Preparation Of Multi-binding Site GO-POSS And Its Improvement In Friction And Wear Properties Of PA6

As an engineering plastic,polyamide 6(PA6)not only has the characteristics of light weight,unique corrosion resistance,and stable chemical properties,but also has the advantages of low manufacturing cost,simple manufacturing process,and strong designability.At present,it has been successfully applied in the fields of aerospace,electronic appliances,and automobile industry.However,with the widespread use of polymer and copolymers in the friction field,problems such as energy consumption caused by friction and failure of mechanical parts caused by abrasion need to be solved urgently.Therefore,it is of great practical significance to develop wear-resistant PA 6 materials to reduce the degree of friction and wear.Firstly,octaamino cage polysilsesquioxane(POSS)and graphene oxide(GO)were dispersed in methanol to prepare different proportions of POSS functionalized GO(GO-POSS).And then through in-situ polymerization PA6/rGO-POSS composites were prepared by grafting different proportions of GO-POSS and PA6.Through Fourier transform infrared spectroscopy,we explored whetherGO and POSS grafted successfully.The PA6/rGO-POSS composites synthesized by GO-POSS in different proportions were dissolved in formic acid solution,the grafting situation of PA6 and GO-POSS was discussed,and the best preparation ratio of GO-POSS was selected according to the grafting situation.The results show that the grafting situation is best when the ratio of GO to POSS is 10:1 and no phosphorus pentoxide(Pb₂O₅)is added.Secondly,a series of PA6/rGO-POSS composite materials were prepared according to the optimal GO-POSS preparation ratio.The synthesized GO-POSS and PA6/rGO-POSS composite materials were comprehensively analyzed and characterized by Fourier infrared spectroscopy,differential thermal scanning calorimeter,X-ray photoelectron spectrometer,and atomic force microscope.Then,the universal testing machine and UMT-2 were used to test the mechanical properties and friction properties of the composite materials,and the true color confocal microscope was used to characterize the depth and width of the wear scars of the composite materials after friction.The results showed that GO-POSS and PA6 were chemically bonded,and PA6 was successfully grafted onto GO-POSS nanosheets.The tensile strength of the composite material after adding GO-POSS increased from61.08 MPa to 71.75 MPa.The elongation has been increased from 171.61%to259.62%,and the mechanical properties have been well improved.The friction coefficient has been reduced from 0.46 to 0.06,the wear rate has been reduced by65.72%,and the depth and width of the wear scar have been reduced by 79.64%and70.69%,respectively.In this paper,GO-POSS was prepared by the covalent reaction of the amino group in POSS and the carboxyl group in GO,and GO-POSS was embedded in the PA6 molecular chain by in-situ polymerization to synthesize PA6/rGO-POSS nanoparticles with high wear resistance nanocomposites.This work supplies a high wear resistance PA6 nanocomposites in the field of engineering plastics,and provides an example for exploring the copolymerization and modification of PA6.