Study on the structure and properties of new metallocene high branched polyethylene

Abstract

The branching composition, distribution and melting crystallization properties of very low density polyethylenes (VLDPE) with different carbon chain length were studied by means of nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). The average sequence length (nE, nH, nB), relative monomer distribution (RMD) and monomer reactivity ratio (rE, rH, rB) were selected to analyze the polymerization characteristics. The crystallization characteristics of wafer thickness (L), relative branching degree (S) and crystallinity (Xc) were discussed by means of SSA thermal classification method. It has been found that the comonomer content and branching degree of VLDPE products with hexene (C6) as co monomers is lower than that of butene (C4) copolymer products; while the crystallinity and lamellar thickness is higher than that of C4 products.