Reinforcement of bulk ultrahigh molecular weight polyethylene by fluorinated carbon nanotubes insertion followed by hot pressing and orientation stretching

The paper is devoted to reinforcement of bulk ultrahigh molecular weight polyethylene. Multi-stage process including insertion of fluorinated carbon nanotubes in ultrahigh molecular weight polyethylene matrix followed by hot pressing and orientation pulling at room temperature was applied. It was shown that fluorinated CNT are more efficient in reinforcement than pristine CNT. Below 250 °C fluorinated CNT did not influence composite thermal stability. SEM study confirmed that fluorinated CNT can act as crystallization centers and fluorinated CNT exhibit improved adhesion to polymer matrix as compared with pristine CNT. Composites with inserted fluorinated CNT have a block structure with high concentration of nanofibrils. The applied procedure resulted in an increase of the composite tensile strength from 22 to 132 MPa or by a factor of 6 as compared with pristine bulk UHMWPE. Previously reported in available literature tensile strength values of reinforced bulk ultrahigh molecular weight polyethylene did not exceed 40 MPa.