Silane crosslinked polyethylene from different commercial PE's: Influence of comonomer, catalyst type and evaluation of hlpb as crosslinking coagent

Abstract

In the present work, the synthetic route to obtain crosslinked polyethylene (PEX) was studied using vinyltrimethoxy silane (VTMS) as crosslink agent and commercial polyethylene (HDPE and LLDPE). Materials were processed with increasing amounts of VTMS (2.5, 5.0 and 7.5 wt.%). After insertion of silane onto polymer chain in solid state, samples were molded by compression. Gel content was used to measure the extension of crosslinking. Melting temperature and degree of crystallinity were evaluated using differential scanning calorimetry (DSC). The microstructure of the starting polyethylene was correlated with the effectiveness of crosslinking and the resultant thermal and mechanical properties of the PEX. Hydroxylated liquid polybutadiene (HLPB) was employed to improve crosslink efficiency, as well as mechanical properties of the material.