| Every researcher will have to weigh the Strength and modulus of ABS halogen-free flame retardant composites against with the limited application range. In this study, ABS halogen-free flame retardant composites will be reinforced by kenaf fibers (KF), and the effect of different dosages and length of the KF were investigated. The results showed that when the content of KF was30percent and the length was10millimetre, the Composites could have a better performance. However, the fibers in the resin cannot get a good enhancement effect because KF contained a large number of absorbing groups in its molecule structures. Therefore, the effects of alkali treatment, coupling agents, graft modification and ABS-g-AA on mechanical properties and microstructure of the composites were investigated. In addition, the results also clearly indicate that graft modification of the fiber significantly improved the compatibility between the fiber with matrix and it was benefit to the mechanical properties of the composites.Using potassium persulfate as an initiator, KF was grafted with glycidyl methacrylate (GMA).The chemical structure of copolymer (KF-g-GMA) was identified by FT-IR. And the influences of reaction condition on grafting ratio were investigated. The results showed that the graft copolymerization could be conducted successfully within3h at90℃and the grafting ratio of KF-g-GMA copolymer increased when the proportion of initiator to GMA was0.15:1and the proportion of GMA to KF was2:1. When KF and KF-g-GMA copolymer was severally added to ABS, the effects of grafting treatment on the structure and performance of composites were discussed. The experiments showed that the grafting treatment was advantageous to interfacial bonding between fiber and resin by the test of scanning electron microscopy. The mechanical properties and suction performance of ABS/KF-g-GMA composite were improved significantly at the same time.In order to improve the flame retardant properties of ABS composites, this experiment also proceed a Flame retardant modified to KF. KF was treated with halogen-free flame retardant APP and APP/PER, respectively, on the basic of physical dipping principle. The flame effect of KF was investigated by selecting intumescent flame retardant system and alkaline treatment. The effects of treated fiber and untreated fiber on structure, thermal behavior and combustion were contrasted and analyzed through infrared spectrum analysis, scanning electronic microscope, oxygen index testing and vertical burning test. Expansion flame retardant mechanism was concluded. The results showed that the limiting oxygen index and flame retardant rating of kenaf could reach32.8and V-0grade when KF treated with alkali liquor and flame retardant. The thermal stability and flame retardancy of KF had a large improvement.Further more, a kind of halogen-free flame retardant monomer was synthesized in this experiment by esterification reaction introducing a monomer containing flame retardant elements P and N into KF structure. The flame retardant and heat resisting properties were improved.Comparing with these two retardant treatments, the composite which was synthesized by esterification reaction had better properties because esterification reaction can change molecular structure, weaken water absorption and improve compatibility.At last, ABS/KF composites were enhanced by mixing with different kinds of TLCP. As a result, enhancement of TLCP-2which was synthesized by melting was obvious. Because TLCP-2was introduced with flexible chains which decreased melting point that conducive to forming. |
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