The amount of vinyl silanes used

Use the amount for best results. With the increase of the amount of coupling agent, the impact strength increased, and when the amount of coupling agent was too large, the impact strength showed a downward trend. The fracture of XLPE is a ductile fracture, the section is irregular, and there is a phenomenon of stress whitening, and the material is simultaneously subjected to tension and shear. After PE cross-linking, due to the increase of polar groups, the degree of branching of the molecular chain increases, the distance between molecules increases, the force becomes smaller, and the impact strength is improved. Therefore, moderate cross-linking is beneficial to the improvement of the impact strength of XLPE. When the degree of cross-linking is too high, the polar groups are too dense, which hinders the movement of the chain segments, so that the forced high elasticity cannot be achieved, and the impact strength decreases instead. With the increase of the amount of silane coupling agent, the tensile strength and impact strength of cross-linked polyethylene showed an upward trend, the elongation at break showed a downward trend, and the flexural strength remained basically unchanged. With the increase of the amount of silane coupling agent, the heat resistance of cross-linked polyethylene is also greatly improved, and the gel content also increases continuously. When the amount of coupling agent reaches 2.0, the gel content is the largest. The extension of time, the gel content increases, and when the time reaches a certain value, the degree of cross-linking reaches the maximum.

At present, the coupling agents used as vinyl silane for cross-linking polyethylene (FE ) are mainly CFS-027 Vinyltrimethoxysilane [CAS 2768-02-7; VTMO; A-171; SILQUEST Y-9818 ; KH171] and CFS-080 Vinyltriethoxysilane [CAS 78-08-0; KBE1003; A-151; VTEOA; KH151] , two commonly used vinyl silanes.