协效剂对棉杆皮聚乳酸复合材料力学性能的影响

Effect of synergist on mechanical properties of cotton stalk bast fibers reinforced polylactic acid composites materials

在废弃棉秆皮纤维增强聚乳酸模压制成的复合材料板中添加阻燃剂后,由于其膨胀体系原理,严重影响了复合材料的力学性能.选用蒙脱土(MMT)和微纤化纤维素(MFC)作为协效剂,利用其特殊的物理结构来提高复合材料的力学性能.同时,蒙脱土也有协效阻燃作用,可以提高材料的阻燃性能.试验结果表明,在加入协效剂后,复合材料的力学性能均有提高,MFC对材料的拉伸强度和冲击强度提高较明显,可分别提高43.74%和41.50%.经XRD测定,加入MMT后,材料的片层间距增加到5.38 nm,说明MMT以片层的形式插入到纤维与基体中,同时极限氧指数增加了6.38%.

The composite boards were moulded by waste cotton stalk bast fibers and polylactic acid （PLA）, whose mechanical properties were seriously affected after addition of flame retardants. Montmorillonite （MMT） and micro fiber cellulose （MFC） with special physical structure were utilized as synergists to improve the mechanical properties of composite materials. At the same time, MMT had synergistic flame retardant ef- fect, which could improve the flame retardant properties of materials. The experimental results showed that the mechanical properties of composite materials were increased after synergist addition. The tensile strength and impact strength was obviously increased by MFC addition and increased by 43.74% and 41.50%, respec- tively. XRD result indicated that the interlamellar space of materials increased to 5.38 nm after MMT addition, and also illustrated MMT inserted into the fibers and matrixs in the form of layers, meanwhile limit oxygen in- dex was increased by 6.38%.