Vinyl ester resin matrix

Yagneswaran and co-workers [25] incorporated mechanically devulcanised waste tyre powder into a vinyl ester resin matrix at various levels of addition and characterised the resulting materials using physical tests, DSC and TGA. As the level of rubber powder increased the composites were found to have reduced heat stability and flexural strength, but increased flexural modulus. 

In most applications, polyester and vinyl ester resins are used as the matrix materials. Epoxies are also used, although they require longer cure times and do not release easily from the pultrusion dies. Hence, thermosetting resins are most commonly used with pultrusion, although some high-performance thermoplastics such as PEEK and polysulfone can also be accommodated. In addition to the resin, the resin bath may contain a curing agent (initiator, cf. Section 3.3.1.2), colorants, ultraviolet stabilizer, and fire retardant. 

Bromination of vinyl-ester resin imparts fire retardancy as manifested by flame spread and lower RHR [50]. However, this fire-retardant system functions primarily in the gas phase causing incomplete combustion. As such, brominated resins produce dense smoke, and an increase in the yield of CO and HBr. Recent interest in the use of non-halogenated organic-matrix composite materials in US Navy submarines and ships has generated the requirement for significant improvement in the flammability performance of these materials including reduction in the amount of smoke, CO and corrosive combustion products. 

PMMA/y-Fe203 composites by in-situ polymerization. The presence of OA on the metal oxide surface increased the compatibility of the metal oxide NPs with the polymeric matrix and yielded bulk homogeneous and highly transparent PMMA/y-Fe203 composites [169]. Magnetic vinyl ester resin nanocomposites... 

The toughening effectiveness of impact modifiers of any kind in unsaturated polyester and vinyl ester resins will depend on the rate of impact or applied strain, atmospheric conditions (temperature, presence of solvents), and the toughness of the base resin. As the applied strain rate increases or the lest temperature decreases the effectiveness of the rubber additive may decrease. This is because the rubbery particles and the matrix resin b me more brittle under these conditions. As a result, when comparing toughness data from different sources, testing... 

In the case of glass fiber cloth reinforced by vinyl ester resins that were immersed in hot water (Morii et al. 1991), it was possible to associate the degradation process with fiber/matrix interfacial failures. This was achieved by considering distinct fiber surface treatments and observing the existence of good correlations between the knee-point stress levels in stress-strain plots and water weight gain data. 

The data tend to fall into two groups. First, a high amplitude fatigue region where the effect of the matrix can be discerned. The NPG/ iso-polyester and the vinyl ester resins have a somewhat longer life for the same stress amplitude than iso- and ortho-polyesters. Secondly, a lower amplitude, higher cycle region where all the laminates have a similar lifetime. 

The most widely used and least expensive polymer resins are the polyesters and vinyl esters. These matrix materials are used primarily for glass fiber-reinforced composites. A large number of resin formulations provide a wide range of properties for these polymers. The epoxies are more expensive and, in addition to commercial applications, are also used extensively in PMCs for aerospace applications they have better mechanical properties and resistance to moisture than the polyesters and vinyl resins. For high-temperature applications, polyimide resins are employed their continuous-use, upper-temperature limit is approximately 230°C (450 F). Finally, high-temperature thermoplastic resins offer the potential to be used in future aerospace applications such materials include polyetheretherketone (PEEK), poly(phenylene sulfide) (PPS), and polyetherimide (PEI). 

The thermoplastic or thermoset nature of the resin in the colorant—resin matrix is also important. For thermoplastics, the polymerisation reaction is completed, the materials are processed at or close to their melting points, and scrap may be reground and remolded, eg, polyethylene, propjiene, poly(vinyl chloride), acetal resins (qv), acryhcs, ABS, nylons, ceUulosics, and polystyrene (see Olefin polymers Vinyl polymers Acrylic ester polymers Polyamides Cellulose ESTERS Styrene polymers). In the case of thermoset resins, the chemical reaction is only partially complete when the colorants are added and is concluded when the resin is molded. The result is a nonmeltable cross-linked resin that caimot be reworked, eg, epoxy resins (qv), urea—formaldehyde, melamine—formaldehyde, phenoHcs, and thermoset polyesters (qv) (see Amino resins and plastics Phenolic resins). 

Matrix materials for commercial composites are mainly liquid thermosetting resins such as polyesters, vinyl esters, epoxy resins, and bismaleimide resins. Thermoplastic composites are made from polyamides, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polysulfone, polyetherim-ide (PEI), and polyamide-imide (PAI). 

The most common advanced composites are made of thermosetting resins, such as epoxy polymers (the most popular singlematrix material), polyesters, vinyl esters, polyurethanes, polyimids, cianamids, bismaleimides, silicones, and melamine. Some of the most widely used thermoplastic polymers are polyvinyl chloride (PVC), PPE (poly[phenylene ether]), polypropylene, PEEK (poly [etheretherketone]), and ABS (acrylonitrile-butadiene-styrene). The precise matrix selected for any given product depends primarily on the physical properties desired for that product. Each type of resin has its own characteristic thermal properties (such as melting point... 

The matrix is considered to be the binder for the microspheres. Typical matrix materials include (a) thermosetting resins such as epoxy resins, unsaturated polyesters, vinyl esters, phenolics, polyurethanes, and silicones (b) thermoplastic resins such as polyethylene, polystyrene, polyvinyl chloride (c) asphalt and (d) gypsiun and cement. 

The matrix resins for foamed composites include rigid pol)ruretha-nes, unsaturated polyesters, vinyl esters, and their hybrid resins, such as, unsaturated polyester-urethane hybrid resins and vinyl ester-urethane hybrid resins. The reinforcing fibers include glass fibers, carbon fibers, and organic fibers such as polyamide fiber (Kevlar, DuPont), polyamide-... 

Three different matrix resins were used in this study a toughened vinyl ester, an untoughened vinyl ester, and an epoxy. Two different fiber layups were used designated by the letters L and P . The vinyl ester laminates were pultruded with the L lay-up while the epoxy laminate employed the P lay-up in order to prevent scaling problems in the epoxy resin system. 

Organic compounds with carbon-carbon unsaturated double bonds, such as carbon disulfide, are powerful swelling solvents and show greater swelling action than their saturated counterparts. Smaller solvent molecules can penetrate a polymer matrix more effectively. The degree of similarity between solvent and resin is important. Slightly polar resins, such as polyesters and the vinyl esters, are attacked by mildly polar solvents. 

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