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Synthesis and characterization of cellulose/PDMAEMA copolymers and nanocomposites with SiO2

In this work cellulose/poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) copolymers were synthesized. The nanofiller SiO2 was added in order to construct nanocomposites. The polymer films were casted directly after synthesis, while the nanocomposites were casted after mixing in the SiO2 filler and additional exposure of the mixture to an absorbed dose (100 kGy) of γ-rays from a 60Co source. Finally, water responsive cellulose/poly(2-(dimethylamino)ethyl methacrylate) and cellulose/poly(2- (dimethylamino)ethyl methacrylate)/SiO2 nanocomposite hydrogels and films were successfully prepared. The chemical reaction of cellulose and 2-(dimethylamino)ethyl methacrylate (DMAEMA) (ratio 1:1 ; 1:3 and 1:5 mol/mol) was carried out in the solvent N, N-dimethyl acetamide/LiCl with a peroxide initiator at 90 °C and using N, N-methylene-bis-acrylamide as a crosslinker. The microstructure and properties of prepared hydrogels and films were investigated by scanning electron microscopy, water contact angle, thermogravimetric analyses (TGA), while the swelling ability was followed gravimetrically. The prepared hydrogels displayed high degree of swelling, between 600 and 900 %. All hydrogels showed hydrophilic surfaces whereat with increasing share of PDMAEMA the contact angle increased from a minimum of 40° for sample from the 1:1 series to a maximum of 53° for sample from the 1:5 series. Based on SEM micrographs the SiO2 nanofiller were well dispersed as no agglomerates were visible. The TGA reveals that all samples display the main mass loss at temperatures above 300 °C where amorphous cellulose and second PDMAEMA mass losses add up. A significant signal in the 1-5 series recorded around 430 °C corresponds to the third mass loss of increased share of PDMAEMA. At temperatures up to 600 ° C the samples show high residue content common to amorphous cellulose.

cellulose based hydrogel ; ionizing radiation ; thermal properties of nanocoposites

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