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Hyperbranched polysiloxysilane (HBPS) with terminal vinyl groups P1 was synthesized by self-condensation reaction using platinum-catalyzed hydrosilylation of 1,1 ,3,5,5-pentamethyl-1,5-divinyltrisiloxane. A number-average molecular weight (Mn) was 5400 with a polydispersity index of 1.49. End-functionalization of the terminal vinyl groups was carried out by epoxidation with 3-chloroperoxybenzoic acid to afford epoxy-terminated HBPS P2. The polymers obtained were characterized by IR, ¹H, 13C, 29Si NMR spectroscopy. The degree of branching of HBPS was estimated as 0.57 in comparison of 29Si NMR spectra of P2 and model compounds. The glass transition temperatures (Tg) of P1 and P2 were observed at -97°C and -77°C, respectively. The 10% weight loss temperatures (T10) of P1 and P2 were over 440°C in nitrogen. [ABSTRACT FROM AUTHOR]

The hyperbranched poly(siloxysilane) possessing rhodamine B (HBPS-RB) group on the terminal position was synthesized by esterification of hyperbranched poly(siloxysilane) with hydroxyl terminal group and RB in the presence of DCC and DMAP. Two derivative hyperbranched poly(siloxysilane)s containing vinyI(HBPS-V) and hydroxyl (HBPS-OH) terminal groups were prepared by hydrosilylation of bis(dimethylvinylsilyl) methylsilox- ane(AB2) and radical addition of 2-mercaptoethanol using AIBN as initiator, respectively. The structures of the polymers were characterized by the ¹H NMR, 13C NMR and Fourier Transform Infrared (FF-IR) spectra. The molecular weights were measured by gel permeation chromatography (GPC). The UV-Visible absorption spectra indicate that 34% RB was conjugated to polymer. Fluorescence spectrum indicated that aggregation of RB was depressed in the polymer because RB molecules were separated by branch of polymer molecules. [ABSTRACT FROM AUTHOR]

Abstract: Hyperbranched poly(ether sulfone) polymers having sulfonyl chloride end-groups is blended at up to 30w% with linear poly(ether ether ether sulfone)s and a two-phase system is generated via spinodal decomposition upon drying from a DMAc solution. Conversion of the end-groups from sulfonyl chloride to sulfonic acid is accomplished using 16M H2SO4 that is also believed to introduce additional sulfonic acid groups at the interface of the linear polymer. The blend films before and after conversion to sulfonic acid have similar tensile strengths as films composed of solely linear polymer (yield stress >40MPa and Young''s modulus >3GPam). These films are designed to test the viability of hyperbranched polymers as fuel cell membranes. Proton conductivities of up to 0.03Scm−1 are observed at 80°C and 90% R.H indicating a good potential for use of hyperbranched polymers as a proton conduction material. [Copyright &y& Elsevier]