Effects Of Environment-friendly Modified PTFE On The Anti-dropping And Tribological Properties Of Plastics

Polytetrafluoroethylene(PTFE) is one of the prior research of the pre-heated polymer,which has the excellent property of chemical-stability and anti-high and low temperature(the usagerange is -200～260℃),anti-radiating,inter-electricity and the lower friction modulus and so on.It is well-known as the"the king of plastics".And it has been widely used in all kinds of fields Such as chemical and mechanical industry. PTFE is used as anti-dripping additive and lubricant in the plastics area mostly.The differences of them are molecular weight.PTFE with high molecular weight can improve the anti-dripping behavior by forming a reticulate structure in the plastics. PTFE with low molecular weigh can improve composite's friction and wear performance when apply in the plastics,rubber,dope and so on.In this thesis,PTFE was choosed to be studied.Environment-friendly PTFE as anti-dripping additive and lubricant were prepared by different methods.The properties of PTFE were characterized and the applied effects were investigated in different plastics.The main research work as follows:1,PTFE as anti-dripping additive and lubricant were prepared by different methods.The changes in properties of PTFE such as particles size,crystallinity, molecular weight and structure were characterized by differential scanning calorimeter(DSC),FT-IR spectroscopy and laser light scatter technique.The results indicate that after being modified,the granularity of PTFE powder was diminished obviously,the crystallinity and velocity of crystallization increased.FT-IR spectroscopy showed that·OH was conglutinated in the surface of PTFE as anti-dripping additive,the structure of PTFE as lubricant has no change.2,The effects of PTFE as anti-dripping additive,DBDPO and inorganic flame retardant Al(OH)₃ on the fire resistance and anti-dripping behavior for different plastics were studied according to UL-94 standard,the anti-dripping mechanism of PTFE was also studied.It showed that PTFE had a crucial impact on dripping behavior of polycarbonate(PC) and ABS.When used with the flame retardant,the sample achieved the highest classification of V-0.The addition of PTFE changes the viscosity of the polymer melt,which modifies the dripping behavior in UL 94 performance.3,The friction and wear properties of polyoxymethylene(POM) and polyamide6 (PA6)composites filled with PTFE lubricant were researched.The contributions of the fillers for mechanical performance and crystallization of materials were also investigated.It was found that POM/PTFE and PA6/PTFE blends have good friction performance.The mechanical performance of POM/PTFE drop to some extent because of the bad compatibility.DSC showed that PTFE impact the crystallization capacity,the crystallinity of the POM/PTFE composites were increased 1.2%owing to the presence of PTFE which acts as nucleating agent during POM crystallization.