Thermal and rheological properties of cellulose-graft-polyacrylamide synthesized by in situ graft copolymerization

Abstract

In order to prepare a cellulose-based water absorbent material in an environmentally-friendly way, a cellulose-graft-polyacrylamide (cellulose-g-PAM) copolymer is synthesized by in situ graft copolymerization through a co-rotating twin-screw extruder. An ionic liquid, namely 1-N-butyl-3-methylimidazolium chloride, is used as the reaction medium and ceric ammonium nitrate is used as the initiator. The graft copolymerization effect is evaluated by the study of the thermal and rheological properties of the copolymers. FTIR and elemental analysis results show that the amide groups of PAM successfully graft onto the cellulose backbone and the graft ratio of the cellulose-g-PAM is increased with the increase in AM content. Thermal analysis shows that the thermal stability of cellulose-g-PAM and the glass transition temperature of PAM are increased as the graft ratio increases due to the formation of PAM long-chain branches which disturb the segment motion of the cellulose chains. In comparison with cellulose, the dehydration peak of cellulose-g-PAM displays a larger endothermic enthalpy and shifts to higher temperature. Rheological results show that the storage modulus curve of cellulose-g-PAM with a high graft ratio exhibits a plateau at low frequency and the tan d curve displays a peak value, indicating that the large amount of PAM branches cause the entanglement of copolymer chains and improve the toughness of the copolymers.

Synthesis of a poly(amidoxime-hydroxamic acid) cellulose derivative and its application in heavy metal ion removal

“…17,19,37,38 In this study, cotton cellulose was graed with EMCA via a free-radical initiation method, which involved CAN as an initiator (Fig. 1b).…”

In situ graft copolymerization of l-lactide onto cellulose and the direct melt spinning

“…In recent years, researches on the chemical graing of cellulose with L-lactide (LLA) have been attracting more and more scientists and the results indicated the potential applicability of cellulose-gra-polylactide (cellulose-g-PLA) in drug delivery system, personal care products and packaging industry. [7][8][9][10][11] Due to the presence of three hydroxyl groups in each glucose residue, cellulose is only soluble in particular solvents such as NaOH/CS 2 , N-methyl morpholine oxide (NMMO), NaOH/urea aqueous solution and ionic liquid (IL), [12][13][14][15][16] but the dissolubility of cellulose in these solvents is only 5-15% with heating and stirring for 2-4 h. The massive solvent and longtime dissolution may cause serious degradation of cellulose and decrease the production efficiency of cellulose bers, 17,18 which limited the industry development and application of cellulose-g-PLA copolymer in the ber eld.…”

Supporting Materials That Improve the Stability of Enzyme Membranes

“…With regarded to the stability of some materials against chemical agents, cellulose would be the most appropriate material for addressing this problem. Cellulose is known to be very stable against physical property and chemical reagents; 36,37 it can only be dissolved in strong acids and bases.…”