Hot consolidated all-PP composites from textile fabrics composed of isotactic PP filaments with different degrees of orientation

Abstract

Abstract. Self-reinforced polypropylene composites (SRPPC) were hot pressed from textile layers (carded mat, knitted fabrics) at three different temperatures (160, 165 and 170°C) by setting a constant pressure (6 MPa) and constant holding time (2 min). Both textiles consist of two kinds of isotactic polypropylene (iPP) fibers differing in their orientation. In these compositions the highly oriented iPP works as reinforcement and the less oriented one fulfills the role of the matrix after hot consolidation. Two textile assemblies, viz. carded (also needle punched) mats and knitted fabrics were hot pressed; and the properties of the resultant SRPPC plates were investigated under tensile and falling weight impact conditions. The microstructure of the SRPPC was analyzed by light microscopy using polished sections and by SEM using cut surfaces.

Modelling of polypropylene fibre-matrix composites using finite element analysis

“…However, for the composite with low fibre content the matrix carried the main proportion of the applied load and tailed when the applied stress reached the matrix yield strength. The large scale yielding of the matrix resulted in increased fibre axial stress [8,9]. This was consistent with the experimental results.…”

“…All-PP composites have been commercialized as PURE ® , a technology from Lankhorst Indutech bv of the Netherlands [8], Milliken and Company, Spartanburg, S.C., introduced Moldable Fabric Technology (MFT), and Curv, produced commercially in Gronau, Germany, by Amoco Fabrics and Fibers Co., a unit of BP Amoco. All-PP composites require a difference between the matrix-PP and the PP fibres that will allow the matrix to consolidate by fusion without changing the fibres, this difference maybe a PP copolymer or even differing orientation [9]. All-PP composites combine by a process analogous to welding [10] and eliminate typical interfacial weakness problems or need for compatabilisers when non-polar PP is used with inorganic fillers [11,12].…”

“…Complicated geometries, loading conditions and material properties often do not yield analytical solutions, due to complexity and the number of equations. In this case, numerical methods are used for approximate solutions, but they still make some simplifying assumptions about the inherent microstructures of heterogeneous multiphase materials, one such method is finite element analysis (FEA) [8,9]. The finite element method is an alternative approach to solving the prevailing equations of a structural problem.…”

Single-polymer composites (SPCs): Status and future trends

“…As a consequence, one-constituent SPCs can also be produced from preforms, like fiber mats, which are composed from the same polymer however with different draw ratios. This was demonstrated by Izer and Bárány [37].…”

Impact resistance of all-polypropylene composites composed of alpha and beta modifications

“…This temperature difference can be widened by various manners of stretching (hot compaction) or difference in the composition (random PP copolymer/PP homopolymer coextrusion, film-stacking). The melting temperature of highly oriented PP fiber is markedly higher than the non-oriented or less oriented one [5].…”