The thermal reaction between N‐phenylmaleimide and 2‐allylphenol was taken as a model reaction in order to obtain information about chain extension and crosslinking mechanisms of the thermal curing of bismaleimides with diallylbisphenol A. Isolation (preparative HPLC) and characterization (1H and 13C NMR, FT‐IR, HPLC/SM) of a monoadduct and two original triadducts (principally low molecular weight products of the reaction) and studies as a function of time (0–6h) of this thermally induced reaction (160–250°C) with equimolar quantites of N‐phenylmaleimide and 2‐allylphenol, as well as with an excess of N‐phenylmaleimide, give direct evidence of the occurrence of an ene‐reaction and further Diels‐Alder and retro Diels‐Alder reactions with rise in temperature.

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Telechelic cis-1,4-oligoisoprenes were prepared by the selective cleavage of weak epoxidized units (E) in epoxidized cis-1,4-polyisoprenes (EPIs) and by the random cleavage of isoprenic units (I) in cis-1,4-polyisoprene (PI). In both cases, cleavage by periodic acid (H 5 IO 6 ) in tetrahydrofuran led to aldehydic and ketonic chain ends. Through variations in the E/(I ϩ E) molar percentage (E%) in the cleavage of EPI and through variations in the H 5 IO 6 /I molar percentage (PA%) in the cleavage of PI, a polydispersity index near 2 and a number-average molecular weight of 2 -20 ϫ 10 3 were obtained. The correlation of the degree of scission with E% and PA%, combined with kinetic, led to the proposal of a two-step mechanism for the H 5 IO 6 cleavage of double bonds.