| In this paper, Tetra pak waste, copper fiber and iron fiber are used as rawmaterials. The main research contents include:(1) The impact of the dimensions ofthe Tetra on the performance of the compsites;(2) The hot-pressing processoptimization of electromagnetic-shielding plate;(3) The influence of copper fiberand iron fiber different additives, fiber length, different filling layers and copperfiber and iron fiber mixed filling process to the average and maximum SE value,volume resistivity, physical properties and mechanical properties of the compositesin9KHz to1.5GHz frequency range. The SE test is according to theelectromagnetic-shield effectiveness measuring method of the military standard ofelectron trade of the People's Republic of China(SJ20524-1995), volume resistivityaccording to volume resistivity and electrical surface resistivity measuring methodof solid insulating material(GB1410-2006-T), according to national standard ofphysical and chemical measuring method of plywood (GB-T17657-1999). Theresults can be concluded as following:(1) Dimensions of the Tetra pak wastes have a great impact on the physical andmechanical performance of the composites. Boards made from Tetra pak wastepowder in diameter of9μm~120μm show a significantly advantage to those madefrom Tetra pak waste grain.(2) Boards present an improvement in mechanical property as the temperatureraised up, for the plastic contained in Tetra pak is getting a lower viscosity, easy toflow and diffuse. With a longer hot pressing time for LDPE to flow and diffuse moreeasily, MOE, MOR and internal bond strength also trend to rise. Considering theinfluence of various factors, the optimized hot-pressing parameters are180℃for420S.(3) The internal bond strength between paper fiber and plastic is better than thatbetween paper fiber and metal fiber. The mechanical property shows a gradualdecrease with the increase of copper/iron fiber filling quantity; but with the increaseof fiber length, it falls after a small peak.(4) The boards present the best SE value in condition of copper fiber fillingquantity100g/m2,copper fiber length3~4mm, or iron fiber filling quantity40g/m2,iron fiber length9mm~10mm. The average SE value of copper/iron fiber fillingboards reaches respectively24.11dB and22.37dB in frequency range of9KHz~1.5GHz.(5) The SE value of boards presents to rise with the increase of fiber filling layers. According to the standards by FCC, the SE value of boards from Tetra packwaste without metal fiber is2.9dB, which is far beyond the practical requirement.When added to3layers of filling layer, the SE value of boards filled with copperfiber and iron separately increases to25.34dB and26.82dB, closing to therequirement. Multilayer material performs better than monolayer material in SEvalue and mechanical property with the same filling quantity and fiber length. Inaddition, the SE value of electromagnetic waves effecting by absorbing is better thanthat by reflecting in multilayer shielding system. Therefore, exhaustion by absorbingshould be added as more as possible to strengthen the whole shielding effect.(6) The SE value of boards wholely filled with copper or iron performs worsethan that of boards filled with copper and iron fixed fiber. The SE value of boardsfilled with copper and iron fixed fiber gets better with the adding of copper. Also,the mechanical property and density of boards fixedly filled with copper and ironfiber will go up with the increasing of copper fiber.(7) In all chapters of this paper, the SE value of boards always oppositelychanges with volume resistivity, although the filled condition is different. |
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