Advanced Materials Research Vols. 581-582

Abstract: Application in paper pulp as dry strengthening agent of homemade water in water cationic polyacrylamide (CPAM) emulsion was studied. Good collaborative effect was achieved when Homemade CPAM was used in bleached wheat straw pulp with strengthening agent E and with cationic additives L as paper pulp strengthening agent. It was also showed that distinct strengthening effect was obtained when homemade CPAM emulsion was applied in mixture of wood pulp which was needle bleached kraft pulp (NBKP) and straw pulp, breaking length and tearing index of hand sheet made of mix pulp was respectively increased by 22.2% and17.0% when the dosage of CPAM was 0.8% of dry fiber. Through analysis of handsheet section scanning electron microscopy (SEM) photos, strengthening mechanism of CPAM emulsion to paper pulp was preliminary studied.

Abstract: A rapid method for analysis of the main components of Radix Glycyrrhizae (RG) was developed using ultra-performanceliquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Previous study demonstrated that RG had antivirus, antioxidant，anti-tumor and other bioactivities. The separation analysis was performed on Waters Acquity UPLC system and the accurate mass of molecules and their fragment ions were determined by Q-TOF MS. Fourty compounds including triterpenoid saponins, flavonoid glycosides and flavonoid aglycones,coumarins, were identified and tentatively deduced on the basis of their element compositions, MS/MS data and relevant literatures. The results demonstrated that triterpenoid saponins, flavonoid glycosides and flavonoid aglycones were the main constituents of RG. Furthermore, an effective and rapid pattern was established allowing for comprehensive and systematic characterization of the complex samples.

Abstract: Ethylenediamine-modified chitosan magnetic nano-adsorbent (EMCN) was prepared and used for the sorption of methyl orange(MO). The kinetics of the sorption fitted well with the pseudo-second-order kinetics model. The activation energy of sorption (Ea) was determined to be 16.47 kJ.mol-1. Adsorption isotherms showed that the sorption process was consistent with both Langmuir and Freundlich isotherm, and the thermodynamic parameters were calculated and indicated that the sorption process was spontaneous and exothermic. The saturated sorption capacity is 247.66, 227.58, 214.19 mg.g-1 at 5°C, 25°C, 45°C(pH=5.6),respectively.

Abstract: Stellerite was activated and organic modified by calcination and hexadecyl trimethyl ammonium chloride (CTAC) to improve its adsorpability of formaldehyde which was one of the iconic pollutants of indoor air pollution. Results showed that the optimum calcining temperature and calcining time were 300 °C and 1.5 h. The optimum amount of anticoagulant, alcohol addition, CTAC addition, bathing temperature and reaction time were 0.5%, 0.7ml, 3 times, 70 °C and 2h, respectively. The organic modified effects of stellerite were characterized by hygroscopicity test, formaldehyde adsorption experiment, scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR). All data indicated that CTAC had entered into the internal of stellerite and the adsorbability of formaldehyde had a huge improvment after organic modification.

Abstract: CaMgZn mixed oxide (CMZ) catalysts were modified by addition of lanthanum nitrate, and the use of modified catalysts (CMZL) for biodiesel synthesis were investigated. The conditions of biodiesel production with modified catalysts were optimized. Using optimized conditions, including lanthanum nitrate addition of 3wt.%, catalyst amount of 5wt.%, reaction temperature of 50°C, methanol to oil molar ratio of 15:1 and reaction time of 1h, the glycerol yield of 86.80% catalyzed by CMZL could be attained, which was higher compared with the CMZ catalyzed process of 82.94%. Brunauer–Emmett–Teller (BET), X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to compare the modified CMZL catalyst with the CMZ bare catalyst. The results indicated that the lanthanum modified catalysts (CMZL) have excellent surface property. The modified catalysts could be suitable for commercial application.

Abstract: Dissolution and regeneration of cotton cellulose using ionic liquids as solvent was investigated. In this paper, modification of celluloses with maleic anhydride (MA) was carried out in ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).The maleylation celluloses with degrees of substitution (DS) between 0.85and 1.46 were accessible in IL. The effects of reaction time, temperature and mass ratio of the MA in cellulose were investigated. These maleylation celluloses were characterized by infrared spectroscopy, thermogravimetric analysis (TGA). Experiments showed that the optimal conditions for grafting were: mass ratio of maleic anhydride and cotton cellulose 0.8; reaction time of 90 min; temperature of 80 °C.

Abstract: Al-pillared bentonite supported Fe₃O₄ nanoparticles were prepared by co-precipitation and characterized with X-ray diffraction (XRD), specific surface area (BET) and scanning electron microscopy (SEM). The supported Fe₃O₄ nanoparticles exist on the surface of clays, with better dispersing and no obvious aggregation than the ones without bentonite support. Batch tests were carried out to investigate the catalytic oxidation Orange II by the obtained heterogeneous catalysts. The effect of pH, temperature and initial H₂O₂ concentration on degradation was discussed, and the regeneration ability of catalyst was also studied.

Abstract: Firstly, 1,4-bis(3-nitro-5-trifluoromethylphenoxy)benzene(I) was synthesized through the nucleophilic substitution reaction of 3,5-dinitrobenzotrifluoride and 1,4-dihydroxybenzene in the presence of potassium carbonate. Then, the diamine monomer 1,4-bis(3-amino-5-trifluoromethylphenoxy)benzene (II) was obtained through the catalytic reduction with hydrazine and Pd/C. These fluorinated polyimides (PI) were synthesized from the fluorinated diamine II with four kinds of dianhydrides, including pyromellitic dianhydride (PMDA), 3,3’,4,4’-biphenyltetracarboxylic acid dianhydride (BPDA), 3,3’,4,4’-oxydiphthalic anhydride (ODPA) and 3,3’,4,4’-benzophenonetetracarboxylicdianhydride (BTDA) respectively, via thermal imidization of poly(amic acid) (PAA). The structure and properties of these obtained fluorinated PIs were characterized. These experimental results showed that these fluorinated PI films exhibited excellent optical transmittance in the visible region and thermal resistance. The PI derived from ODPA showed the best optical transparency with the transmittance higher than 85.38 % at 450 nm. These PIs also exhibited good thermal properties with 5 wt% thermal decomposition temperature above 533 °C.

Abstract: Modified MPS-SiO₂ particle was obtained by the bonding of 3-methacryloxypropyl trimethoxysilane (KH-570) on the surface of silica gel particle. The methacrylic acid (MMA) monomers were grafted on the surface of MPS-SiO₂ particle to prepare the grafting particles SiO₂-g-PMAA. The effects of reaction conditions on the graft degree were explored. The results indicate that the MMA monomers can be easily grafted on the surface of silica gel particle by using the method of graft polymerization. During the graft polymerization, the grafted polymer layer is a hindrance to the subsequent graft polymerization. Then the grafting degree of the polymer under a certain condition has a limiting value. The reaction conditions, such as monomer concentration, the amount of initiator, reaction temperature, have remarkably influence on the graft polymerization of SiO₂-g-PMAA.

Abstract: A microextraction technique of solid phase membrane tip extraction (SPMTE) prior to gas chromatograph was developed to determine fifteen pesticides (organochlorine （OCPs） and pyrethroid). In the SPMTE procedure, multiwalled carbon nanotubes (MWCNTs) were used as the adsorbent enclosed in SPMTE device and then several important parameters influenced extraction efficiency were comprehensively optimized. Under the optimum conditions, the method obtaine good linearity in the range of 1–500.0 and 1.5–750.0 ng mL^-1 for OCPs and pyrethroid pesticides, low limits of detection in the range of 0.018–1.064 ng mL^-1(S/N=3). Seven target analytes are detected in river sample, none of the other samples tested show any pesticide residue. The developed method is a simple, feasible, and inexpensive microextraction technique.