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The radical homopolymerization of N‐tert‐butyl acrylamide (t‐BuAAm) and its copolymerization with methyl acrylate (MA) is studied in ethanol/water solutions over a range of initial monomer and initiator levels between 50 and 70 °C. While short‐chain branching for poly(t‐BuAAm) samples could not be detected by 13C NMR, the reduced rate of monomer conversion with lowered monomer content indicates the formation of mid‐chain radicals (MCR) by backbiting. Adding water as a cosolvent to ethanol significantly increases reaction rates, in agreement with recent pulsed‐laser studies that quantify the influence of solvent composition on homopropagation kinetics. However, the measured drifts in comonomer composition with conversion are well represented by a single pair of reactivity ratios (rMA = 1.12 ± 0.01, rt‐BuAAm = 0.71 ± 0.01) over the complete range of experimental conditions. A mechanistic model developed to describe t‐BuAAm homopolymerization is extended to capture the impact of reaction operating conditions (monomer content and composition, solvent composition, initiator content, and temperature) on the features of t‐BuAAm/MA copolymerization, thus providing a tool for product and process optimization. The model structure can be used to support the development of other acrylate/acrylamide systems as part of the continued efforts to utilize "green" solvents to reduce the environmental impacts of polymerization processes. [ABSTRACT FROM AUTHOR]

Coordination‐insertion copolymerization of ethylene with polar monomers can directly provide value‐added functionalized polyolefins. Studies on the reactivity of catalysts toward polar monomers can help understand the copolymerization process and then tune the polymerization strategically. In this contribution, the reactivity picture of 2‐diphenylphosphonyl‐8‐phenylnaphthol nickel complex toward fundamental polar monomers was explored by stoichiometric reactions. The insertion rates are in the order of methyl acrylate (MA)>n‐butyl acrylate (BA)>N, N‐dimethylacrylamide (DMAA)>methyl methacrylate (MMA)>vinyl triethoxysilane (VTEoS)>N‐vinyl‐pyrrolidinone (NVP). Acrylic derivatives of MA, BA and DMAA with electron‐withdrawing group favor 2,1‐fashion while non‐acrylic NVP with electron‐donating group prefers 1,2‐fashion. Notably, the 1,1‐disubstituted MMA and bulky VTEoS perform a preferential 1,2‐insertion accompanying by 2,1‐insertion in the percentage of 82 : 18 and 62 : 38, respectively, because of the stronger steric effect. These insights correlate to the copolymerization of polar monomers with ethylene. Linear functional polyethylene with in‐chain and terminal incorporation of BA, DMAA or VTEoS is afforded at a high activity. [ABSTRACT FROM AUTHOR]

Increasing the interfacial adhesion with compatibilizer has been proved to be an effective method to enhance the mechanical properties of composites. In this paper, sodium methacrylate (NaMAA) was introduced to enhance the interfacial adhesion between polypropylene (PP) and ethylene propylene diene monomer (EPDM) via the peroxide‐induced dynamic vulcanization. NaMAA‐induced compatibilization enhanced the phase interface efficaciously and reduced the diameter of EPDM particles from ~8 to ~4 μm. Silica (SiO2) was used in the matrix to improve the mechanical properties of the thermoplastic vulcanizates (TPVs). It was found that SiO2 had little influence on the compatibility between EPDM and PP; however, it improved the tensile strength and stiffness of the TPVs without a severe reduction in the elasticity. The interfacial compatibility of modified EPDM/PP TPVs was verified by Fourier transform infrared, rubber process analyzer, and scanning electron microscope. With 3 wt% of NaMAA and 12 wt% of SiO2, the tensile strength improved from 8.5 to 12.7 MPa and the elongation at break was ranged from 320% to 410%. [ABSTRACT FROM AUTHOR]

With oleic acid grafting modification, a series of hyperbranched-linear polymer surfactants (HLPS) were prepared by hydroxyl-terminated hyperbranched polymer (HBP), which was gained through a step synthesis method using trimethylolpropane and AB monomer. The AB monomers were obtained through the Michael addition reaction of methyl acrylate and diethanol amine. The structures of HLPS were characterised by Fourier transform infrared spectrophotometer and nuclear magnetic resonance (NMR), which indicated that HBP was successfully modified by oleic acid. Furthermore, the properties of surface tension and critical micelle concentration of HLPS solution showed that HLPS can significantly reduce the surface tension of water. The morphology of the HLPS solution was characterised by dynamic light scattering, which revealed that HLPS exhibited a nonmonotonic appearance in particle size at different scattering angles owing to the different replaced linear portions. The relationships of the surface pressure to monolayer area and time were measured using the Langmuir-Blodgett instrument, which showed that the surface tension of monolayer molecules increased with the increasing of hydrophobic groups. In addition, the interface conditions of different replaced HLPS solutions were simulated. [ABSTRACT FROM AUTHOR]

Acrylic resin monomers, especially acrylates and methacrylates, are important occupational allergens. To analyse patterns of concomitant patch test reactions to acrylic monomers in relation to exposure, and to suggest possible screening allergens. We reviewed the patch test files for the years 1994-2009 at the Finnish Institute of Occupational Health for allergic reactions to acrylic monomers, and analysed the clinical records of sensitized patients. In a group of 66 patients allergic to an acrylic monomer, the most commonly positive allergens were three methacrylates, namely ethyleneglycol dimethacrylate (EGDMA), 2-hydroxyethyl methacrylate (2-HEMA) and 2-hydroxypropyl methacrylate (2-HPMA), and an acrylate, namely diethyleneglycol diacrylate (DEGDA). The patterns of concomitant reactions imply that exposure to methacrylates may induce cross-reactivity to acrylates, whereas exposure to acrylates usually does not lead to cross-allergy to methacrylates. Screening for triethyleneglycol diacrylate (TREGDA) in the baseline series was found to be useful, as 3 of 8 patients with diagnosed occupational acrylate allergy might have been missed without the screening. A short screening series of four allergens, EGDMA, DEGDA, 2-HPMA and pentaerythritol triacrylate (PETA), would have screened 93% of our 66 patients; each of the remaining 5 patients reacted to different acrylic monomer(s). [ABSTRACT FROM AUTHOR]

The Cu(0)/Me6‐TREN‐catalyzed single‐electron transfer mediated living radical polymerization (SET‐LRP) of methyl acrylate in the presence of the classic 4‐methoxyphenol free radical inhibitor was investigated. Kinetic experiments, combined with 1H NMR, and MALDI‐TOF MS analysis of the resulting polyacrylates demonstrated that SET‐LRP is a robust synthetic method that does not require the purification of the monomers to remove the radical inhibitor. It is anticipated that these results will contribute to the expansion of technological and fundamental applications of SET‐LRP since it allows the synthesis of polymers with a structural perfection that previously was not accessible by any other method, starting from unpurified monomers, solvents, initiators, and ligands. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3174–3181, 2008 [ABSTRACT FROM AUTHOR]