Methacrylic acid

About: Methacrylic acid is a research topic. Over the lifetime, 13058 publications have been published within this topic receiving 173201 citations. The topic is also known as: α-Methacrylic acid & 2-Methylacrylic acid.

Morphological Origin of the Multistep Relaxation Behavior in Semicrystalline Ethylene/Methacrylic Acid Ionomers

Abstract: Ethylene/methacrylic acid (E/MAA) ionomers contain polyethylene crystallites, amorphous polymer segments, and ionic aggregates. While the property changes observed upon neutralization of the MAA units are often attributed to the formation of ionic aggregates, no quantitative description currently exists for how these three structural motifsalone or in combinationcontrol any of these material properties. In this paper, we define such relationships for perhaps the most basic mechanical property of interest: the small-strain modulus. At temperatures just below the melting point of the primary crystallites, the ionomers can be satisfactorily described as two-phase composites of crystallites and ionically cross-linked rubber; however, at room temperature, the modulus is far higher than such a description predicts. We trace this effect to a synergy between the ionic aggregates and secondary crystallites, which together form percolated rigid pathways through the amorphous phase at room temperature. When the sec...

Functionalization of Aluminum Nanoparticles Using a Combination of Aryl Diazonium Salt Chemistry and Iniferter Method

Abstract: In this work, we propose an original strategy for the functionalization of aluminum nanoparticles (Al NPs), based on a combination of aryl diazonium salt chemistry and the photopolymerization iniferter method. It consists in grafting coupling agents, derived from diazonium salts, at the surface of Al NPs and in initiating the photopolymerization of methacrylic acid (MAA) directly from the surface. The hybrid NPs were fully characterized using XRD, TEM, TGA, and XPS. The results show that the obtained hybrids exhibit a core-double shell structure, the metallic core being preserved while a thin natural oxide layer and a strongly anchored organic shell surround it. The controlled and living character of the photopolymerization process allowed for the control of the polymer shell thickness with the polymerization time. Interestingly, the formation of compact aryl layers derived from the diazonium salts at the surface of Al NPs appears to provide an efficient protection against oxidation.

Nitroxide-Mediated Copolymerization of Methacrylic Acid and Sodium 4-Styrenesulfonate in Water Solution and One-Pot Synthesis of Amphiphilic Block Copolymer Nanoparticles

Abstract: The SG1-mediated copolymerization of methacrylic acid and a small percentage of sodium 4-styrenesulfonate was performed in water solution at 76 °C, using BlocBuilder as an alkoxyamine initiator under acidic conditions. Unexpectedly, these conditions, which could be considered as rather unfavorable due to the instability of SG1 in acidic water, led to very good results in term of polymerization kinetics and control over polymer chain growth. It appeared that low temperature and short reaction time were the key parameters to maintain a good living character to the chains as evaluated by in situ 31P NMR. The aqueous system was then used directly as the polymerization medium for the emulsion copolymerization of methyl methacrylate and styrene performed at 90 °C. This one-pot procedure led to the synthesis of amphiphilic block copolymers that self-assembled into stable core–shell nanoparticles.