Abstract

Abstract

Low flammable foam-like materials based on renewable bio-based polymers and sodium montmorillonite clay (MMT) were created using water as a solvent and following a simple freeze-drying process. Composites were formed by adding layers of the previously created gel precursors to a Polyvinyl alcohol / MMT based aerogel. A multi-step and a one-pot processes were followed to make the multi-layered aerogels, and the resultant properties of the different processing systems were compared. Similar adhesion between layers was observed in both processes although the multi-step required a longer manufacturing time.

With the aim of improving the mechanical properties, chemical crosslinking of the Polyvinyl alcohol base was induced prior to lyophilization by immersing the material in a sodium borate solution. It was found that the mechanical response under compression was enhanced in regards to the non-crosslinked systems. A highly retardant composite material was fabricated by superposing an alginate/MMT at the external layer as the most promising system for fire protection

Abstract

This study aims to develop innovative flame-retardant additives from renewable resources, which will ensure high fire protection, low environmental impact, low toxicity and good processability in conventional polymer manufacturing processes in bio-epoxy matrices.

Abstract

The development of sustainable composites has become in a major strategy for different sectors, such as the offshore renewable energy industry.

Thermoset polyurethanes (PUR) offer some advantages for their use in structural composite parts, like their good thermal properties, adhesion with different types of fibers, ultra-fast curing, low viscosity and corrosion resistance, highlighting their resistance to fatigue and consequent durability. However, PUR have some environmental drawbacks, such as their petrochemical origin and low recyclability.

Consequently, biobased PUR (BIO-PUR) formulated based on polyols derived from vegetable oils have aroused keen interest. Moreover, it is possible to incorporate recycled monomers in their formulation, which are obtained from highly degraded plastics collected from the sea.

In addition, it is necessary to consider the PUR end of life to improve the composite sustainability. An interesting solution is the incorporation of dynamic bonds into the PUR network, with reversible capacity such as Diels-Alder, to improve the polymer recyclability.

Therefore, this work has focused on the development of a new formulation of BIO-PUR with the required mechanical properties for structural applications in the marine environment. In addition, the integration of recycled monomers and DA bonds have been explored to improve the circularity of the developed resin. To this end, aspects ranging from analysis and synthesis to the characterization of the resins have been covered.