Olof Frisk Fibre damage in WPC for two different compounding processes WSE2016 Riga
Presentation WPC&NFC Compounding techniques The challange The fibre Methods Overview
Olof Frisk 50% Industrial PhD student at KTH Byma since jan 2015, part of the EnWoBio group Civilingengör LiTH 1981 Exportrådet Wienna (Swedish Trade Office) Nynäs Petroleum (Process oil industry) Perstorp (High pressure laminate) Since 1992 self employed at OFK Innovation OFK Plast 2008 (2015), recycling, compounding WPC, profile extrusion Novoplast 2015 recycling, compounding
Novoplast
Overall objectives with my research New building materials and processing methods in biocomposites with enhanced thermal and mechanical properties for structural applications. Thermoplastic processing techniques should be applied for products such as profile extrusion and injection moulding.
WPC, NFC Wood plastics or Natural fibre composites is defined as a bio-based material or product made thereof, being the result of the combination of one or several cellulosic materials with one or several thermoplastics or thermosets and being or to be processed through plastic processing techniques. Source: CEN/TS 15534-1 (2007). Changes made by OF
WPC Wood particles, wood flour, as reinforcement combined with a synthetic or bio-based polymer as matrix Heat and pressure Injection moulding Profile extrusion
Compression moulding common for NFC
Woodflour vs TMP (CTMP) Aspect Ratio, L/D, is greater than 10 for a fibrous material, typically greater than 50. Woodflour typically less than 5!
Mixing fibre in a compounder Distributive mixing Dispersive mixing
WPC compounding Segmented screws on a spline. Mainly used for compounding into pellets Hollow, full length screws. Mainly used for profile extrusion, fed with compounds but also for compounding with preblends and for direct extrusion
Corotating extruder principle Polymer&additives Fiber inlet Often two vent zones with one vacuum
Internal batch mixer (new tech)
Internal batch mixer Tempearture controle High fill loadings Water reduction Low bulkdensity possible Batchfeeding & up scaling to production rate possible Price!
The feeding challenge with TMP
Fiber breakage challenge In order to concider fibre-based bicomposites for structural application, it is critical to enhance their mecanical and thermal properties while maintaining or improving their processing. Severe fiber breakage and loss of properties at fiber loading greater than 30%-40%, in strength, have previously been reported.
Fiber breakage for pulp Cellulose fibre dimensions before and after different processing steps. Sample Length (mm) Diameter (mym) Aspect ratio Kraft pulp 2.02 31.0 65 PP-KC40 0.98 27.9 35 PP-KC50 1.01 28.0 36 PP-KC60 0.83 28.1 30
Research stage one To establish whether internal batch mixing is comparable or even superior to traditional compounding with a co-rotating twin screw extruder
Compounding Trials has been made by compounding a commercial TMP, 40% per weight, with HDPE in a corotating lab extruder. A MAPE was added but no lubricants Same formulation compounded in an internal batch mixer with 40, 60, 70, and 80% TMP fibre.
To establish the fiber breakdown and fiber distribution in each compounding process, a method for extraxtion in boiling xylene was devloped to remove the matrixe. Extraction
Remaining research and evaluation! The extracted fibres will be measured in a PulpEye analyzer. Length, thickness and distribution. Mecanical properties has been measured on injection moulded probe bars, fibre content of 40%. Prel results autumn 2016, ready for publication
Further trials & research A small corotating compounder has been purchased by Novoplast (W&P ZDS 53) for further trials. Ready for use autumn 2016 Feeding development Improve creep behavier in the composit
Thats it! Thank you for your attention! Questions?