苎麻落麻的表面处理及其复合材料的性能研究

采用甲基丙烯酸甲酯、丙烯腈接枝，硅烷偶联剂(A-151)偶联，聚氯乙烯(PVC)包覆等方法对苎麻落麻纤维进行表面处理；测试了处理前后落麻纤维的吸水率、单丝强度及其与环氧树脂(EP)、酚醛树脂(PF)和不饱和聚酯(UP)等的接触角；观察了偶联和包覆后落麻纤维的表面状况；选取偶联和包覆后的落麻纤维制备了UP/落麻毡和PP/落麻纤维复合材料，测试了其拉伸和弯曲性能并观察了处理前后复合材料的拉伸断面形貌。结果表明，接枝、偶联和包覆不仅降低了落麻纤维的吸水速率。而且也降低了平衡吸水量；接枝对落麻纤维单丝强度影响最大，偶联次之，包覆最小；接枝、偶联和包覆均能大幅度改善落麻纤维与EP、PF和UP的浸润性；偶联和包覆后的落麻纤维表面都比处理前粗糙；偶联使UP/落麻毡复合材料的拉伸强度、拉伸弹性模量提高了21％，弯曲强度提高了34％，弯曲弹性模量提高了40％，包覆使PP/落麻纤维复合材料的拉伸、弯曲强度提高了20％左右。

STUDY ON SURFACE TREATMENT OF RAMIE NOIL FIBER AND PROPERTIES OF ITS COMPOSITES

The surface of ramie noil fibers was treated by methyl methacrylate and acrylonitrile grafting modification, silicane coupling agent A-151 coupling and polyvinyl chloride(PVC) encapsulating, etc. The water absorption and single fiber strength of ramie noil fibers before or after treatment, and the contact angles between the fibers and epoxy resin(EP), phenolic resin(PF) and unsaturated polyester(UP), were tested. The surface status of the ramie noil fibers after coupling and encapsulating modification was observed. Ramie noil fibers after coupling and encapsulating modification were used to prepare UP/ramie noil felt and PP/ramie noil fiber composites. The tensile and flexural properties of these composites were tested, and tensile fracture morphology of the composites whose fibers were treated or untreated was observed. The results showed that grafting, coupling and encapsulating not only reduced the water absorption of the ramie noil fibers but also lowered the water absorption counterbalance quantity. Grafting influenced the single fiber strength of the ramie noil fibers most, coupling the second and encapsulating the least. Grafting, coupling and encapsulating all evidently improved sockage between the ramie noil fibers and EP,PF and UP. The surface of the ramie noil fibers after coupling and encapsulating modification was coarser than that of unmodified ones. Coupling increased the tensile strength and modulus of elasticity in tension of UP/ramie noil felt composites by 21% ,the flexural strength by 34%,and the modulus of flexure by 40%.Encapsulating increased the tensile and flexural strength of PP/ramie noil fiber composites by 20% or so.