Mechanical and fire characterization of composite material made of polyethylene matrix and dry chemical powder obtained from end-of-life extinguishers

Abstract

A fire extinguisher is a portable element designed to fight emerging fires, with a useful life of around 20 years. After this period, they are withdrawn from the market. All their components (shell, hose, and so on) are usually separated and recycled, except the chemical powder used as extinguishing agent, which usually consists at monoammonium phosphate (MAP), widely used in the production of agricultural fertilizers. Although there are several companies dedicated to this task, in the case of remote areas or islands such as the Canary Islands, there are no options to recycle this component and the shipping is unaffordable. As a result, the companies of this sector (distributors of fire-fighting systems) tend to accumulate them in large quantities. In order to give a second use to this dry chemical powder, this work analyzes its potential as an additive for a polyethylene matrix. This would not only take advantage of a currently unused raw material but would also improve the fire resistance performance of polyolefins thanks to the fireproof properties of the extinguishing agent. Samples with different proportions of dry chemical powder were elaborated and tested to determine their mechanical and fire properties, achieving composites with significant improved fire performance regarding the net matrix.