Emulsion Copolymerization Of Acrylic Acid Research Articles

Dual‐responsive shape memory hydrogels with self‐healing and dual‐responsive swelling behaviors

AbstractShape memory hydrogels (SMHs) can fix the hydrogels in a provisional shape and restore the initial shape under external stimulation. Herein, a dual‐responsive shape memory hydrogel with dual‐responsive swelling and self‐healing properties is presented in this work. The SMHs were fabricated by one‐step emulsion copolymerization of acrylic acid (AAc), acrylamide (AAm) and stearyl methacrylate (SMA). Sodium alginate (SA) was introduced as an interpenetrating polymer in the network. With ionic cross‐linking between ‐COO− and Fe3+ or saline‐reinforced hydrophobic association, the hydrogels can be fixed in a provisional shape, which can be restored by immersing the hydrogels in vitamin C solution or pure water, respectively. When the as‐prepared hydrogels were immersed in FeCl3 solutions, additional ionic cross‐linking between Fe3+ and ‐COO− could be formed, thus constructing the dual physically cross‐linked (DPC) network, which endows the hydrogels with excellent fracture stress (2.6 MPa) and toughness (5.47 MJ/m3). Besides, the reversible physical cross‐linkings endowed the hydrogel with outstanding self‐healing capability. Furthermore, the pH and saline responsive swelling properties of the SMHs are additional fantastic properties. Therefore, we believe that this simple strategy provides a great opportunity for the preparation of SMHs with multiple intellectual performances.

New hybrid acrylic/collagen nanocomposites and their potential use as bio-adhesives

Nowadays material science is trying to design products that combine the adaptability of synthetic polymers with the structure and functionality of biopolymers. In this context, the present work investigates the production of hybrid nanocomposites based on acrylic and hydrolyzed collagen (HC) to obtain a waterborne dispersion with film forming capability. For this purpose, the emulsion copolymerization of acrylic acid (AA) and butyl acrylate (BA) in the presence of different concentrations of HC was investigated. The synthesized acrylic–HC latexes are able to form films with promising properties for their potential application as bio-adhesives, where adhesiveness could be controlled by both the degree of neutralization and the moisture content.

Obtaining a powdered silicone-acrylic copolymer by emulsion copolymerization

Based on experimental studies, a method for obtaining a powdered silicone-acrylic polymer by emulsion copolymerization of acrylic acid and 3-methacryloxypropyl-trimethoxysilane using a reaction initiator (ammonium persulfate) for implementing the modifications in the polymer cross-link to impart improved physicochemical properties to the final product was presented in the paper.The optimum conditions of synthesis were determined. Based on the study of the kinetics of the copolymerization reaction by the graviometric method, it was found that it is advisable to conduct the reaction for 4.5 hours at a temperature of 90 oC, since the copolymer yield after this time was 45.3 %.During the synthesis, silicone-acrylic polymer, which is a white powder without strong smell, insoluble in organic solvents was obtained. The copolymer was characterized using IR spectrum analysis and dispersion determination.The obtained silicone-acrylic copolymer is recommended for use in paints and varnishes as a surface modifier.

Preparation of copolymers of acrylic acid and 3-methacryloxypropyl-trimethoxysilane by the method of emulsion copolymerization

The method for preparing silicone acryl polymer by emulsion copolymerization of acrylic acid and 3-methacryloxypropyl-trimethoxysilane with a reaction initiator (ammonium persulfate) is presented in the article on the basis of experimental studies. The optimum conditions of synthesis are determined. Based on the study of the kinetics of the reaction by gravimetric copolymerization method, it was found that it is desirable to conduct the reaction for 4,5 hours at 90 o C, since after this time yield of copolymer was 53,3 %. During synthesis it is obtained silicone acryl polymer that is a viscous transparent liquid without sharp odor, soluble in organic solvents. The properties of the silicone acryl polymer are investigated and characterized: molecular mass is calculated, determined the composition of the copolymer is determined and IR spectral analysis is conducted. This polymer is suitable for use in paints and varnishes as a surface modifier.

PREPARATION AND CHARACTERIZATION OF SOME ACRYLIC ACID CHELATING COPOLYMERS BY EMULSION TECHNIQUE

ABSTRACT Binary chelating copolymers were prepared by emulsion copolymerization of acrylic acid (AA) with butyl acrylate (BuA), butylmethacrylate (BuMA) and styrene (St) using potassium persulphate/sodium meta bisulphite as a redox initiation system and sodium dodecylbenzene sulfonate as an emulsifier. It was found that the rate of copolymerization was decreased with increasing AA content. Based on the copolymerization data of (BuA/AA), (BuMA/AA) and (St/AA) in emulsion polymerization process, the reactivity ratios of the systems were calculated and discussed. The structures of the designed chelating copolymers were characterized and investigated via spectrophotometric measurements and thermal analysis. Some of the best stable copolymeric emulsions having enhanced physico-mechanical properties were introduced in water-borne paint formulations. The prepared chelating copolymers showed semiconducting properties at room temperature.

Distribution of emulsified monomers with different water solubility

The location and distribution of acrylic acid and styrene in emulsions made with a cationic surfactant, cetyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecylsulfate (SDS), were determined with ultra-violet spectroscopy, conductivity, and potentiometry. In these systems, the acrylic acid remains in the aqueous phase near the micelle surface, whereas the styrene is located in the micelles or in emulsified droplets. In the absence of acrylic acid, some of the styrene is solubilized in the micelle interior and some is adsorbed at the micelle inner surface. Upon addition of acrylic acid, all the styrene is displaced to the center of the micelles. The interaction between acrylic acid and CTAB micelles is stronger than that between acrylic acid and SDS micelles. With CTAB, acrylic acid is adsorbed at the micelle surface, whereas with SDS, acrylic acid remains in the intermicellar solution. These differences can account for the differences reported in the emulsion copolymerization of acrylic acid and styrene using CTAB or SDS.