ISSN:
1436-2449
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Summary Block copolymers comprising of a central rubbery polyisobutylene PIB segment connected to two or four glassy polystyrene PSt segments (i.e., triblocks or H blocks) have been prepared and characterized. The syntheses were accomplished by coupling living polystyrene anions PStΘ to chlorosilanetelechelic PIB's, for example, Cl-Si-PIB-Si-Cl. The latter prepolymers were obtained by hydrosilylating olefin-telechelic PIB's with chlorohydrosilanes. The conditions necessary for the syntheses have been developed with the aid of model kinetic experiments using 2,4,4-trimethyl-1-pentene. The rate of hydrosilylation of this model olefin in the presence of H2PtCl6 gave the following reactivity order for the chlorohydrosilanes investigated: MeSiHCl2⩾Me2SiHCl 〉 HSiCl3. Increasing the silane/olef in ratio, temperature, and catalyst concentration enhances the rate of hydrosilylation and conversion. The block copolymers have been characterized by fractional solvent separation followed by RI-UV dual detector GPC, osmometry, and high resolution 1H NMR spectroscopy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00263243
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