Scalable manufacturing of cellulose microfibril cryogel without organic solvent by adding tiny dosage of polyamide-epichlorohydrin

Abstract

Large-scale applications of versatile cellulose cryogels have received much concern but remains challenging due to their complicated post-treatment and brittleness nature. A organic solvent-free and mechanical-assisted strategy was proposed here to effectively exfoliate cellulose microfibrils. The flexible, ultralight, elastic, and multi-scale cellulose hybrid cryogels were manufactured by adding tiny dosage of polyamide-epichlorohydrin (PAE), which was employed here as flexible and crosslinked skeleton. Undergoing freeze drying and vacuum heating, a series of CMFs/PAEx cryogels were successfully acquired with superior mechanical and thermal insulation performances. CMFs/PAE0.5 cryogel achieved 2.5 folds stress at 80% compressive strain and 2.4 folds elastic recovery with respect to CMFs/PAE0. The hydrophobic modification of the CMFs/PAEx cryogels were readily accessible by dip-coating of palm wax and endowed these cryogels with good water repellency (contact angle of ∼128^o). Overall, the proposed strategy open up novel perspectives for the design of cellulose cryogels and beyond.