Bright blue fluorescence-emitting hyperbranched polysiloxane simultaneously carrying unconjugated carbon–carbon double bonds and hydroxyl groups is reported for the first time.
A novel silicon-containing hyperbranched epoxy (SHBEp) has been explored via a one-pot A 2 + B 3 polycondensation reaction using (3-glycidyloxypropyl)trimethoxysilane (A-187) and excess neopentyl glycol (NPG) under solvent-free and catalyst-free conditions. We investigate for the first time bismaleimide (BMI) toughening effect using the fabricated polymer, and a series of SHBEp/BMI thermosets are then constructed, and then their mechanical properties like impact strength, flexural strength, and thermal stability are studied; meanwhile the toughening effect of SHBEp and conventional epoxy resin E51 is also compared. The results indicate that a proper addition of SHBEp (8 wt%) can significantly improve the toughness and thermal performance of thermosets compared to E51 with the same content. It is, therefore, revealed that the polymer is promising to act as an effective BMI toughener. Unexpectedly, a bright blue photoluminescence is observed when the SHBEp is excited under 365 nm UV light, and its average fluorescence lifetime and absolute fluorescence quantum yield are 4.30 ns and 4.61% respectively. It is demonstrated by our primary investigation that the epoxide and hydroxyl groups simultaneously help the light emission. Thus, the SHBEp bearing unconventional chromophores is also particularly expected to be a new light-emitting material. † Electronic supplementary information (ESI) available: GPC curve, the predicted 29 Si NMR of the obtained polymer, TGA and DSC curves, and additional hyperbranched polysiloxanes. See
In this Communication, novel water-soluble hyperbranched polysiloxanes (WHPSs) simultaneously containing hydroxyl and primary amine groups are developed. The polymers are constructed via melt polycondensation, that is, transesterification reaction between ethoxyl groups of (3-aminopropyl)triethoxysilane and hydroxyl groups of dihydric alcohols, using a one-step process under catalyst-free conditions. Surprisingly, the resultant WHPSs can emit bright blue fluorescence in the 100% solid state under the irradiation of UV light, and their photoluminescence intensities in aqueous solutions continuously go up along with increasing concentrations. Interestingly, their hydrolyzates display more intense luminescence compared to the unhydrolyzed. The efficient and easily controllable preparation strategy provides a remarkable and versatile platform for the fabrication of neoteric fluorescent materials for various potential applications.
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