On recyclability of thermosetting polymer and wood dust as reinforcement in secondary recycled ABS for nonstructural engineering applications

The management of thermosetting plastic solid waste has become serious issue worldwide due to its highly stable long-chain molecular structure and its recycling is the only way to reduce harmful effects. Also, depletion of natural resources like wood at alarming rate creates worldwide environment issues. In this article, feedstock filament for three-dimensional printing (in nonstructural engineering applications) of thermoplastic composite based on secondary (2 degrees) recycled acrylonitrile butadiene styrene (ABS) as matrix reinforced with waste bakelite powder (BP) (thermosetting) and wood dust (WD) with twin-screw extrusion (TSE) process has been prepared (to impart desired mechanical/thermal/rheological and morphological properties).The results indicated that reinforcement of BP/WD initially increases the melt flow rate (MFR) of composite filament as compared to 2 degrees recycled ABS. However, with increase in percentage of reinforcement beyond a certain limit, the MFR of the composite filaments starts decreasing. The mechanical, rheological, morphological, and thermal properties related to fused filaments prepared by TSE process have been explored in this research work and it has been observed that ABS composite filaments reinforced with 10% by weight of BP possess high peak strength (PS), high energy carrying capacity, more thermal stability, and contains low porosity. Based upon combined optimized extrusion parameter settings for maximizing the PS and percentage break elongation, 10 kg load, 225 degrees C processing temperature, and 70 r min(-1) are the best settings for both the composite filaments (ABS + BP, ABS + WD), and the corresponding values for ABS + BP and ABS + WD composite filament are 30.58 MPa (5.15%) and 25.65 MPa (6.05%), respectively.