Advanced Materials Research Vols. 557-559

Abstract: The application of wheat straw fiber reinforced cement-based composites (WFCC) was restricted because of the poor mechanical properties and lots of extractives of wheat straw in cement paste. In order to overcome the natural defects, the wheat straw was modified respectively by different mass fractions of NaOH, Na₂SiO₃ and H₃PO₄ solutions. The results show that, the various indexes of wheat straw fiber soaked by NaOH solutions (mass fraction 5%) for 12 hours were optimal. Moreover, its ultimate tensile strength and fracture elongation were respectively increased by 104.81% and 78.57%. Meanwhile, the modified fiber bundles arranged densely without damage phenomenon in WFCC, and surface of fiber was covered in massive cement hydration products, and the interfacial adhesion between fiber and hardened cement paste was improved.

Abstract: It’s necessary to find some substitute for asphalt because of the rising price and the tension supply of petroleum asphalt with the gradually decreasing of fossil oil. Indoor tests on the pertableance of binding material made of crumbed rubber particles, botanic asphalt and petroleum asphalt as well as the pertableance of its premix are carried out. The results show that botanic crumbed rubber asphalt pertables as well as asphalt rubber, which means botanic crumbed rubber asphalt can be used as binding material in road asphalt concrete. The study provides a theory basis for the possibility of partially replacing petroleum asphalt with botanic asphalt. Botanic asphalt has much higher comparative advantages than petroleum asphalt in the aspects of social benefit and economic benefit, so there must be a bright prospect for botanic asphalt.

Abstract: The leaching characteristics of cement-fly ash pastes were investigated by MIP, XRD and TG. The results show that the microstructure of hardened cement-fly ash paste deteriorates partly after leaching of soft water. At the leaching duration of 180 days, the hardened paste containing fly ash deteriorated a little more serious than the plain cement paste, but the incorporation of fly ash in a proper ratio was helpful to defer the trend of deterioration of the hardened paste microstructure. The microstructural stability of hardened cement-fly ash paste wasn’t damaged severely during the 180 days leaching duration.

Abstract: The 0.95MgTiO₃-0.05CaTiO₃ (95MCT) powders and ceramics were prepared by a sol-gel method by using Mg(NO₃)₂•6H₂O, Ca(NO₃)₂•4H₂O and Ti(C₄H₉O)₄ as the starting materials. The effects of calcination temperature on phase formation, morphology and particle size distribution of the proposed powders were examined, and the microwave dielectric properties of 95MCT ceramics made from different size particles were investigated. The dried gels were calcined at 600 °C, 700 °C, 800 °C and 900 °C, and the derived particle sizes of powders were 10-20 nm, 50-100 nm, 60-120 nm and 120-150 nm, respectively. The proper sizes, which range from 50-150 nm, lowered the sintering temperature of 95MCT ceramics effectively from 1400 °C to 1175 °C due to the high surface energy. Sintered at 1175 °C, the 95MCT ceramic prepared from 50-100 nm size particles had compact structure and exhibited good microwave dielectric properties: εr = 21.33 and Q×f = 36,315 GHz.

Abstract: The comfort properties of fifteen bamboo/cotton interwoven fabrics with different specifications were tested, such as moisture sorption property, air permeability, capillary effect property, etc. then the author tasked fifteen bamboo/cotton interwoven fabrics as clustering object, water—vapour transmission rate、air permeation rate、weft liquid capillary effect height and warp liquid capillary effect height as clustering index, using the grey clustering analysis to evaluate the bending，creasing and draping properties synthetically. The results show that: The first grey type including 1#、2#、4#、7#, achieved optimal standard；The second grey type including 3#、5#、6#、8#、10#、11#、13#，achieved good standard；The third grey type including 9#、12#、14#、15#，their comfort properties were poor.

Abstract: Millimeter size Hollow carbon spheres (HCSs) with high specific surface area were successfully prepared from resole-type phenolic resin by suspension polymerization method at ordinary pressure. During the polymerization process, large sums of small molecule gathered at the center and formed the hollow part, bigger spheres with a broad size distribution were then formed under stirring force and surface tension, the maximum external diameter of the obtained HCSs was 1.2mm and the hollow diameter was about 0.35mm. After activating at 800°C under a stream of steam, the specific surface area and total pore volume of the HCSs were reached as 1117m²/g and 0.61cm³/g.

Abstract: With Ag-loading MWNTs antibacterial agent as functional material, the antibacterial functional PET fibers were prepared by melt blending spinning-draft one-step method. The crystallinity and the orientation of specimens were characterized by differential scanning calorimetry, polarization microscope and sound velocimeter. Moreover, the mechanical properties and antibacterial properties were measured. The results showed that the antibacterial PET fibers had good spinnability when the content of Ag-loading MWNTs less than 1.0 % (wt); compared with pure PET fibers, the degree of crystallinity, the degree of orientation and the fracture strength were improved, but the elongation was decreased; the antibacterial PET fibers exhibited excellent antibacterial properties against E.coli by the method of flask shaking.

Abstract: The present study studied the effect of chitosan coating with antibrowning agents, including naphthylacetate and cinnamon oil, and modified atmosphere packaging (MAP) on browning of sweet persimmons stored at - 0.3 ~ 0 °C for 3 months. The browning on the surface of sweet persimmons was effectively inhibited by chitosan - based coating and MAP treatment. After 3 months’ storage, samples coated + MAP exerted the lowest browning index(BI), polyphenol oxidase (PPO) activity and malondialdehyde (MDA) content, which indicated that the coated + MAP treatment could offer an excellent inhibitory effect on the browning. Both edible coating and MAP treatment cause changes in respiration rate of sweet persimmons. This research could be valuable for the development of application to edible coating and MAP for improving the shelf - life properties of sweet persimmons.

Abstract: The properties of raw constant viscosity natural rubber were measured using a rubber processing analyzer. The results show that the rubber processing analyzer can characterize well the effect of viscosity stabilizer on the dynamic mechanical properties of raw constant viscosity rubber by applied strain sweep or frequency sweep. In linear viscoelastic region, the increment of the dynamic torque S’ of the constant viscosity natural rubber prepared with hydroxylamine hydrochloride decreases with the increase in the level of hydroxylamine hydrochloride . In the range of low frequency, the increment of the dynamic modulus G’ of constant viscosity natural rubber prepared with hydroxylamine hydrochloride is obvious lower than those of natural rubber and constant viscosity natural rubber prepared with aniline. G’ of the constant viscosity natural rubber prepared with aniline is just only a little higher than that of natural rubber. Hydroxylamine hydrochloride and aniline can decrease the molecular weight of rubber, and change the molecular weight distribution. The dynamical properties of constant viscosity natural rubber are dependent on the molecular weight and the molecular weight distribution.

Abstract: In this paper, a flame retardant dimethyl-2-(methacryloyloxyethyl) phosphate (DMMEP) was applied onto wool fabrics by graft copolymerization technique in water media. The paper discussed the technological conditions of the formation of wool-g-DMMEP such as the pH value of reaction, reaction temperature and time etc. The weight gain of wool fabrics was chosen to be the indicator of optimized technological condition. The results showed that DMMEP treated wool fabrics have high limiting oxygen index(LOI). Wool fabric with weight gain 4.27% has high LOI 34.6%, which is hard ignited in air. Char residues of DMMEP treated wool fabrics are more rigid and solid.