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Domat, Switzerland

Arnold M.,University of Applied Sciences Rapperswil | Henne M.,University of Applied Sciences Rapperswil | Bender K.,EMS CHEMIE AG | Drechsler K.,TU Munich
Journal of Composite Materials | Year: 2016

Modifying the impact toughness of carbon composite by means of introducing thermoplastic inserts in the interlaminar layer is state of the art. However, these inlayers reduce the electrical conductivity through the thickness of the composite. Because the combination of good electrical conductivity and high fracture toughness is desirable, a detailed investigation was carried out into additive-enhanced polyamide 12 compound. The modification consisted in compounding graphite, graphene and carbon nanotubes with polyamide 12 in various proportions. After it was introduced into the interlaminar layer, the samples' electrical conductivity was measured and their mechanical properties assessed. Afterwards, these results were compared with various inserts made with unmodified polyamide 12. It turned out that the coarse-mesh laid scrim showed only a slight fall in conductivity. Furthermore, it provided promising results regarding the increase of the interlaminar toughness. Thus, the expensive modification of polyamide 12 can be avoided by using discrete laid scrim. © 2015 The Author(s). Source

Filled polyamide molding materials, in particular polyamide molding materials with medium filler content, are producible from a polyamide blend and for example by compounding with chopped or endless fibers on two-screw extruders, and have a combination of reduced water absorption and good mechanical properties, which results in very good dimensional stability and reduced variation of the electrical properties of the produced molded part, such as an antenna housings of stationary or mobile communication devices. These thermoplastic polyamide molding materials are suitable for manufacturing molded parts and other semi-finished or finished parts, for example by extrusion, injection molding, pressing, direct process or direct compounding, respectively, wherein the compounded polyamide molding material is directly processed by injection molding or other shaping methods.

The invention describes a new synthetic fiber material of polyhydroxyether, as well as a melt-spinning method for its production. The new material can be used, in particular, for stabilization of the reinforcement fibers of high-performance fiber composite materials before they are embedded in the matrix material. During this usage, the polyhydroxyether fiber material dissolves at a temperature above its glass transition temperature entirely in the matrix material, so that the reinforcement fibers can be arranged largely free of kinking. In addition, it forms cross-links with the matrix material to form a homogeneous matrix and thus does not constitute a disruptive third phase in the composite material. The compatibility of the matrix and reinforcement fiber is also improved. It was possible to improve the bending strength of test slabs by 12% as compared to that of reference slabs with polyester filament.

Moulded articles having reduced surface carbonization and longer retention of the mechanical properties and methods of producing same are presented. In an embodiment, the moulded article comprises polyamides with nanofillers, which can be produced by means of injection moulding or extrusion, in particular by extrusion blow moulding, coextrusion blow moulding or sequential blow moulding with and without 3D hose manipulation. For example, the polyamide moulding materials for the production of moulded articles have reduced surface carbonization in the moulded articles in subsequent long-term use at elevated temperatures.

The present invention relates to reinforced polyamide molding materials with high notch impact strengths, comprising low viscous polyamides and flat glass fibers as a reinforcing medium, characterized in a polyamide matrix, comprising the following components: (A) 0 to 60 wt.-% of at least one aliphatic, partly crystalline polyamide with a solution viscosity, measured in m-cresol (0.5 wt-%), of

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