Chitosan-calcium hydroxide composite and its preparation and application as stiffener for paper

Abstract

The invention belongs to the technical field of biological polymer materials and relates to preparation of chitosan-calcium hydroxide composite. The chitosan-calcium hydroxide composite is prepared by evenly dispersing chitosan into acetic acid solution, evenly dispersing calcium hydroxide powder and performing full dispersion under the ultrasonic condition. The chitosan in the chitosan-calcium hydroxide composite is well compatible with the paper, has a small physicochemical property difference with paper fiber, is friendly to paper relics and is well permeable and infiltrative to the paper fiber; the calcium hydroxide can absorb CO2 in air, generating calcium carbonate which has the effect of stopping reaction between the air and the paper, the paper has better ageing resistance and better performance, no obstruction is caused to character recognition, and the texture of the paper is unaffected. Therefore, the chitosan-calcium hydroxide composite as novel stiffening material for paper documents is used for protecting the paper documents and has promising application prospect.

Description

technical field [0001] The invention relates to the preparation of a chitosan-calcium hydroxide composite material, which belongs to the technical field of biopolymer materials; the invention also relates to the application of the composite material—as a paper reinforcement agent applied to paper documents and cultural relics conservation and restoration. Background technique [0002] Paper documents and cultural relics are an important part of Chinese historical relics. They are precious documents for studying Chinese history and even world history and ancient art, and have extremely important research value. Paper cultural relics handed down from generation to generation or unearthed over time, due to factors such as mold growth, immersion hydrolysis, gas erosion, mechanical wear, dust coverage, etc., have caused yellowing, mildew, pulverization, brittle fracture, decay and fragmentation, and stains all over the surface. It can't even be flipped, which greatly reduces ...

AI Technical Summary

Problems solved by technology

Sun Zhenqian et al. ("Chemical and Biological Engineering" 2005, (1): 39-41) reported that hydroxypropyl chitosan has a better reinforcement effect on paper cultural relics; Cao Yuhong et al. ("China Paper" 2008, (27): 32-35) reported that cellulose-chitosan grafts can improve the folding endurance and tensile strength of paper cultural relics, and have a good protective effect; Qiu Jianhui et al. ("Journal of Nanjing University of Aeronautics and Astronautics" 2006, (38 ): 126-130) reported a multifunctional reinforcement glue prepared by modified fluororesin, hydroxy chitosan and modified nanomaterials, which has the functions of thickening fibers, powdering and consolidating, embrittlement reinforcement, mildew and antibacterial, etc. A variety of protective functions; patent CN103276627A discloses that the compound of hydroxyethyl cellulose, nano-magnesium hydroxide and nano-titanium dioxide can strengthen the tensile strength of paper cultural relics, improve acid corrosion resistance and antibacterial performance, but the tensile strength of this compound The strength has increased by 28.5% on the original basis, and the enhancement of the mechanical properties of paper is relatively limited

There are also researchers who use composite natural polymers as reinforcement materials for paper documents. Patents ZL201110329836 and ZL201110304943 disclose artemisia polysaccharide-guar gum and konjac polysaccharide-chitosan blends for the protection of paper documents. It can improve the mechanical properties of the paper. After reinforcement, the tensile strength is 0.67~1.13kN / m, and the folding endurance is 1.2~1.75. However, the use of composite polymers is prone to gelation, which increases the difficulty of spraying, making composite materials It is difficult to achieve a uniform surface of the paper, in addition, it will increase the cost of the strengthening agent

Images