Epoxy resins, crosslinked cycloaliphatic

Tpo maximize the utility of crosslinked cycloaliphatic epoxy resins in some of the more critical application areas, improved toughness is required. Such improvements can often be made through modification with various flexibilizing agents, but as a rule this improvement is accompanied by a severe degradation of the strength and heat distortion temperature of the cured system. 

The control resin network used in this study was a diglycidyl ether-based epoxy resin crosslinked with a cycloaliphatic diamine. Cooligomeric modifiers were prepared having varying percentages of TFP and DP siloxane and aminoethylpiperazine end groups. Both siloxane and ATBN and CTBN elastomers were used as epoxy modifiers, the latter two having been included to facilitate direct comparisons between modifiers in similarly prepared networks. 

The viscosity of the epoxide prepolymers in many instances is reduced by additions of thin liquid epoxy compounds fliat may include cycloaliphatic epoxides or lactones. Various epoxidized vegetable oils, like epoxidized linseed, sunflower, soybean, and others are also used in some formulations. Table 3.4. lists come cycloaliphatic epoxy monomers used for such purposes. Vinyl ethers polymerize at a faster rate than do cycloaliphatic epoxides. They are, therefore, included in some formulations. Other materials fliat are included for such purposes or to control viscosity can be epoxy novolacs, glycidyl ethers of long chain alcohols. To control viscosity, polyols might also be used, because it is assumed that hydroxy group bearing compounds crosslink with the epoxy resins. 

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