The Preparation And Application Of Flame Retardant Thermotroplc Liquid Crystalline Polymer By Solution Method

Thermotropic liquid crystalline polymer (TLCP) has attracted a great deal of attention to both academia and industry in the last decades, due to their high performance and wide applications. TLCP has good mechanical properties and processing properties, besides considering its liquid crystallinity, thermal behavior and mechanical properties in the molecular design of liquid crystalline polyester.If some special function molecular groups are introduced, the liquid polyester will have special performance, which will further improve the application value of liquid crystal materials.The phenolics containing phosphorus elements and a series of liquid crystal copolymerization are synthesized by solution in this article. As a result, the main chain of liquid crystal copolymerization contains mesomorphis, and contains flame retardant elements phosphorus on the side. The structures and properties of liquid crystal are investigated by IR,hot-stage polarizing optical microscope, wide-angle X-ray diffractometry (WAXD) and thermogravimetry analysis (TG). The results show that the three kinds of liquid crystal are thermotropic, which has nematic liquid crystal texture with high crystallinity and neat crystal structures. The liquid crystal copolymerization Y-3synthesized by phenolics containing phosphorus DOPO-A has a good thermal stability, when loss its weightlessness is5%,the temperature is more than239℃and the char yield is41.1%.The effect of the three kinds of liquid crystal on ABS composites is investigated.The result shows that the three kinds of liquid crystal can produce microfibrillar structure in ABS matrix,form enhance skeleton.So the addition of the three kinds of liquid crystal,especially make the tensile strength improved,the improvement of Y-3on tensile strength of ABS composites is the biggest.Compared with ABS, the tensile strength of ABS/Y-3composites increases6.3MPa,and Y-3doesn’t make bad effect on impact strength of ABS.At the same time,when Y-3makes the mechanical property of ABS composites improved,it also makes ABS has flame retardant,the oxygen index of ABS has increased from17.0%to21.2%.When the three kinds of liquid crystal and RDP add together with ABS composites,the flame retardant of ABS composites get improved.Among them,the effect of Y-3on ABS/RDP composites is the most obvious.Compared with ABS.the oxygen index of ABS/Y-3/RDP composites increases by4.98%,and the tensile strength increases by4.83MPa.G series(industrial grade) thermotropic liquid crystal are synthesized by industrial raw material, compared with Y series(analytically pure) thermotropic liquid crystal, G series thermotropic liquid crystal make little effect on mechanical property and flame retardant of the ABS composites and ABS/RDP composites.It shows that the synthetic route of flame retardant liquid crystal is feasible, and it has the industrial popularization value.