Peroxide Crosslinking of Ethylene Homo- and Copolymers in the Presence of Antioxidants and Fillers.

The crosslinking of LDPE and an ethylene ethylacrylate copolymer by dicumyl peroxide in the presence of stabilizers (antioxidants) was studied. For this purpose a linear shear vulcameter was used, the gel concentration estimated and the heat expansion measured. The temperature dependence of the decomposition of the peroxide is not influenced by the presence of stabilizers. These substances, however, give rise to an incubation time and influence the rate constant of the peroxide decomposition. The onset of the gel formation and the appearance of a Young's modulus in the entropy-elastic region require fundamentally different quantities of dicumyl peroxide. From the varied properties of the crosslinked samples it is concluded that in the course of crosslinking two different processes (entanglements and crosslinking) prevail, whcih also influence the shape of the vulcametric curve.