Advanced Materials Research Vols. 236-238

Abstract: Five offset papers were applied to analyze the influences of the linting and picking problem based on the measurement of paper moisture, tightness, fiber composition and fiber length. The results showed that under the same conditions of paper making with the same raw materials, the printing surface strength increased and linting and picking problem reduced when the paper moisture or tightness are appropriately increased. The paper made with wood materials has a better surface strength and printability than bamboo and straw. The paper which contain less tiny fibers and long fibers, but more medium fibers is less likely to cause the problem of linting and picking.

Abstract: Near infrared (NIR) spectroscopy has received a great deal of attention in forest products industry. The physical, mechanical and chemical properties of inorganic materials can be predicted using the NIR spectroscopy and multivariate analysis (MVA). NIR spectroscopy is suitable for quantitative analysis, especially the process monitoring and quality control. The present paper reviews the application of NIR spectroscopy and MVA in the forest products industry, such as tree improvement and silviculture, pulp and paper, lumber products and the online monitoring.

Abstract: A thermal-responsive polymer was prepared by partially acetalyzing poly(vinyl alcohol) (PVA). The completely reversible polymer aggregation and dissolution occur above and below a low critical solution temperature (LCST) for the aqueous solution of the modified PVA. The partially acetalized PVA (APVA) with higher molecular weight and higher degree of acetalysis exhibited a lower LCST transition and was used as an anionic polymer for polymer complexation. Water-soluble polymer, cationic polyhexamethylene guanidine hydrochloride (CPHGH) with antimicrobial property, was also prepared. In conjunction with APVA, CPHGH created the unique antimicrobial polymer multilayers on the surfaces of rayon fibres via layer by layer (LbL) assembly. AFM images revealed that the particles generated by multilayers became larger after the material was treated at 60°C; while the roughness of the surfaces was increased as the layer number increased and then decreased. Moreover, antimicrobial tests also demonstrated that the rayon fiber assembled with (CPHGH/APVA) multilayers exhibited higher antimicrobial activity against E. coli and s. aureus.

Abstract: 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.

Abstract: In the presented work, a series of the phosphate amphoteric cassava starch were synthesized by a two-step semi-dry process with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CTA) as the cationic reagent and phosphate mixture as the anionic reagent. The structure of the amphoteric starch was characterized by FTIR and XRD. The reinforcing effects of the amphoteric starch on the secondary fiber were also studied. The results indicated that the reaction occurred not only in the amorphous region, but also in its crystalline region. When the cationic starch reacted with different amount of phosphates, the degree of cation substitution (DSc) of products was decreased with the dosage of the phosphates. When cationic starch with different DSc reacted with the same amount of phosphates, the degree of anion substitution (DSa) of products was decreased with the DSc. All the amphoteric starch showed reinforcing effect on the secondary fiber. The No. 7 sample showed better reinforcing effects on paper strength due to its higher total degree of substitution (0.095), proper DSa/DSc ratio (DSc = 0.067, DSa = 0.028) and interior modification of the starch granule. Compared with the control sample, the secondary fiber paper with 1.0 wt % (relative to dried pulp) of 7# modified starch showed 23.5%, 20.3% and 29.4% increases in tensile index, tearing index, and burst index, respectively.

Abstract: Modifing wheat straw pulp fibers via in situ graft copolymerization has been regarded as one of the effective approaches to improve paper properties. In this work,modified fibers were prepared by in situ graft copolymerization of caprolactam onto fibers surface using potassium persulphate-sodium bisulfite as a free radical initiator under alkaline medium. The optimum process parameters of the grafting reaction were followed: the ratio of modifier dosage to fiber was 0.5 ,the ratio of initiator dosage to fiber was 0.1, the ratio of sodium bisulfite to potassium persulphate was 4:5, pulp consistency was 5% ,the reaction time was 2h,the reaction temperature was at 60°C. Fourier transform infrared spectroscopy (FT-IR) was performed to confirm the existence of the grafted copolymers on the surface of fibers. Furthermore, the paper physical properties of the grafted pulp are improved remarkably.

Abstract: As one of the main emission sources of PCDD/Fs, the pulp and paper industry has always been public concerns. In China, the consumption of non-wood fiber as raw material of pulp accounts for a relatively larger proportion in the total productivity. Here, the unintentionally produced PCDD/Fs emissions of five Chinese non-wood pulp and paper mills were investigated. The results showed that the increment of PCDD/Fs after bleaching with chlorine was about 1.71-28.19 times in pulp and 3.96-28.82 times in wastewater based on the existing technologies. In order to reduce the unintentional production of PCDD/Fs, the BAT/BEP transformation program was proposed as cleaner production initiatives featured by less or free use of chlorine in bleaching process, and evaluated by reduction effects and costs. The study showed the application of Elemental Chlorine Free (ECF) sequences in bleaching process with improving technologies in other production stages would effectively decrease the generation of PCDD/Fs, other pollutant load as well as the water consumptions.

Abstract: This paper deals with the preparation of Plate-shaped Calcium Carbonate and Its Application in the Paper Coating. calcium oxide and carbon dioxide were used as major materials to preparetion the Plate-shaped Calcium Carbonate, The best reaction conditions as follows: w(CaO)：w（H2O）=1：5, V（CO2）：V（atmosphere）=1：2. Then use the Plate-shaped Calcium Carbonate in spreading. The results show that the Plate-shaped Calcium Carbonate is a high-performance product that can obviously enhance the paper’s smoothness, whiteness, air permeability, printing ink absorbance.

Abstract: In this paper, the technology of pressurized hot water extraction of hemi-cellulose and the effects of the pre-extraction on APMP pulping process of the Pink Sheets bamboo are investigated. The results show that the yields of pentosan and bamboo chip are the highest under the conditions of the maximum temperature 170 °C, liquid ratio 1:5, holding time 2h. And the yield of bamboo chip is lowered generally, the color of bamboo is deepened, the pulp strength is degraded, but the refining energy is reduced largely after pre-extraction.

Abstract: The Polyamide Polyamine Epichlorhydrin Resin was obtained by using adipic acid, diethylene triamine and epoxy chloropropane as raw materials. The factors that would affect the properties of PAE resin were considered, including the reaction time, the dosage of the epoxy chloropropane, the injection time of epoxy chloropropane and the soaking time, and the wet strengthening property of PAE resin were studied through experiments. The results are as following: the ratio of epoxy chloropropane to diethylenetriamine is 1:1, the injection time of epoxy chloropropane is 8.5 min, the reaction temperature is 75 °C and the soaking time is 35min~40min. Under the optimum conditions, the PAE has a higher wet-strength and solid content, and its viscosity up to 25~35cp.