Browsing by Author "Gomes, Elson"
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- Polyols and rigid polyurethane foams derived from lignin side-streams of the pulp and paper industryPublication . Fernandes, Isabel P.; Pinto, João A.; Gomes, Elson; Oliveira, Cátia F.; Pinto, Paula C.R.; Mesquita, L.M.R.; Piloto, P.A.G.; Rodrigues, Alírio; Barreiro, M.F.Lignin is one of the major components of the side-streams of the pulp and paper industries and of the emerging lignocellulosic biore neries. Find new strategies for lignin valorisation, apart from e vironmental issues, will contribute to close the lignocellulosic value-chain. In this context, this work will focus on the synthesis of polyols through oxypropylation and their subsequent incorporation into rigid polyurethane (RPU) foam formulations. Two E. globulus lignin streams were tested: (i) lignin isolated from industrial kraft liquor and (ii) depolymerized lignin resulting from an oxidation process developed at the LA LSRE-LCM to produce vanillin and syringaldehyde. This work is therefore part of the LA LSRE-LCM global strategy towards the consolidation of the integrated process to valorise lignin from the kraft pulp industry, which accounts with more than 25 years of experience.
- Valorization of lignin side-streams into polyols and rigid polyurethane foams—a contribution to the pulp and paper industry biorefineryPublication . Pinto, João A.; Fernandes, Isabel P.; Pinto, Virgínia; Gomes, Elson; Oliveira, Cátia F.; Pinto, Paula C.R.; Mesquita, L.M.R.; Piloto, P.A.G.; Rodrigues, Alírio; Barreiro, M.F.Valorization of industrial low-value side-streams are of great interest, contributing to boosts in the circular economy. In this context, lignin side-streams of the pulp and paper industry were oxypropylated to produce biobased polyols and tested in the synthesis of rigid polyurethane (RPU) foams. E. globulus lignins, namely a lignin isolated from an industrial Kraft black liquor and depolymerized lignins obtained as by-products of an oxidation process, were used. RPU foams, synthesized with 100% lignin-based polyols and using a 1.1 NCO/OH ratio, were characterized concerning apparent density, morphology, thermal conductivity, thermal stability, and heat release rate (HRR). Foams containing the lignin-based polyols presented densities varying from 44.7 to 112.2 kg/m3 and thermal conductivity in the range of 37.2–49.0 mW/mK. For the reference foam (sample produced with 100% wt. Daltofoam TP 32015 polyol), values of 70.9 kg/m3 and 41.1 mW/mK were obtained, respectively. The achieved results point out the viability of using the generated lignin-based polyols at 100% content in RPU foams, mainly when depolymerized lignins are used. Moreover, fire retardancy was favored when the lignin-based polyols were introduced. The proposed strategies can contribute to establishing the integrated pulp and paper biorefinery concept where material synthesis (polyols and RPU foams) can be combined with chemical production (vanillin and syringaldehyde).