Direct Synthesis of Controlled Poly(styrene‐co‐acrylic acid)s of Various Compositions by Nitroxide‐Mediated Random Copolymerization

Abstract

Styrene and acrylic acid were copolymerized under controlled conditions, in 1,4‐dioxane solution at 120 °C and 2 bar, using an alkoxyamine initiator based on the N‐tert‐butyl‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl) nitroxide, SG1. A broad composition range from 90/10 to 10/90 was investigated. With slightly different initiator concentrations and a similar initial proportion of free SG1 (4.5 mol‐% with respect to the initiator) the polymerizations exhibited very similar rates, irrespective of the proportion of acrylic acid in the comonomer mixture (80% conversion within 8 h). In all cases, the copolymers presented number average molar masses, $\overline M _{\rm n}$, that increased linearly with overall monomer conversion, and polydispersity indexes that ranged between 1.2 and 1.4. Moreover, $\overline M _{\rm n}$ followed the calculated values, based on the initial concentrations of monomers and initiator. The variation in the initiator concentration allowed to target various molar masses, but some limitation appeared at low initiator concentration owing to chain transfer to 1,4‐dioxane. From the kinetic data, the reactivity ratios were determined: rA = 0.27 ± 0.07 for acrylic acid and rS = 0.72 ± 0.04 for styrene. Depending on the initial comonomer composition, chains exhibited no or small composition drift, and hence a slightly pronounced gradient structure.Reactivity ratios for acrylic acid and styrene.magnified imageReactivity ratios for acrylic acid and styrene.

One‐Pot Synthesis of Pegylated Fluorescent Nanoparticles by RAFT Miniemulsion Polymerization Using a Phase Inversion Process

“…The copolymer was dried under reduced pressure in order to remove the residual AA monomer. The composition of the copolymer is found to be PEO 44 -b-PAA 13 -TTC-C 12 (M nth ¼ 3 350, M n SEC ¼ 4 120, M w =M n ¼ 1.04, PS calibration), [19] where 13 stands for the DP n of the PAA block, determined by 1 H NMR. Another macroRAFT agent possessing 10 PAA units (PEO 44 -b-PAA 10 -TTC-C 12 ) was synthesized following the same protocol (M nth ¼ 3 140, M n SEC ¼ 4 170 g Á mol À1 , M w =M n ¼ 1.07, PS calibration).…”

“…Another macroRAFT agent possessing 10 PAA units (PEO 44 -b-PAA 10 -TTC-C 12 ) was synthesized following the same protocol (M nth ¼ 3 140, M n SEC ¼ 4 170 g Á mol À1 , M w =M n ¼ 1.07, PS calibration). [19] …”

“…Sampling is performed at regular time intervals and monomer conversions are determined by gravimetry for styrene (Equation S1) and SEC using the UV-visible detection for BDPMA (Equation S2). Instrumentation 1 H, 13 C, 19 F and 11 B NMR spectra were recorded in CDCl 3 on a JEOL ECS (400 MHz) spectrometer. All chemical shifts are referenced to Me 4 Si (TMS).…”

Ability of nitrones of various structures to control the radical polymerization of styrene mediated by in situ formed nitroxides

“…For instance, functional TEMPO, such as 4-oxo-TEMPO, was used in the polymerization of styrene and acrylates [10]. Later on, more active acyclic nitroxides containing an α-hydrogen, such as DEPN (N-tert-butyl-N-(1-di-ethylphosphono-2,2-dimethylpropyl)-N-oxyl) [11][12][13][14][15][16][17] and TIPNO (2,2,5,5-tetramethyl-4-phenyl-3-azahexane-3-oxyl) [18] and [19], were developed with great success in the controlled radical polymerization of a broader range of monomers, including styrene and derivatives, acrylates, acrylamide, acrylonitrile, acrylic acid and dienes. Recently, an alkoxyamine derived from TIPNO was prepared in one-step [20] and used in the controlled radical polymerization of styrene and isoprene at 125 °C.…”

Synthesis of Narrow Molecular Weight Distribution Norbornene-Lactone Functionalized Polymers by Nitroxide-Mediated Polymerization: Candidates for 193-nm Photoresist Materials

“…Traditionally, NMP mediated by TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl) was limited to the polymerization of styrenics only [3,4]. The development of the TIPNO (2,2,5-trimethyl-4-phenyl-3-azahexane nitroxide) and the SG1 (N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide) families of nitroxides subsequently extended the ability of NMP to polymerize acrylic monomers [5][6][7] and acrylamides [8][9][10]. The successful control of methacrylates with SG1 was not achieved until Nicolas et al demonstrated that with a small amount of styrene or acrylonitrile as the controlling co-monomer, the polymerization of methyl methacrylate (MMA) could be effectively controlled with relatively low dispersity and the ability to re-initiate a second batch of monomer [11][12][13].…”