN POLYMER BLENDS

The mechanism of toughening and brittle-tough transition of polymer blends was investigated in this article. A new phenomenon was found: the rigid dispersed phase particles. as a stress concentrator like elastic dispersed phase particles, can increase the impact strength of the polymer blends, and promote the behavior of the brittle-tough transition. But the effect of the rigid dispersed phase on the tensile yield strength is not remarkable. The same fact is got and testified by the TEM: the cold drawing plastically deformation of the rigid dispersed phase particles of CPP do occur in the tensile direction under the hydraulic pressure produced by the matrix. The polymer blends can absorb energy by deformation of dispersed phase particles. As stress concentrator. polymer blends can induce the matrix to produce crazing and yield shearing bands to absob energy, and promote the behavior of the brittle-tough transition of polymer blends. When the dispersed phase is elastic, the polymer blends are mainly toughened by the crazing and yield shearing bands coming into being in matrix. When the dispersed phase is rigid, the polymer blends are mainly toughened by deformation of dispersed phase particles. As the modulus of dispersed phase increases, the polymer blends are toughed by from matrix to dispersed phase. Any polymer blends can usually be toughened simultaneously by the two ways.