Polypropylene/polyamide-6 blends based on commingled plastic wastes

Abstract

Synthetic polymers possess many advantages, including well-balanced supply, low cost, and good processability compared to other conventional materials, so that these properties have led to useful applications of polymers from cheap daily necessities to expensive industrial composites. However, these polymers, generally obtained from the petrochemical industry have been rarely recovered and reused, causing environmental pollution. These problems can be reduced by either recycling or using biodegradable polymers [1]. Among these, as an economically desirable way of reusing recycled polymeric compounds with satisfactory cost/performances and application potentials, we can recycle mixed waste plastics in the form of blends. This approach of reusing is attractive, because it avoids the difficult task of separating waste plastics [2, 3]. Furthermore, polymer blending techniques have been utilized to improve the performance of polymeric materials by combining the best characteristics of each constituent, making it possible to fit the customers’ specifications at relatively cheap price [4, 5]. Nonetheless one technical problem associated with plastics waste is its heterogeneous composition, immiscibility and poor interfacial adhesion between dispersed phase and matrix, resulting in the polymer blends having poor physicomechanical properties such as low tensile strength and impact toughness [3, 6]. To solve this problem, compatibilizers such as graft or block copolymers are now being used as a well-established route, whose segments can give rise to interactions with the blend components, by not only reducing the interfacial tension but also improving the phase dispersion and adhesion through interpenetration and entanglements at the polymer/polymer interface [6]. In the work described in this letter, using polypropylene (PP)/nylon blend based on commingled polymer wastes which was melt-processed with styreneethylene-butylene-styrene (SEBS) as a compatibilizer, we invetigated the effect of compatibilizer on its fractured surface morphologies, rheological behavior, and mechanical properties. Especially through rheological measurements, we focus on flow behavior of the polymer blends which is of great importance to optimize their processing conditions.