THE EFFECT OF CROSS-LINKING ON TOUGHNESS OF COMPOSITE LDPE SILICA

The effect of crosslinking on the toughness of LDPE filled with two di fferent grades of silica was investigated. An elastic plastic fracture mechanism based on the J integral has been used to evaluate the resul ts of notch impact resistance. Crosslinking of the matrix in PE/silica composites leads to improved toughness when compared to uncrosslinked composites. The increase of toughness results mainly from an increase in the amount of plastic deformation and, consequently, higher ultima te deformation at fracture. A positive effect of crosslinking on the d evelopment of plastic deformation was also demonstrated by SEM, showin g that the fracture is entirely cohesive.