Reversible addition–fragmentation chain transfer (RAFT) was applied to the copolymerization of styrene and maleic anhydride. The product had a low polydispersity and a predetermined molar mass. Novel, well‐defined polyolefin‐based block copolymers were prepared with a macromolecular RAFT agent prepared from a commercially available polyolefin (Kraton L‐1203). The second block consisted of either polystyrene or poly(styrene‐co‐maleic anhydride). Furthermore, the colored, labile dithioester moiety in the product of the RAFT polymerizations could be removed from the polymer chain by UV irradiation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3596–3603, 2000

ABSTRACT:The seeded batch emulsion copolymerization of styrene and acrylic acid was studied. The polymerization rate was investigated with pH as the main parameter. Some attempts were made to evaluate the average number of growing chains per particle during Stage II of the emulsion polymerization process. The final latex products were characterized by means of conductometric aqueous titration and potentiometric titration in an organic solvent mixture. The distribution of the acid groups over the aqueous phase, the particle surface, and the interior of the particles together with the kinetic results provided insight into important features governing the incorporation of acrylic acid. The results indicate that pH is the dominating parameter for the incorporation process. An optimal incorporation on the surface of the particles is observed for a low value of pH. In that case, all the acid groups are protonated.

We present a systematic study of incorporating carboxyl groups into latex particles to enhance colloidal stability and the physical properties of the latex. Statistical copolymers of methacrylic acid and methyl methacrylate) were synthesized via catalytic chain transfer polymerization (CCTP) in emulsion. The vinyl‐terminated oligomers were in turn successfully utilized as chain transfer agents for the formation of diblock and pseudo triblock copolymers via sulfur‐free reversible addition–fragmentation chain transfer polymerization (SF‐RAFT). These copolymers were characterized using 1H NMR, size exclusion chromatography (SEC), dynamic light scattering (DLS), dynamic mechanical analysis (DMA), contact angle measurements and matrix‐assisted laser desorption/ionization time of flight mass spectroscopy (MALDI‐TOF‐MS) techniques. © 2019 The Authors. Journal of Polymer Science Part A: Polymer Chemistry published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, E1–E9

The activation rate parameter (k act) in atom transfer radical polymerization (ATRP) for a poly(ethylene-co-butylene) (PEB) macroinitiator bearing a bromoisobutyryl initiating group catalyzed by CuBr/2L and CuCl/2L (L = N - n-pentyl-2-pyridylmethanimine) has been determined using the nitroxide exchange reaction with hydroxy-TEMPO in combination with gradient polymer elution chromatography (GPEC). With GPEC and 1H NMR analyses, the fraction of activated chains that is terminated via combination with hydroxy-TEMPO was estimated at 95%. Concentrations of the activating copper(I) complexes during the exchange experiments have been determined using UV−vis spectroscopic measurements. Compared to bromide, the use of chloride as the copper counterion results in a strong increase in k act by more than a factor of 2. The improved control in ATRP for mixed halide initiating systems as R−Br/CuCl compared to R−Br/CuBr systems is therefore not entirely attributed to an increased ratio of initiation to propagation rate through halogen exchange, but also finds its origin in an increased rate of activation.

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