63263-63-8 2-Butenedioic acid,(1,1,3,3-tetramethyl-1,3-disiloxanediyl)di-3,1-propanediylbis(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl) ester 63263-62-7 2-Butenedioic acid,(1,1,3,3-tetramethyl-1,3-disiloxanediyl)di-3,1-propanediylbis(2,2,3,3,4,4,5,5-octafluoropentyl) ester