Investigation on the Tensile Properties of Virgin and Recycled HDPE for Boatbuilding Applications Through Experimental Tests

The search for novel materials suitable for the construction of boat structures and components has acquired paramount importance in the last few years, driven by technological developments in terms of processes and formulations. Particularly, specific types of plastics have attracted attention due to manufacturing techniques that are able to exploit the material’s mechanical properties at their best while ensuring execution simplicity and precision. This is the case of High-Density Polyethylene, commonly known with its acronym HDPE and increasingly used for the construction of small workboats. The numerous positive features of HDPE for marine applications can be summed up in high flexibility, toughness and durability, anti-corrosion properties, and excellent resistance to marine growth. In addition, HDPE can be recycled in several ways for different applications and may give origin to regenerated polyethylene as well, positioning itself in a market that favours materials capable of increasing the eco-sustainability of the final products. Despite all these benefits, the quite limited knowledge and expertise related to the different formulations of the materials available on the market and the presence of several suppliers can lead to incorrect applications that might jeopardise its large-scale diffusion. Moreover, the properties of regenerated HDPE must be thoroughly investigated to understand its potential scope of use. For these reasons, almost all Ship Classification Societies are still working on proper regulations applicable to this material, with some tentative proposals from RINA and Bureau Veritas. The present paper aims to fit into this context by presenting a mechanical characterisation activity to evaluate tensile properties of both virgin and recycled materials through experimental tests. After describing the different types of HDPE employed, the authors present the testing approach and its results.