Study Of Whisker-modified Thermosetting Resin

The whisker- reinforced polymer composites are widely used in many fields. The high price of excellent quality whiskers such as SiC whisker and Si3N4 whisker limited their applications. However, aluminum borate whisker, which has high ratio of properties to price, and potassium titanate whisker have not only lower price but also good properties. They show good foreground in polymer matrix composites.According to molecular design, a series of reactive inter-molecular-coordination borate eaters containing allyl, amino, butoxy, and hydroxy as coupling agent were synthesized. The structure of the borate esters were characterized by IR spectrum. The effects of materials ratio, amount of solvent, and synthetic processing to yield and reactive rate of the borate ester were discussed. And the optimum processing conditions were selected. Their hydrolytic stability, solubility, and physical properties were investigated, also. The results indicated that the hydrolytic stability of inter-molecular-coordination borate eater containing nitrogen be improved greatly, and for the existing of these reactive radicals, borate esters show good appetency and reactivity with organic polymer matrix.Aluminum borate whisker-modified polymer matrixes such as epoxy resin and bismaleimide (BM1) resin were investigated in this paper. The results show the whiskers can improve the mechanical properties and heat resistance of the composites. There are optimum values between the flexural strength and impact strength with the whisker content. However, the flexural modulus and heat distortion temperature increased with the increasing whisker content. And the optimum whisker contents were selected. The coupling agents have great effects on the properties of the whisker-reinforced polymeric composites. The borate ester coupling agents synthesized by ourselves show better coupling effect than silane and aluminate ester coupling agents. The borate ester coupling agents solved the bad interface adhesion between polymer and aluminum borate whiskers. And the optimum content of borate ester was selected by experiments.The properties of potassium titanate whisker- and calcium sulphate whisker-modified epoxy resin and BMI resin were studied. The investigation shows the potassium titanate whiskers and calcium sulphate whiskers can improve the mechanical propertiesand heat resistance. The appropriate coupling agents and their contents were chosen by experiments.The BMI resin matrix composites modified by aluminum borate whiskers and potassium titanate whiskers show excellent friction- and wear- resistance. By mixing the aluminum borate whiskers and potassium titanate whiskers , the abrasion of the composites decreased obviously, whereas, the friction coefficient increased. The friction-and wear- mechanism of the whisker-modified composites was discussed, also.The composites of whisker-reinforced glass fiber/polymer were investigated in this paper. The results show the whiskers can improve the interlayer scission strength evidently. The spindly whiskers can distribute in the interlayer of the whisker/glass fiber/polymer composites just like a nail, which improved the interlayer scission strength of the composites. The potassium titanate whisker shows better modification effect than aluminum borate whisker and calcium sulphate whisker because of its high aspect (length to diameter) ratios and long length and good properties. The flexural strength, flexural modulus, and wet and heat resistance of the composites increased by adding the whiskers. And the water absorption of the composites decreased. SEM shows the whisker nailed just like a nail in the composites.