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Lin L.,Chinese Academy of Sciences | Lin L.,National Research and Development Center for Processing Technologies of Agricultural Products | Huang X.,Chinese Academy of Sciences | Huang X.,University of Sichuan | And 5 more authors.
Advanced Materials Research | Year: 2013

A Box-Behnken experimental design and response surface methodology (RSM) was employed to optimize the parameters of ultrasonic extraction of phenolics from longan seed based on the single-factor experiments. The effects of extraction temperature, methanol concentration and extraction time on the extraction yield of phenolics from longan seed were investigated. The major parameter influencing the extraction was the extraction temperature. In this experiment, the maximal extraction yield of phenolics was obtained with 5.931 ± 0.016% (n = 3) at extraction temperature 82°C, methanol concentration 50% and extraction time 41 min. Under optimal conditions, the activity predicted by the model agreed well with experimental data. © (2013) Trans Tech Publications, Switzerland.

Yongzhen L.,Key Laboratory of Rubber plastics QUST | Yongzhen L.,Key Laboratory of Tropical Crop Products Processing | Jidong H.,Key Laboratory of Rubber plastics QUST | Guozhen C.,Key Laboratory of Rubber plastics QUST | And 2 more authors.
Journal of Applied Polymer Science | Year: 2010

Polymorpholine-2,5-dione-block-polylactide (PMD-b-PLA) was synthesized via two-step anionic ring-opening polymerization at room temperature. First step of ring-opening polymerization was the ring-opening of mor-pholine-2,5-dione (MD). It was carried out in an airtight and dry polymerization tube using potassium ethoxide/THF (0.2M/L) as an initiator for 90 min. Then lactide was ring-opened in THF solution by the potassium alcoholate of PMD. From the FTIR of the copolymer, we can find all the peaks in PLA and PMD. The 1H-NMR of copolymer gave us a proof to the principle of the anionic ring-opening polymerization and the fraction of PMD in the copolymer was calculated as 86.3%. DSC analysis of copolymer indicated that it was a copolymer with one T g (63.6°C) and two T ms (155.6 and 171.4°C) instead of a mixture of PMD and PLA. The yields of the PMD and the copolymer were 32 and 26%, respectively. © 2010 Wiley Periodicals, Inc.

Chen S.,Chemistry and Chemical Engineering SchoolInstitute of Physical ChemistryLingnan Normal UniversityZhanjiang | Chen J.,Chemistry and Chemical Engineering SchoolInstitute of Physical ChemistryLingnan Normal UniversityZhanjiang | Xu K.,Key Laboratory of Tropical Crop Products Processing | Pan R.,Chemistry and Chemical Engineering SchoolInstitute of Physical ChemistryLingnan Normal UniversityZhanjiang | And 3 more authors.
Polymer Composites | Year: 2015

The objective of this study was to investigate three kinds of filler with completely different morphology on mechanical properties of natural rubber (NR). Coal gangue (CG) are derived from natural deposits are composed principally by illite and quartz. CG, carbon black (CB), and multiwalled carbon nanotube (CNT) were used as hybrid fillers in NR. CNTs were dispersed into NR latex by ultrasonic irradiation and then the mixed latex were coagulated to obtain the CNTs/NR masterbatch, then mechanical mixing method was employed to prepare the CG/CB/CNTs/NR composites. The addition of CG, CB, and CNTs to NR was varied with the total filler loading fixed at 35 phr. The mechanical properties of NR composites were studied in terms of tensile and dynamic mechanical analysis (DMA). The results showed that the tensile strength and modulus 300% (M300) of all hybrid samples were higher than the composites only loaded CG; and the highest tensile strength of NR loaded with hybrid fillers achieved at sample of loading amount of CG 17.5, CB 15.5, and CNTs 2 phr, whose M300 and elongation at break was obviously higher than that of only CB loaded NR composites; The inclusion CG improves the tensile strength of NR without the sacrifice of its extensibility, while CB and CNTs brings together the enhancement in the ultimate strength and the reduction in the extensibility. DMA results revealed that the existence of CG can improve the dispersion of CB and CNTs in NR matrix. © 2015 Society of Plastics Engineers.

Xu H.,East China University of Science and Technology | Xu H.,Key Laboratory of Tropical Crop Products Processing | Fang L.,Key Laboratory of Tropical Crop Products Processing | Wu C.,Key Laboratory of Tropical Crop Products Processing
Journal of Macromolecular Science, Part B: Physics | Year: 2011

To improve the dispersion stability of carbon black (CB) in an acrylic resin coating, a hindered phenolic antioxidant (AO80) was chosen to modify the CB by a solid state method based on the blending of CB and AO80 in an internal mixer. The modified CB (m-CB) was directly introduced into the acrylic resin with 50% solid content in butyl acetate by ball milling without any other treatment. That the majority of the m-CB particles were nanosized in ethanol was proven by a particle size analyzer. Transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM) micrographs indicated that the m-CB particles were also dispersed in the acrylic resin as nanoscale particles. Compared with the unmodified CB, the modification of CB can decrease the viscosity of the acrylic resin/m-CB nanocomposite and improve its flow property. The adhesion and gloss of the acrylic resin/m-CB nanocomposite were also improved. More importantly, the UV shielding and stability of the acrylic resin/m-CB nanocomposite were enhanced. © 2011 Copyright Taylor and Francis Group, LLC.

Sun Y.,Hangzhou Normal University | Liu Y.,Zhejiang Academy of Agricultural Sciences | Li Y.,Key Laboratory of Tropical Crop Products Processing | Lv M.,Key Laboratory of Tropical Crop Products Processing | And 3 more authors.
Carbohydrate Polymers | Year: 2011

Antibacterial membranes were prepared from a mixture of hydrolyzed curdlan and chitosan. The elongation-at-break and water vapor transmission rate of curdlan/chitosan blended membranes were substantially improved when the temperature was high (90 °C) due to curdlan gel formation and the interaction between the hydroxyl groups of curdlan and the amino groups of chitosan. This was confirmed by Fourier transform infrared spectroscopy. The membranes were further investigated for their miscibility between the two components using differential scanning calorimetric measurements, dynamic mechanical analysis, optical microscopy, and scanning electron microscopy. High reaction temperatures (90 °C) and low curdlan contents caused better interactions between components, and allowed membranes to be prepared with higher storage moduli and lower water absorption rates. The 4 bacteria strains were chosen as target bacteria using the optical density method to prove the antibacterial activity of the membranes obtained. The resulting curdlan/chitosan membranes exhibited outstanding antibacterial activity. © 2010 Elsevier Ltd. All rights reserved.

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