Polypropylene (PP)/vapor grown carbon fiber (VGCF) composites by melt compounding using a counter-rotating twin screw extruder were prepared, then by melt spinning PP/VGCF monofilaments with a high draw ratio of 9 were obtained. The properties and structure of the PP/VGCF composites and monofilaments were characterized by tensile testing, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Increasing the aspect and draw ratios resulted in an increase in the tensile strength of PP/VGCF monofilaments. The improvement of the tensile strength was observed for the addition of a small amount of 1 wt%, however, it was not observed for the addition of 3 wt%. Although the composites continued to be aggregates, VGCF was found to disperse in the PP matrix and increased the nucleation speed of the composite monofilaments, thereby leading to an increase in the crystallization rate of the as-spun monofilament owing to nanoscale structures formed from VGCF by drawing.

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Waste silk fiber is an important by-product in silk industry. In order to perform the efficient recycling of this waste silk resource, the papermaking technology was adopted, and silk/bamboo paper was produced. Beating treatment of fibers and chemical modification of silk fibroin fiber by epoxy reagent were carried out. The study of mechanical property, morphology and FT-IR spectrum showed that beating treatment could realize fibrillation of fibroin fibers effectively, however the strength of composite papers was rather weak. Proper beating treatment and modification still need to improve the mechanical property of the silk/bamboo hybrid paper.

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In recent years, noise pollution is one of the serious social problems, and many efforts have been paid to the development of efficient sound absorbing material. Normal sound absorbing materials are made of inorganic fibers, and inorganic fiber has difficulty with processing after the disposal. From the viewpoint of environmental protection, therefore, sound absorbing material made of natural fiber is expected. Furthermore, normal sound absorbing materials consist of single-layered structure and the sound absorbing properties have a limit level of frequency. Now, it is expected that the multi-layered structure improve the sound absorbing properties.
Under these circumstances, eco-friendly and also high performance sound absorbing material with density graded structure was developed by using wool fibers in this study. As a result, it was cleared here that the density graded structure is good for the sound absorbing performance.

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We studied the significance of three processing parameters of supplied air pressure, yarn speed and overfeed ratio to the number and static strength of tangles of interlaced yarn and the correlation between the number of tangles and static strength of tangles by statistical method. Interlaced yarn was characterized by the number and static strength of tangles. Interlaced yarn was produced by the interlacer with a yarn duct of elliptical cross-section. Factorial analysis and correlation analysis methods were used. After analysis and discussion, overfeed ratio is the most significant processing parameter to the number of tangles. Yarn speed is the most significant processing parameter to the static strength of tangles.

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