Study Of The Properties And Preparation Of PA66/PTFE Composite Materials

Polyamide 66(PA66) has broad market prospects as a good wear-resistant material. But PA66 material has many shortcomings that including high water absorption rate, size instability, high mold Shrinkage rate and poor electrical properties, which because it contains large amounts of amide functional group. Polyamide is a thermoplastic crystalline polymer, which is why it has the poor flammability retardant. And its wear resistance, heat resistance and low temperature impact resistance also need to be improved, which limit its application. Polytetrafluoroethylene (PTFE) resin's F-C bond has high bond energy, which is why it has the good physical and chemical properties, such as low coefficient of friction and good heat resistance. So PTFE is a good solid lubricating material. Thus, according to collaboration technology modified PA66 with PTFE, which can use their Synergistic effect to improving it's wear resistance,heat resistance and reducing it's water absorption rate and so on. Hollow glass beads (GB), which can further increase product's dimensional stability, to prevent cracking, and thus improving the wear resistance and mechanical performance of the composite materials while reducing its cost.In this paper, PA66 is the matrix, and then modified PA66 with PTFE and GB.PA66/PTFE and PA66/PTFE/GB composite materials were prepared through high-speed mixer and twin screw extruder. The affect of friction and wear properties and mechanical properties of PA66 by different content of PTFE and GB, were studied. The wear surface of composite materials and brittle fracture surface and impact fracture surface were observed by scanning electron microscopy (SEM) and analyzed.The research results show that:the friction and wear properties of PA66 modified by PTFE can be increased. The wear resistance of the PA66/PTFE composite materials modified by GB can be improved, but the coefficient of friction little improved. The composite materials modified by PTFE increase its flexural capability, but reduce the tensile strength and impact resistance capabilities. The PA66/PTFE composite materials modified by GB increase its flexural capability, the level of increase at about 10%, and increased tensile elastic modulus a lot. But it reduces the tensile strength and impact strength. Studies have shown that the quality of the shares when the PTFE to 9 and GB to 10, the mechanical properties and the friction and wear properties of composite materials achieved the best.The PA66/PTFE and PA66/PTFE/GB composite materials's structure were observed by SEM, and found the PTFE fiber-forming phenomenon in PA66 material. And a small amount of GB promotes the growth of PTFE micro-fiber. The interface between the composite materials bond well. The compatibility of the GB after surface treatment and PTFE is also well. And the formation mechanism of PTFE micro-fiber in PA66 material was studied.