Functional polyisobutylene-containing oligomers and polymers
A method of making functional polyisobutylene (PIB)-containing oligomers and polymers. By the disclosed method, the synthesis of functional PIB-containing polymers can be achieved directly under cationic polymerization conditions and does not include any post-polymerization reactions. The desired functionality is introduced by direct Electrophilic Aromatic Substitution (EAS) reaction using substituted phenyl ring carrying desirable functionalities that do not react with Lewis acid but have weak association with Lewis acid, which still allow living polymerization and EAS reaction under living cationic polymerization conditions. In the disclosed method functional polyisobutylene or isobutylene containing oligomers and polymers can be prepared using stoichiometric or near stoichiometric ratios of the capping or functionalization reagent to polymer end-chain.
1. A method of preparing a PIB oligomer or polymer in a one step reaction, comprising:
disposing an amount of an initiator having the structure R 1 X n into a reactor;
disposing an amount of isobutylene into the reactor;
reacting the initiator with the isobutylene under cationic polymerization conditions to form a reaction mixture comprising an intermediate having the structure
disposing a capping reagent into the reaction mixture; and
reacting the capping reagent with the intermediate in the reactor under cationic polymerization condition to form the PIB oligomer or polymer having the structure
where:
R 1 is an initiator core structure independently selected from alkyl, heteroalkyl, aryl, heteroaryl, alkenyl, heteroalkenyl, alkynyl, heteroalkynyl and alkoxy;
X is an initiating site bonded to the initiator core structure independently selected from halide, alkoxy, ester;
m is an integer from 2 to about 1,000;
n is 2 to 3;
the capping reagent selected from one or more of following structures 1 to 3;
Ar-(EDG-R 2 —Y) q 1
(Ar) p —Ar-(EDG-R 2 —Y) q 2
PAr-(EDG-R 2 —Y) q 3
where EDG is an electron donating group selected from O, NR 3 , S, R 4 ;
R 2 can be independently selected from H, alkylene, heteroalkylene, alkenylene, heteroalkenylene, alkynylene, heteroalkynylene, arylene, heteroarylene;
R 3 can be independently selected from H, alkyl, heteroalkyl, alkenyl, heteroalkenyl, alkynyl, heteroalkynyl, aryl, heteroaryl;
R 4 can be independently selected from H, alkylene, heteroalkylene, alkenylene, heteroalkenylene, alkynylene, heteroalkynylene, arylene, heteroarylene;
p is an integer from about 1 to about 20;
q is an integer from about 1 to about 20;
Y can be independently selected from (meth)acrylate, OH, epoxy, oxetane, cyanate, isocyanate, urethane, urea, NR 5 R 6 , SR 7 , Si(OR 8 ) i R 9 3-I , where R 5 , R 6 , R 7 , R 8 , R 9 can be independently selected from H, alkyl, heteroalkyl, alkenyl, heteroalkenyl, alkynyl, heteroalkynyl, aryl, heteroaryl;
a ratio of the capping reagent to intermediate end-chain calculated as ratio=equivalents of the capping reagent/equivalents of intermediate end-chain is in the range of 0.7 to 2; and
the PIB oligomer or polymer has an endcap functionality of 1.6 to 2.0.
2. The method of claim 1 wherein a ratio of the capping reagent to intermediate end-chain calculated as ratio=equivalents of the capping reagent/equivalents of intermediate end-chain is in the range of 0.8 to 2.
3. The method of claim 1 wherein a ratio of the capping reagent to intermediate end-chain calculated as ratio=equivalents of the capping reagent/equivalents of intermediate end-chain is in the range of 0.9 to 1.4.
4. The method of claim 1 wherein a ratio of the capping reagent to intermediate end-chain calculated as ratio=equivalents of the capping reagent/equivalents of intermediate end-chain is substantially stoichiometric.
5. The method of claim 1 wherein EDG for capping reagent 1) is selected from NR 3 , S, R 4 .
6. A PIB oligomer or polymer prepared by the method of claim 1 .
7. A curable composition comprising the PIB containing oligomer or polymer of claim 1 and optionally further comprising one or more of a co-monomer, catalyst, filler, antioxidant, reaction modifier, adhesion promoter, rheology modifier.
8. Cured reaction products of the curable composition of claim 7 .
9. The method of claim 1 wherein Y is selected from (meth)acrylate, epoxy, urethane and urea.
10. The method of claim 1 wherein the capping reagent is structure 1
Ar-(EDG-R 2 —Y) q , and 1
EDG is selected from O or S;
R 2 is selected from alkyl, alkenyl or alkynyl;
Y is selected from (meth)acrylate, epoxy, urethane and urea.
11. The method of claim 1 wherein n is 2.
12. The method of claim 1 wherein the initiator is dicumyl chloride.
13. The method of claim 1 wherein the PIB oligomer or polymer has an endcap functionality of 1.8 to 2.0.