Novel polyisobutylene/poly(dimethylsiloxane) bicomponent networks. I. Synthesis and characterization

✍ Scribed by Melissa A. Sherman; Joseph P. Kennedy

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 170 KB
• Volume: 36
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(199808)36:11<1891::aid-pola24>3.0.co;2-8

✦ Synopsis

The synthesis of novel polyisobutylene (PIB)/poly(dimethylsiloxane) (PDMS) bicomponent networks is described. The synthesis strategy (see Figure 1) was to prepare well-defined and -characterized allyl-tritelechelic polyisobutylenes [ f(PIB{ C{C|C) 3 ] and SiH-ditelechelic poly(dimethylsiloxanes) (HSi-PDMS-SiH) and then crosslink these moieties by hydrosilation. The f(PIB{C{C|C) 3 was prepared by living isobutylene polymerization followed by end-quenching with allyltrimethylsilane, whereas the HSi-PDMS-SiH was obtained by equilibrium polymerization of octamethylcyclotetrasiloxane and tetramethyldisiloxane. The detailed structures of the starting polymers were characterized by GPC and 1 H-NMR spectroscopy. A series of PIB/PDMS bicomponent networks of varying compositions and average molecular weights between crosslinks ( M V c ) of Ç 20,000 g/mol were assembled. Optimum crosslink- ing conditions were defined in terms of H 2 PtCl 6 catalyst concentration, nature of solvent, time, temperature, and stoichiometry of Ç CH 2 CH|CH 2 /ÇSiH groups, allowing for the convenient synthesis of well-defined model bicomponent networks. Swelling studies and elemental analysis confirm the correctness of the synthetic strategy. ᭧ 1998