Silane-Grafted / Moisture-Curable Ethylene—Propylene Elastomers for the Cable Industry

Abstract

Abstract The present study has shown the capability of VTMOS grafting and moisture crosslinking of EP Elastomers. These capabilities are very large and have been shown to be dependent on various parameters. In EP copolymers, the crosslinking potential appears to be a function of the ethylene content, molecular weight, and molecular weight distribution. In the case of diene containing terpolymers, the process is shown to be limited by the diene content of the polymer through probable parasitic condensation reactions of grafted alkoxy silane. The good performance of the EP elastomers in silane-grafting/moisture-crosslinking can be also utilized in the modification of LDPE when crosslink rate improvement (elimination of hot-water treatment/hot-water treatment time reduction) or higher flexibility and lower shrinkage are needed. The positive results of this study made possible the development of EP elastomer compounds using silane-grafting and moisture-crosslinking for electrical applications. In Table IX and Table X are reported two EP elastomer compounds respectively for low-voltage and medium-voltage cable insulation applications. The key features of the above mentioned two EP elastomer compounds are the following: • high flexibility (comparable to conventional peroxide cure compound) • good mechanical properties • very fast extrusion (for productivity) • easy/versatile processing • high crosslinking state (set properties) • crosslinkable in ambient conditions.