Vinylester resins

CTBN and derivatives are also used in unsaturated polyester and vinylester resins but with less success. Studies have shown that the elastomer additive alone is very often immiscible in a polyester resin. 

Incorporation of monofunctional epoxy POSS into an amine-cured epoxy network increased and broadened the Tg without changing the crosslink density and enhanced the thermal properties. Additionally, it was found that the thermal and thermal-mechanical properties of resultant styrene-POSS vinylester resin nanocomposites were dependent on the percentage of POSS incorporated into the resin [171]. Over a range of POSS incorporations, the Tg of the copolymers changed very little, but the flexural modulus increased with increasing POSS content. 

Glass fibre strand was treated with gamma-methacryloxypropyltrimethoxysilane as a coupling agent and used to reinforce a vinylester resin. The interface was studied by FTIR spectroscopy and showed that the silane was able to migrate into the resin and influence curing at a distance (200 pm) greater than the thickness of the interphase (328). 

Vinylester Resin—Thermosetting resins that consist of a polymer backbone with an acrylate or methacrylate termination. 

These specifications are demanding for polyester or vinylester resin systems. They are more easily achieved with urethane methacrylate which allows a higher level of filler loading. Phenolic resin composites can achieve this performance without fire retardant additives but they are difficult to process. 

In this process, the mold is filled with reinforcement, covered with a vacuum bag, evacuated by vacuum which draws resin into the mold and through the reinforcement until it is saturated. Vinylester resins are particularly suitable for this application. A technique developed by Intermarine Savannah uses grooved cores which facilitate the rapid and even distribution of resin throughout the laminate. This process is quicker than hand lay-up, enables a higher fiber fraction to be attained and provides a cleaner working environment. 

The fiber tension is very important as this controls the resin pick-up, normally 35-40% volume fraction. Tensions are about lN/1000 filaments for wet winding and 3N/1000 filaments for other types of winding. If the tension is too high, the fiber does not spread and is damaged by abrasion in the guide and if too low, produces waviness in the applied fiber. The type of fiber size and size content must be carefully chosen to help achieve good resin wet out. The principal matrix materials are epoxy, polyester and vinylester resins, but thermoplastic prepregs such as PEEK can also be applied. 

Ashland Speciahty Chemical Co., Dublin, Ohio, USA—polyester resins including Hetron vinylester resin. 

Dow Chemical Company, Midland, Michigan, USA—manufacture epoxy and vinylester resins. Dowty Aerospace Propellers, Gloucester, England—produces composite propeller blades utilizing a fail-safe root retention system. 

DSM Composite Resins (DSM BASF Structural Resins), Zwolle, Netherlands—manufacture polyester and vinylester resins. Combined its saturated polyester resin business with BASF in... 

Ray D, Sarkar BK, Das S, Rana AK (2002) Dynamic mechanical and thermal analysis of vinylester resin matrix composites reinforced with untreated and alkali-treated jute fibers. Compos Sci Technol 62 911-917... 

The economic design of high-quality tanks for storing hypochlorite solutions has been a long-standing problem [75]. Iitanium would be an excellent material of construction, but only at a yery high cost. Rubber-lined carbon steel has been widely used in both horizontal and vertical tanks. Fiber-reinforced polymers are attractive candidates, but results often have been unsatisfactory. Vinylester resins (e.g., Derakane 411) are preferred, and polyester resins also may be satisfactory. Those with high chemical resistance are best, and bisphenol A resins, for example, are preferred to those based on isophthalic acid. 

D. Ray, B.K. Scirkar, md N.R. Bose, Impact fatigue behaviour of vinylester resin matrix composites reinforced with alkah treated jute fibres. Compos. A 33,233-241 f2002). 

Fibre-reinforced polymer (FRP) composites are composed of fibres and matrices, which are bonded through the interface to ensure that the composite system as a whole gives satisfactory performance. Part 1 deals with FRP composite matrix materials which provide the foundation for composite materials. Chapter 2 reviews the chemistry of phenolic resins together with their mechanical and thermal properties. Chapter 3 discusses polyester thermoset resins as matrix materials. An overview of the chemistry of vinylester resins, together with their mechanical and chemical properties, as well as their use as a matrix material in the construction industry, is provided in Chapter 4. The final chapter in Part 1 begins with a review of the epoxy resins commonly available on the market, and then focuses on the principal characteristics of epoxy resin composite systems and their practical applications. 

Vinylester resins as a matrix material in advanced fibre-reinforced polymer (FRP)... 

Abstract This chapter discusses the use of vinylester resin as a matrix in polymer composite materials to be used in civil engineering applications. 

It then reviews the chemistry of vinylester resins together with their mechanical and chemical properties as well as the applications of vinylester resin and composites in the construction industry. The chapter includes indications on future applications of vinylester-based fibre-reinforced composites along with a section devoted to sources of further and relevant information. 

Key words vinylester resin, polymer matrix composites, fibre-reinforced... 

Chemistry and properties of vinylester resins as matrix materials... 

This section is devoted to describing the chemistry of vinylester resins (including polymerization reactions) along with their mechanical, thermal and chemical (corrosion resistance and dimensional stability) properties. In general, vinylester resins are deemed to combine the best properties of epoxies and unsaturated polyesters in particular, they are easily handled at room temperature, and offer mechanical properties comparable to epoxy resins (Table 4.2). Moreover, they have better chemical resistance than cheaper... 

Polymerization structures of vinylester resins (a) bisphenol-A epoxy vinylester resin (b) novolac epoxy vinylester resin. 

An alternative way to obtain vinylester resins is through the novolac epoxy ehemieal structure (Fig. 4.3(b)). In this case, a phenol diepoxide is obtained the novolac backbone structure is particularly suitable for improved resistance to acids in liquid and in vapour form and at higher temperatures than are allowed by bisphenol-A vinylester resins. 

The resulting polymer, which is unsaturated on its terminal positions, is mixed with an unsaturated monomer, usually styrene. These reactive groups can form a cross-linked network with or without the addition of a comonomer. In many industrial products, vinylester resins include 40-50 wt% styrene, while in dental applications a common comonomer is triethylene glycol dimethacrylate. For some applications, such as filament winding, the styrene content needs to be limited (not normally exceeding 35-40%), reducing at the same time the quantity of volatile organic compounds (VOC) and therefore the environmental impact of the resin. 

To the vinylester resins, thixotropic agents are added, for example silica fume (silicon dioxide in microspheres, which is a by-product of the glass industry), to obtain a behaviour adequate to their use also in open moulds. In addition, to improve their toughness, CTBN polymers (carboxyl-terminated copolymers of butadiene and acrylonitrile) are widely employed as reactive modifiers. This occurs since the CTBN-modified vinylester oligomers act as compatibilizers for blending additional butadiene copolymer (Burchill and Pearce, 1996). 

Summary scheme of applications of vinylester resin and composites in the construction industry. 

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