Analysis of the emission- and odour-behaviour of biofibre-reinforced polyamide in correlation with the conditions during processing
Final Report Abstract
Within the scope of the project, composites with cellulose regenerated fibers based on bio polyamide as matrix material were produced on a twin-screw extruder and characterized with regard to mechanical and thermo-mechanical parameters, emissions and odor properties. Special attention was paid to the optimization of the processing procedures with regard to emission reduction and improvement of odor properties in order to be able to use the corresponding material combinations in vehicle interiors. The investigation of different cellulose fibers showed that the cellulose regenerated fiber Cordenka (CRF) performed best in terms of odor evaluation. It was also found that the odor properties (odor grade, odor level) become worse with increasing CRF fiber content and are dependent on the temperature of the melt. For the odor level, a significant correlation with the torque was found. By reducing the torque, a reduction in the odor level can be achieved by means of a temperature increase at lower speeds. With respect to the odor properties for cellulose fiber (CRF) and glass fiber (GF) composites, a processing window with speed range, temperature range, throughput could be defined. In the project, a method for determining the VOC emissions of Bio-PA was developed and validated, since conventional methods did not produce results. Comparative measurements showed that the VOC emissions of Bio-PA composites, in contrast to other material composites such as PP-GF, are at a significantly low level, but the results of the odor tests are usually above the required limits. After compounding, the odor can be further improved by further processing steps (e.g. thermal stress due to injection molding process), but in this case the VOC emissions of PA-CRF composites increase with increasing fiber content. By varying the screw configuration, no significant correlations to mechanical properties, odor and VOC emissions could be found. PA 6.10 and PA 10.10 behave differently due to the ratio of the CH2/CO-NH groups, especially with regard to the melting temperature and water absorption. Moisture leads to poorer odor grades and increased odor levels and VOC emissions, especially for CRF composites. When PA 6.10 was used as the matrix material, it was found that VOC emissions were higher for GF composites than for CRF composites; when PA 10.10 was used as the matrix material, VOC emissions were higher for CRF composites. As part of the project, an emission chamber was developed with which emissions can be sampled directly in the extrusion process, transferred to absorbent or collected in sample bags. This allows odor and emission samples to be measured directly without further sample preparation.
Publications
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Project Presentation - Emission and Odor Analysis of Natural Fiber reinforced bio-based Polyamide, In: 20th Conference Odour and Emissions of Plastic Materials, 20-21 March 2018, Kassel
Wolff, S. & Heim, H.-P.
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Influence of Processing Parameters on Odor Characteristics of Compounds produced from renewable Raw Materials, In: 22nd Conference Odour and Emissions of Plastic Materials, 2-3 March 2020, Kassel
Wolff, S.; Dörr, C. & Heim, H.-P.
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Odor and Emission Characteristics of cellulose Bio-Polyamide Compounds, In: 23nd Conference Odour and Emissions of Plastic Materials, 23-24 March 2021, Kassel
Wolff, S.; Dörr, C.; Schulz, G. & Heim, H.-P.
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Influence of Processing Glass-Fiber Filled Plastics on Different Twin-Screw Extruders and Varying Screw Designs on Fiber Length and Particle Distribution. Polymers, 14(15), 3113.
Rüppel, Annette; Wolff, Susanne; Oldemeier, Jan Philipp; Schöppner, Volker & Heim, Hans-Peter
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The impact of accelerated aging on the mechanical and thermal properties and VOC emission of polypropylene composites reinforced with glass fibers. International Polymer Processing, 38(1), 111-125.
Rüppel, Annette; Wolff, Susanne & Heim, Hans-Peter
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Emission and Mechanical Properties of Glass and Cellulose Fiber Reinforced Bio-Polyamide Composites. Polymers, 15(12), 2603.
Wolff, Susanne; Rüppel, Annette; Rida, Hassan Ali & Heim, Hans-Peter
