Pultrusion of braided and axial reinforced thermplastic prepregs and their non-destructive determination of the void content
Pultrusion is a well established mass production method to continuously and automatically produce axial fibre reinforced profiles with constant cross sections. Today, only profiles with thermosetting matrices found widespread application, although it is well known that thermoplastic matrices offer numerous advantages. One reason is the scepticism of the producers, due to a lack of fundamental understanding of the process. Until now, pultruded profiles with thermoplastic matrices can only be produced with low process speed or with insufficient qualities.
This work has various goals. A better understanding of both the processes of heating of the matrix as well as the impregnation of the glass fibres should be found by experiments and by theoretical calculations. The predominantly used prepreg, a hybrid yarn consisting of glass fibres and polypropylene fibres, offers not only the possibility of the production of unidirectional reinforced profiles, but also the possibility of textile processing. Therefore, the pultrusion process was also combined with a braiding machine, in order to produce pipes with an off-axis reinforcement component.
In order to characterise the quality of the specimens produced, suitable mechanical properties were found, and a method for nondestructive determination of void contents at low fibre volume fractions was developed. This lead to the definition of a quality number, taking into account both mechanical and morphological properties.
Thermoplastics offer the advantage of formability under applied heat. This enables the use of pultruded profiles with thermoplastic matrices in applications with requirements that can not be fulfilled by thermoset pultrudates, e.g. bent profiles for the reinforcement of curved flat structures. A device enabling a continuous production of such profiles was modified and tested.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
Thermoplastics processing, Pultrusion, Nondestructive Testing, Braiding, Forming
Institute / chair: Fachbereich Maschinenbau und Verfahrenstechnik der Universität Kaiserslautern
Technical consultant for expert services: Prof. Dr.-Ing. K. Friedrich (Betreuer), Prof. Dr.-Ing. Dr. h.c. G. W. Ehrenstein
Publication year: 2000
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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