Advanced Materials Research Vols. 236-238

Abstract: Cellulase is potential tool for modification of pulp properties to save energy requirement during refining process. In this paper, bleached Simao Pine kraft pulp was treated with NOV476 cellulase under different enzyme dosage for action mechanism analysis. Pulp viscosity was measured to evaluate the damage of fiber by enzyme. Fourier transform infrared spectroscopy (FT-IR) was performed to study the enzyme treatment on the pulp chemical structure and crystallinity index. The fiber morphology difference before and after treatment was also revealed by the SEM and AFM observation. When the cellulase dosage was lower than 1u/g, the fiber mean length slightly increased. With the further increase of cellulase dosage beyond 1u/g, the fiber mean length was less reduced than the control sample. The fiber mean width increased steadily after enzyme treatment in the dosage range of 0~0.1 u/g. Enzyme treatment did change the fiber chemical structure and crystallinity index through FT-IR analysis. With the increase of NOV476 cellulase dosage, the pulp viscosity decreased steadily. The SEM analysis showed the surface of cellulase treated fiber had some fluffing phenomenon and there was obvious intertexture between fiber and fiber. AFM images further demonstrated that the fiber surface of controlled pulp was covered by primary layer. After enzyme treatment, the primary layer of fiber cell wall was peeled off.

Abstract: Alkaline sulfite/anthraquinone (AS/AQ) pulping of wheat straw under different conditions was conducted in this study. A transition point of kappa number at approximately 6.5 was observed based on all experimental results. This transition point can be regarded as the phase transfer point in AS/AQ pulping from bulk to residual delignification. Effective delignification without great lost of pulp yield can be achieved before kappa number was below this transition point during AS/AQ pulping of wheat straw. It is found that the ratio of cooking liquid to solid should not be lower than 6, if good mass transfer of chemicals and lignin dissolving is needed. As the ratio of Na₂SO₃ to NaOH dosage ranged from 0.4 to 2.4, low proportion of Na₂SO₃ allows effective delignification while no serious degradation of carbohydrate. Moreover, similar to kraft pulping, addition of AQ in the range of 0.05% to 0.25% is useful to remove lignin and protect the carbohydrate during AS/AQ pulping. Finally, although the transition point of kappa number may be changed while different raw material used for same pulping process or different pulping process for same raw materials, it is of interest and important for mill practice.

Abstract: The case was carried out to study the variance of fiber feature, chemical composition and pulping property between heartwood and sapwood of poplar I-69. As results showed, the mean fiber length in heartwood and sapwood of poplar I-69 were 770 and 1146µm separately, with the length-to-width ratio of 42.56 vs 51.76, and the wall-to-lumen ratio of 0.40 vs 0.59, respectively. The heartwood of poplar I-69 differed from sapwood in contents of chemical compositions, with holocellulose of 82.65% vs 81.35%, α- cellulose of 42.83% vs 42.82% and lignin of 18.01% vs 21.68%, respectively. Both the heartwood and sapwood of poplar I-69 were suitable for pulping material. By investigating pulp yield and Kappa number, it was proven that the caustic soda dosage and the duration of reaction temperature were major factors influencing KP pulping properties of poplar I-69 sapwood. Under the same technical conditions of pulping, the pulp of the poplar I-69 sapwood was lower in Kappa number and higher in yield and in viscosity compared with those of heartwood. The tensile index, tear index and burst index of paper made by sapwood were higher than those made by heartwood. The sapwood of poplar I-69 showed overall better pulping aptitude in comparison with heartwood.

Abstract: In forest breeding programs, growth has typically been used as a selection trait of prime importance in Populus tomentosa, whereas less attention has been given to fiber characteristics and basic wood density. Given this context, we investigated phenotypic relationships between different fiber properties, growth and basic wood density traits in nine triploid clones and one diploid clone based on a clonal trial established in 2004 in northern China. We found that fiber width showed, on average (1.4%), the lowest phenotypic variation followed by fiber length (2.2%), coarseness (5.3%). Basic wood density showed, on average (1.9%) phenotypic variation. All phenotypic correlations between fiber properties were positive ( p＜0.05), ranging from moderate to strong, suggesting that selection for one trait could simultaneously affect other traits. Phenotypic correlations, on average, were quite weak but positive between growth and fiber properties and slightly negative between basic wood density and different fiber properties ( p＜0.05). Individually, some of the triploid clones showed negative correlation between growth traits and fiber length. As a result, selection for fiber properties alone could reduce overall stem volume and would not directly indicate basic wood density traits and vice versa.

Abstract: The beating characteristic of PPTA fiber and its influence on the performance of paper-based functional materials based on PPTA fiber and resin has been investigated in this study. The results show that the morphology of PPTA-pulp had significant influences on the mechanical and electrical properties of the composites. The sample contained with PPTA fiber of 35 °SR showed the increase in tensile strength, tearing strength and dielectric strength by 147.7%, 119.3% and 69.9% as compared with the untreated PPTA fiber.

Abstract: A series of core-shell type cationic soap-free latex were prepared by using styrene(St), butyl acrylate(BA) and methyl methacrylate(MMA) as main materials and introducing rosin as the functional monomer. In this reaction, starch(CS-8), which has low relative viscosity , was used as the emulsifier and dispersant. The influencing factors of the reaction were especially studied and the optimum conditions were got. Then the products were characterized by using scanning electron microscope (SEM), FT-IR, laser particle sizer, particle charge detector(PCD). The results show that the excellent performance and good sizing effects of SAE are achieved when the reaction conditions are as follows: the starch amount is 8%(wt), the charge for the initiator(APS) is 0.5%, and the amount of rosin is 2%(wt). And the water-resistant performance of paper is improved significantly when the rosin is chosen as the functional monomer.

Abstract: In this paper, the domestic old book paper(DOBP) was subjected to deinking process. Surface and colloid characterisitics of DOBP deinking pulp(DIP) system was investigated. The relation between surface and colloid characterisitic changes and efficiency of deinking (brightness and residual ink particles content) was studied. Technical conditions that affect the deinking pulp’s colloid chemical behavior were also analyzed here.The results showed that colloid-chemical behavior of DOBP deinking system could be changed during the deinking process. The colloid-chemical behavior, such as Zeta potential and surface tention, had a certain corresponding relation with deinking efficiency of DOBP deinking system. When Zeta potential of the deinking system was more great, and surface tension was more low in a certain range(Zeta potential was -17.0~ -16.0mV and surface tension was 59.0~61.0mN/m), brightness and ink removal efficiency of DOBP will be improved.

Abstract: In this paper, two types of fiber surface treatment methods, namely heat treatment and chemical coupling, were used to improve the basalt fiber surface properties. The basalt fiber surface was heated under 250Celsius degree for 30minites, and then was treated by silane coupling agent ethanol solution with different concentrations. X-ray photoelectron spectroscopy (XPS) was utilized to study the surface chemical compositions of basalt fiber after treatments. The XPS analysis indicated that chemical bonds between basalt fiber and KH-550 have occurred, and silanols were adsorbed to the surface of basalt fibers by an ether linkage between the silanols and the hydroxyl groups of the fibers. When the concentration of KH-550 is 0.8wt%, the optimal bonding condition is formed between basalt fiber and silane coupling agent.

Abstract: Considering nonlinearity, time-variation and inertia during temperature control of large supercritical extraction units, especially under the disturbance of system flow and pressure, a multi-artificial neural network (ANN) predictive control policy was proposed. It contains a radial basis function (RBF) ANN, aiming to approach nonlinear extraction temperature object and predicting output variable based on this model. There is also a back propagation (BP) ANN controller, seeking the optimal controlling signal by feedback correction and rolling optimization on purpose to overcome the time-variation and inertia. The experimental results indicate that this control strategy has excellent dynamic response performance, small steady state error and strong robustness.

Abstract: A kind of poly(N-isopropylacrylamide) (PNIPAM) gel was synthesized by radical polymerization of N-isopropylacrylamide monomer in the present of crosslinker N,N-Methylenebisacylamide using short reaction time. This kind of PNIPAM gel exhibits higher swelling ratio at low temperature and much faster deswelling rate than conventional gel, which could be attributed to the presence of loops, dangling chains and other incomplete structure in the gel caused by short reaction time.