Study On Preparation And Tribological Properties Of Porous PPS Composites

Currently,friction coefficient of polyphenylene sulfide(PPS)self-lubricating material is generally high and it can not suitable for use under harsh conditions,such as high speed and high load.But,certain disadvantages are associated with this type of oil lubrication,for example,it increases the cost of equipment and has a negative impact on the environment and products.Due to these limitations and downsides,there exists an interest in porous self-lubricating materials with sweating effect for economical,ecological and even technical reasonds.In this paper,an attempt has been made to prepare porous PPS self-lubricating composites by molding-leaching and vacuum melting process under high temperature condition,which is used NaCl as pore-forming agent and PPS as matrix.The aim of our work is to prepare a kind of self-lubricating material with sweating effect-porous PPS composite material impregnated with lithium-base grease in the pores.The effect of velocity,load and pore-forming agent content on tribological properties of the new porous PPS self-lubricating composites were investigated.The micro-structure of polymer composites,worn surfaces,and transfer films were analyzed by SEM.And the wear mechanisms were discussed.The main contents of this work are summarized as follows:1.The influence of NaCl content on the tribological properties under different load conditions,and micro-structure of polymer composites were investigated.Results indicated that the friction coefficient and wear rate reached their lowest values at 30 wt.%NaCl.In comparison with pure PPS under dry friction condition,the friction coefficient of porous PPS self-lubricating composites decreased by 90%,and the wear resistance increased by 12941 times.2.The porous PPS composite materials were prepared by using NaCl as pore-forming agent and zeolite as filler for PPS and the tribological properties were also discussed.Results indicated that the lowest friction coefficient and wear rate was obtained by porous PPS self-lubricating composites filled with lwt.%zeolite and impregnated lithium-base grease,which were 0.024 and 1.79 × 10-16m3/(Nm)at the load of 150N,respectively.It showed excellent self-lubricating performance and super wear resistance.Compared with pure PPS under dry condition,the friction coefficient decreased by 90%and the wear resistance increased by 4.67 × 104 times.The wear resistance enhanced by 3.61 times than PPS/30 wt.%NaCl composites.3.The tribological behaviors of porous PPS/PTFE composites were investigated by using NaCl as micro-and mesoporous Ti02 whiskers as nano-porogen.The effects of mesoporous TiO2 whiskers and non-perforated TiO2 whiskers on the friction and wear properties of porous PPS/PTFE composites under different loads were studied respectively.Results showed that porous PPS/PTFE composites with 7 wt.%mesoporous TiO2 whiskers reached the lower friction coefficient and wear rate at the load of 100N,when the load increase to 200N,the porous PPS/PTFE composites filled with 3 wt.%mesoporous TiO2 whiskers reached the lowest friction coefficient and wear rate,which were recorded as 0.019 and 9.27×10-16 m3/(Nm).Compare with pure PPS and under dry condition,the wear resistance increased largely.Compare with porous PPS/10PTFE/30wt.%NaCl composites friction coefficient decreased by 20%,wear resistance increased by 5 times.