Acrylate resins, separators

Vecchio C, Fabiani F, Gazzaniga A. Use of colloidal silica as a separating agent in film forming processes performed with aqueous dispersion of acrylic resins. Drug Dev Ind Pharm 1995 21(15) 1781-1787. 

Acrylic polymers also include water emulsions of acrylic resins, acrylate resins used in ceramic applications, and the precursor of carbon fiber, namely acrylonitrile. The table includes also some information on acrylic elastomers. Polymethylmethacrylate is discussed under a separate subsection. 

Since most of the applications of the PMMA type acrylic resins are based on their high degree of transparency and UV resistance characteristics, there has been little commercial interest or motivation in developing acrylic blends. This is understandable because unless there is complete, molecular level miscibility between the components, it is not possible to maintain a high degree clarity in the blends. Nevertheless, several examples of commercial blends of acrylic resins are known. These will be discussed under separate headings. 

To understand the different reactions taking place in a film of ICRs formed on an iron or steel substrate, an experiment was described where the reaction on the iron surface and the reaction in the polymer film could be studied separately. The principal electrode configuration is shown in Figure 11.40. °° The conducting polymer film was formed on a platinum electrode. An insulating acryl resin film covered the main part of a separate iron... 

One-pack or two-pack polyurethane surface coatings, which may sometimes be combined with acrylic resin systems. The one-pack system, which has a long shelf life, is an adduct of resin with polyisocyanate dissolved in a moisture-free solvent. When applied to a surface the film cures and hardens, as moisture in the air reacts with the isocyanate groups in the resin. The two-pack system consists of a polyisocyanate (frequently derived from an aliphatic isocyanate monomer) and a polyol as separate components. Once the two components are mixed, the shelf life is very limited. 

By laminating conventional polyethylene and polypropylene microporous membranes together, it is possible to obtain a separator with the desired shutdown function together with protection from rupture. Microporous membrane of liquid crystalline polyester, polyphenylene ether, aromatic polyamide, polyimide, polyamide imide resin, acrylic resin, and cross-linked polymer are now being studied as candidates for lamination with polyethylene in order to gain even greater heat resistance. 

To achieve needed comfort, dentures must be custom-made. To form the customized denture, in which the artificial teeth are embedded, a wax pattern is used. The wax pattern is inserted in a plaster or dental stone in a split mold flask. After removal of the wax, the surface of the resulting mold cavity is painted with a separating medium, usually an aqueous alginate solution, followed by the addition of the acrylic resin. The separating medium aids in removal of the cured acrylic from the mold. 

The data of Table 2 indicates that water-borne acrylic/BKUA-2260 adhesives have excellent metal adhesion whereas water-borne acrylic/ CK-1834 dispersion adhesives and water-borne neoprene adhesives have poor metal adhesion. The dispersing aids employed in the last two systems were investigated as possible causes of this lower metal adhesion. The surfactant system employed to disperse CK-1834 and similar phenolics is listed at the bottom of Table 7. In order to separate out the effects of the dispersing agents and at the same time maintain a stable system, the CK-1834 phenolic and the acrylic resin were put into acetone solution. The components of the dispersant system were individually added and their effect on the metal adhesion of the system was determined. The data of Table 5 clearly shows that the oleic acid and its salts are the principle cause of the reduced metal adhesion The peel strengths fall off dramatically when these components are added. Furthermore, the dark violet color, characteristic of the phenolic-iron complex, disappears, indicating that the oleic acid interferes with the phenolic substrate interaction and forms a weak boundary layer. 

Amberlite XAD-7 is a nonionic moderately polar acrylic resin that has been used to purify anthocyanins. Lacking ionic groups, it presumably separates compounds... 

Bio-Rex 70 2.4 0.70 Weakly acidic cation exchanger with car-boxylate groups on a macroreticular acrylic matrix for separation and fractionation of proteins, peptides, enzymes, and amines, particularly high molecular weight solutes. Does not denature proteins as do styrene-based resins. 

A reaction vessel explosion at BASF s resins plant in Cincinnati (July 19, 1990) killed one and injured 71. The BASF facility manufactures acrylic, alkyd, epoxy, and phenol-formaldehyde resins used as can and paper-cup liner coatings. The explosion occurred when a flammable solvent used to clean a reaction vessel vented into the plant and ignited. The cleaning solvent that was not properly vented to a condenser and separator, blew a pressure seal, and fdled the 80-year-old building with a white vapor cloud. 

The two matrices in these cements are of a different nature an ionomer salt hydrogel and polyHEMA. For thermodynamic reasons, they do not interpenetrate but phase-separate as they are formed. In order to prevent phase separation, another version of resin glass polyalkenoate cement has been formulated by Mitra (1989). This is marketed as VitraBond, which we term a class II material. In these materials poly(acrylic acid), PAA, is replaced by modified PAAs. In these modified PAAs a small fraction of the pendant -COOH groups are converted to unsaturated groups by condensation reaction with a methacrylate containing a reactive terminal group. These methacrylates can be represented by the formula ... 

Fig. 67 Schematic of phase behaviour for blend of novolac epoxy resin with nearly symmetric poly(methyl acrylate-co-glycidylmelhacrylate)-0-polyisoprene. Ordered L can be swollen with up to about 30% of resin before macroscopic phase separation occurs, producing heterogeneous morphologies containing various amounts of L, C, worm-like micelles and pristine epoxy. At lower concentrations, disordered worm-like micelles transform into vesicles in dilute limit. According to [201]. Copyright 2003 Wiley...

A practical consideration in using XAD-8 resin should be noted. Despite exhaustive cleaning of the resin before use, the resin bleeds on the order of 3 mg C/L in 0.1 N NaOH (5). A major component of the bleed is acrylic acid, which has a low capacity factor on XAD-8 at pH 2, and is separated to a large extent from the sample during successive reconcentration steps. However, a small amount of contamination from resin bleed may be present in the final product. 

---