相容剂SMA对PPO/PA66/SEBS-g-MAH合金力学性能的影响及其机理

Effect of Compatibilizer SMA on the Mechanical Properties of PPO/PA66/SEBS-g-MAH Alloy and Its Mechanism

采用马来酸酐-苯乙烯共聚(SMA)提高PPO/PA66/SEBS-g-MAH合金中PPO和PA66的相容性,研究SMA含量对3种PPO/PA66/SEBS-g-MAH合金拉伸强度、冲击强度和弯曲强度等力学性能的影响。结果表明,当SMA添加量为1~3份时,PPO/PA66/SEBS-g-MAH合金的拉伸强度、弯曲强度和冲击强度均得到了较大的提高,制备得到综合性能较好的PPO/PA66合金。但是,当SMA的含量超过3份时,合金的冲击强度和断裂伸长率均逐渐下降。这是由于,SMA中的MAH与PA66的端氨基发生反应,而SMA中苯乙烯链段与PPO具有较好的相容性,可以促进PA66在PPO中的分散;另外,SMA中的强极性MAH基团导致PA66部分分子链断裂。因此,当SMA含量较低时,增容作用占主导,使合金的力学性能得到一定程度的提高;当SMA含量较高时,MAH基团过多,导致基体PA66分子链断裂,使合金的力学性能降低。

Maleic anhydride-styrene copolymer(SMA)was used to increase the compatibility of PPO and PA66 in PPO/PA66/SEBS-g-MAH alloy,and the effects of SMA content on tensile strength,impact strength and bending strength of three PPO/PA66/SEBS-g-MAH alloys were investigated.The results showed that when the addition of SMA was 1~3 phr,the tensile strength,flexural strength and impact strength of the PPO/PA66/SEBS-g-MAH alloy were all enhanced,and PPO/PA66 alloy with good mechanical properties was obtained.When the amount of SMA exceeded 3 phr,the impact strength and elongation at break of the alloy began to decrease.The reason is that MAH in SMA reacted with the terminal amino group of PA66,and the styrene segment in SMA had a good compatibility with PPO,which promoted the dispersion of PA66 in PPO;The strong polar MAH group of SMA caused part of the molecular chain of PA66 to break.As a result,when the addition of SMA was low,the compatibilization played a leading role and the mechanical properties of the alloy were improved.However,when the addition of SMA was high,there were too many MAH groups,which led to the fracture of PA66 molecular chain in the matrix and reduced the mechanical properties of the alloy.