Process for the preparation of hydroxyl-functionalized polysiloxanes
摘要:
A method for producing a hydroxyl-functionalized polysiloxane having secondary or tertiary hydroxyl groups, said method comprising the steps of: i) reacting a hydroxyalkyl allyl ether having a secondary or tertiary alcohol group with a siloxane under anhydrous conditions and under transition metal catalysis, said hydroxylalkyl allyl ether conforming to Formula (I) wherein n is 0, 1, 2, 3, 4 or 5, preferably 0; m is 1, 2, 3, 4 or 5, preferably 1; spacer group A is constituted by a covalent bond or a C1-C20 alkylene group; R1 is hydrogen, a C1-C8 alkyl group, a C3-C10 cycloalkyl group, a C6-C18 aryl group or an aralkyl group; Ra, Rb, Rc, Rd, R2, R3, R4 and R5 may be the same or different and each is independently selected from hydrogen, a C1-C8 alkyl group, a C6-C18 aryl group or a C6-C18 aralkyl group, with the proviso that at least one of R3 and R4 is not hydrogen; and said siloxane conforming to Formula (II) wherein m is 1, 2, 3, 4 or 5, preferably 1; R6, R7, R8 and R9 may be the same or different and each represent a C1-C8 alkyl group, a C3-C10 cycloalkyl group, a C6-C18 aryl group or a C6-C18 aralkyl group; and ii) in the presence of the reaction product of step i), performing a ring opening polymerization of at least one cyclic siloxane monomer.
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