Epoxidized oils, modification

Although DGEBA resins provide the backbone of most epoxy formulations, they may be blended with other types to achieve modifications. Epoxy novolacs, having higher functionality, increase the cross-linking density, which improves heat resistance but decreases impact resistance. Incorporation of epoxidized oils increases flexibility at the expense of heat and chemical resistance. Low-viscosity polyfunctional epoxies based on polyols or polyhydric phenols reduce viscosity and can increase functionality without impairing cured properties. Monofunctional reactive diluents will also decrease viscosity and form part of the polymer backbone, to impart a measure of flexibility without the possibility of migration. Properties of commercially available epoxy resins and diluents from various suppliers are listed in Table 1. 

Modification of epoxidized oils and polymerization of the resulting products... 

As the name suggests, epoxidised NR is prepared by chemically introducing epoxide groups randomly onto the NR molecule. This chemical modification leads to increased oil resistance, greater impermeability to gases, but an increase in the glass transition temperature, Tg, and damping characteristics the excellent mechanical properties of NR are retained. 

Scheme 2, The modification of acrylated epoxidized soybean oil (AESO) shown using cyclohexane dicarboxylic anhydrade or maleic anhydride. These AESOs were cured with styrene or other comonomers (20).

Because palm oil and its products have lower iodine values, the epoxide contents of EPOP are lower than that of ESBO. As plasticizers and stabilizers, EPOP are therefore not expected to perform better than ESBO, but their performance could be made comparable by slight modifications of the formulations. PVC jungle and rain boots plasticized and/or stabilized with EPOP have been produced that are comparable in performance to those plasticized and/or stabilized with ESBO (120). 

Fig. 17.6. Epoxidation of soybean oil (a), followed by hydrolysis to form polyols (b). Modification of polyols to form polyesters (c), soybean oil based acrylates (d), and epichlorohydrin modified soybean oil (e).

Hwang, H.S. S.Z. Erhan. Modification of epoxidized soybean oil for lubricant formulations with improved oxidative stability and low pour point./. Am. Oil Chem. Soc. 2001, 78, 1179-1184. 

The formulations described in this paper were prepared using a dispersion disk and degassed In vacuum. The basic formulation of the resin matrix consisted of 33 parts of cycloaliphatic diepoxid, 33 parts of cresolnovolac epoxide, 33 parts of cycloaliphatic epoxy diluent, 0.5 parts of silane and 0.5 parts of photolnltlator (resin A). In addition fused silica 150 parts (resin B), 186 parts (resin C), 233 parts (resin D) was added. In the toughened mixture (resin E) the cycloaliphatic epoxide of resin D was substituted by 41.7 parts of a dispersion of 20Z silicone elastomer In epoxy resin. In the flexlbilized modification (resin F) 33 parts of epoxldlsed soya bean oil were added to resin D. 

Castor oil has been extensively used as a polyol precursor in polyurethane synthesis because of the reactive hydroxyl functional groups [OH) contained in its molecule, but polyurethanes derived from hydroxylated epoxides of linseed, soybean, and rapeseed oils have also been reported. Soybean oil is another remarkable triglyceride rich in unsaturated fatty acids that are susceptible to chemical modification for desired polymeric materials. In comparison with castor oil, soybean oil also requires strategies to functionalize them. Lubguban et al. proposed the acylglycerol... 

Modern biobased lubricants are mainly based on rapeseed oil, sunflower oil, soybean oil, and animal fats. These oils easily undergo oxidation due to their content of polyunsaturated fatty acids such as linoleic acid and linolenic acid. Efforts have been made to modify the oils to provide a more stable material and a product more competitive in performance to mineral oil-based lubricants. This modification can involve partial hydrogenation of oil and a shifting of its fatty acids to high oleic acid content [21]. Other reported changes that address the problem of unsaturation include alkylation, acylation, hydroformylation, hydrogenation, oligomerization (polymerization), and epoxidation [20, 22]. 

Also similar to styrene and methyacrylates is the use of divinylbenzene as a comonomer. Acrylated, epoxidized soybean oil was polymerized with divinylbenzene or modified with phthalic anhydride before polymerization to give materials with increased glass transition temperatures [43]. Modification of the soybean oil with cinnamate esters and subsequent... 

Other sources of oils which may be epoxidized are also studied, especially palm oil which is readily available in Asia and Africa. Modification of epoxidized soybean oil is also studied to develop grades which lower concentration of this plasticizer and have retention of mechanical properties obtainable with DOR ... 

The epoxidation of NR and other unsaturated polymers has been reported in the literature. However, there are little data on the properties of these materials and, where they do exist, they tend to be conflicting. The above reactions established criteria for the chemical modification of NR, which led to the development of clean epoxidized natural rubber (ENR). These new polymers have improved oil resistance and decreased gas permeability, whilst retaining many of the properties of NR and also exhibiting some novel features. 

Some plant oils have, naturally, high functionality and can be used without modifications to produce different polymeric materials. Such is the case for V. galemensis, a natural epoxidized planL which contains 60-65% vemo-Uc acid. Castor oil is a hydroxyl-containing oil with -90% of ricinoleic cid. 

Table A.3 shows long-chain a-olefin-MA copolymers are potentially useful for preparing oil additives, wax extenders for paper, sizing agents for paper and textiles, cosmetics dispersants, and many other applications. Gulf s product literature on PA-18 points out that modification of the anhydride residue with aqueous bases, ammonia, amines, alcohols, and epoxides may provide a host of potentially useful products.

Vernonia oil has a molecular structure similar to that of epoxidized soybean oil and initial results have shown that vernonia oil is an excellent PVC plasticizer and stabilizer.23" Since vernonia oil is expected to be less expensive than epoxidized soybean oil, we have little doubt that it will be able to substitute for the epoxidized soybean oil in PVC modification and capture this large market. 

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