Modification de Polymères Insaturés par Époxydation

Abstract

SynopsisConditions of epoxidation of unsaturated polymers were studied. Perphthalic monoacid appeared to be one of the most efficient epoxidation agents, particularly when the double bond is enriched with electrons. Some properties of the new polymers thus obtained were revealed and functional crosslinkings were achieved.Si certaines reactions d'oxydation des elastomeres! et en particulier du caoutchouc naturel,? ont fait l'objet de nombreux travaux, il ne semble pas que la creation de groupes epoxydes par reaction d'un peracide organique sur une double liaison ait ete clairement etudiee, En effet, les auteurs":" qui ont utilise les peracides dans les reactions de modification des polymeres n'ont pas mis en evidence les derives epoxydes, Ils obtiennent generalement des composes hydroxyles plus ou moins esterifies par les acides residuels. Quant a la chaine propre a I'elastomere, elle est fortement degrades.On a done utilise un reactif plus specifique des doubles liaisons polyiso-

Effect of acid concentration and other reaction parameters on epoxidation of natural rubber latex

“…The peak assignments were done as per Roux et al (1969), and quantitative analysis were performed as per the method described in ASTM D3677, Part 11. The peak assignments were done as per Roux et al (1969), and quantitative analysis were performed as per the method described in ASTM D3677, Part 11.…”

Moisture-sorption properties and studies on the dilute solution behavior of epoxidized natural rubber ENR 50

“…(a) Aside from oxirane ring closure, modification of the unsaturated hydrocarbon poly- mer backbone also gives M(H 2 CA)C-CH(OH)M an allylic moiety, 1 hydroxyesters, 1,5 diols, 5 and cyclization of the modified backbone with closure to form substituted furans and pyrans. 5,6 (b) Chain scission of the UHP backbone; 1 chain scission is reported to be higher, the higher the extent of epoxidation.…”

“…It has long been known that the epoxidation of unsaturated hydrocarbon polymers (UHP) leads to secondary reactions besides oxirane-ring formation. 1 Whether conducted in a dilute solution of a UHP or with UHP in latex form, 3 the reaction conditions may lead to the following secondary reactions:…”

“…For example, controlled epoxidations of natural rubber (NR) in solution 1 or latex 2,3 enable the conversion of cis-1,4-isoprenyl units to predominantly 2-methyl-2,3-oxybutyl units. In latex modification, a priori expectation of the nonuniformity of the reaction between peroxy acid and isoprenyl repeat units is not evident; the rate of epoxidation and the extent of epoxidation are reported not to be affected by the change in the average particle size of the unmodified latex.…”

Studies on the Epoxidation of Natural Rubber

“…The thin film thus formed was used to obtain spectra. The quantitative analysis was carried out by the method described by Roux et al [8] and Davey and Loadman [9].…”