Acrylic acid, polymerization

BASF Corporation, Hoechst Celanese Chemical Group, Inc., Rohm and Haas Company, and Union Carbide Corporation (December 1993). Prevention of Acrylic Acid Polymerization in Storage. Philadelphia, PA Rohm and Haas Company. 

PVA and PAcr.Ac. are compatible polymers on the whole range of composition [40-45], These blends are homogeneous and the films are transparent evidencing a good clarity [43,57] or semitransparency [43], However a heterogeneous IPN [45] was obtained by acrylic acid polymerization in a PVA matrix. 

The autoaccelerated character of acrylic acid polymerization is strictly correlated with such a form of monomer organization. The fast zip-up propagation takes place along oriented double bonds. Template mechanism of polymerization in these systems was also confirmed by examination of the tacticity of the polymer obtained. 

In order to verify the theory. Tan and Alberda van Ekenstein recalculated also data for acrylic acid polymerization (Table 8.3). 

Bamford and Shiiki found that initial rate of acrylic acid polymerization in the presence of polyethyleneimine is a fnnction of the ratio template concentration to monomer concentration. The following eqnation was proposed to describe the rate of polymerization ... 

The kinetics of acrylic acid polymerization in the presence of N-vinylpyrrolidone and acrylamide (up to 35%) or styrene (up to 20%) copolymers has been investigated. 

In the two-step process, the second-stage reactor is similar to the first-stage reactor but is packed with an optimized catalyst for aldehyde oxidation, based on Mo V oxides, and is run under different operating conditions. Care must be exercised during the separation and purification phases to avoid conditions favouring acrylic acid polymerization, e.g., by addition of a radical polymerization inhibitor such as the hydroquinone monomethyl ether. Selectivities to acrylic acid are higher than 90% at total conversion of the aldehyde. Overall yields referred to propylene are in the range 75-85%. Most acrylic acid produced is esterified for the production of acrylate esters. 

In at least one experiment (105°C, 4 M AA, 0.5 M H2SO4) there was visual evidence of acrylic acid polymerization, giving a faster apparent rate constant. Polymerization should be minimized by reduced acrylic acid concentrations and increased catalyst concentrations. 

Lamination by photografting has been employed in obtaining barrier materials. For instance, acrylic acid graft polymerized between two low-density polyethylene (LDPE) films decreases the penetration of oxygen dramatically. Poly(vinyl alcohol) (PVA) interior films photolaminated by acrylic acid polymerization to LDPE films serve as a barrier material for oxygen and water. Such laminates have potential use in packaging industry [137]. 

Ethyl acrylate and acrylic acid polymerize easily, and overheating must be avoided in the distillation. The flask is heated in an oil bath which is not permitted to rise above 115°. The diphenyl ether which is added serves to expel the acrylic acid at the end of the distillation. 

Protein substrates [172] are expected to be similar to the starch grafts the fundamental problem remains the control acrylic acid polymerization to the oligomers range, in order to have complete biodegradabiUty. 

Ion-retardation resins, which consist of acrylic acid polymerized inside a strong anion-exchange resin on a polystyrene divinylbenzene matrix [30], are also effective for removal of SDS from proteins. Passage of a protein-SDS complex through the resin results in complete retention of SDS and elution of protein with 80-90% recovery [31]. The capacity of the resin for SDS is more than 2.2mg/g, which effectively reduces the SDS level to less than one molecule of SDS per protein molecule. Because SDS binds tenaciously to the resin, it cannot be removed and the resin must be discarded after use. In the presence of buffers, adsorption of SDS by an ion-retardation column is reduced, resulting in incomplete removal of detergent from the protein. This can be circumvented by prior removal of buffer by SEC or, more conveniently, by the addition of a few grams of size exclusion gel to the head of the ion-retardation resin bed to retard the buffer [4]. 

Hu (2003) Ozone Acrylic acid polymerization chitosan attachment Antibacterial activity [43]... 

Another type of initiation of acrylic acid polymerization is the initiation by redox systems. Some redox systems investigated for the polymerization of acrylic and methacrylic acid are listed in Table 11. W. Kem obtained poly(acrylic add) on the cathode during electrolysis of an aqueous acrylic acid solution with KCN or BaCl2. Active initiator is the freshly generated hydrogen. The electrode material can be platinum, lead, iron, or mercury [508]. 

Thermal initiation of acrylic acid polymerization has been reported to be very rapid at elevated temperatures. The resultant product is said to be partially insoluble as well as being partially degraded [30]. 

The use of persulfate-bisulfite redox couples to initiate acrylic acid polymerizations has been reported [4,22]. For example, at 60°C, to a solution of 232 gm of water, 0.50 gm (0.0019 mole) of potassium persulfite, and 0.2 gm (0.0017 mole) of potassium metabisulfite, 167 gm (1.16 moles) of a 60% aqueous solution of acrylic acid has been added over a 0.5-hr... 

Because acrylic acid is the heavier component, the bottom of the column must remain below 90°C to avoid undesired acrylic acid polymerization. From Equation (223), assuming that pure, saturated acrylic acid leaves the bottom of the column, the pressure at the bottom of the column is 118 mm Hg, which is 5.26 ft of liquid assuming that liquid acrylic acid and liquid acetic acid have the same density as liquid water. The pressure drop per tray will be approximated by the height of liquid on the tray. The height of liquid on each tray will be approximated by the weir height. Because there are 25 trays, the pressure drop in the column is... 

Barth, J., Meiser, W., Buback, M. (2012). SP-PLP-EPR study into termination and transfer kinetics of non-ionized acrylic acid polymerized in aqueous solution. Macromolecules, 45, 1339-1345. 

Chevrel, M.-C., Brun, N., Hoppe, S., Meimaroglou, D., Falk, L., Chapron, D., et al. (2014). In situ monitoring of acrylic acid polymerization in aqueous solution using rheo-Raman technique. Experimental investigation and theoretical modelling. Chemical Engineering Science, 106, 242-252. 

No product was formed in the absence of catalyst. In all samples, carbon is not in balance that is attributed to the acrylic acid polymerization. 

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