Electric and electronic equipment waste: reuse in elastomeric composites

In the context of an imperious necessity to reduce the high amount of electric and electronic equipment waste, mainly by recycling also the plastics, not only the noble metals, the paper aims to reuse as reinforcing fillers some blends of polystyrene fraction of WEEE and the non-metallic part of printed circuit boards (WPCB). Elastomeric materials based on a styrene-butadiene block-copolymer that can be used as masterbatch for shoe sole materials are targeted. An improved processability is achieved using a paraffin-naphthenic oil. By optical microscopy, dispersed oil drops are observed into the homogeneous structures obtained based on the compatibility between WEEE and polystyrene blocks of elastomer and WPCB functionalities with polybutadiene phase. Physical interactions between the components are evidenced by FTIR. The variation of the tensile stress-strain curves is influenced by the waste dosages. The mechanical properties decrease with increasing the waste dosage, but maintaining the properties for the targeted application until 15-20% filler blend. The hardness of composites is direct proportional with the waste amount. By ESEM, some discontinuities and brittle interface between glass fibers and polymer matrix suggest the failure mechanism of composites. By dynamo-mechanical analysis and differential scanning calorimetry, changes in glass transition temperatures of polystyrene and polybutadiene resulted due to the certain compatibility between high molecular mass polystyrene from WEEE and polystyrene phase and the dilution of polybutadiene phase with epoxy-glass fibers filler from WPCB. The reinforcing effect leads to an increase of storage modulus and viscosity. Analyzing the results, it can be concluded that new materials for the production of shoe soles are obtained using oil extended styrene-butadiene block-copolymer and 15-20% blends of WEEE and WPCB.

Automated summary

The paper aims to reuse polystyrene fraction of WEEE and non-metallic part of printed circuit boards as reinforcing fillers for shoe sole materials. By adding paraffin-naphthenic oil, improved processability is achieved. The mechanical properties of the materials decrease with increasing waste dosage, but properties for the targeted application are maintained until 15-20% filler blend. The addition of waste leads to an increase in storage modulus and viscosity, indicating a reinforcing effect.