Vinylester matrix composite

Botaro, V.R., Novack, K.M., and Siqueira, E.J. (2012) Dynamic mechanical behavior of vinylester matrix composites reinforced by Luffa cylin-drica modified fibers. /. Appl. Pofym. 

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... 

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). 

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

Ramirez F, Carlsson L, Acha B (2008) Evaluation of water degradation of vinylester and epoxy matrix composites by single fiber and composite tests. J Mater Sci 43(15) 5230-5242 Roberts RC (1978) Design, strain and failure mechanisms of GRP in a chemical environment. 

Ray, D., Sarkar, B.K., Rana, A.K., and Bose, N.R. (2001) The mechanical properties of vinylester resin matrix composites reinforced with alkali-treated jute fibers. Composites Part A, 32, 119-127. 

Addition poly(imide) oligomers are used as matrix resins for high performance composites based on glass-, carbon- and aramide fibers. The world wide market for advanced composites and adhesives was about 70 million in 1990. This amounted to approximately 30-40 million in resin sales. Currently, epoxy resins constitute over 90% of the matrix resin materials in advanced composites. The remaining 10% are unsaturated polyester and vinylester for the low temperature applications and cyanate esters and addition poly(imides) for high temperatures. More recently thermoplastics have become important and materials such as polyimides and poly(arylene ether) are becoming more competitive with addition polyimides. 

Kevlar 29 and versions thereof (K 129 and Kl j.) are also used extensively in lightweight body armor as well as composite liners (with vinylester, polyester or epoxy as the matrix). A quick look at the properties of different Kevlar aramid fibers in Table 4.2 shows why K29 is better than K49 for lightweight body armor applications. K29 has a higher strain to failure than K49. That means that the total work of fracture, i.e. the area under the stress-strain curve, is larger for K29 than K49. Hence, the energy absorbed in the fracture process is higher for K29... 

Polymer matrix materials are categorized into thermoplastics and thermosets. Thermoplastics soften and melt above a specific temperature and become solid when cooled. They can be formed by repeated heating and cooling. In contrast, thermosets normally cure by irreversible chemical reaction (between two components, a resin and a hardener, for example, for epoxy (EP)) and chemical bonds are formed during the curing process. This means that a thermoset material cannot be melted and reshaped once it is cured. Thermosets are the most common matrix materials used for FRP composites in construction nowadays. The most common thermosets are unsaturated polyester (UP), EP, and vinylester (VE) [9]. Because of their organic material nature, aU of these matrix materials are sensitive to elevated temperatures and fire. 

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. 

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

Vinylester resins as a matrix material in advanced FRP composites 71... 

Giass fibre-vinylester composite (randomly oriented fibres) (fibre/matrix ratio 67%) 1.84 19.3 269 1.07 14.90... 

It is of note that the respective amounts of char and flammable volatiles produced by the thermal decomposition of the composite are highly dependent on the chemical nature of the organic phases, i.e., the polymer matrix and synthetic fibres, if present (Levchnick and Wilkie, 2000 Mouritz, 2007). As regards the main thermosetting polymers used in construction (i.e., polyesters, vinylesters and epoxies), pyrolysis yields a large amount of volatiles but retains a small amount of char (10-20% of the initial mass). FRP composites based on these thermoset matrices are thus highly flammable materials. 

Pultrusion is mainly used to process glass-, aramide-, carbon fiber rovings with a wide variety of thermoset matrices such as polyester-, vinylester- and epoxy-resins [10]. The processing speed can be up to 5 m/min. In addition, thermoplastic matrix based composite pultrusion has been developed over the last 20 years. Due to the higher viscosity of thermoplastics in compaxison to thermosets, the processing speed is about ten times slower in terms of thermoplastic pultrusion [11]. 

Its polymer matrix, vinylester resin, can be affected by long-term exposure in severe conditions. Prior to aging tests, matrix films (30 pm < thickness <45 pm) and composite thick samples (0.5 mm < thickness <2 mm) were cured at 80 °C for 12 h and post-cured at 160 °C for 2-A h. Following this process, the material s cure is enhanced and unreacted free species are eliminated. 

An epoxy matrix is assumed for the FRP composite, although properties of polyester, vinylester, or other common matrices can be substituted. The distribution type and COVs for as-built composite modulus and ultimate tensile strength are given in Table 5.3. Mean values for ultimate tensile strength and modulus of elasticity of a lamina are calculated for a set of constituent materials for a specific fiber volume fraction assuming a 5% void volume fraction other statistical properties were obtained from Atadero et al. (2005) for wet lay-up, field-manufactured composites, in order to emulate the possible variation in properties of FRP composites cured under ambient conditions. 

---