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The high versatility of polyurethanes (PU’s) is encouraging the development of new formulations for new applications, like their use as a matrix for structural composites. PU’s based technology offers some advantages, such as fatigue resistance and fast curing cycles. However, their high reactivity hinders some manufacturing processes like Resin Transfer Moulding (RTM). This work aimed to achieve a PU resin (PUR) formulation with the required latency and reactivity for the RTM. For this purpose, different catalytic systems based on an epoxide and LiCl were investigated. The reactivity of the systems was evaluated through Differential Scanning Calorimetry (DSC) and rheology tests, and the curing reaction and viscosity were modelled. Furthermore, the RTM process of a representative composite part was simulated. Results demonstrated the processability improvements when the LiCl was incorporated into the isocyanate component of the formulation combined with a monool or a diol. It was observed that these combinations contribute to the encapsulation of the LiCl between the as formed urethane groups by hydrogen bonding, providing the desired latency and acting as a delayed action catalyst. Once the reaction started and the encapsulation was deactivated, an alkoxide was formed to act as a catalyst. Encapsulation was more effective with the diol, providing a higher latency.

Hybrid biobased polyurethane flexible foam composites containing a residue from surf industry (polyurethane powder) as filler and graphite or graphene residue were synthesized. It was observed that the addition of the powder at low contents did not modify the final properties considerably, since the cell structure was not compromised. Moreover, the powder increased the capacity of the foams to retain the carbonaceous fillers. The compressive properties of the hybrid foams were not altered with the addition of the graphite and graphene. Finally, hybrid composites showed selective absorption capacity since the presence of the carbonaceous fillers provided the foams oil absorption capacity without modifying the hydrophobic nature of the matrix foams.

As a consequence of the high production and simultaneous consumption of polyurethanes (PU) a great volume of PU waste is landfilled. In this scenario, suitable and efficient routes for PU waste recycling have been searched for many years. In this work two series of PUs using different recycled PU sources were synthesized: a thermoplastic PU series using a glycolysated polyol obtained from the glycolysis of elastomeric PU waste (chemical recycling) and a PU flexible foam series loaded with PU dust waste created in the shaping of PU surf tables (mechanical recycling). Results showed that the incorporation of recycled components in the formulation improved mechanical properties both in the case of thermoplastic polyurethanes and polyurethane foams. The optimum glycolysated polyol was fixed in 15% over the total polyol weight for thermoplastic PUs. In the case of foams, a maximum of 20% PU dust over the polyol weight was incorporated.

Precursors have been satisfactorily synthesized from lignocellulosic biomass for later use in the synthesis of polyurethanes resulting in competitive final properties with those of petroleum derived polyurethanes.