Injection of Polypropylene Reinforced with Short Glass Fibers: Rheological Behavior

Abstract

An experimental study of the thermorheological behavior of polypropylene (PP) reinforced with short glass fibers during the injection processing is described in this paper. This study was carried out using a proprietary rheometer which was designed and developed within our laboratory and is mounted on the injection machine. We have studied the variations of PP viscosity and elasticity, during isothermal flow, as a function of temperature, shear rate and glass fiber content. Furthermore we have studied the influence of the injection thermomechanical parameters during non-isothermal flowing and a pressure drop inside the feed channels and within a molding cavity of cylindrical cross section.

Novel Approach for Modeling the Dynamics of Fiber Breakage in Polymer Matrix Composites during Capillary Extrusion

“…Figure 1 illustrates this explanation. Benhadou et al 8 proposed this idea, suggesting that the fiber breakage process inside the mold runners (Fig. 1a) can be easier studied from capillary extrusion (Fig.…”

Superimposed effects in high‐shear‐rate capillary rheology of polystyrene melt

“…For the purpose of further extending the measuring range to a much higher level (e.g. 10 5 –10 7 s −1 ), the online capillary rheometers have been developed based on the injection‐molding machine [2–4]. It is worthy to note that under high shear rates or high pressures, the increasing influences of the end pressure loss, pressure dependence of the melt viscosity, dissipative heating, and melt compressibility on the capillary flow may evidently affect the reliability of the rheological measurement [5, 6], provided that no proper treatments are applied.…”

“…A few of works have been carried out to characterize the high‐shear‐rate rheological behavior of polymer melt [2–4, 18]. Under the shear rates of about 10 6 s −1 , the degradation of polymer [2], the second Newton plateau [2–4], and shear thickening behavior [4] were observed. Nevertheless, to the best knowledge of the authors, there is a lack of reports on the systematical analyses for the aforementioned four effects in capillary rheology under high shear rates, which may be responsible for the unique rheological behaviors.…”

Rheological and thermal analysis of the filling stage of injection moulding

“…The most important machine parameters are listed in Table 2. There are some instrumented injection moulds [1][2][3][4][5] but the one developed by us is basically different from them. The material enters in the centreline of the mould from the sprue bush and goes to the parting line.…”

“…Many laboratory instruments can be found on the market but only a few of them are suitable for measuring the flow properties of polymeric material in the processing environment. On-line extrusiometers are wide-spread instruments, but injection moulding machines are hardly used for rheological tests [1][2][3][4][5][6]. One of the main goals of our research is to develop a special injection mould which is suitable to determine the rheological properties of polymers at a high deformation rate.…”