Method for preparing a graft copolymer with a polyolefin backbone and polyorganosiloxane pendant groups
A method for preparing a graft copolymer having a polyolefin backbone and polyorganosiloxane pendant groups can be catalyzed by a Lewis Acid catalyst, Piers-Rubenstzjan catalyst, or hydrosilylation reaction catalyst. The graft copolymer prepared by the method is useful as a thermoplastic elastomer or as a compatibilizer in compositions containing both a polyolefin and a polyorganosiloxane.
1. A method for preparing a copolymer comprising:
1) combining starting materials comprising
A) a silane grafted polyolefin comprising units of formulae
where each R is independently selected from a monovalent hydrocarbon group of 1 to 18 carbon atoms or a monovalent halogenated hydrocarbon group of 1 to 18 carbon atoms, each R 1 is independently a divalent hydrocarbon group of 2 to 50 carbon atoms, each R 5 is independently selected from R or OR, and each R 15 is independently H, a monovalent hydrocarbon group of 1 to 18 carbon atoms or a monovalent halogenated hydrocarbon group of 1 to 18 carbon atoms, subscript m≥1, and subscript n≥1;
B) a polyorganosiloxane of formula
where R 6 is H; and each R 7 is independently selected from R and R 6 ;
C) a Lewis acid catalyst; and
D) a solvent; thereby preparing a reaction product comprising a graft copolymer.
2. The method of claim 1 , where the graft copolymer comprises units of formulae:
where each R 3 is independently R or OR, each R 4 is independently R, H, OR, or OH or the silyl moiety of formula —R 1 —SiR a (OR) b ; and subscript o is 5 to 500.
3. A method for preparing a copolymer comprising:
1) combining starting materials comprising
A) a silane grafted polyolefin silane grafted polyolefin comprising units of formulae
where each R is independently selected from a monovalent hydrocarbon group of 1 to 18 carbon atoms or a monovalent halogenated hydrocarbon group of 1 to 18 carbon atoms, each R 1 is independently a divalent hydrocarbon group of 2 to 50 carbon atoms, each R 8 is selected from R and H, subscript m≥1, and subscript n≥1;
B) a polyorganosiloxane formula
where R 9 is selected from OR or OH, and each R 10 is independently selected from R and R 9 and subscript o is 5 to 500;
C) a Lewis acid catalyst; and
D) a solvent.
4. The method of claim 3 , where the graft copolymer comprises units of formulae:
where each R 16 is independently R or H, each R 17 is independently R, OR, or OH, and subscript o is 5 to 500.
5. The method of claim 1 , where C) the Lewis Acid catalyst is selected from C 5 F 4 )(C 6 F 5 ) 2 B; (C 5 F 4 ) 3 B; (C 6 F 5 )BF 2 ; BF(C 6 F 5 ) 2 ; B(C 6 F 5 ) 3 ; BCl 2 (C 6 F 5 ); BCl(C 6 F 5 ) 2 ; B(C 6 H 5 )(C 6 F 5 ) 2 ; B(C 6 H 5 ) 2 (C 6 F 5 ); [C 6 H 4 (mCF 3 )] 3 B; [C 6 H 4 (pOCF 3 )] 3 B; (C 6 F 5 )B(OH) 2 ; (C 6 F 5 ) 2 BOH; (C 6 F 5 ) 2 BH; (C 6 F 5 )BH 2 ; (C 7 H 11 )B(C 6 F 5 ) 2 ; (C 8 H 14 )B(C 6 F 5 ); (C 6 F 5 ) 2 B(OC 2 H 5 ); or (C 6 F 5 ) 2 B—CH 2 CH 2 Si(CH 3 ).
6. The method of claim 5 , is tris(pentafluorophenyl)borane.
7. The method of claim 1 , where subscript m is 1 to 10 and 0.01 mole %<m/(m+n)<10 mol %.
8. The method of claim 1 , where each R is independently selected from an alkyl group, an alkenyl group, or an aryl group.
9. The method of claim 1 , where each R 15 is a hydrogen atom.
10. The method of claim 1 , where the silane grafted polyolefin and the copolymer further comprises an endblocking group at each terminus, where each endblocking group may independently be a saturated monovalent hydrocarbon group or an unsaturated monovalent hydrocarbon group having one or more double bonds.
11. The method of claim 1 , further comprising forming A) the silane-grafted polyolefin by a method comprising grafting a silane moiety onto a polyolefin by metallocene catalysis before step 1).
12. The method of claim 1 , further comprising: recovering the graft copolymer from the reaction product.
13. The method of claim 1 , further comprising using the copolymer as a compatibilizer in a composition comprising a polyolefin and a polyorganosiloxane.