Innovative fire and water insulation foam using recycled plastic bags and expanded polystyrene (EPS)

In recent decades, there has been a significant rise in the production and consumption of plastics and polystyrene products (notably Expanded Polystyrene or EPS), and the reuse of their waste nowadays, due to their pollution potentials, has come to the forefront of attention. In this paper, new green building insulation is offered and examined, combining recycled plastic layers and EPS boards. The waste plastic bags turned into plastic sheets during the simple recycling process, and a monolithic EPS was divided into several boards with different thicknesses. Then, the recycled plastic bags were placed between EPS boards. Two composites of plastic sheets and EPS boards were prepared. The first composite consists of three layers (two layers of EPS with a thickness of 20 mm each, and a 10-millimeter plastic layer consisting of 36 recycled plastic bags). The second composite includes five layers (three layers of foam with a thickness of 10 mm each, and two layers of plastic paper, each consisting of 24 recycled plastic bags). All samples were similar in dimension, thickness, foam density, and type. The two new composites were then compared with the control sample in compressive strength, water absorption, and flame spread test. Even though a dramatic reduction of compressive strength has been observed, the results reveal the suitability of both three- and five-layer composites, which considerably improves fire and water resistance compared to the control sample.