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P. Czub

Application of epoxidized soybean oil for the control of viscosity of epoxy compositions

Polimery 2006, No 11-12, 821


Summary

The results of research concerning the possibility of application of epoxidized soybean oil (EOS) as a reactive diluent to reduce the viscosity of low-molecular-weight epoxy resins were presented. Fluxing curve of the composition of the resin „Rütapox 0162” with EOS as a function of EOS content has been determined (Fig. 1). On the base of the courses of flow curves registered at various temperatures, 25-65°C, (Fig. 2, Table 2) and calculated on this basis the values of flow index (n), consistence coefficient (k) and flow activation energy (Ea), the rheological characters of the compositions were determined. They were classified as non-Newtonian liquids showing the features like of viscoplastic Bingham's liquids. It was found that the curing of EOS containing compositions with isophorone diamine run with decrease in heat release (even to 50%) and lower peak temperature (Table 5) what significantly facilitated these materials' processing. EOS incorporated into the structure of cured epoxy resin causes decrease in its tensile strength (Fig. 3), flexural strength, compression strength and hardness (Fig. 4) but simultaneously causes increase in impact strength (Fig. 4) and relative elongation at break (Table 6). Significant decrease in Tg value was also observed. As a result of EOS content choice the various EP/EOS compositions can be obtained - showing the features characteristic for the constructional plastic up to elastomers. Decrease in crosslinking density of EP resin, being a result of EOS fragments' incorporation, causes the lowering of thermal stability of the composition (Fig. 5, Table 7) and its chemical resistance (Table 8) as well as higher water absorption.


Key words: low-molecular-weight epoxy resins, epoxidized soybean oil, reactive diluents, viscosity, mechanical and thermal properties, chemical resistance


e-mail: pczub@usk.pk.edu.pl


P. Czub

Application of epoxidized soybean oil for the control of viscosity of epoxy compositions