Chemical modification of styrene-butadiene-styrene (SBS) rubber by reacting grafting with maleic anhydride

V.L.LASSALLE; M.D.FAILLA; E.M.VALLÉS; R.TORREGOSA-MACIÁ; C.M.CEPEDA- JIMÉNEZ; J.M.MARTÍN MARTÍNEZ

JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY

Año: 2003 vol. 17 p. 1713 - 1766

0169-4243

Abstract In present work, styrene-butadiene-styrene rubber (SBS) has been functionalized with, maleic anhydride (MA). The influence of this modification on the surface properties of SBS has been studied. Special emphasis has been taken to examine the improvement of the adhesion between functionalized SBS surfaces when polyurethane thermoplastics adhesives are employed. The grafting of MA onto SBS was carried out in the presence of different concentrations of 2,5-dimethyl-2,5 di (tertbutylperoxy) hexane (DBPH) as initiator to generate oxi radicals by thermal decomposition, which induce the grafting reactions.  The modification process was performed in the moltenstate using a Brabender mixer to premix the reactants and a hot press to initiate the functionalizing reaction. The effect of functionalizing agents concentration on the efficiency of the grafting reaction has been evaluated.. FTIR spectroscopy was employed to verify the grafting. Changes of surface energy on the modified rubbers were estimated by measurements of contact angle. Adhesion properties were evaluated by standard peeling test using commercial polyurethane adhesive (Desmocoll 540). Reasonable grades of MA grafting on SBS were obtained. Grafted species seemed to be specially concentrated on the surface of the SBS molded sheets, although smaller  concentrations of the functionalizing agents exist in the bulk polymer. The surface energy of the modified rubbers slightly increases with respect to the original polymer but a very important enhancement of peeling strength is observed.