Recycling and application of wasted polytetrafluoroethylene via high-energy ball milling technology for nitrile rubber composites preparation

Wasted polytetrafluoroethylene fibers were recycled using high-energy ball milling technique, and the recylced polytetrafluoroethylene (r-PTFE) was employed to prepare nitrile rubber (NBR)/r-PTFE composites. The structure of r-PTFE and properties of NBR/r-PTFE composites were investigated by polarized optical microscope, laser particle size analyzer, differential scanning calorimetry, and scanning electron microscopy, respectively. The results show that increasing the milling time from 4 to 7 h leads to decreasing the average particle size, the degree of crystallinity and the number-average molecular weight of r-PTFE, whereas no obvious change is found by further prolonging the milling time. It is also clear that the NBR/r-PTFE composite with the r-PTFE obtained from a longer milling time possesses a higher mechanical and solvent resistance property. Compared with pure NBR, NBR/r-PTFE composites with r-PTFE for 7 h milling show a 21.9% increase in modulus at 300% and 27.8% decrease in swelling index. POLYM. ENG. SCI., 56:643–649, 2016. © 2016 Society of Plastics Engineers