丁腈橡胶对聚甲醛树脂的增韧机理研究

研究了丁腈橡胶（ＮＢＲ） 对聚甲醛（ＰＯＭ） 树脂的增韧机理，并比较了ＰＯＭ／ＮＢＲ 体系和ＰＯＭ／ 热塑性聚氨酯（ＴＰＵ） 体系的异同．结果表明，高丙烯腈（ＡＮ） 含量的ＮＢＲ 有着和ＴＰＵ 相近的溶度积参数，且其分子上的氰（ＣＮ） 基或双键对ＰＯＭ 分解时产生的甲醛及大分子自由基的捕捉作用，有利于改善ＮＢＲ 和ＰＯＭ 之间相容性，因而可和ＰＯＭ 树脂形成良好的合金体系；当ＮＢＲ 含量达４０ｗｔ％ 时，ＰＯＭ／ＮＢＲ 体系出现脆 韧转变，从逾渗机制、剪切带机制、类互穿网络（ＩＰＮ） 作用机制等角度进行考察的结果证明，ＮＢＲ 对ＰＯＭ 树脂的增韧行为以及ＰＯＭ／ＮＢＲ 共混合金体系的脆 韧转变规律与ＰＯＭ／ＴＰＵ 体系相一致．

STUDY ON THE TOUGHENING MECHANISM OF POM/NBR BLENDS

The toughening mechanism of POM/NBR blends was studied. The results indicate that NBR with high AN content has similar solubility parameter with TPU, and the CN groups or double bond of NBR can capture the formaldehyde or macromolecular free radicals which were produced during POM degradation. This can enhance the compatibility between NBR and POM, thus they can form good alloy. When NBR content reaches 40wt%, the alloy exhibits brittle\|ductile transition. The investigation from percolation, rubber\|band and quasi\|IPN mechanisms indicate that, toughening behavior of NBR to POM and the alloy's B\|D transition rule are consistent with POM/TPU system.