A major drawback of conventional emulsion polymers arises from the presence of migrating low molar mass surfactants that contribute to poor water barrier properties and low adhesion to substrates. In this paper, we demonstrate how living polymer chains obtained by reversible addition–fragmentation chain transfer (RAFT) can be used as an efficient stabilizer in emulsion polymerization, leading to the production of surfactant-free latexes, which then form cross-linked films with beneficial properties. Hydrophilic poly(methacrylic acid) (PMAA) chains obtained by RAFT performed in water are used to mediate emulsion polymerization and produce film-forming latex particles from mixtures of methyl methacrylate, n-butyl acrylate, and styrene. Stable dispersions of particles with sizes between 100 and 200 nm are obtained, with very low amounts of coagulum (<0.5 wt %). The particles are stabilized by the PMAA segment of amphiphilic block copolymers formed during the polymerization. Remarkably, low amounts of PMAA chains (from 1.5 down to 0.75 wt %) are enough to ensure particle stabilization. Only traces of residual PMAA macroRAFT agents are detected in the final latexes, showing that most of them are successfully chain extended and anchored on the particle surface. The glass transition temperature of the final material is adjusted by the composition of the hydrophobic monomer mixture so that film formation occurs at room temperature. Conventional cross-linking strategies using additional hydrophobic comonomers, such as 1,3-butanediol diacrylate (BuDA), diacetone acrylamide (DAAm), and (2-acetoacetoxy)ethyl methacrylate (AAEM), are successfully applied to these formulations as attested by gel fractions of 100%. When particles are internally cross-linked with BuDA, chain interdiffusion between particles is restricted, and a weak and brittle film is formed. In contrast, when DAAm-containing chains undergoes cross-linking during film formation, full coalescence is achieved along with the creation of a cross-linked network. The resulting film has a higher Young’s modulus and tensile strength as a result of cross-linking. This synthetic strategy advantageously yields a surfactant-free latex that can be formed into a film at room temperature with mechanical properties that can be tuned via the cross-linking density.

中文翻译：

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亲水的MacroRAFT介导的乳液聚合：交联和无表面活性剂薄膜的胶乳的合成

常规乳液聚合物的主要缺点是由于迁移的低摩尔质量的表面活性剂的存在而引起的，这导致差的阻水性能和对基材的低粘附性。在本文中，我们证明了通过可逆加成-断裂链转移（RAFT）获得的活性聚合物链如何在乳液聚合中用作有效的稳定剂，从而生产出不含表面活性剂的胶乳，然后形成与乳胶交联的交联膜。有益的特性。亲水性聚（甲基丙烯酸）（PMAA）通过RAFT得到的链在水中用于介导乳液聚合和农产品进行成膜自甲基丙烯酸甲酯的混合物的胶乳颗粒，Ñ丙烯酸丁酯和苯乙烯。获得具有非常少量的凝结物（<0.5重量％）的尺寸在100至200nm之间的稳定的颗粒分散体。颗粒通过聚合过程中形成的两亲嵌段共聚物的PMAA链段稳定。值得注意的是，少量的PMAA链（从1.5至0.75 wt％）足以确保颗粒稳定。在最终的胶乳中仅检测到残留的PMAA macroRAFT剂痕迹，表明它们中的大多数已成功扩链并锚定在颗粒表面。最终材料的玻璃化转变温度通过疏水性单体混合物的组成进行调节，从而在室温下形成膜。使用其他疏水性共聚单体（例如1,3-丁二醇二丙烯酸酯（BuDA））的常规交联策略，经100％凝胶分数证明，双丙酮丙烯酰胺（DAAm）和甲基丙烯酸（2-乙酰乙酰氧基）乙酯（AAEM）已成功应用于这些配方。当颗粒通过BuDA内部交联时，颗粒之间的链间扩散受到限制，并且形成了薄而脆的膜。相反，当含DAAm的链在成膜过程中发生交联时，随着交联网络的产生，可以实现完全聚结。由于交联，所得膜具有较高的杨氏模量和拉伸强度。这种合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。如100％的凝胶分数所证明的，它们已成功应用于这些制剂。当颗粒通过BuDA内部交联时，颗粒之间的链间扩散受到限制，并且形成了薄而脆的膜。相反，当含DAAm的链在成膜过程中发生交联时，随着交联网络的形成，可以实现完全聚结。由于交联，所得膜具有较高的杨氏模量和拉伸强度。这种合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。如100％的凝胶分数所证明的，它们已成功应用于这些制剂。当颗粒通过BuDA内部交联时，颗粒之间的链间扩散受到限制，并且形成了薄而脆的膜。相反，当含DAAm的链在成膜过程中发生交联时，随着交联网络的产生，可以实现完全聚结。由于交联，所得膜具有较高的杨氏模量和拉伸强度。该合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。颗粒之间的链相互扩散受到限制，并形成了弱而脆的膜。相反，当含DAAm的链在成膜过程中发生交联时，随着交联网络的产生，可以实现完全聚结。由于交联，所得膜具有较高的杨氏模量和拉伸强度。这种合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。颗粒之间的链相互扩散受到限制，并形成了弱而脆的膜。相反，当含DAAm的链在成膜过程中发生交联时，随着交联网络的产生，可以实现完全聚结。由于交联，所得膜具有较高的杨氏模量和拉伸强度。这种合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。由于交联，所得膜具有较高的杨氏模量和拉伸强度。这种合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。由于交联，所得膜具有较高的杨氏模量和拉伸强度。这种合成策略有利地产生了无表面活性剂的胶乳，该胶乳可以在室温下形成具有可通过交联密度调节的机械性能的膜。