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Inorganic nano fillers have demonstrated great potential to enhance the properties of natural rubber (NR). The present article reports the successful development of a NR nanocomposite reinforced with nano silica (Si[O.sub.2]). Its dynamic mechanical properties, thermal aging resistance, and morphology are investigated. The results show that the Si[O.sub.2] nanoparticles are homogenously distributed throughout the NR matrix in a form of spherical nano-cluster with an average size of 80 nm when the Si[O.sub.2] content is 4 wt%. With the introduction of Si[O.sub.2], the thermal resistance and the storage modulus of NR host significantly increase, and the activation energy of relaxation of the nanocomposite, compared to the raw NR, increases from 90.1 to 125.8 kJ/mol. POLYM. ENG. SCI., 48: 1674-1677, 2008. [C] 2008 Society of Plastics Engineers, INTRODUCTION Natural rubber (NR) with excellent chemical and physical properties has been widely used in various areas (1-3). The raw NR is usually reinforced with antiageing agents (4), (5) and [...]

ABSTRACT A derivative of sym-triazine (HTT) was chosen as a new nonammonia preservative for concentrated natural rubber latex (CNRL) in place of NH3-TT/zinc oxide (ZnO). The preservation effects of the HTT for CNRL, drying characteristics, mechanical properties, and cytotoxicity of the vulcanized natural rubber (NR) film were investigated. The results show that the CNRL was preserved steadily for more than 6 months with 0.3% HTT, and the volatile fatty acid number, viscosity, and mechanical stability of CNRL all met the requirements of ISO 2004:2010(E). The drying characteristics of the vulcanized NR film preserved by HTT retained no change compared with those of the film preserved by NH3-TT/ZnO. The tensile strength and elongation at break of the vulcanized NR film preserved by HTT were 32.17 MPa and 853.80%, respectively; these were very similar to those of the film preserved by NH3-TT/ZnO, whereas the tear strength reached 68.43 kN/m, and this was much higher than that by NH3-TT/ZnO. The results of the cytotoxicity and dermal irritation tests prove that HTT is not especially harmful to humans. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41749. [ABSTRACT FROM AUTHOR]

In the present paper, soluble Ca content in banana pulp was analyzed with pretreatment of digestion model in vitro. All the samples were digested by strong acid (perchloric acid and nitric acid with 1 : 4 ratio) and determined by AA700 flame atomic absorption spectrophotometry (FAAS). Meanwhile, the reproducibility of the analytical method was investigated. The results showed that (1) Content of Ca was 1.479 mg x g(-1) x DW in eighty percent maturity banana pulp. And the relative standard deviation was 4.12%. (2) Contents of Ca in the soluble and insoluble fractions were 1.108 and 0.412 mg x g(-1) x DW, respectively in eighty percent maturity banana pulp with pretreatment of digestion model in vitro. The extraction rate was 74.9% and the residue rate was 27.8%. (3) The relative standard deviations of the analytical results of Ca contents in those two fractions were 2.56% and 9.10%, respectively, in the reproducibility tests. It was showed that the digestion model in vitro did not affect the reproduction quality significantly. Moreover, the deviation between the theoretical value and the summation value of the extraction and the residue rates was only 2.7%, which showed good availability of the digestion model in vitro to be used as a pretreatment method in mineral element analysis process. (4) Relative standard deviation and recovery yield in the determination procedure were 0.11% (n = 9) and 99.2%, respectively.

In the present paper, trace elements contents of cuprum, zincum, manganese and ferrum in mungbean and their primary speciation distribution during enzymatic hydrolization were investigated with ICP-AES OPTIMA 5300DV plasma emission spectroscopy. The trace elements were separated into two forms, i.e. dissolvable form and particulate form, by cellulose membrane with 0.45 microm of pore diameter. All the samples were digested by strong acid (perchloric acid and nitric acid with 1 : 4 ratio ). The parameters of primary speciations of the four elements were calculated and discussed. The results showed: (1) Contents of cuprum, zincum, manganese and ferrum in mungbean were 12.77, 31.26, 18.14 and 69.38 microg x g(-1) (of dry matter), respectively. Different treatment resulted in different elemental formulation in product, indicating that more attention should be paid to the trace elements pattern when producing mungbean beverage with different processes. (2) Extraction rates of cuprum, zincum, manganese and ferrum in extract were 68.84%, 51.84%, 63.97% and 30.40% with enzymatic treatments and 36.22%, 17.58%, 7.85% and 22.99% with boil treatment, respectively. Both boil and enzymatic treatments led to poor elemental extraction rates, which proved that it was necessary to take deep enzymatic hydrolysis treatment in mungbean beverage process as the trace element utilization rate was concerned. (3) Amylase, protease and cellulose showed different extraction effectiveness of the four trace elements. Generally, protease exhibited highest efficiency for the four elements extraction. All of the four trace elements were mostly in dissolvable form in all hydrolysates and soup. (4) Relative standard deviations and recovery yields are within 0.12%-0.90% (n = 11) and 98.6%-101.4%, respectively. The analysis method in this paper proved to be accurate.