Epoxidised vegetable oils

Purity (many additives are technical grade substances, (isomeric) mixtures, e.g. fatty amides or epoxidised vegetable oils)... 

By the reaction of epoxidised vegetable oils with HCl, HBr or various organic acids (R-COOH), the epoxidic ring is opened with the formation of polyols having chlorohydrin, bromohydrin or hydroxyalkyl esters structures (reactions 17.17, 17.18 and 17.19) [31-34]. 

By the reaction of alcohols (in excess) with epoxidised vegetable oils in the presence of acids as catalysts - liquid polyols are formed (reaction 17.22). For example by the alcoholysis of epoxidised soybean oil with methanol, at the reflux temperature of methanol (the boiling point of methanol is 64.7 °C), in the presence of an acidic catalyst (H2S04, p-toluene sulfonic acid, HBF4 [31, 34, 44, 45], solid acidic clays [39], supported acidic catalysts), liquid soybean oil based polyols are obtained, with an hydroxyl number of around 170-173 mg KOH/g, a functionality of about 3-4 OH groups/mol and a viscosity of around 4,000-7,000 mPa-s at 25 °C. After the neutralisation of the acidic catalyst or by the filtration of solid acid catalysts, the methanol is distilled under vacuum and recycled back into the process. 

As is the case with hydrolysis of epoxidised vegetable oils, by alcoholysis the hydroxyl numbers obtained are always lower than theoretically expected. The explanation is the same the intermolecular and intramolecular reactions between the formed hydroxyl groups and the unreacted epoxidic rings. These reactions conserve the number of hydroxyl groups and do not generate new hydroxyl groups. By intramolecular reactions dimers and trimers of lower hydroxyl number and higher functionality are formed. 

Is monoglyceride or hydrolysed epoxidised vegetable oil preferable in the preparation of polyurethanes and for what reasons ... 

The preparation of epoxy resins from a large number of vegetable oils such as sunflower, cotton-seed, linseed, vernonia, soybean, castor and Mesua ferrea has been reported. " However, most of these epoxy resins exhibit poor mechanical properties which limit their applications. Vegetable oil-based epoxy resins rather than epoxidised vegetable oils are also used as reactive diluents. These are low viscosity materials used in conjunction with industrial epoxy resins to reduce viscosity and to increase the molecular mass of the latter. As a reactive diluent can also act as a solvent for the resin system, it enables the production of high-solid and low VOC (volatile organic compound) coatings. 

A novel triglyceride-based a, p-unsaturated ketone, obtained by photoperoxidation from high oleic sunflower oil, can be cross-linked with diamino diphenyl methane through the aza-Michael addition reaction. The reaction of p-toluidine with either enone-containing methyl oleate or epoxidised methyl oleate, produces an alternative to amine-cured epoxidised vegetable oil thermosets. ... 

Epoxidised vegetable oils are flammable as hydrocarbon is their major constituent. However, vegetable oil-based epoxy resin can be made flame... 

The commercial use of epoxy resins has grown steadily since their introduction in 1947. Bio-based epoxy resins and epoxidised vegetable oils are... 

F. E. Okieimen, Studies in the utilisation of epoxidised vegetable oils as thermal stabiliser for polyvinyl chloride , Ind Crops Products, 2002,15,71-5. 

Researchers are exploring the feasibility of manufacturing epoxidised vegetable oil-based polymer composites. Composite materials have been manufactured utilising vegetable oil-based epoxy resins and a range of... 

Different amines and different ratios of the amine to the epoxy have been used to cure several epoxidised vegetable oils [16]. The bis(p-aminocyclohexyl)methane diamine afforded the highest performance and amine epoxy ratios of 0.8 and 1.0 gave thermosets with superior performances. 

A more recent study of the reaction of primary amines with epoxidised vegetable oils is discussed in Chapter 7. It deals with the Diels-Alder reactions involving furan derivatives. 

Use of anhydride hardeners to crosslink epoxidised oils has received more attention. Boquillon and Fringant [19] studied the kinetics of the polycondensation of epoxidised linseed oil with various aromatic and cycloaliphatic anhydrides at 150-170 °C and characterised the ensuing networks by measuring their Tg and flexural modulus (which both increased with increasing proportion of anhydride) as well as dynamic mechanical properties and their crosslink density. These materials, based partly on renewable resources, displayed adequate properties in terms of applications of thermosets associated with a relatively low Tg (35-110 °C). A similar investigation in which epoxidised vegetable oils substituted with <50% of bisphenol A diglycidyl... 

These studies opened the way to a new area of macromolecular science based on renewable resources pursued by approaches based on pristine oils and their commercial derivatives. The bulk reaction of epoxidised vegetable oils with an excess of furfurylamine was studied in green chemistry conditions and formd to take place through two parallel mechanisms occurring at approximately the same rate. That is, aminolysis of ester bonds and oxirane ring-opening, as shown in Scheme 7.5 for the case of epoxidised linseed oil [12], These reactions were followed by Fourier-Transform infrared spectroscopy and H-nuclear magnetic resonance spectroscopy, respectively, and both reached completion. 

This approach was also applied to other epoxidised vegetable oils with entirely similar results, which proved its wide scope and reproducible features. 

The most widely used alternatives are ahphatic esters, together with aromatic phosphates, the trimellitates, citrates, the aliphatic polyesters and the epoxidised vegetable oils. 

Barium/cadmium (Ba/Cd) and barium/cadmium/zinc (Ba/Cd/Zn) based stabilisers are general purpose stabilisers for plasticised PVC. Large quantities are consumed in leathercloth, calendered sheeting, extrusions, injection moulded footwear and flooring. They are not suitable for cable extrusion due to their inferior electrical properties. They exhibit synergism with phosphite chelators such as tris nonyl phenyl phosphite, and are often used with 3-5 phr of epoxidised vegetable oils as co-stabilisers. 

Calcium/zinc stabilisers (Ca/Zn) are chiefly used in applications such as food packaging where their non-toxic properties are of paramount importance. Although cheap, their heat stabilising efficiency is relatively poor, and they are often used as co-stabilisers with aminocrotonates and epoxidised vegetable oils, particularly in food grade extruded or calendered film. Their use in blow-moulded... 

Phosphite chelators such as tris-nonyl phenyl phosphite are used as co-stabilisers with Ba/Cd and Ca/Zn to improve heat and light stability at an addition level of about 0.5 phr. Similar co-stabilising effects are shown by the epoxidised vegetable oils such as epoxidised soya bean oil, used at 3-5 phr. Epoxies may also be used at higher levels of 10-15 phr as secondary plasticisers to improve low temperature performance, when their presence also improves compound heat stability. Epoxidised soya bean oils are regarded as non-toxic and are therefore widely used as co-stabilisers in rigid and flexible food packaging applications. 

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