The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become a 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.
The Papnash pond is an oldest pond of Bidar, Kamataka state. It is situated at 77 degrees-32 longitude and 17 degrees-55 latitude, located 551 m above mean sea level. It has been used daily for bathing and washing of clothes by large number of pilgrims. The samples were collected fortnightly during October 1999 to September 2000 to analyze physico-chemical and biological status of water, such as temperature, pH, total alkalinity, total hardness, dissolved oxygen, free carbon dioxide, chloride, organic matter, nitrite, phosphate, sulphate and algal flora. Variations in physico-chemical parameters were noted. The results also revealed that the pond water was hard, alkaline and polluted. Totally 39 species of algae were reported from the four classes. 相似文献
