Preparation of Nanometer Silica by Freeze-Drying Chemical Precipitation Method

Nanometer SiO2 with different sizes and shapes is synthesized by coprecipitation technique using sodium silicane as Si source, ammonium chloride as precipitant, ethanol as dispersant, CTAB as regulator. Nanometer SiO2 is obtained from the titration precipitation method and reverse titration precipitation method, respectively．Morphology size distribution and structure of SiO2 particles is characterized by laser particle size analyzer ,microscope and FTIR.The results show that the optimum condition of synthesizing nanometer SiO2 were as follows, the concentration of sodium silicane was 0.4 mol/L, volume ratio of ethanol to water was1:8,pH value was 8.5, concentration of CTAB was 6mmol/l.Spherical silica particles ranging from 3 to 6nm are prepared by the method of reverse titration precipitation and freeze-drying

Modified Natural Polymer Materials for Paper Protection

Natural polymer materials, such as cellulose, chitosan, starch, are compatible with paper fiber , which can be used for paper reinforcement. However, due to the poor performance of aging, flexibility, adhesion, it needs to be modified. The progress of the modification of some natural materials in paper artifacts protection is introduced.Research and application of some natural materials in paper artifacts protection is summarized. And the development prospects of paper artifacts protection are also discussed

Study on properties of epoxy resin and polyurethane modified with organic silicon

In order to solve the problem of poor compatibility of traditional resins, improve its adhesion, toughness, corrosion, heat resistance, salt spray, and other properties of the coating, the epoxy resin and polyurethane was modified with organic silicon. Some modified methods were introduced and summarized, the prospects for the research development in the future were look forward

Progress on Modified Polyurethane for Preservation of Paper Cultural Relic

Paper cultural relics have extremely high value in research and collection. However, as the time goes on and the environment changes, there will be unfavorable conditions on paper relics, like yellowing, moulding, chalking, aging and embrittlement to some extent. Nowadays, the protection and repair of paper cultural relics are the research emphasis in the field of relics protection. The modified Polyurethane (PU) is an effective material for protecting paper cultural relics and overcome the disadvantages of traditional PU material, including poor polar-solvent resistance and poor heat resistance. Therefore, in this article, the synthesis, properties, applications of modified PU material were summarized and prospects for the research development in the future were look forward

Research progress on water-soluble chitosan

Chitosan has good film-forming property, adsorption, biocompatibility, biodegradability and antimicrobial properties, but it can only be dissolved in weak acidic aqueous solution and cannot be directly dissolved in water, which greatly limits its application. In order to increase its solubility in water, chitosan is modified, the research on the water-soluble derivatives of chitosan is reviewed in this paper, and its application in the protection of paper relics is briefly introduced. Chitin is a kind of natural polysaccharide macromolecular polymer synthesized by biology in animals and plants, which mainly comes from shrimp shelsl, crab shells, insect shells and so on. Chitosan (CS) is obtained by deacetylation of chitin. The chitin is deacetylated under homogeneous conditions, and water-soluble product can be obtained by controlling the degree of deacetylation at about 50% [1]. The primary hydroxyl group, secondary hydroxyl group and amino group on the glucosamine unit in the chitosan molecular chain, with strong reactivity, which can be modified and embellished by functionalization to improve its solubility

Study on the application of oligomers in paper reinforcement protection

In order to improve the strength of paper, solve the problem of poor permeability of traditional resins to paper, the low molecular weight hexamethylenediisocyanate (HDI) trimer was investigated, and the chemical and physical properties of paper samples were tested in this work. Results showed the paper treated by HDI trimer had good mechanical property, the tensile strength was increased from 1105 to 4151 N/m, the folding endurance was increased from 20.8 to 275; and had good glossiness and brightness. Therefore, the prepared HDI trimer has great application prospects in the protection of paper

Surface Tension of Polyurethane Solution and Thermodynamic Model

A new improved polyurethane materials was studied to improve the strength of paper, delay the aging of paper, solve the problem of poor permeability of traditional resins to paper, and meanwhile to provide basic data for industrial design and applications, the surface tension of composite solutions consisting of nano-SiO2-based polyurethane, organosilicon-based polyurethane and epoxy cyclohexane-epichlorohydrin polyurethane dissolved in ethyl acetate had been measured at temperatures ranging from 283.15 K to 308.15 K. The surface tension was fitted with the related equation between surface tension and temperature under normal pressure. The mean relative deviations between the calculated value and the experimental value were derived. The results showed that the model estimation of the surface tension of the composite solution were in good agreement with the experimental data, the paper coated by the polyurethane materials had better mechanical property. Therefore, the prepared polyurethane material has great application prospects in the protection of paper

Genome-Wide Identification and Analysis of the Aux/IAA Gene Family in <i>Panax ginseng</i>: Evidence for the Role of <i>PgIAA02</i> in Lateral Root Development

Panax ginseng C. A. Meyer (Ginseng) is one of the most used traditional Chinese herbal medicines, with its roots being used as the main common medicinal parts; its therapeutic potential has garnered significant attention. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) is a family of early auxin-responsive genes capable of regulating root development in plants through the auxin signaling pathway. In the present study, 84 Aux/IAA genes were identified from the ginseng genome and their complexity and diversity were determined through their protein domains, phylogenetic relationships, gene structures, and cis-acting element predictions. Phylogenetic analyses classified PgIAA into six subgroups, with members in the same group showing greater sequence similarity. Analyses of interspecific collinearity suggest that segmental duplications likely drove the evolution of PgIAA genes, followed by purifying selection. An analysis of cis-regulatory elements suggested that PgIAA family genes may be involved in the regulation of plant hormones. RNA-seq data show that the expression pattern of Aux/IAA genes in Ginseng is tissue-specific, and PgIAA02 and PgIAA36 are specifically highly expressed in lateral, fibrous, and arm roots, suggesting their potential function in root development. The PgIAA02 overexpression lines exhibited an inhibition of lateral root growth in Ginseng. In addition, yeast two-hybrid and subcellular localization experiments showed that PgIAA02 interacted with PgARF22/PgARF36 (ARF: auxin response factor) in the nucleus and participated in the biological process of root development. The above results lay the foundation for an in-depth study of Aux/IAA and provide preliminary information for further research on the role of the Aux/IAA gene family in the root development of Ginseng

Surface Tension of Polyurethane Solution and Thermodynamic Model

594-597A new improved polyurethane materials was studied to improve the strength of paper, delay the aging of paper, solve the problem of poor permeability of traditional resins to paper, and meanwhile to provide basic data for industrial design and applications, the surface tension of composite solutions consisting of nano-SiO2-based polyurethane, organo siliconbased polyurethane and epoxy cyclohexane-epichlorohydrin polyurethane dissolved in ethyl acetate had been measured at temperatures ranging from 283.15 K to 308.15 K. The surface tension was fitted with the related equation between surface tension and temperature under normal pressure. The mean relative deviations between the calculated value and the experimental value were derived. The results showed that the model estimation of the surface tension of the composite solution were in good agreement with the experimental data, the paper coated by the polyurethane materials had better mechanical property. Therefore, the prepared polyurethane material has great application prospects in the protection of paper