Novel method of the surface modification of the microcrystalline cellulose powder with poly(isobutyl vinyl ether) using mechanochemical polymerization

Abstract

The surface modification of microcrystalline cellulose (MCC) powder with poly(isobutyl vinyl ether) (PIBVE) chains of block copolymers of MCC and PIVBE (MCC-block-PIBVE) was produced by ball milling of MCC with isobutyl vinyl ether (IBVE) in vacuum at 77K. The polymerization of IBVE was initiated by mechano-cations of MCC (MCC+) on the MCC powder surface in vacuum at 77K. MCC+s located on the surface of MCC powder were produced by heterogeneous scissions of the β-1,4 glycosidic linkages comprising MCC main chain by ball milling in vacuum at 77K, and existed on the powder surface of MCC in vacuum at 77K as cations isolated from counter mechano-anions. The counterion-free MCC+s on the powder surface of MCC interacted with IBVE during milling, covalently bonded to IBVE, and simultaneously formed counterion-free cations (MCC-IBVE+) on the MCC powder surface. The counterion-free MCC-IBVE+s initiated a novel cationic polymerization of IBVE on the surface of MCC powder under vacuum, produced MCC-block-PIBVE, and gave rise to a surface chemical modification of MCC powder with MCC-block-PIBVE. This scheme is supported by 1H NMR, FT-IR, ESR, GPC, and MO calculations.