Advanced Materials Research Vols. 396-398

Abstract: Hydrophobic modification of cellulose fibres was conducted by plasma-induced polymer grafting in an attempt to increase the hydrophobicity of paper. Two hydrophobic monomers, i.e., butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) were grafted on cellulose fibres, induced by atmospheric cold plasma. Various influencing factors associated with the plasma-induced grafting were investigated, including the contact time and reaction temperature with monomers, and the dosage of monomers. Contact-angle measurement, infrared spectrum (IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to ascertain the occurrence of the grafting. The results showed that the hydrophobic property of the modified paper sheet was improved significantly after the plasma-induced grafting. The water contact angle on the surface of the paper reached up to higher than125°.

Abstract: An ultrasonic device with frequency of 20 kHz was used to investigate the effect of different operational parameters such as ultrasonic power, temperature and initial molecular weight on dextran degradation. Results show that the molecular weight of dextran can be controlled by ultrasonic treatment. Higher the ultrasonic power and lower the temperature could increase the degradation rate (R).The initial molecular weight plays an important role in at the initial stage of dextran degradation (within 20 minutes). A smilar limiting molecular weight (Mw≈8.7×104) was obtained after 2 hours ultrasonic treatment for four different initial molecular weight dextrans, suggesting that the limiting molecular weight is independent on the initial molecular weight of dextran. Ultrasonic treatment can be used as a safe, simple and effective method to control the molecular weight of dextran.

Abstract: Water extraction and ethanol reflux extraction of γ-aminobutyric acid (GABA) in brown rice were compared with the yield and the recovery. In the water extraction, the effects of temperature and time on the extraction process of GABA were investigated, the results showed that the optimum extraction condition was incubated at 50°C for the 3h, and the GABA content was 30.73mg/100g, the recovery of the water extraction was lower, just 60.5% on average. The single factor and orthogonal tests of the extraction conditions were discussed for the ethanol reflux extraction. The result indicated that the best extraction condition is incubated in 70% ethanol, at 80°C, solid to liquid ratio 1:7 (g/mL), GABA content was 50.45 mg/100g, the recovery was 98.5%.

Abstract: The aqueous solution polymerization of acrylic acid, acryl amide and oxidized starch under microwave irradiation was studied, and a polymer dust suppressants was synthesized. It just needs 2 mins to preparation it. The polymer dust suppressants were characterized by IR and scanning electron microscopy (SEM). Prepared several coal models by polymer dust suppressants solution (2.0 g/L) was mixed with coal, and to determine compressive strength, temperature resistance, wind corrosion resistance and water corrosion resistance. The result showed that the polymer dust suppressant can effectively reduce the coal loss and particle pollution in transportation.

Abstract: Two mild alkaline oxidative pretreatments of rice straw followed by enzymatic hydrolysis were investigated. In addition to measuring the composition variance, the pretreated rice straw solutions were analysed by the UV/Vis spectra. These two mild oxidative pretreatment of rice straw cause the removal of lignin, hemicellulose and neutral detergent solubles (NDS), where the H₂O₂/NaOH pretreatment solubilize the lignin and the O₃/NaOH pretreatment oxidative degrade the lignin. These two mild oxidative pretreatment of rice straw enhance susceptibility to enzymatic hydrolysis, and speed-up the enzymatic hydrolysis. The conversion yield of cellulose and hemicellulose presented in the O₃/NaOH pretreated rice straw was 92.6%, compared to 82.3% and 52.5% in the H₂O₂/NaOH pretreated and untreated rice straw, respectively.

Abstract: A Titanium-modified phenol-formaldehyde resin (Ti-PF) was prepared. FT-IR was adopted to characterize the molecular structure of the modified resin. And the curing behavior and curing kinetic characteristics were studied by differential scanning calorimetry (DSC). The initial curing temperature Ti, the exothermic peak temperature Tp and the end curing temperature Td of Ti-PF are 153.1°C, 172.5°C and 193.9°C, respectively, all about 10°C higher than that of the unmodified phenolic resin. The Kissinger and Crane equations were applied to establish the curing kinetic parameters of Ti-PF. The kinetic analysis indicates the activation energy for the Ti-PF is 79.9kJ•mol-1, lower than that of the unmodified phenolic resin(87.6kJ•mol-1). In addition, the thermal degradation behavior of the cured Ti-PF was studied by thermal gravimetric (TG) method. TG results show that the char yield of Ti-PF is 73.3% at 850°C, while that of the unmodified phenolic resin is only 62.3%. It demonstrated that titanium-modified phenolic resin has much better thermal stability compared with the unmodified one.

Abstract: In this study, total polyphenols content (TPC) and ascorbic acid content (AAC) in CAW were quantified. Total antioxidant activity, reducing capacity, and free radical scavenging activity of CAW were assayed. The TPC and AAC were 160 mg GAE /100ml and 132 mg/100 ml，respectivity. CAW exhibited effective antioxidant activities in the employed in vitro experiments, including total antioxidant activity, reducing capacity, and free radical scavenging activity, which indicates that phenolic compounds and ascorbic acid may play a key role in the antioxidant function of CAW.

Abstract: The texture properties of rennet gels made with different concentrations of milk fat and protein were investigated. The textural variables, water-holding capacity and apparent viscosity of rennet gels were closely correlated with the reduced fat ratio in the reconstituted milk powder. The demonstrable difference in textural variables was found using the principal component analysis. The apparent viscosity of these gels significantly decreased and the water-holding capacity showed less change compared to the rennet gel made with raw milk. Totally, the gel produced by reconstituted milk powder had less hardness and adhesive, low gumminess, chewiness and viscosity, and more cohesiveness.

Abstract: This study was to screen strains for glutathione over-production. A high GSH-producing strain HSJB1 was isolated from soil.According to the morphological, physiological and biochemical characteristics of cells, this strain was primarily identified as Saccharomyces cerevisiae. The glutathion fermentation conditions of this strain by shake flask culture were studied.The optimal fermentation medium was as follows: glucose 20g/L, (NH4)2SO4 5g/L, peptone 12.5 g/L, KH2PO4 9.0 g/L, MgSO4•7H2O 1.0 g/L, NaCl 0.2 g/L, ZnSO4•H2O 0.01 g/L. The optimal culture conditions were as follows :pH 5，broth quantity 30ml/250ml, temperature 28°C，inoculum 10%. Under the optimal conditions, the glutathione productivity and biomass were 53.60 mg/L and 3.8 g/L, respectively, which were 11.2% and 11.8% higher than those in the original conditions, respectively.

Abstract: The main objective of this study was to optimize the hydrolyzing conditions of L-Arabinose from corn fibers. The response surface methodology was used for the optimization. Independent variables were the concentration of the oxalic acid (2-4%), the hydrolysis time (3.5-4.5h) ,the dosage of the oxalic acid(6-10ml/g,v/w)and the reaction temperature (80-100°C). Significant regression model describing the changes of L-Arabinose yield with respect to hydrolysis parameters were established with the coefficient of determination, R2= 0.9501.Data were analyzed by Design Expert 7.0 and regression analysis. The L-Arabinose yield ranged from 7.53% to 11.46%. The models had significant effects on L-Arabinose yield at P<0.05. Optimum the hydrolysis time, the concentration of the oxalic acid, the dosage of the oxalic acid and the reaction temperature were 3.86h, 3.97%, 6mL/g (v/w) and 100°C, respectively. This combination gave 11.46% L-Arabinose yield.