Jin Li

Research Development of Biodegradable Modification of Poly (vinyl alcohol) Film

Polyvinyl alcohol (PVA) is a kind of biodegradable film material, and its degradation process is mainly done through PVA-degrading enzymes, but the film biodegradation cycle is longer, so it needs other polymers with favorable biodegradability to improve the degradation rate in the nature environment. In this paper the biodegradation mechanism of PVA films and the influence of structural feature on biodegradability were described. The research development of starch-based biodegradable PVA films by blending starch to reduce the biodegradation cycle was emphasized and the biodegradable films modified by chitosan to improve film properties was briefly described.

Preparation and Application of Starch-Acrylamide-Diallyl Dimethyl Ammonium Chloride Graft Copolymer

The starch-acrylamide-diallyl dimethyl ammonium chloride graft copolymer (St-AMDADMAC copolymer) was prepared firstly. Then the synthesized St-AM-DADMAC copolymer was analyzed by FTIR and SEM. Finally the synthesized St-AM-DADMAC copolymers were applied in making packaging paper, the first pass retention and the mechanical properties of the made packaging paper were determined. The FTIR of St-AM-DADMAC copolymer indicated that AM and DADMAC can be grafted in the chain of starch. The SEM of starch and St-AM-DADMAC copolymer indicated that the surface of starch had been changed obviously by grafting copolymerization. The first pass retention increased with the increase of degree of cationic of St- AM-DADMAC copolymer. When the dosage of St-AM-DADMAC copolymer was about 1% and the degree of cationic of St-AM-DADMAC copolymer was about 25.96%, the mechanical properties of the packaging paper were improved best.

Study on Application of Nanosilica in Paper Coating

The application of nanosilica in coating of art paper and ink-jet paper is studied. The results show that when nanosilica is used in art paper coating, the dispersity and flowability of the art paper coating are excellent. The surface strength, smoothness and gloss of the paper coated with art paper coating with nanosilica are improved and its yellowing rate is decreased. When nanosilica is used in ink-jet paper coating, the dispersity of prepared ink-jet paper coating is of better, the coated paperboard with ink-jet paper coating with nanosilica is of ink transfer larger, K&N value higher and whiteness higher. The smoothness and gloss of paperboard coated with ink-jet paper coating with silica are improved. The combination application of more kinds of adhesives improves the print gloss of paperboard coated with ink-jet paper coating with silica.

Application of Precipitated Silica in Low Basis Weight Newspaper

Filler is one of the most important components of paper. Silica is a kind of excellent filler for its special chemical structure. Silica was prepared in the laboratory, and applied into paper. The dispersion properties of the silica with different sizes in paper sheets, the effect of smash on dispersion property of silica in paper sheets, the effect of silica on the zeta potential of newspaper pulp system, the effect of retention agent cationic polyacrylamide on zeta potential of newspaper pulp system and the effect of silica on properties of paper sheet were measured. The results show that the fineness of the silica used in paper is the most important factor which affects the dispersion. The addition of silica and the use of retention agent cationic polyacrylamide increase the zeta potential of the newspaper pulp system. The addition of precipitated silica increases the whiteness of paper slightly and the opacity obviously.

Preparation and Properties of Cationic Starch with High Degree of Substitution

Using sodium hydroxide as its alkali catalyzer, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride as its quaternary agents, cationic starch with high degree of substitution was made by semi-dry process. The prepared cationic starch contains quaternary ammonium groups by the infrared spectrum analysis. From the scan electron microscope pictures of starch and cationic starch, cationic starch can be clearly seen to have substituted the quaternary ammonium salt groups and the structure of mutual penetration of flexible quaternary ammonium salt groups and rigid starch has formed. The tensile strength of paper improved by cationic starch with high degree of substitution is far more than that by cationic starch with low degree of substitution and poly diallyl dimethyl ammonium chloride. The scan electron microscope pictures of the surface and fracture of the paper show that the distribution of the paper fiber which added additives are apparently tight and uniform and there are many small fibers obtained on the surface of paper samples. The fibers of the paper sample which added additives have more fracture themselves and have less extraction entirely. It indicates that the force between fibers has been strengthened by cationic starch additive.

Research on Preparation of Cationic Polyacrylate Emulsion Paper Strengthening Agent

Strengthening agent of cationic polyacrylate emulsion was prepared through semi-continuous seeded pre-emulsion processes. By single factor experiment, investigated the factors which influence on properties of emulsion, such as the proportion of hard and soft segment monomer, the dosage of AM, DMDMAC, emulsifier and initiator, reaction time and temperature, addition time and other factors. The results show that the emulsion has a good enhancement when the monomer ratio of St: MMA: BA is 2:1:3, initiator dosage is 0.7%, the dosage of emulsifiers, AM and DMDMAC are 6%, the amount of protective colloid is 0.3%. Compared to the strength performance between paper with added emulsion and blank paper, find that the performance of paper with added emulsion polymer gets different improves: paper quantitative increase 4.08%, folding strength degree improves 66.67%, tearing degree improves 356.52%, ring compressive strength improves 50.00%, tensile strength improves 44.11%, and bursting strength improves 50.88%

Study on Factors Affecting Properties of Silica

Silica was prepared by precipitation method in the laboratory, and the factors which affect the performance of silica were evaluated. The results show that the reduction of concentration of base solution and reaction temperature and the increase of pH value could improve the specific surface area of precipitation silica. Specific surface area of silica prepared in laboratory is greater than which was prepared in production line and DBP absorption value and particle size are smaller than the latter. Drying process and drying methods have important influences on performance of precipitation silica. Mechanical pulverization could reduce the particle size of silica slightly and the stacking density obviously.

Research on Application of High Degree of Substitution Cationic Starch in Paper Coating

Different degrees of high degree of substitution cationic starch (HCS) were prepared and applied in paper coating. Effects of HCS on coating properties and coated paper properties were investigated, and the comparison of effects of HCS and PDMDAAC was made. The results show that the best amount of HCS in coating formula is between 2% and 4%. When the amount of HCS is 4%, whiteness of coated paper was the highest. The color density was the highest when the amount of HCS is about 4% and the degree of substitution is 0.64. HCS with degree of substitution 0.849 is better than PDMDAAC in some respects, and the print image density achieved satisfactorily.

Application of Cationic Starch Graft Copolymer in Flocculating of Wastewater from Bleaching

Corn starch, acrylamide and diallyl dimethyl ammonium were used as the raw materials and ammonium persulfate as initiator, cationic starch graft copolymer was prepared, and then the prepared cationic starch graft copolymer is applied to flocculate wastewater from bleaching. The results show that The flocculation of cationic starch graft copolymer to wastewater from increases first and then decreases after the reach of the peak with the increase of the cationic degree of the cationic starch graft copolymer, addition amount, flocculating temperature and flocculating time. When the cationic degree of the cationic starch graft copolymer is 27.38%, the addition amount is 7.5%, the flocculating temperature is 50°C and the flocculating time is 30min, the flocculation of cationic starch graft copolymer to wastewater is the best. The flocculation of alum/cationic starch graft copolymer is better than cationic starch graft copolymer is used only. Introduction

Effect of Cationic Polyacrylate Emulsion Properties on Paper Coating Properties

Cationic polyacrylate emulsions with different properties were prepared in lad and used as surface sizing agent, the results showed that as the increase of solid content, the properties of paper increase at first but keep constant if the solid content increase further; as the increase of the pH value of the emulsion, the strength of the paper decrease, smoothness increase, gloss and whiteness decrease, saturation and printing density increase; the increase of the size of emulsion has adverse effects on the properties of the paper, so the size should not be too large; the viscosity should not be too large and not be too low, it should be kept in a moderate level.