Recycling polymeric waste from electronic and automotive sectors into value added products
Abhishek Kumar1, Veena Choudhary1, Rita Khanna2(), Romina Cayumil2, Muhammad Ikram-ul-Haq2, Veena Sahajwalla2, Shiva Kumar I. Angadi3, Ganapathy E. Paruthy3, Partha S. Mukherjee3, Miles Park4
1. Centre for Polymer Science and Engineering, Indian Institute of Technology Delhi, Hauz Khas New Delhi 110016, India 2. Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney NSW 2052, Australia 3. CSIR- Institute of Minerals and Materials Technology, Advanced Materials Technology Department, Bhubaneshwar, Orissa 751013, India 4. Industrial Design, Australian School of Architecture and Design, The University of New South Wales, Sydney NSW 2052, Australia
• Polymer fraction was separated from waste PCBs by froth floatation.
• Addition of waste PCBs to polypropylene reduced the overall impact strength.
• Up to 9 wt.% rubber was added to PP/25 wt.% PCB composites as impact modifier.
• Mechanical, structural, rheological properties of composites were investigated.
• Electronic and automotive waste were successfully utilized in PP composites.
The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become global waste management issue. The addition of up to 25% polymeric waste PCBs (printed circuit boards) as fillers in polypropylene (PP) composites was partially successful: while the tensile modulus, flexural strength and flexural modulus of composites were enhanced, the tensile and impact strengths were found to decrease. As a lowering of impact strength can significantly limit the application of PP based composites, it is necessary to incorporate impact modifying polymers such as rubbery particles in the mix. We report on a novel investigation on the simultaneous utilization of electronic and automotive rubber waste as fillers in PP composites. These composites were prepared by using 25 wt.% polymeric PCB powder, up to 9% of ethylene propylene rubber (EPR), and PP: balance. The influence of EPR on the structural, thermal, mechanical and rheological properties of PP/PCB/EPR composites was investigated. While the addition of EPR caused the nucleation of the β crystalline phase of PP, the onset temperature for thermal degradation was found to decrease by 8%. The tensile modulus and strength decreased by 16% and 19%, respectively; and the elongation at break increased by ~71%. The impact strength showed a maximum increase of ~18% at 7 wt.%–9 wt.% EPR content. Various rheological properties were found to be well within the range of processing limits. This novel eco-friendly approach could help utilize significant amounts of polymeric electronic and automotive waste for fabricating valuable polymer composites.
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