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ABSTRACT Vinyl ester resins (VERs) often contain high concentrations of a petroleum-based reactive diluent, such as styrene. Reactive diluents that can be derived from lignin, including phenyl methacrylate (PM), 2-methoxyphenyl methacrylate (MG), and 4-propyl-2-methoxyphenyl methacrylate (M4PG), were synthesized and investigated as potential styrene replacements. A commercial VER was blended with each lignin-derived reactive diluent, and styrene, in 7:3 and 1:1 weight ratios and cured to ≥ 94%, based on near-IR spectral analysis. The substituents on the aromatic ring of the lignin-derived reactive diluent are shown to have small effects on viscosity, thermogravimetric, and thermomechanical properties of the cured resins, where, in general, the smaller the reactive diluent, the greater the glass-transition temperature ( Tg) and the lower the viscosity. Increasing purity of the reactive diluents through chromatographic separations substantially increases the Tg and degradation temperatures of the resins. The results suggest that PM, MG, and M4PG are effective bio-based reactive diluent replacements for styrene. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43817. [ABSTRACT FROM AUTHOR]

Lignin is a copious paper and pulping waste product that has the potential to yield valuable, low molecular weight, single aromatic chemicals when strategically depolymerized. The single aromatic lignin model compounds, vanillin, guaiacol, and eugenol, were methacrylated by esterification with methacrylic anhydride and a catalytic amount of 4-dimethylaminopyridine. Methacrylated guaiacol (MG) and methacrylated eugenol (ME) exhibited low viscosities at room temperature (MG: 17 cP and ME: 28 cP). When used as reactive diluents in vinyl ester resins, they produced resin viscosities higher than that of vinyl ester-styrene blends. The relative volatilities of MG (1.05 wt % loss in 18 h) and ME (0.96 wt % loss in 18 h) measured by means of thermogravimetric analysis (TGA) were considerably lower than that of styrene (93.7 wt % loss in 3 h) indicating the potential of these chemicals to be environmentally friendly reactive diluents. Bulk polymerization of MG and ME generated homopolymers with glass transition temperatures ( Tgs) of 92 and 103 °C, respectively. Blends of a standard vinyl ester resin with MG and ME (50 wt % reactive diluent) produced thermosets with Tgs of 127 and 153 °C, respectively, which are comparable to vinyl ester-styrene resins, thus demonstrating the ability of MG and ME to completely replace styrene as reactive diluents in liquid molding resins without sacrificing cured-resin thermal performance. [ABSTRACT FROM AUTHOR]

In this study, a fatty acid-based comonomer is employed as a styrene replacement for the production of triglyceride-based thermosetting resins. Styrene is a hazardous pollutant and a volatile organic compound. Given their low volatility, fatty acid monomers, such as methacrylated lauric acid (MLA), are attractive alternatives in reducing or eliminating styrene usage. Different triglyceride-derived cross-linkers resins were produced for this purpose: acrylated epoxidized soybean oil (AESO), maleinated AESO (MAESO), maleinated soybean oil monoglyceride (SOMG/MA) and maleinated castor oil monoglyceride (COMG/MA). The mechanical properties of the bio-based polymers and the viscosities of bio-based resins were analyzed. The viscosities of the resins using MLA were higher than that of resins with styrene. Decreasing the content of MLA increased the glass transition temperature (Tg). In fact, the Tg of bio-based resin/MLA polymers were on the order of 60°C, which was significantly lower than the bio-based resin/styrene polymers. Ternary blends of SOMG/MA and COMG/MA with MLA and styrene improved the mechanical properties and reduced the resin viscosity to acceptable values. Lastly, butyrated kraft lignin was incorporated into the bio-based resins, ultimately leading to improved mechanical properties of this thermoset but with unacceptable increases in viscosity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

The article presents a study on the viability of acrylated fatty acid methyl esters (AFAME) as a natural substitute for styrene in the production of polyurethane applications. The study aims to eliminate styrene in the polyurethane applications such as coatings, adhesives, and foams because of its harmful effects on the environment. The results demonstrate that AFAME as a styrene replacement gives a mixture of reduced elastic modulus but a mixture of 17.5 weight percentage of AFAME and styrene exhibits acceptable properties.

The article discusses the results of a study which characterized the molecular relaxation behavior of vinyl ester (VE) resins made from fatty acid with reduced concentration of styrene. The dynamic mechanical analysis of fatty acid-based VE resins showed an increase level of viscoelastic response than the commercial resins. The thermomechanical properties of fatty acid-based VE resins are also similar or slightly improved than commercial resin.

Abstract: Vinyl ester (VE) resins with a bimodal distribution of molecular weights were prepared via methacrylation of epoxy monomers. Bimodal VE resins and neat polymers had viscosities and mechanical properties similar to that of commercial resins. E-glass composites were prepared and also found to have similar mechanical and thermo-mechanical properties relative to composites fabricated using commercial resins. However, the fracture toughness of the bimodal resins was superior to that of the commercial resins partially as a result of increased molecular relaxations that were manifested in a broader glass transition. Overall, bimodal resins allow for the use of low styrene content (∼33wt%), while maintaining excellent thermal, mechanical, and fracture properties for the neat resins and composites. [Copyright &y& Elsevier]

One method of reducing styrene emissions from vinyl ester (VE) and unsaturated polyester resins (UPE) is to replace some or all of the styrene with fatty acid-based monomers. Methacrylated fatty acid (MFA) monomers are ideal candidates because they are inexpensive, have low volatilities, and free-radically polymerize with vinyl ester. The viscosity of VE resins using these fatty acid monomers ranged from 700–2000cP, which is considerably higher than that of VE/styrene resins (∼100cP). In addition, the Tg of VE/MFA polymers were only on the order of 80°C, which is significantly lower than that of VE/styrene polymers. Decreasing the length of the base fatty acid chains from 18 to 12 carbon atoms improved the Tg by 20°C, while lowing the resin viscosity from ∼2500 to ∼1000cP. Residual unsaturation sites on the fatty acid backbone decreased the cure rate of the resins thereby decreasing polymer properties. Ternary blends of VE, styrene, and fatty acid monomers also effectively improved the flexural, fracture, and thermo-mechanical properties and reduced the resin viscosity to acceptable levels, while using less than 15wt% styrene, far less than commercial VE resins. [Copyright &y& Elsevier]