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Study on the Synthesis of Polyether Waterborne Polyurethane and Its Application in Paper Strengthening

Author: ShangWei
Tutor: YangHaiTao
School: Shandong Institute of Light Industry
Course: Pulp and Paper Engineering
Keywords: Water-based polyurethane Imidazole Close Paper Physical properties
CLC: TS727
Type: Master's thesis
Year: 2011
Downloads: 131
Quote: 1
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Abstract

In this paper, a closed water-based polyurethane synthetic paper additives, and its application in papermaking. In synthetic polyurethane prepolymer process, this thesis studied a variety of conditions on the ultimate synthesis of the prepolymer product, such as blocking agent selected, the concentration of a variety of raw materials, end selection, analysis and detection some relevant properties and technical specifications of the materials used in the synthesis and pharmaceutical, such as purity, moisture content, hydroxyl value, the NCO group content and the closure rate. Found: good toluene-2 ??,4 - diisocyanate end of NCO-capped sealers with imidazole, and the deblocking temperature of the synthesis of the polyurethane prepolymer product is also ideal, for the actual production needs, and ultimately successfully synthesized a closed water-based polyurethane. Study polyurethane prepolymer closed - deblocked Mechanism aspect of the deblocked isocyanate group with the fiber hydroxy Reaction Mechanism, an isocyanate group content, the choice of the blocking agent, and closed time were investigated on the sealing effect of the impact. And polyurethane paper pulverized with a vibration ball mill ultra fine powder, then after methylation, alkaline hydrolysis and acetylation process by nuclear magnetic resonance (1H-NMR, 13C-NMR) and infrared spectroscopy (FT-IR) analysis and detection. The study found that: in the polyurethane process, the the deblocked polyurethane pre-mers, re-exposing the strong reactivity of the-NCO group, and-NCO groups react with the cellulose-OH, production carbamoyl ester bond, so that the hydrogen bonding between the original paper fibers can be transformed into chemically bonded, thereby greatly enhancing the paper physical strength, especially wet strength of paper. In the experimental study polyurethane prepolymer polyurethane paper, we study the polyurethane prepolymer emulsion in the paper coating and papermaking Add observed by electron microscopy, FT-IR analysis and physical properties detected: polyurethane emulsion coating weight of 7g / ㎡ the filter paper tensile index (dry), and tensile index (wet) were increased to 1.74 times and 19.59 times the filter paper base paper. The folding endurance increased to 47.05 times the base paper. In addition to tensile strength, after urethanization processing, the physical strength of the paper have improved This is mainly because the coating on the surface of the paper, and polyurethane prepolymer deblocked processing with a closed aqueous polyurethane emulsion. between the fibers is connected to many needle-like and wire fluff adhesive substance, these substances form a bridge between the fibers, in particular fibers and fiber cross structure, part of the hydroxyl groups of the cellulose and polyurethane prepolymerized body reaction of the carbamoyl ester structure, combined with the hydrogen bonding between the fibers conversion is the binding, thereby enhancing the connection between the fibers. Research lignin - polyurethane copolymer type high-strength paper of experiments, we explore the pigment to the wood, polyurethane emulsion of raw materials, copied to create new technology with high strength properties of paper and through the physical detection and scanning electric mirror detection method, its analysis. The study found: closed polyurethane deblocked prepolymerized physical-OH reaction of cellulose and lignin to produce a stable chemically bonded via a bridging role between the fibers, as well as connection between the lignin and fibers better. To enhance and improve the physical indicators of the paper. Add lignin later, the paper polyurethane dry tensile index, wet tensile index, folding endurance, tear and stiffness compared with blank paper, can be increased 1.28 times, 12.95 times, 11.4 times, 1.17 times and 1.22 times; when the lignin content of 20% and a wet strength / dry strength is 35.6%. In addition, we also studied the impact of of fiber beating the performance of the paper polyurethane effect. The study results showed that: as the degree of beating increases, the more exposed hydroxyl groups, the better the effect of polyurethane, the physical properties of the paper also will improve and enhance the paper of the best overall performance, when beating degree 70oSR when, . Folding endurance 38 when OSR 4.57 times the dry tensile index, wet tensile index increased by 1.24,2.52, stiffness, tear 38 when OSR 1.23,1.22 times.

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