Preparation of hypercrosslinked PolyHIPEs by using a bio-derived monomer

The interest on adapting bio-derived species to polymer synthesis has been increased in the last decade. Terpenes that can be obtained by extracting from the essential oils of tree sap and citrus fruit have an important place on this subject. In this respect, beta-myrcene, which is a promising linear conjugated diene, is attracting the interest of researchers. However, the free radical copolymerization of beta-myrcene is difficult mainly because of concurrent Diels-Alder reactions with electron-deficient vinyl monomers via their s-cis forms. Here, we developed polyHIPEs from the high internal phase emulsions (HIPEs) of beta-myrcene. For this purpose, HIPEs were prepared by using either 50 or 40 vol% of beta-myrcene in the continuous phase. Meanwhile, the influence of 4-vinylbenzyl chloride (VBC), divinylbenzene (DVB), and 1,3-butanedioldiacrylate (BDDA) on the copolymerization crosslinking of beta-myrcene within precursor HIPEs was explored. For this purpose, HIPEs were prepared by altering the amount of comonomers between 0 and 60 vol% of the total monomer composition. The resulting HIPEs showed excellent stability. However, crosslinking could not be achieved in all cases, due to the altered monomer composition. On the other hand, crosslinked polyHIPEs were hypercrosslinked with Friedel-Crafts alkylation method. Characterization of the resulting materials showed the Brunauer-Emmett-Teller specific surface area (delta(BET)) of the polyHIPEs was increased from 2.25 m(2) g(-1) to 60.18 m(2) g(-1) by hypercrosslinking.

Automated summary

The interest in using bio-derived species for polymer synthesis has been growing over the past decade, with terpenes extracted from tree sap and citrus fruit essential oils playing a significant role. Among these, beta-myrcene, a promising linear conjugated diene, is of particular interest to researchers. However, challenges exist in the free radical copolymerization of beta-myrcene due to competing Diels-Alder reactions with electron-deficient vinyl monomers. In this study, polyHIPEs were successfully synthesized from high internal phase emulsions of beta-myrcene, with stability demonstrated in resulting materials but varying success in achieving crosslinking. Hypercrosslinking with the Friedel-Crafts alkylation method significantly increased the specific surface area of the polyHIPEs.