Abstract: These compositions comprise at least one compound (A) and at least one compound (B) containing electron enriched or depleted olefinic double bonds, respectively.

Abstract: These prepolymers having maleimide functions (f) consist in the reaction products of at least one maleic anhydride represented by formula (I); of at least one compound (II) having at least one —NH2 function and at least another function F selected from the group consisting of —OH, —NH2, —NH—, —COOH, —COOR3 or —OOCR3; of at least one compound (III) capable of forming the chain of the prepolymers by polycondensation and/or polyaddition, said compound(s) (II) having first reacted with said maleic anhydride(s) (I) in order to open the maleic anhydride rings with formation of maleamic acid functions (f′), said maleamic acid functions having then been at least partially closed again under the action of heat into maleimides N-substituted by groups functionalized by a function F, the chain of said prepolymers having been formed by polycondensation and/or polyaddition of the N-substituted maleimide formed bearing the function F; of compound(s) (III) of uncyclized p

Abstract: Compounds having the formula ##STR1## wherein X is selected from O, (CH.sub.2).sub.m O, S, (CH.sub.2).sub.m S, NH, (CH.sub.2).sub.m NH, COO.sup.-, (CH.sub.2).sub.m COO.sup.-, .sup.- OOC and .sup.- OOC (CH.sub.2).sub.m ;m is 1 to 6;n is 1 to 100;R.sub.1 is selected from H, (C.sub.1 -C.sub.20) alkyl, (C.sub.1 -C.sub.20) alkoxy and (C.sub.1 -C.sub.20) ester; andA is a saturated organic linking group selected from residues of polyol, polythiol, polyamine, and polyacid, are prepared by reacting compounds according to formula II ##STR2## with hydrogen peroxide in the presence of (a) tungstic acid or its metal salts, (b) phosphoric acid or its metal salts, and (c) at least one phase transfer catalyst.