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This study introduces bis(1‐cyanocyclohex‐1‐yl)trithiocarbonate (TTC‐bCCH) as a novel trithiocarbonate chain transfer agent and compares its reactivity with the previously described bis(2‐cyanopropan‐2‐yl)trithiocarbonate (TTC‐bCP) for the reversible addition‐fragmentation chain transfer (RAFT) polymerization of styrene (St), n‐butyl acrylate (nBA), and methyl methacrylate (MMA). Significant findings include the effective control of Mn and low dispersities from the onset of polymerization of St and nBA showing swift addition‐fragmentation kinetics, leading to similar behaviors between the two RAFT agents. In contrast, a fourfold decrease of the chain transfer constant to MMA is established for TTC‐bCCH over TTC‐bCP. This trend is confirmed through density functional theory (DFT) calculations. Finally, the study compares thermoplastic elastomer properties of all‐(meth)acrylic ABA block copolymers produced with both RAFT agents. The impact of dispersity of PMMA blocks on thermomechanical properties evaluated via rheological analysis reveals a more pronounced temperature dependence of the storage modulus (G′) for the triblock copolymer synthesized with TTC‐bCCH, indicating potential alteration of the phase separation. [ABSTRACT FROM AUTHOR]

Photo‐iniferter reversible addition‐fragmentation chain transfer (PI‐RAFT) polymerization of N‐vinylformamide (NVF) is demonstrated by using purple light. PNVFs with predetermined molar masses and narrow molar mass distributions are obtained. High RAFT chain‐end fidelity is confirmed by matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) and electrospray‐ionization time‐of‐flight mass spectrometry (ESI‐TOF‐MS), and chain extension experiment. To demonstrate the potential of this approach, an original poly(N‐vinylpyrrolidone)‐b‐poly(N‐vinylformamide) (PVP‐b‐PNVF) diblock copolymer is synthesized and characterized by aqueous size‐exclusion chromatography (SEC), asymmetric flow field‐flow fractionation (A4F), and 1H diffusion‐ordered spectroscopy nuclear magnetic resonance (1H DOSY NMR). Finally, selective hydrolysis of PNVF block to corresponding pH‐responsive poly(N‐vinylpyrrolidone)‐b‐poly(N‐vinylformamide) (PVP‐b‐PVAm) is performed. [ABSTRACT FROM AUTHOR]

Although various successful strategies have been reported in the past for the postpolymerization modification of the reversible addition-fragmentation chain transfer (RAFT) terminal group in homogeneous media, no solution is proposed for the tedious case of aqueous polymer dispersions where most of the thiocarbonylthio terminal group is buried into the core of the polymer particle. In this work, ozone is proposed to tackle this important academic and industrial challenge. After preliminary model ozonolysis reactions performed on a xanthate RAFT agent and a derived low molar mass poly( n-butyl acrylate) (PBA) in dichloromethane solution, it is shown that the hydrophobic nature and strong oxidant properties of ozone are responsible for its efficient diffusion in aqueous PBA latex particles obtained by RAFT and selective and complete transformation of the xanthate terminal group into a thiocarbonate end-group. In addition to the beneficial total discoloration of the final product, this chemical treatment does not generate any volatile organic compound and leaves the colloidal stability of the polymer particles unaffected, provided that a PBA latex with a sufficiently high Mn of 5000 g mol−1 is selected. [ABSTRACT FROM AUTHOR]