Vinyl ester resins catalysts

Because of all these minor components (e.g., catalysts and inhibitors, added to major ones) the cure of vinyl ester resins is very complex, involving many competitive reactions. There are some new variables to account for, such as the inhibitor and initiator concentrations and induction time. Several papers [81,96,200,201] use the mechanistic approach, claiming that the phenomenological models do not explicitly include these facts, resulting in a new parameter characterization after each change in resin formulation [96]. Despite these arguments, the phenomenological approach is the most widely used and is based on an autocatalytic model which has been successfully applied to epoxy resins. Many authors [30,34,74,199,202,203] proposed the Equation 2.30 to describe the cure kinetic of unsaturated polyesters ... 

Two resins were used to do the first study on laminate construction. The first was a brominated epoxy vinyl ester resin with antimony pentoxide and the second was a brominated unsaturated polyester resin. They were both promoted to cure at room temperature with methyl ethyl ketone peroxide catalyst. The panels were then postcured at 250°F (121°C) for 8 h. Panels were prepared that varied in glass content from 25% to 70% and panel thickness varying from 0.05 in. to 0.25 in. and were tested at the same testing facility. A summary of the FSI test data for the first set of panels tested are shown in Figures 23.1 and 23.2. This graph in Figure 23.1 plots the FSI value versus the panel thickness. This data would indicate that the thickness of the test panel has no effect on the measured... 

Superox. [Reichhold] Peroxide derivs. catalyst, polymerization initiator for polyester, vinyl ester resins, vinyl monomers. 

The systems can include many options surfiice veil, chopped liners, sprayed resin systems, hoop winding strands, helical winding strands, resin bath, unidirectional tape, woven roving tape, pigmented resin surfaces, wax-resin surfaces, gel coats, BPO catalyst, epoxy resins, vinyl ester resins, filled resin systems, abrasive resin systems, polyester foam, syntactic foam, and charting film. 

Cumene hydroperoxide (CUHP) was especially developed for vinyl ester resins. It can be used as a blend with BP, when at 70°C, the BP starts the cure, with the hydroperoxide taking over when the temperature reaches 100°C. This catalyst is particularly suitable for thick parts. 

Darvan Dispersing agents, Vanderbilt Dechlorane Plus Fire-retardant additive. Occidental D.E.H. Epoxy catalyst resins, Dow Delrin Acetal resin, DuPont Delrin ST Tough acetal homopolymer, DuPont D.E.N. Epoxy novolac resins, Dow Derakane Epoxy vinyl ester resins, Dow... 

Fig. 13. Vinyl ester resin coating containing (a) only adhesion promoter (control sample) (b) the complete self-healing system including HOPDMS, PDES, catalyst microcapsules and adhesion promoter (c) HOPDMS, PDES, and adhesion promoter (d) catalyst microcapsules and adhesion promoter. All samples were healed at 50°C.

Bisphenol A diglycidyl ether [1675-54-3] reacts readily with methacrylic acid [71-49-4] in the presence of benzyl dimethyl amine catalyst to produce bisphenol epoxy dimethacrylate resins known commercially as vinyl esters. The resins display beneficial tensile properties that provide enhanced stmctural performance, especially in filament-wound glass-reinforced composites. The resins can be modified extensively to alter properties by extending the diepoxide with bisphenol A, phenol novolak, or carboxyl-terrninated mbbers. 

We make polyethylene resins using two basic types of chain growth reaction free radical polymerization and coordination catalysis. We use free radical polymerization to make low density polyethylene, ethylene-vinyl ester copolymers, and the ethylene-acrylic acid copolymer precursors for ethylene ionomers. We employ coordination catalysts to make high density polyethylene, linear low density polyethylene, and very low density polyethylene. 

The same authors recently described the synthesis of similar rhodium-complexed dendrimers supported on a resin having both interior and exterior functional groups. These were tested as catalysts for the hydroformylation of aryl alkenes and vinyl esters (52). The results show that the reactions proceeded with high selectivity for the branched aldehydes, with excellent yields, even up to the tenth cycle. The hydroformylation experiments were carried out with first- and a second-generation rhodium-complexed dendrimers as catalysts, with a mixture of 34.5 bar of CO and 34.5 bar of H2 in dichloromethane at room temperature. Each catalyst was easily recovered by simple filtration and was reusable for at least six more cycles without... 

Common to all reinforced plastics are two ingredients, resin and reinforcement. Resin is an oiganic material, usually of high molecular weight, that can be molded and set into a final shape. Resins are of two basic types. Thermoplastic resins soften upon heating, are shaped in a mold, and retain that shape when cooled. Common examples are nylon, polyethylene, polypropylene, and polycarbonate. Thermosetting resins are placed in a mold and cured by the use of a catalyst, heat, or both, until they harden in the shape of the mold. Common examples are polyester, vinyl ester, epoxies, phenolics, and p olyure thanes. 

The synthesis of vinyl esters of the higher monocarboxylic acids is troublesome and costly. The preparation may involve transvinylation with vinyl acetate and the higher carboxylic acid with a costly mercuric salt as a catalyst. In this procedure, the equilibrium situation is unfavorable and yields of product usually are low. Alternatively, a similar catalyst may be used for the addition of acetylene to the carboxylic acid. This procedure requires pressure equipment not usually available in a synthesis laboratory. The allyl esters, on the other hand are readily prepared by conventional esterification procedures. Therefore, they are of potential interest as plasticizers which might copolymerize with resins such as vinyl acetate that normally give rise to hard resins. Unfortunately, allyl esters of more ordinary carboxylic acids homopolymerize sluggishly. Their ability to enter into copolymer systems also seems to be marginal. 

Polyester and vinyl esters. Polyester matrices have had the longest period of use, with wide application in many large structural applications. (See Table 2.31.) They will cure at room temperature with a catalyst (peroxide) which produces an exothermic reaction. The resultant polymer is nonpolar and very water resistant, making it an excellent choice in the marine construction field. The isopolyester resins, regarded as the most water-resistant polymer in the polymer group, has been chosen as the prime matrix material for use on a fleet of U.S. Navy mine hunters. 

Cure conditions (temperature, time and catalyst S5retem) can be used to control particle development during cure if the resin/LR blend is miscible prior to cure. However, very few miscible systems have been developed. Figure 2 shows the fracture surface of a tough blend of vinyl ester with poly(epichlorohydrin) elastomer. This system is single phase before cure. Under the proper cure conditions a fine particulate phase develops as shown in Figure 3. 

Rhodium-complexed dendrimers supported on a resin were evaluated as catalysts for the hydroformylation of aryl olefins and vinyl esters. Up to 99% yields and an outstanding selectivity for the branched aldehydes (up to 38 1) were obtained at room temperature and 69 bar CO H2 = 1 1. The dendritic catalysts were recycled by simple filtration and reused even up to the 10th cycle without any loss of activity and selectivity ]82]. 

Uses Solvent for liquids, gases, vinyl resins, wire enamels polyacrylic fibers gas carrier catalyst in carboxylation reactions organic synthesis (manufacture of aldehydes, amides, amines, esters, heterocyclics). 

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