Authors: Hong Bo Tang, Min Sun, Yan Ping Li, Si Qing Dong
Abstract: In order to improve the property of pueraria lobata starch, and enlarge application fields of pueraria lobata starch, this study involved in the optimization of determining parameters in hydroxyropylation conditions and the property of acid-modified hydroxypropyl pueraria lobata starch with low substitution degree (DS).Characterizations were carried out by analyzing the spectrum of the thermograms of differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The fludity was used for characterizing the degree of acid hydrolysis. The substitution degree was measured by the spectrophotometric method. The optimized hydroxyropylation conditions were as follows: reaction temperature 40°C, reaction time 18h, amount of sodium hydroxide 1.2%, amount of anhydrous sodium sulfate 12%, respectively. The properties such as the transparency, freeze-thaw stability, blue value, swelling power, retrogradation, acid and alkali resistance of acid-modified hydroxypropyl pueraria lobata starch were compared with those of pueraria lobata starch and acid-modified pueraria lobata starch. It was shown that acid hydrolysis and hydroxyropylation increased the decomposition temperature, but reduced the enthalpy value from the thermal analysis.
3921
Authors: Zhao Du, Bin Bin Yang, Er Hong Duan, Bin Guo
Abstract: In this work, the breakthrough curves of styrene in fixed beds packed separately with hydrochloric acid-modified sepiolite were determined. And the Temperature Programmed Desorption (TPD) method is applied to research the desorption activation energy on modified sepiolite and untreated sepiolite. The results showed that in compared with the original sepiolite, the hydrochloric acid-modified sepiolite had more surface basic groups, pore volume and higher surface area so that their adsorption capacities of styrene were improved. The sepiolite modified with 12% hydrochloric acid solution had more micropore volume and higher surface area than the other modified sepiolite, and thus its adsorption capacity of styrene was the highest. The activation energy for desorption of styrene on the modified is higher than on the original sepiolite, this show that using hydrochloric acid modified sepiolite can enhance its adsorption of styrene.
2058
Authors: Jun Ping Zhuang, Xue Ping Li
Abstract: Bamboo is thought as an alternative feedstock for the production of fine chemicals, such as fuel ethanol and lactic acid to reduce our reliance on fossil fuels. Pretreatment is an essential step in the enzymatic hydrolysis of biomass for bioethanol production. In this study, hydrolysis of bamboo fiber for fermentable sugars production in hydrochloric acid used as a catalyst in saturated formic acid solution were studied. The purpose of this study is to investigate the effects of the hydrochloric acid concentration, temperature, the ratio of solid to liquid and reaction time on the fermentable sugars production. The optimum conditions were: adding 4% hydrochloric acid in saturated formic acid solution, temperature of 65 °C, 4% of the ratio of solid to solvent, with a reaction time of 90 min, under these conditions, the hydrolysate contained 23.52% glucose and 28.51% reducing sugars.
2442
Authors: Yun Xiong, Xu Zhang, Ming Zhu Liu
Abstract: Guar gum grafted sodium polyacrylate have been prepared via aqueous solution graft polymerization. Furthermore, the polymers were then surface-crosslinked using trimethylolpropane triglycidyl ether (TMPTGE) to improve the properties of swollen hydrogel. Polymerization conditions were systematically optimized to achieve the optimum swelling capacity. FTIR and DSC spectra confirmed that sodium acrylate had been grafted onto guar gum chains. SEM observations showed morphology of the samples. The results confirmed that introducing guar gum into the superabsorbent could improve the swollen hydrogel mechanics performance, including hydrogel strength, resilience and dispersion, although making the water absorbency decreasing slightly. The good mechanics performance will make it feasible in hygiene application.
39
