Alkylpolyglycoside inducing poly (butylene terephthalate) non-woven graft copolymerization of chitosan

In order to improve the wettability and biocompatibility of the poly （butylene terephthalate） non-woven （PBTNW）, the method of surface modification is used to graft copolymerization of chitosan （CS） onto the PBTNW under alkylpolyglycoside （APG） inducing. The product is thoroughly characterized with the Fourier transform infrared spectroscopy （FrIR）, the electron spectroscopy for chemical analysis （ESCA）, the thermogravimetric （TG） and the scanning electron microscopy （SEM）. It is found that chitosan is successfully grafted onto PBTNW. In addition, the water contact angles, hemolysis tests and cytotoxicity evaluation tests show an improvement in wettability and biocompatihility as a result of graft copolymerization of chitosan. So the CS-grafted PBTNW exhibits greater superiority than the original PBTNW. The CS-grafted PBTNW can be a candidate for blood filter materials and other medical applications.

Composition and Properties of Thermo-regulated Non-woven Fabrics

A series of non-woven fabrics were fabricated by blending S0- 80wt% of thennoregulated fibres containing n-elcosane, n-nonadecane or n-octadecane with 0 - 40wt% PET fibres and 0- 20wt% PP fibres. The phase change properties, thermal conductivity, thermal resistance, heat flux and inner temperature difference between wool felt and the thermoregulated non-woven fabrics of the non-woven fabrics were measured respectively. The thereto-regulated non-woven fabrics absorb heat at 25- 34℃ and release heat at 10- 25℃. The measured highest enthalpy of the non-woven is approximately 18J/g. During a heating process, heat flux of the non-woven fabrics is composed of three parts, heat absorbed by the cold textile touching the hot plate, heat transmitted from the hot plate to the cold plate, and the heat absorbed by PCM from the hot plate during the phase change process. The measured maximum inner temperature difference in a temperature rising process between the wool felt and the thermo-regulated non-woven fabric is approximately 8℃. The inner temperature difference （Tr-Ts〉0） lasts 16 - 45 min By contrary, the measured maximum inner temperature difference in the temperature decreasing process is approximately - 6. 5℃. The inner temperature difference （Tr-Ts〈0） lasts 16 - 50 min, The temperature regulation properties are obviously observed.

Effect of Inclined Water Jets on Tensile Strength of Bicomponent Hydroentangled Nonwoven Fabrics

The effects of inclined water jets on bicomponent hydroentangled fabrics were investigated. The PET/COPET and PA6/PET hydroentangled fabrics were made by using designed inclined water jet apparatus. Effects of basis weight, water jets inclination angle and water jet pressure were discussed. The comparison was made on the average tensile strength of fabrics made by perpendicular water jets （0^o inclination angle） and inclined water jets of 20^o with pressure levels of 3 bars and 7 bars. It was found that increases of water jet pressure, the fabrics tensile strength were increased. Furthermore, increases of water jets inclination angle, fabric tensile strength of 60 g/m^2 fabrics decreased while for 100 g/m^2 fabrics tensile strength increased.

Theoretical Permeability of Two-layered Nonwoven Geotextiles

The two-layered nonwoven geotextile, which consists of a layer constructed with fine fibers for providing optimal filtration characteristics and another layer constructed with coarse fibers for providing the required mechanical properties, is desirable for drainage and filtration system. Based on Darcy’s law and drag force theory, a mathematical model on vertical permeability coefficient of two-layered nonwoven geotextile is estabilished. Comparison with experimental results shows that the present model possesses 83.6% accuracy for needle-punched two-layered nonwoven geotextiles. And experimental results also show that with the increasing of needle density the vertical permeability coefficient of two-layered nonwoven geotextiless firstly decreases and then increases, reaching the smallest value at 470 p/cm2.

Stress Distribution of Holed Geotextile Cross-section in Civil Engineering

Stress distribution of holed geotextile cross-section under uniaxial and double-axial tension is analyzed with the boundary element method (BEM). The calculation results indicate that stress distribution of holed geotextile cross-section is greatly related to the dimension of the specimen, the size of the hole, the shape of the hole and the tensile condition, and the stress concentration area of holed geotextile from the side of the hole to 3-4 times of the hole diameter should be strengthened in order to improve quality of the projects. These results could provide guidance for engineering application of geotextiles.

Performance of a Nonwoven Geotextile Reinforced Wall with Unsaturated Fine Backfill Soil

The use of marginal backfills in GSE （geosynthetic stabilized earth） walls has not been recommended by different standards specifications. Restrictions are motivated by the poor hydraulic conductivity of fine soils that are capable of developing of water pressures. However, the use of granular materials can expend the cost of the construction. As a result, local soils, granular or not, have been increasingly used. Unsaturated conditions of fine soils may result in convenient performance even using extensible reinforcements. This paper evaluates the performance of a full scale model of a nonwoven geotextile reinforced wall constructed with fine grained soil backfill. The unsaturated condition was maintained and matric suctions, displacements and reinforcement strains were monitored during the test. Results have shown that the unsaturated condition of the backfill allowed maximum reinforcement peak strain of 0.4 %. For the case of a wrap faced wall on a firm foundation the performance and good agreement between measured strains and factors of safety from limit equilibrium analyses have shown the maintenance of unsaturated conditions as an economical alternative to the use of high quality fill.