Topic
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.
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Patent•
02 Aug 1985
TL;DR: Alkali soluble thickeners as mentioned in this paper are aqueous emulsion copolymers of an alpha, β-monoethylenically unsaturated carboxylic acid, typically methacrylic acid.
Abstract: Alkali soluble thickeners are disclosed which are aqueous emulsion copolymers of: (A) about 20-70 weight percent of an alpha, beta-monoethylenically unsaturated carboxylic acid, typically methacrylic acid; (B) about 20-80 weight percent of a monoethylenically unsaturated monomer lacking surfactant capacity, typically ethyl acrylate; (C) about 05-60 weight percent of a nonionic urethane monomer which is the urethane reaction product of a monohydric nonionic surfactant with a monoethylenically unsaturated monoisocyanate, preferably one lacking ester groups like alpha, alpha-dimethyl-m-isopropenyl benzyl isocyanate; and (D) from 0 up to about 2 weight percent of a polyethylenically unsaturated monomer These emulsion copolymers are solubilized in water with the aid of an alkali, like ammonium hydroxide When the copolymers are added to latex paints and neutralized, the viscosity of the paint is increased, brush drag is increased, and the paint rheology is otherwise improved
282 citations
TL;DR: In this paper, the phase morphology of the resulting ternary blends and its relationship with impact behaviors were studied systematically, and an optimum range of particle sizes of the dispersed domains for high impact toughness was identified.
Abstract: Polyactide (PLA) was blended with an ethylene/n-butyl acrylate/glycidyl methacrylate (EBA-GMA) terpolymer and a zinc ionomer of ethylene/methacrylic acid (EMAA-Zn) copolymer. The phase morphology of the resulting ternary blends and its relationship with impact behaviors were studied systematically. Dynamic vulcanization of EBA-GMA in the presence of EMAA-Zn was investigated by torque rheology, and its cross-link level was evaluated by dynamic mechanical analysis. Reactive compatibilization between PLA and EBA-GMA was studied using Fourier transform infrared spectroscopy. The dispersed domains in the ternary blends displayed a “salami”-like phase structure, in which the EMAA-Zn phase evolved from occluded subinclusions into continuous phase with decrease in the EBA-GMA/EMAA-Zn ratio. An optimum range of particle sizes of the dispersed domains for high impact toughness was identified. Also, the micromechanical deformation process of these ternary blends was also investigated by observation of the impact-fra...
281 citations
TL;DR: This study proposes some new normoxic gel formulations that have a less complicated chemical formulation than the MAGIC gel and shows that cupper(II)sulphate operates as a catalyst in the oxidation of ascorbic acid.
Abstract: Polymer gel dosimeters offer a wide range of potential applications in the three-dimensional verification of complex dose distribution such as in intensity-modulated radiotherapy (IMRT). Until now, however, polymer gel dosimeters have not been widely used in the clinic. One of the reasons is that they are difficult to manufacture. As the polymerization in polymer gels is inhibited by oxygen, all free oxygen has to be removed from the gels. For several years this was achieved by bubbling nitrogen through the gel solutions and by filling the phantoms in a glove box that is perfused with nitrogen. Recently another gel formulation was proposed in which oxygen is bound in a metallo-organic complex thus removing the problem of oxygen inhibition. The proposed gel consists of methacrylic acid, gelatin, ascorbic acid, hydroquinone and copper(II)sulphate and is given the acronym MAGIC gel dosimeter. These gels are fabricated under normal atmospheric conditions and are therefore called 'normoxic' gel dosimeters. In this study, a chemical analysis on the MAGIC gel was performed. The composition of the gel was varied and its radiation response was evaluated. The role of different chemicals and the reaction kinetics are discussed. It was found that ascorbic acid alone was able to bind the oxygen and can thus be used as an anti-oxidant in a polymer gel dosimeter. It was also found that the anti-oxidants N-acetyl-cysteine and tetrakis(hydroxymethyl)phosphonium were effective in scavenging the oxygen. However, the rate of oxygen scavenging is dependent on the anti-oxidant and its concentration with tetrakis(hydroxymethyl)phosphonium being the most reactive anti-oxidants. Potentiometric oxygen measurements in solution provide an easy way to get a first impression on the rate of oxygen scavenging. It is shown that cupper(II)sulphate operates as a catalyst in the oxidation of ascorbic acid. We, therefore, propose some new normoxic gel formulations that have a less complicated chemical formulation than the MAGIC gel.
276 citations
TL;DR: X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy results all demonstrated that polymer chains were successfully produced and the dispersity of GO sheets in solvents was improved significantly.
Abstract: Exfoliated graphite oxide (GO) sheets with hydroxyl groups and amine groups on the surface were prepared by modification of graphite. Atom transfer radical polymerization (ATRP) initiator molecules were grafted onto the GO sheets by reactions of 2-bromo-2-methylpropionyl bromide with hydroxyl groups and amine groups. Poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) chains on the surface of GO sheets were synthesized by in-situ ATRP. X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy (TEM) results all demonstrated that polymer chains were successfully produced. After grafting of PDMAEMA, the dispersity of GO sheets in solvents was improved significantly. Poly(ethylene glycol dimethacrylate-co-methacrylic acid) particles were deposited on GO sheets via hydrogen bonding between MAA units on polymer particles and amine groups of PDMAEMA. TEM and scanning electron microscopy were used to characterize the structure of the nanocomposites.
258 citations
TL;DR: In this article, a series of lightly crosslinked, nearly monodisperse, and random copolymerized microgel particles, based on methacrylic acid (MAA) and N-isopropylacrylamide (NIPAM) of various content, were synthesized in aqueous solution with sodium dodecyl sulfate at pH = 3.1 ± 0.2 and 70 °C.
Abstract: A series of lightly cross-linked, nearly monodisperse, and random copolymerized microgel particles, based on methacrylic acid (MAA) and N-isopropylacrylamide (NIPAM) of various content, were synthesized in aqueous solution with sodium dodecyl sulfate at pH = 3.1 ± 0.2 and 70 °C. The polymerization kinetics, the colloidal stability, and the size of the microgel particles varied with the comonomer composition. The volume phase transitions of the MAA/NIPAM copolymer microgel particles with different PMAA contents in very dilute aqueous solution (C< 1 × 10-5 g/mL) were investigated by laser light scattering (LLS), as a function of both pH at 25 °C, and temperature at two different pH values of 3.4 and 7.5. To our knowledge, the volume phase transition of such submicron-sized hydrogels sensitive to multiple environmental changes was studied for the first time by LLS. The equilibrium swelling ratio, the critical transition pH, and the critical transition temperature (Tc) were strongly dependent on the comonomer...
249 citations