Fiber- and property-degradation during processing and recycling of discontinuous fiber-reinforced plastics
Fibre damage may occur by discontinuous fibre reinforced plastics during the compounding process as well as during their processing leading up until the finished fabricated part through interaction either between fibres, between fibres and the machine’s components or also through additives (e.g. colour pigments). These interactions manifest themselves in the reduction of the average fibre length, which is present in the finished unit. Fibre strength testing has been so far either not possible or is limited due to suitable testing methods with low slenderness ratios of already processed fibres being unavailable. Experimental determination of single fibre strength is now possible with the help of a micro-bending machine developed at the Chair of RPE. This therefore offers the possibility to investigate and quantify the damage behaviour of the mostly brittle fibre material beyond the processing stage. Since the remaining fibre strength can now be determined in discontinuously reinforced parts, a gap in the calculations has been bridged and a broader knowledge about combined effects during the fibre damage has been obtained.
The damage progression of the fibres during dyeing, whose pigments are harder than the fibre material, is quantitatively shown from the processing steps up to the specimen. The loss of compound qualities can be explained by the fibre weakening in connection with the fibre breakage now enforced during processing. The multiplicity of tests helps to empirically describe the correlations and to give first explanations. The knowledge of these fundamental facts offers the possibility to deduce rules and actions to avoid the excessive fibre damage during the dyeing process.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
fibre damage, fibre strength, micro-bending test, pigments, reinforced plastics
Institute / chair: Fachbereich Maschinenbau und Verfahrenstechnik der Universität Kaiserslautern
Technical consultant for expert services: Prof. Dr.-Ing. Rainer Renz (Betreuer), Prof. Dr.-Ing. Dr. h.c. Klaus Friedrich
Publication year: 2002
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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