Hydroxyl-Terminated Polyisobutylene

The hydroxyl-terminated homo- and copolymers of butadiene have been utilized in the preparation or modification of urethane elastomers and sealants (102). Owing to the presence of unsaturation in these polymers, reinforcement with certain fillers such as carbon black can be achieved. Hydroxyl-terminated polyisobutylenes have also been used for the preparation of NCO-terminated prepolymers (103). Very recently (104). a,u-di-(hydroxy)polyisobutylenes have been prepared by a different route. Polyurethane films prepared from these polyisobutylene glycols have exhibited excellent hydrolytic stability and very low water absorption (105). However, these materials are not yet commercially available. 

The same chemistry was used for the three-arm star telechelic polyisobutylene synthesis (171). These two functional groups (that is, propenyl and hydroxyl) afford the possibility of almost any kind of functional groups to be introduced at the chain ends of polyisobutylene. By derivation of hydroxyl and propenyl terminated polyisobutylene, telechelics containing carboxylic (191. 192), -SiCl and H-SiH (193. 19A). acryloyl and methacryloyl (195). 

---