Preparation And Characterization Of Cellulose Hydrogels Based On Diene Synthesis Reaction

Diene synthesis reaction (Diels-Alder reaction) can occur in mild conditions. They canreact in water, and even doesn’t require a catalyst. It can be used for the synthesis of naturalproducts and also can be used for preparation of polymer. Hydrogel is a hydrophilicthree-dimensional network, which can be formed either by ionic bond, the van der Waalsforces, hydrogen bonding interactions or covalent bond. As a renewable resource and withgood hydrophilicity, celluloses are valuable materials. Hydroxypropyl methyl cellulose hasgood biocompatibility, and also has a rich yield. It has a wide range of applications ineveryday life, such as the injection molding device, pharmaceutical, and paint. Therefore, theresearch aimed to use diene synthesis reaction to prepare cellulose hydrogels. The first step isusing diene group for modification of hydroxypropyl methyl cellulose, and then generatingpolymeric diene. The polymeric dienophile HMC-AMI has been prepared withhydroxypropyl methyl cellulose and dienophile group under the dehydration conditions.Afterwards, the cellulose-based hydrogels are prepared by diene synthesis reaction. Basedon the as-prepared cellulose hydrogels, the cellulose-polyacrylamide interpenetratingpolymer networks hydrogel is fabricated by the photopolymerization of acrylamide.Preparation and characterization of the hydrogels in the paper is divided into thefollowing two parts:In the process of preparing cellulose-based hydrogel, first, a monomer was synthesizedby the reaction between succinic anhydride and furfuryl amine. Second, the polymeric dienewas prepared by the reaction between the as-synthesized monomer and different ratios ofhydroxypropyl methyl cellulose. Polymeric dienophile was prepared by hydroxypropylmethyl cellulose with N-maleoyl alanine (AMI). Then cellulose-based hydrogels werefabricated by Diene synthesis reaction of the as-prepared polymeric diene and polymericdienophiles. The characteristics of hydrogels were researched by FTIR, SEM, etc. The resultsshow that cellulose hydrogels’ swelling behavior can be adjusted by varying temperature andcrosslinking density.In the process of fabricating cellulose-polyacrylamide IPN hydrogels,cellulose-based hydrogels were prepared by chemically cross-linking between as-prepared polymeric diene and polymeric dienophile through Diene synthesis reaction, which wereemployed as the first network. The second network was subsequently obtained by in situphotopolymerization of acrylamide in the hydroxypropyl methyl cellulose hydrogels. Thecharacteristics of hydrogels were researched by FTIR. The results show that the two networksco-existed in the IPN hydrogels, which exhibited uniform porous structure. The mechanicaland swelling properties of IPN hydrogels were strongly dependent on the weight ratio of twonetworks. This work created double network hydrogels, which combined the advantages ofnatural polymer and synthesized polyacrylamide in one system, and improved the physicalproperties of the IPN hydrogels.