Self-condensing vinyl polymerization (SCVP) provides an efficient approach for synthesis of hyperbranched polymers. However, most of the inimers employed for SCVP need to be synthesized before use. Here, we report a facile strategy to synthesize hyperbranched polymers under mild conditions by using a commercially available hydroxyl-substituted methacrylate as the inimer. The hyperbranched structures of the resulting polymers were confirmed by nuclear magnetic resonance, differential scanning calorimetry and size-exclusion chromatography equipped with online light scattering and viscosity detectors. The synthesis can be performed under mild reaction conditions. Particularly, this approach can be applied to not only the SCVP of vinyl monomers but also the self-condensing ring-opening polymerization of cyclic esters for preparation of hyperbranched polyesters. The present study provides a facile strategy to synthesize hyperbranched polymers.
Poly(p-dioxanone) (PPDO) has received significant attention due to its good biocompatibility and fast biodegradation profiles. In addition, PPDO is a polymer with high potential in biomedical applications. However, the conventional syntheses of PPDO via the ring-opening polymerization (ROP) of p-dioxanone (PDO) often use a metallic catalyst, which significantly limits its biorelated applications. This investigation was focused on the synthesis of metal-free PPDO by using phosphazene base t-BuP 4 as the catalyst. The effects of the reaction conditions including temperature, reaction time, initiators, and feed molar ratios were studied in detail by nuclear magnetic resonance spectroscopy, viscosimetry, differential scanning calorimetry, and thermogravimetric analysis. The results showed that t-BuP 4 exhibited especially high activity in catalyzing alcohol or aniline to initiate the ROP of PDO, consequently resulting in metal-free PPDOs. The polymerization was optimum at a reaction temperature of approximately 1008C and 88.7% of PDO was consumed. The viscosity-average molecular weights of the resulting polymer reached as high as 2.09 3 10 4 g/mol. The molar ratios of [PDO]/[t-BuP 4 ] also had an obvious effect on both the polymerization and the resulting polymer. Increasing [PDO]/[t-BuP 4 ] ratios facilitated the molecular weight growth, whereas the conversions of PDO significantly decreased. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43030.
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