Superfine wool powder was blended and extruded with poly(propylene) (PP) to produce blend pellets, and the extruded pellets were hot‐pressed into a blend film. SEM photographs show that the powder could be uniformly incorporated with PP after extrusion. FT‐IR spectra shows that no substantial changes occurred in the chemical structure of both PP and wool powder in the blend film. X‐Ray diffraction analysis indicates that crystallinity of the blend film was much higher than that of the wool powder and little lower than that of PP. TG‐tested results indicate that the thermal stability of the blend film declined with an increase in the powder content. Endothermic peaks of the wool powder in the blend film become more obvious as the powder content increases. Mechanical properties decline greatly with an increase in the wool powder content in the blend film.magnified image

To manufacture the hygroscopic sheets available for functional application, superfine down powder (SDP) and stearic acid modified superfine down powder (MSDP) were, respectively, blended and extruded with polypropylene (PP) to produce composite pellets, and the extruded pellets were hot-pressed into composite sheets. The chemical reaction between SDP and stearic acid was characterized using the attenuated total reflection attachment on the Fourier transform infrared. PP/MSDP composites showed more uniform powder dispersion in PP matrix, higher compatibility, and better mechanical properties than that of PP/SDP composites, which showed an evident decrease in tensile strength and elongation at break compared with pure PP. It was worth noting that the Young's modulus of PP/SDP composites was higher than that of pure PP, but lower than that of PP/MSDP composites. The addition of SDP led to a large increase in water absorption of PP/SDP composites. However, the water absorption of PP/MSDP composites decreased slightly compared with that of PP/SDP composites. Furthermore, the effects of SDP and MSDP on the microstructural and thermal properties of different composites were also investigated, respectively.

ABSTRACT:In this study, the silk treated by steam explosion was pulverized into fine powder with a mean particle size of 1.829 m, then the feasibility of the application of the protease treatment to produce finer and more uniform silk powder was investigated. The results indicated that after the enzymatic treatment, the mean diameter of the silk powder was reduced from 1.829 to 1.546 m and the equivalent diameter distribution became more concentrated; thus, the uniformity of the particles was improved. The infrared spectra analysis demonstrated that the silk powder remained the ␤-sheet crystalline structure. X-ray diffraction analysis showed the crystallinity of the polished silk powder was very slightly strengthened. It was found that the treatment reduced some polar amino acid in the sericin; however, the composition of the kinds of the amino acids did not change. In addition, the hot water-solubility and moisture regain of the polished silk powder declined very slightly.

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