Vinyl ester resins silica

Peimchem Mortar. [AtochemN.Am.] Two-component, silica-filled chmnical-resistant vinyl ester resin-based mortar mortar for construction in pulp/pa-per, chemical process, food and b er-age plant industries. 

Synonyms Dimethyl silicones and siloxanes, reaction prods, with silica Uses Rheology control agent, reinforcing agent, free-flow agent for adhesives. coatings, powd. coatings, defoamers, elastomers, inks, lubricants. liq. resins, sealants, silicones, toners thixotrope for vinyl ester resins... 

Keywords fumed silica, unsaturated polyester resins, vinyl ester resins, intermolecular interactions, rheology... 

Two grades of fumed silica with a different degree of surface treatment and different polarity have been used a nontreated, hydrophilic Wacker HDK N20 (BET surface area 200 nP/g, 1.8 SiOH/nm equivalent to 100 % residual SiOH) and a fully silylated hydrophobic Wacker HDK H18 (carbon content 4.5 % C, 15 % residual SiOH), the latter being covered by a chemically grafted PDMS layer. Both silicas are products finom Wacker-Chemie GmbH, Germany. The resins used are an unsaturated polyester resin Palatal P4 (UP resin), a co-condensate of a diol, maleic acid and orthophthalic acid, and the vinyl ester resin Atlac 590 (VE resin), a co-condensate of glycidine, methacrylic acid and bisphenol A. Both resins have a styrene content of 35 % and are provided by DSM, The Nertherlands. 

Vinyl esters resins are characterized by pendant OH groups in the chain which are able to form strong H-bonds to the silanol groups of silica particles. Due to the strength of this interaction the adsorption of vinyl ester molecules at silica surfaces should be almost irreversible and result in a kind of steric stabilization of the silica particles. The formation of a silica network is suppressed and the relative viscosities achieved remain low. 

The results of our rheological study demonstrate that interactions between resin molecules and fumed silica particles significantly influence the network stability and its formation. In order to get a deeper understanding of the nature of such interactions a C CPMAS study at different cross -polarization times Xcp from 0.5 to 8 ms has been performed. At short Xcp spectra intensities are enhanced by C resonances of the least mobile chain fragments. This study includes two different fumed silicas, hydrophilic Wacker HDK N20 and fully silylated Wacker HDK H18, with an unsaturated polyester resin Palatal P4 and a vinyl ester resin Atlac 590, respectively. Figure 6 depicts the C CPMAS spectra of N20 and H18, respectively, in Palatal P4/35 % styrene at... 

Vinyl ester resins Melamine-polyesters Epoxy Resins medium to highly polar strong specific interactions fuUy silylated filmed silica HDK H18... 

The results presented so far indicate that no single nanoscale reinforcement generates ideal results, either alone or when used in conjunction with more conventional reinforcement materials. To control wear, a hard reinforcement such as silica is preferred whereas to reduce friction a low shear stress reinforcement such as M0S2 is more effective. Thus a combination of nanoscale reinforcements in vinyl ester resin has been investigated in further tests and the benefits of the mixed compositions on friction (Fig. 9.7) and speed at seizure (Fig. 9.8) have been demonstrated without compromising wear performance. 

A number of cement materials are used with brick. Standard are polymer resin, silicate, and sulfur-based materials. The most widely used resins are furane, vinyl ester, phenolic, polyester, and epoxies. Carbon-filled furanes and phenolics are good against nonoxidizing acids, salts, and solvents. Silicates and silica-filled resins should not be used in hydrofluoric or fluorosilicic acid applications. Sulfur-based cements are limited to 93°C (200°F), while resins can be used to about 180°C (350°F). Silicate-based cements are available for service temperatures up to 1000°C (1830°F). 

The normal lining construction consists of a membrane on the steel shell and one layer of acid brick in a resin mortar. The membrane materials used have been a silica filled latex rubber or, more recently, a silica filled urethane. Either of these membranes is installed by troweling it onto the steel shell. The mortars used have been polyester or vinyl ester based and are used in the back joints, bed joints, and side joints. That is, the brick are completely surrounded by the mortar, except, of course, for the face. The equipment in which this type of construction is used includes the chlorine dioxide storage tank, the chlorine dioxide generator spent acid tank, and the chlorine dioxide bleach tower. 

Polyester resins can be purchased with fumed silica already in, the resin and fumed silica can be added to vinyl esters by the customer. To insure uniform dispersion, fumed silica should be thoroughly mixed into the resin using a high shear dissolver or equivalent. 

Hi-Sil T-700 Silica, fumed thixotrope, resins vinyl ester... 

The aim of this paper is to present comprehensive models of interactions by comparing rheological results, analytical data from spectroscopic methods such as solid-state NMR and IR, and quantum chemical calculations. Furthermore we demonstrate how these interactions influence the rheology of fumed silica in unsaturated polyester (UP) and vinyl ester (VE) resins. 

The common commercially available fibers used in composites are fiberglass, graphite (carbon), aramid, polyethylene, boron, silicon carbide, and other ceramics such as silicon nitride, alumina, and alumina silica. Many matrix choices are available, both thermosetting and thermoplastic. Each type has an impact on the processing technique, physical properties, and environmental resistance of the finished composite. The most common resin matrices include polyester, vinyl esters, epoxy, bismaleimides, polyimides, cyanate ester, and triazine. 

Chem. Descrip. Polyhydtoxy carboxylic add amides with 20% It. aromatic naphtha, 19% xylene, 5% isobutanol, 5% ethylbenzene Uses Rheology control agent for fumed silica-modified thermoset resin systems, e.g., unsat. polyesters, vinyl esters, epoxy resins wetting agent and dispersant for fumed silica stabilizes thixotropic behavior Features Reduces or prevents separation... 

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