THERMAL-BEHAVIOR AND ADHESIVE PROPERTIES OF SOME CYANOACRYLATE ADHESIVES WITH INCREASED HEAT-RESISTANCE

Cured adhesive layers produced from ethyl-(ECA), allyl-(ACA), and allyloxyethyl-(AOECA) 2-cyanoacrylates were studied by means of thermogravimetry and differential scanning calorimetry. Polymer films of ECA-based adhesive compositions comprising various amounts and types of 2-cyano-2,4-pentadienoic acid (CPDA) esters were also examined. The influence of the modifier type, as well as the chemical structure of the cyanoacrylates used, was followed upon the glass transition temperatures (T(g)) and the rates of thermal degradation of the corresponding polymers. In the case of cured adhesive mixtures containing unsaturated CPDA esters and when poly (ACA) and poly (AOECA) were studied, a significant increase of their heat resistance was established, as compared with poly(ECA). This fact was explained with the formation of three-dimensional structure of the polymer film due to crosslinking reactions. A different course and character of these reactions were found comparing the thermal behavior of poly (ACA) and cured compositions containing unsaturated CPDA esters. A good agreement was found between data from the thermal analyses and the tensile shear and impact strength tests. It was shown that the modification of ECA with unsaturated CPDA esters is a possible way of increasing the heat resistance of the basic adhesive.