Morphology, thermal, mechanical and electrical insulation properties of poly(4-methyl-1-pentene)/poly(ethylene-co-vinyl alcohol)-coated TiO2 nanocomposites

Poly(4-methyl-1-pentene) (PMP) nanocomposites were prepared by solution mixing of poly(ethylene-co-vinyl alcohol) (EVOH)-coated TiO2 (c-TiO2) nanoparticles. The effects of c-TiO2 addition on the microstructure, thermal, mechanical and electrical insulation properties of prepared nanocomposites were evaluated. The tensile-fracture morphology observed by SEM showed that there was obvious cavitation structures in the nanocomposites. Introduction of small amounts of c-TiO2 has been significantly improve the tensile strength of PMP matrix but elongation at break was gradually reduced with the increase of the c-TiO2 content. The insulation resistance is higher for all of the nanocomposites, as compared to the pristine PMP, indicating improved electrical insulation property. XRD patterns confirm that pristine PMP and PMP/c-TiO2 nanocomposites have the same crystal structure, Form I. This indicated that only one crystalline modification was developed in the nanocomposites and the multiple melting behaviors seen in the DSC heating run may reflect the melting of crystalline regions of various sizes and perfection.