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.

Fabrication of molecularly imprinted hybrid monoliths via a room temperature ionic liquid-mediated nonhydrolytic sol-gel route for chiral separation of zolmitriptan by capillary electrochromatography.

Abstract: A room temperature ionic liquid (RTIL)-mediated nonhydrolytic sol-gel (NHSG) protocol was explored for the fabrication of new molecularly imprinted silica-based hybrid monoliths for chiral separation of a basic template zolmitriptan by CEC. The RTIL-mediated NHSG protocol involved free-radical copolymerization and NHSG process. Three carboxylic acids (trifluoromethyl acrylic acid, cinnamic acid, and methacrylic acid (MAA)) were examined as both the functional monomers and the catalysts for the NHSG condensation of methacryloxypropyltrimethoxysilane (MPTMS) to form silica-based framework. RTIL was incorporated to reduce gel shrinkage and also to act as the pore template. The effects of carboxylic acids and RTIL on the performance of the silica-based hybrid molecularly imprinted polymer (MIP) monoliths were investigated in detail to realize excellent chiral recognition and to give new insights into the mechanism of the RTIL-mediated NHSG strategy. Excellent chiral separation of (R)/(S)-zolmitriptan was achieved when the molar ratio of MAA to MPTMS was 1:4 and 1:2 with RTIL involved. The synergism of the free-radical copolymerization of the C=C bond of carboxylic acids and MPTMS with the NHSG condensation of MPTMS catalyzed by the carboxylic acids was demonstrated. The incorporation of RTIL increased porosity, and hence improved selectivity of the prepared hybrid monoliths.

Tuning Micellization and Dissociation Transitions of Thermo- and pH-Sensitive Poly(ethylene oxide)-b-poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid) in Aqueous Solution by Combining Temperature and pH Triggers

Abstract: We report in this article on the active control of multiple micellization and dissociation transitions of thermo- and pH-sensitive water-soluble block copolymers, poly(ethylene oxide)-b-poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid) (PEO-b-P(DEGMMA-co-MAA)), in aqueous solutions by combining temperature and pH triggers. Two block copolymers and one random copolymer P(DEGMMA-co-MAA) were prepared by atom transfer radical polymerization of a mixture of methoxydi(ethylene glycol) methacrylate (DEGMMA) and tert-butyl methacrylate (t-BMA) with a molar ratio of 100: 13 from a PEO macroinitiator and a small molecule initiator, respectively, and subsequent removal of t-butyl group. PDEGMMA is a thermosensitive water-soluble polymer exhibiting a lower critical solution temperature in water at 25 °C. The cloud point of P(DEGMMA-co-MAA) in water can be readily tuned from 24 to 60 °C by changing the solution pH. The block copolymers dissolved molecularly in cold aqueous buffer solutions with a pH o...

Dual Stimuli-Responsive Poly(2-hydroxyethyl methacrylate-co-methacrylic acid) Microgels Based on Photo-Cleavable Cross-Linkers: pH-Dependent Swelling and Light-Induced Degradation

Abstract: Dual stimuli-responsive p(HEMA-co-MAA) microgels were prepared in a facile way by inverse miniemulsion copolymerization of 2-hydroxyethyl methacrylate (HEMA) with methacrylic acid (MAA) and two kinds of newly synthesized photodegradable cross-linkers. The pH-dependent swelling behavior induced by the protonation/deprotonation of the methacrylic acid groups in the network-forming polymer was investigated by means of the particle volume change as determined by DLS measurements. Photolytic degradation experiments were conducted by irradiation with UV light which led to particle disintegration caused by cleavage of the photolabile cross-linking points. The degradation behavior of the microgels was investigated with respect to degradation rates and changes in the degree of swelling. Those parameters were found to depend on the pH value of the solvent, the light intensities, and the irradiation wavelengths applied. For similar conditions, the degradation profile was demonstrated to strongly depend not only on t...

Temperature effect on chiral recognition of some amino acids with molecularly imprinted polymer filled capillary electrochromatography.

Abstract: L-Aromatic amino acid imprinted polymers were prepared using azobisnitriles as either photoinitiators or thermal initiators at temperature ranging from 4 to 60 degrees C. Methacrylic acid (MAA) was used as functional monomer and ethylene glycol dimethacrylate (EDMA) was used as cross-linker. The result polymers were ground and sieved to particles < or = 10 microns, filled into the capillary columns and used for enantiomeric separations in capillary electrochromatographic (CEC) mode. The polymer particles < or = 25 were packed into high performance liquid chromatographic (HPLC) columns and used for enantioseparations in the HPLC mode. The mobility and chiral separation of some amino acids were studied on CEC and HPLC columns at different temperature. The relationships of separation factor and column temperatures and demonstrated in linear between logarithm of the separation factor (in alpha) and the inverse of absolute temperature (1/T). Some thermodynamic parameters, such as the apparent change of enthalpy (delta H zero) and the apparent change of entropy (delta S zero), were obtained using van't Hoff plots. The information obtained from the thermodynamic study is discussed in developing strategies for chiral recognitions of amino acids by molecular imprinting technique.