DSC and DMA Studies on Silane-Grafted and Water-Crosslinked LDPE/LLDPE Blends

摘要

Effects of silane grafting and water crosslinking reactions on crystallizations, melting behaviors, and dynamic mechanical properties of the LDPE/LLDPE blends are investigated using DSC and DMA. From DSC data, cocrystallization of LDPE and LLDPE does not occur, but cocrosslinking of these two polymers is evidenced at the experimental temperature of l00degC, a temperature lower than melting temperatures of both polymers. The water crosslinking reactions of the LLDPE-rich blends enable development of a new phase having a melting endotherm in between that of LDPE and LLDPE. From the thermal fractionation data, interaction between LDPE and LLDPE is observed, and compatibilization of the blends can be achieved by the crosslinking reactions. From DMA data, the storage moduli of the blends are not found to be consistent with their degrees of crosslinking. The storage moduli of the b!ends are not simply determined by the degree of crosslinking but determined by very complicated but unclear factors.