Synthesis of New Organic Crosslinking Reagents Containing SiH Bonds and Curing System Thereof

Abstract

New organic crosslinking reagents 1 containing SiH bonds have been syntheslzed by platinum-catalyzed “Selective Hydrosilylatron” (SHS) reaction of either 1,9-decadiene 2a or diallyl ether of bisphenol A 2b with 2,4,6,8-tetramethylcyclotetrasiloxane [CH3(H)SiO]4 (3) (hereafter called hydrocyclotetrasiloxane) (eq 1). Identification of the new crosslinking reagents 1 was well performed by 1H NMR. The cyclic structure of the starting hydrocyclotetrasiloxane 3 was retained in the product 1 after the SHS reaction, as evidenced by 13C NMR analysis. The storage stability of 1 was significantly influenced by the amount of Pt catalyst still remaining in it. It could get much better when a decreased amount of Pt catalyst was used for SHS reaction and benzothiazole was added. Curing system composed of 1a and allyloxy end-blocked poly(propylene oxide) 4a was examined. Curing ability of the system was found to be dependent on temperature, amount of the Pt catalyst employed, and the number of the SiH bond per molecule of 1a. Rubbery materials could be obtained in a short period of time.