Enhanced Dispersion of Particle Additive into Polymers Using Twin Screw Extrusion with Ultrasound Assistance

Most plastics products are made from a base polymer mixed with complex blends of materials known collectively as additives, to ensure that the physical, mechanical and surface properties of the final product is optimised in all aspects. This will include safer, cleaner product possessing optimal colour and properties. Fine additives such as fillers or coloured pigments are most widely used and the improved technique for dispersing particles into polymer is highly demanding in industrial practice. A USV (ultra-sonication and vibration) assisted process during twin screw extrusion system was implemented and the dispersion results tested in our labs and the technology transferred to our industrial partner’s manufacturing facility. Particle additives such as clay, organic and inorganic pigments were compounded and tested using USV assisted twin screw extrusion. Introduction Ultrasonication has long been used as a pre-treatment method for fine particle size distribution due to the important delamination effect which can improve the accuracy of the particle size or morphology measurement (1), In recent years ultrasonication was used to help enhance and extend polymer extrusion properties, via ultrasonic activation effect, to modify the properties at the interface between the molten polymer material and the metallic screw and barrel, allowing thus high speed processing, and at the same time increasing productivity and product quality (2). For the past decade, development by researches of applications using ultrasonications as high frequency sound waves to enhance injection moulding and extrusion has been carried out. There are many publications in form of scientific papers, (3) (4) (5); and patents (CA 2658970 A1, Avraam Isayev, WO 2011161467 A1, Paul Beaney, WO 1993004118 A1, and WO 2001053386 A1, Lanty Patrick De) and there is particular interest to try and disperse fine particulates in polymers at high concentrations. Experimental procedure With the help of project partner Sonic Systems, ultrasonication equipment manufacturers USV assisted twin screw extrusion system was implemented and tested in our lab and the results are presented in this work. Particle additives such as clay, organic and inorganic pigments were compounded using a co rotating intermeshing twin screw extruder with specially designed USV system that could be attached to an open port of the extruder barrel where the polymer melt could come in full contact with the ultrasonic horn.