Thermoplastics can melt under heat by EPS melting machine, hence the waste generated in the process or that resulted from the end-of-life of products can be easily recycled. In simple terms, thermoplastic wastes such as those from EPS products can be milled in to a powder and blended with cement, sand and wire mesh to produce sandwich blocks. Yet, this causes a large drop in the polymer molecular weight due to thermal degradation. In addition, the ensuing material has very different characteristics when compared to the original one. Nonetheless, similar to the thermoset polymers, thermoplastic materials such as EPS can be recycled using chemical approaches.
One easy way of recovering polymers is by using appropriate solvents. These solvents must have the ability to dissolve the polymer with negligible degradation of their properties. As example, toluene was used as solvent to recycle EPS and it was proved to be more effective than benzene, ethylbenzene or p-xylene, at 360 ºC for 20 min . Another option is to use metal-based catalysts at 300–450 ºC. Using this process styrene monomer is obtained with a high selectivity using relative low temperature. Furthermore, oxides such as MgO, CaO or BaO can be used as catalysts. In fact, using BaO it was observed a 90 wt. % conversion of PS into styrene. Similarly to the PU recycling reactions, in all these chemical approaches, purification may be required.
Afterwards, the recycled products can be used as partial substitute of the petroleum-based styrene monomer to produce PS products. However, during these approaches, the material loses its cellular structure. Thus, to produce recycled EPS by EPS melting machine, it is necessary to blend the recycled PS resin with the expanding agent. This can be achieved using i.e. co-extrusion. The ensuing recycled beads can be molded into new and recycled EPS products.
Similar to the approach used in PUF, LCA is essential to evaluate the benefits of the recycling EPS. From the results available in literature, it can be observed that the manufacturing process of EPS is the major contributor of the overall environmental impacts while recycling has the lower impact. From these observations, it is concluded that recycling is in fact a suitable alternative to the disposal of EPS wastes
Related Post
Small EPS briquette machine for recycling stations
2022.06.17
EPS waste needs to be shredded before melting ?
2024.02.5
What are some common types of EPS shredders used i...
2024.01.26
How to recycle the EPS foam waste?
2022.02.6
What are some common patterns or configurations us...
2024.01.30
how to recycle EPS trimming from EPS block cutting...
2024.03.28
Leave a Reply