alkyl radicals such as methyl ethyl n propyl isopropyl n butyl cyclopropyl pentyl hexyl cyclohexyl cyclohexylmethyl preferably n butyl n propyl methyl or ethyl yielding of course such moieties as for example ch 2 ch 2 ch 2 ch 2 ch 2 ch 2 ch 2 c 6 h 10 wherein the silicon is preferably attached at the meta position of the cyclohexyl moiety and the like preferably the moiety of ch 2 m ch u2550 ch ch 2 n is in its trans configuration and preferably m is 1 and n is zero preferably the ch 2 m cyclopentenylene and cyclohexenylene moieties have their unsaturation at the carbon atom to which the silicon is attached e g str3 preferably for the ch 2 p phenylene moiety p is 1 or 2 and the sir 1 r 2 r 3 moiety is attached to the phenyl moiety at its 3 position preferred ch 2 p t moieties are illustrated as str4 with p preferably being 1 or 2 in those instances wherein r 1 is c 1 7 alkyl or c 1 7 alkoxy then methyl ethyl tert butyl methoxy and ethoxy are preferred the c 1 7 alkyl of c.