松木纤维表面超支化接枝改性及其对PP复合材料性能的影响

摘要

In order to improve the interface bonding performance between pine woodfiber and polypropylene (PP),the hyper-branched polyamide was grafted gradually onto thefiber surface by surface grafting modification. The grafting-modifiedfibers,PP and compatilizer were melting blended to prepare composites. The functional groups and thermal properties of the modifiedfibers or unmodifiedfibers were analyzed by Fourier transform infrared spectroscopy and thermal gravimetric analyzer,and the tensile strengths of the composites were determined. The results show that a large number of amino groups are successfully introduced onto thefiber surfaces after modification with the hyperbranched polyamide. The heat resistanceof thefiber increases after 1.0 generation grafting modification with the hyperbranched polyamide,however,the heat resistance of thefiber decreases after 2.0 or 3.0 genera-tion grafting modification with the hyperbranched polyamide. The tensile strength of the pine woodfiber reinforced PP composites are improved after the modification with the hyperbranched polyamide,the 2.0 generation modifiedfiber reinforced PP composite shows the highest tensile strength. For the unmodified or KH–550 modifiedfiber reinforced PP composite,the tensile strength of composite with 20 meshfiber is higher than that with 40 meshfiber,however,for thefibers modified by the hyperbranched polyam-ide,the tensile strength change of the relevant composite with thefiber size is the opposite.%为了改善松木纤维与聚丙烯(PP)之间的界面结合性能，采用接枝改性技术在纤维表面逐步接枝超支化聚酰胺，并用接枝改性后的纤维与PP及相容剂熔融共混制备复合材料。采用傅里叶变换红外光谱及热重分析对改性前后纤维的官能团及热性能进行了分析表征，并对纤维增强PP复合材料的拉伸强度进行了测定。结果表明，经超支化聚酰胺改性后，纤维表面成功引入了大量的氨基基团。经1.0代超支化聚酰胺接枝改性后，纤维的耐热性有所增加，但经2.0及3.0代超支化聚酰胺接枝改性后，纤维的耐热性均有所下降。经超支化聚酰胺接枝改性后，纤维增强PP复合材料的拉伸强度均有所提高，其中2.0代超支化聚酰胺改性的纤维增强PP复合材料拉伸强度最高。对于未改性或KH–550改性的纤维，其目数为20目时的复合材料拉伸强度较目数为40目的高，但超支化聚酰胺接枝改性的纤维增强复合材料拉伸强度随纤维尺寸的变化情况与此相反。