Advanced Materials Research Vols. 236-238

Abstract: First attempt to predicting physical properties of paper by Near Infrared Spectroscopy (abbreviated as NIRS) mathematical model, Acacia is a kind of fast-growing tree which is a potential resource in pulp and paper industry. The mathematical models of physical properties of Acacia unbleached kraft paper were established by software OPUS6.5 of Near Infrared Spectroscopy. Spectral data of Acacia unbleached kraft paper were acquired by Near-Infrared. Physical properties, which include quality, whiteness, tensile index, burst index and tear index, of the paper were measured by GB methods. NIRS mathematical models between the spectral data and the laboratory reference values were established and optimized by software OPUS6.5 partial least squares (abbreviated as PLS). The NIRS mathematical models were evaluated by its parameters, and used to predict the physical properties of unknown samples rapidly and accurately. Compared with NIRS mathematical model of physical properties of Acacia unbleached kraft pulp, the NIRS mathematical models of paper have a better prediction on unknown samples; Compared with traditional laboratory methods, predicting properties of paper by the NIRS mathematical models of paper is rapid, accurate and non-destructive.

Abstract: Refining is an energy-intensive papermaking process where energy consumption contributes about 18% of the total manufacturing cost. Through the application of cellulases before refining, mills can reduce their energy requirement for refining of pulps and realize the aim of energy consumption. In the present study, two kinds of cellulase within or wothout the cellulose binding domains (CBDs) were used to treat the pulp aimed at reducing the refining energy consumption in production of grease proof paper. In order to compare and evaluate these effects on reducing the pulp refining energy consumption, these two cellulases were compared based on their effects on Schopper-Riegler freeness (°SR), fiber morphology and paper properties ( tensile index, tear index). Orthogonal test was used to examine the interaction of enzyme dosages and contact time on the beatability of the pulp. Results showed that the cellulase of Refinase M (within the CBDs) was excellent in reducing the refining energy consumption, when pretreated with 0.02% of Refinase M about 18.5% of the refining energy can be saved, and the properties of paper were not affected obviously. Moreover, results showed that the existence of CBDs in cellulases play a significant role in reducing the energy consumption. Examination of the fiber surface by SEM show notable improvement in fibrillation.

Abstract: The glyoxalted polyacrylamide(GPAM) resins were obtained by cross-linking reaction between glyoxal and cationic polyacrylamide(CPAM) through aqueous solution copolymerization. The based CPAM was synthesized with acrylamide(AM) and diallyl dimethyl ammonium chloride(DADMAC) as raw materials by living free radical solution polymerization. Various synthesis conditions were discussed and the optimum conditions for copolymer’s synthesis were as follows: the amount of DADMAC 20%(wt), the charge of the initiator 0.5%(wt), the dosage of chain transfer agent(2-mercaptoethanol) 1.0%(wt), and the charge of crosslinking monomer 9.0%, the dosage of glyoxal 25%(wt), the pH value of the tertiary reaction 7.5-8.0 and the tertiary temperature about 65°C. The structure of the resulting product was characterized by FT-IR, ¹H-NMR. Then the GPAM resins were used in the process of paper-making as wet-end additive, the results showed that the paper sheets can get a significant increase in strength properties from the added novel product.

Abstract: Carboxymethyl cellulose (CMC) is the most widely used co-binder and rheology modifier in paper coating. This work presents an investigation on the effects of CMC on coating structure development by measuring viscosity of the coating colors and by characterizing properties of the dried coatings. The results showed that CMC addition increased coating color viscosity and impeded latex migration to the surface during drying. However brightness, porosity and K&N ink absorbency of the coatings increased. It was assumed that viscosity increase and colloidal interactions between CMC and pigment particles caused less latex to migrate to the surface during drying, which in turn results in higher brightness and porosity of the coatings.

Abstract: In recent years, conductive paper produced by in-situ chemical polymerization of pyrrole and aniline in aqueous electrolytes has aroused a great interest. The in-situ chemical polymerization process is a process in which a monomer such as aniline or pyrrole is polymerized in the presence of pulp fibers. This approach can not only impart to paper specific functions, but also provide a new possibility for the processing and utilization of conductive polymers. In this paper, the research progress on inherently conducting polymer coated paper was overviewed.

Abstract: The chemical composition of surface sizing agent BLD-02 was researched, as well as its synthesis method. BLD-02 was analyzed by infrared spectroscopy, and the main monomers were styrene, acrylate and acrylonitrile. In the process of synthesis, these monomers were prepared for copolymer latex by seed emulsion polymerization. Through a series of pre-trial, the results showed that when the contents of initiator and emulsifying agent were 0.3% and 3% (the percentage of total) respectively, the weight ratio of hard monomer to soft monomer was 2/3 and the reaction temperature was 75°C, the synthetic emulsion with higher viscosity, smaller particle size and well-dispersion was prepared. Results showed that the infrared spectrum and properties of the synthetic emulsion, to some extent, were as same as that of BLD-02.

Abstract: Ink-jet printing is a non-contact printing, drops are jetted on the substrates to form images through the nozzles at a certain speed. Dot is the smallest unit in printing; the qualities of printing are seriously affected by dot gain. Ink spreading and penetration are discussed in this paper, influences on dot gain in ink-jet printing are studied, the original Young's equation and Washburn formula are theoretically amended, more scientific and rational models and formulas are obtained in the actual process of ink-jet printing, which offers reference standard and theoretical basis to improve the quality of ink-jet printing.

Abstract: lignin (L)-based phenolic prepolymers with different phenol (P) substitution degrees were synthesized using the modified(M) L with laccase. It was found that the ML showed lower molecular value, polydispersity and higher reactivity compared to unmodified sample, and up to 30% of phenol can be substituted by MF to give LPF wood adhesive having better bonding strength in comparison to a control unmodified lignin phenol formaldehyde wood adhesive. MF was characterized using FTIR and GPC. FTIR showed that after the treatment of laccase, the methoxyl group increased, which was mainly due to the demethylation, and laccase/mediator system made the ether bonds of L cleave to produce more alcohol hydroxyl, as a result, the reactivity of ML was improved.

Abstract: In order to develop cotton fabric underwear with the health care function, the cotton fiber was modified with the collagen (CMCF) using periodate oxidation method. The aldehyde groups on the glucose chains of the oxidized cotton cellulose were reacted with the amino groups of collagen to obtain the CMCF, and the oxidized cellulose was crosslinked with collagen in aqueous acetic acid media. The effects of collagen concentration, treatment time, reaction temperature, pH value of solution and periodate concentration on the amount of collagen crosslinked on cotton fiber were respectively discussed, and the optimal reaction technology was obtained. XPS characterization of the modified cotton fiber showed a characteristic peak about 400.0–405.0 eV corresponding to collagen, which indicated that the collagen was combined on the surface of cotton fiber. The mechanical properties of the collagen modified cotton fiber were improved. The resulting CMCF is a new natural ecological fiber and has the extensive application as a carrier for the controlled release of drugs.

Abstract: The kinetics of reed kraft pulp oxygen delignification process is studied, suitable kinetics model determined is -dk/dt=Aexp(-E/RT) [OH^-]^b[P_O2]^c K^a, and the parameters in the model is calculated. The function for estimation of the kappa number at different reaction time is established for the reed kraft pulp oxygen delignification process. The reaction order fitted is 6.72 for delignification (a), 0.87 for alkali concentration (b), and 0.62 for oxygen pressure(c), respectively. The activation energy E is 80.96KJ/mol and frequency factor A 1.5×10⁴.