A vibration-injection molding equipment was developed to prepare isotactic polypropylene injection samples to investigate their crystal form and orientation. Wide-angle X-ray scattering experiments (WAXD) were conducted in two modes: theta-theta mode and tube-fixed mode. Through vibration-injection molding, in additional to a form, b form, or g form can be obtained under different conditions. At high melt temperature (230), b-PP can be induced and the core of the sample contains more b-PP than the surface. At low melt temperature (190), g-PP can be induced and the core and the surface of the sample contain approximate same proportion of g-PP. Pole figures show that a-PP of a static sample just orientates slightly along M direction, while that of vibration samples orientate much stronger. The orientation of the normal of (040)a plane of the sample obtained at T 5 2308C, f 5 0.5 Hz, and P v 5 75 MPa is preferred in M direction, and the orientation of the normal of (040)a plane of the sample obtained at T 5 1908C, f 5 1.5 Hz, and P v 5 35 MPa is preferred in N direction. b-PP and g-PP do not show obvious orientation.
Porous metal fiber media have traits of metal materials and functional materials. Porous metal fiber media are gaining popularity in engineering applications due to their special properties, such as lower density, larger specific surface area, higher mechanical strength and excellent permeability. In this paper, the recent development of fabrication methods and the various properties of porous metal fiber media were reviewed. Porous metal fiber media are divided into structural and functional applications. The mechanical and physical properties of porous metal fiber media, including tensile property and compressive property were analyzed. Porosity and the sintering process play an important role in the mechanical properties of porous metal fiber media.
In recent years, the research in porous metal got rapid development in China, especial in
Northwest Institute for Non-ferrous Metal Research (NIN). Many porous metals with different raw
material and different shapes were developed, which successfully employed in many fields. We
believe we will earn more rapid development in the future.
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