Mao Fang Huang

Comparison of Four Different Extraction Methods of Oil from Macadamia integrifolia

Four different extraction methods, solvent extraction, ultrasonic wave-assisted extraction, Soxhlet extraction and supercritical CO2 extraction, were used to extract oil from Macadamia integrifolia, which also named Macadamia nut oil. Fatty acid compositions of Macadamia nut oil were analyzed by gas chromatography and mass spectrometry (GC-MS). The results showed the highest extraction rate was 74.63% via Soxhlet extraction, while supercritical CO2 extraction was 70.53%, ultrasonic wave-assisted extraction was 57.19% and Solvent extraction was 50.37%. Six unsaturated fatty acids, including Z-9-Hexadecenoic acid, E-11-Hexadecenoic acid, 9,12-Octadecadienoic acid, 9-Octadecenoic acid, E-9-Octadecenoic acid and 9-eicosenoate, were identified in the oil by GC-MS．The relative extraction rate of unsaturated fatty acids were 36.53%, 44.21%, 60.62%, 56.81%, respectively. Though the extraction rate was the highest via Soxhlet extraction, the relative content of Z-9-Hexadecenoic acid and 9,12-Octadecadienoic acid were both higher extracted by supercritical CO2 extraction than Soxhlet extraction, which were 15.38% and 1.55%,. As supercritical CO2 extraction has no solvent residual problem, it would be the trend of the development inSubscript text the future to extract Macadamia nut oil.

Determination of Chlorbenzuron Residues in Tea by UPLC-MS/MS

Residual amount of chlorbenzuron derived from tea was determined by UPLC-MS/MS. Chlorbenzuron was extracted with acetonitrile, purified by carbon/NH2 SPE cartridge, and then determined by ultra high-performance liquid chromatography with tandem mass spectrometry. The values o f lower limit of determination (10 S/ N) of 1.0 ug/kg-1 was found for Chlorbenzuron.Linear relationships in the range within 200 ug/L-1 was found . Recovery and precision of the method was tested by standard addition method at 3 concent ration levels. Results obtained was as follows: recovery 79.2 % - 89.6 %; RSD ( n= 6) of repeatability 0.72 % -5.85 %.It is suitable for the determination of chlorbenzuron residual in tea.

Structure and Thermal Stability of Sugarcane Bagasse Cellulose Regenerated from Dialkylphosphate Ionic Liquids

A phosphate-based ionic liquid, 1-ethyl-3-methylimidazolium diethylphosphate ([EMI[DE), was synthesized and used to dissolve sugarcane bagasse cellulose under microwave radiation. The original and regenerated cellulose were both characterized by X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. The results showed that cellulose had a more porous and less crystalline structure after regeneration, whereas chemical composition had no change. Thermal stability of the regenerated cellulose was somewhat lower, corresponding to the decreased crystallinity. In short, the treatment with [EMI[DE led to desirable structural modification on sugarcane bagasse cellulose via physical process. This is of great benefit to the subsequent downstream processes, such as enzymatic hydrolysis and ethanol fermentation.

The Evaluation of Storage Lifetime of Vulcanized Nature Rubber Dried by Microwave Using Thermogravimetric Point Slope Method

The storage lifetime of nature rubber vulcanizes dried by microwave and hot-air was investigated by using thermogravimetric point slope (TPS) method. The results showed that the storage lifetime at ambient temperature of nature rubber vulcanizes dried by microwave was 9 years which was 1.2 years longer than hot-air. Microwave drying nature rubber vulcanizes showed a better thermal-oxidation ageing resistance and a longer storage lifetime. It provided theoretical guide and basis for practical application.

Homogeneous Grafting of Bagasse Cellulose in Ionic Liquid

A new cellulose graft copolymer was synthesized by the homogeneous graft polymerization in ionic liquid. The methyl methacrylate was successfully grafted onto the bagasse cellulose in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) as a homogenous media. The obtained copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM). The results of thermal analysis curves exhibited two separated pyrolysis with cellulose and the grafted pMMA. Moreover, the homogenous reaction media applied can be carried out in completely recycled ionic liquid, and the modified cellulose has a potential value for oil absorbent.

Fatigue Damage of a Cutter Used for Cutting Cashew Nut under Random Load

To study the fatigue damage of a cutter used for cutting cashew nut, the integratedsimulation platform is established with Hypermesh, LS-Dyna, LS-PrePost, and nCode GlyphWorks.The simulation model is established by Hypermesh. LS-Dyna is used to calculate the k file.LS-PrePost is used as the post-processing software. The rain-flow counting, load superposition andextrapolation are executed using Rainflow module in nCode GlyphWorks. The analysis of thefatigue damage of the cutter is executed using Stress Life module in nCode GlyphWorks. Theequivalent stress time history of different elements in the upper and lower cutters, rain-flowcounting histogram after load spectrum superposition, rain-flow counting histograms after loadspectrum extrapolation, and damage histogram of the cutter are obtained. The results show that thecutter has excellent mechanical properties, and the minimum fatigue life of the cutter is about 495days, which is a conservative solution.

Preparation and Characterization of Nanocrystalline Cellulose/Natural Rubber (NCC/Nr) Composites

Surface modified nanocrystalline cellulose (NCC) was prepared by silicon-69, and then blended into natural rubber latex to prepare nanocomposites. The nanocomposites properties of tensile properties, tear strength, morphology and thermal dynamic mechanical properties were measured by mechanical property testing, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA), respectively. The results showed that modified NCC is homogeneously distributed throughout NR matrix, which leads to the enhancement on mechanical properties. Moreover, the storage modulus (E) of modified nanocellulose filled NR is higher than unmodified nanocellulose filled NR, and the tanδ is reversed.

Effect of Microwave Drying on Structure and Properties of Natural Rubber

The morphological structure and properties of wet natural rubber (NR) granulates dried by microwave were studied, which compared with wet NR granulates dried by hot-air. The results show that the molecular weight of NR dried by microwave is higher than that of NR dried by hot-air, and the molecular weight distribution of NR dried by microwave is narrower than that of NR dried by hot-air. The wet NR granules dried by microwave are rough on surfaces and the cutting traces produced during the processing remained on surfaces; whereas the wet NR granules dried by hot-air are smooth on surfaces resulted from melt adhered, and the cutting traces disappeared; the thermal-oxidative resistance of NR vulcanizates dried by microwave improved significantly.

Thermal-Oxidation Degradation of Microwave Drying Nature Rubber

The effects of drying methods on thermal-oxidation degradation and ageing behavior of nature rubber (NR) was investigated using Fourier transform infrared/Attenuated total reflection (FTIR-ATR) and thermogravimetric analysis. Examining the samples of thermal-oxidation ageing for 24h by FTIR-ATR spectroscopy allowed appearance of obvious carboxyl absorption of hot-air drying NR at 1723cm-1, decay of methylene stretch and C=C plane stretch during thermal-oxidation ageing process, to be monitored. TG and DTG were used to determine thermal-oxidation degradation temperature in air atmosphere and active energy using Coats-Redfern equation. Showed from the results, the degradation temperature and active energy of microwave drying NR was higher than hot-air drying, thermal-oxidation resistance was more excellent by FTIR analysis, indicating a higher thermal-oxidation stability of microwave drying NR.

Study on Crosslink Density of Natural Rubber with Different Initial Moisture Contents Dried by Microwave

In this work, the crosslink density of uncured natural rubber with different initial moisture contents, 3.80%, 10.05%, 19.76%, 23.68%, respectively, dried by microwave at frequency of 2450MHz was studied using nuclear magnetic resonance spectrometer. Seen from the results, the effect of initial moisture content of wet natural rubber on crosslink density and processability were obvious. With the increment of initial moisture content of wet natural rubber, the crosslink density of natural rubber after microwave dried with the frequency of 2450MHz decreased gradually. The crosslink density and A(Mc) of natural with the lower initial moisture content was bigger compared with natural rubber with the higher initial moisture content.