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Synthesis of Modified Epoxy Acrylate Resin and Application as Paper Wet Strength Agent

Author: ZhouPeng
Tutor: ZhangXiuMei
School: Zhejiang University of Technology
Course: Materials Physics and Chemistry
Keywords: water soluble epoxy acrylate resin unsaturated bonds wet strength UV curing strengthening mechanism
CLC: TS727
Type: Master's thesis
Year: 2011
Downloads: 112
Quote: 1
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Abstract

Wet strength papers have been widely used accompanied with the development of papermaking industry, and the wet strength agents become more and more important in paper wet end chemistry. As the awareness of environmental protection and low carbon increase, it has become an important issue to seek new kinds of environment friendly and energy-saving wet-strength agents in papermaking industry. This study adopted a new cross-linking mechanism which could form hydrophobic network between fibers by radical polymerization of unsaturated double bonds to enhance the wet strength of paper. This paper attempted to prepare an epoxy acrylate resin (EA) and modify it to water soluble, for applying as a wet strength agent in wet end.In this paper, an epoxy acrylate resin (EA) was synthesized and the profiles of reaction conditions of EA were studied, including temperature and catalyst dosage of its maximum. The optimum conditions of synthesis of EA were selected as adding acrylic acid and epoxy group at the ratio of 1.05:1, 1.0% (wt%) N,N-dimethylethanolamine as a catalyst and 0.5%(wt%) hydroquinone as polymerization inhibitor and reaction temperature 95℃. In this experiment, EB was made through the reaction of EA with maleic anhydride acid.The optimum reaction conditions were selected as adding 1.0%(wt%) N,N- dimethylethanolamine as a catalyst at reaction temperature 80℃for 1 h. Based on the factors affecting on EB water-soluble, the results showed that EB water-soluble was better when carboxyl content was higher and the neutralization degree was taller. .By studying the influence of EB on wet strength properties of paper, it found that UV curing had the best strength improving effects when adding cationic retention aids and making paper as sheets at suitable neutral condition.When paper sheets were made under the condition of pH 7-8, by adding 2.0% EB into softwood bleached pulp (slowness 30°SR) and adding 0.4% cationic polyacrylamide as retention aid, paper wet strength retention rate could reach 19.01% after cured by UV radiation, increased over 224% relatively compared with the samples without EB. The study also found that the addition of EB had little effect on dry tensile, burst and tear resistance of paper, but it could enhance the paper wet strength effectively. EB had the advantages of fast light curing speed, convenient source and pollution-free as a wet strength agent.The mechanism of epoxy acrylate resin as wet strength agent was studied at the same time. Through microscopic analysis of paper surface, it could be found that fiber surface glued by a layer of stick substance on the sheets added with EB, and after curing, the structure of the substance could changed to prevent fiber swelling. By FT-IR tracking of the changes of EB functional groups in sheets, it showed that sheets added with EB appeared conjugated C=O(at 1730cm-1)and C=C(at 1635cm-1) absorbance. The stretching vibration peak of a conjugated C=C disappeared after curing, but the characteristic peak of bisphenol A polycarbonate emerged, which demonstrated that radical polymerization of double bonds occurred. This confirmed the cross-linking mechanism of radical polymerization of unsaturated double bonds during the curing.

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