{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T09:37:55Z","timestamp":1768815475229,"version":"3.49.0"},"reference-count":35,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2021,6,25]],"date-time":"2021-06-25T00:00:00Z","timestamp":1624579200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Energies"],"abstract":"<jats:p>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\u201349.0 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).<\/jats:p>","DOI":"10.3390\/en14133825","type":"journal-article","created":{"date-parts":[[2021,6,25]],"date-time":"2021-06-25T11:07:40Z","timestamp":1624619260000},"page":"3825","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Valorization of Lignin Side-Streams into Polyols and Rigid Polyurethane Foams\u2014A Contribution to the Pulp and Paper Industry Biorefinery"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6853-9921","authenticated-orcid":false,"given":"Jo\u00e3o A.","family":"Pinto","sequence":"first","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"},{"name":"Laboratory of Separation and Reaction Engineering (LSRE), Associate Laboratory LSRE-LCM, Department of Chemical Engineering, Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0069-4503","authenticated-orcid":false,"given":"Isabel P.","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]},{"given":"Virginia D.","family":"Pinto","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]},{"given":"Elson","family":"Gomes","sequence":"additional","affiliation":[{"name":"Laboratory of Separation and Reaction Engineering (LSRE), Associate Laboratory LSRE-LCM, Department of Chemical Engineering, Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4397-5399","authenticated-orcid":false,"given":"C\u00e1tia F.","family":"Oliveira","sequence":"additional","affiliation":[{"name":"Laboratory of Separation and Reaction Engineering (LSRE), Associate Laboratory LSRE-LCM, Department of Chemical Engineering, Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"given":"Paula C. R.","family":"C. R. Pinto","sequence":"additional","affiliation":[{"name":"Laboratory of Separation and Reaction Engineering (LSRE), Associate Laboratory LSRE-LCM, Department of Chemical Engineering, Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"RAIZ\u2014Forest and Paper Research Institute, Rua Jos\u00e9 Estev\u00e3o N\u00ba 221, 3800-783 Eixo, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2385-4282","authenticated-orcid":false,"given":"Lu\u00eds M. R.","family":"Mesquita","sequence":"additional","affiliation":[{"name":"Institute for Sustainability and Innovation in Structural Engineering (ISISE), Polytechnic Institute of Bragan\u00e7a, Campus Santa Apol\u00f3nia Ap. 1134, 5300-253 Bragan\u00e7a, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2834-0501","authenticated-orcid":false,"given":"Paulo A. G.","family":"Piloto","sequence":"additional","affiliation":[{"name":"Associate Laboratory of Energy, Transports and Aeronautics\u2014Institute of Science and Innovation in Mechanical and Industrial Engineering (LAETA-INEGI), Polytechnic Institute of Bragan\u00e7a, Campus Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0715-4761","authenticated-orcid":false,"given":"Al\u00edrio E.","family":"Rodrigues","sequence":"additional","affiliation":[{"name":"Laboratory of Separation and Reaction Engineering (LSRE), Associate Laboratory LSRE-LCM, Department of Chemical Engineering, Faculty of Engineering of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6844-333X","authenticated-orcid":false,"given":"Maria-Filomena","family":"Barreiro","sequence":"additional","affiliation":[{"name":"Centro de Investiga\u00e7\u00e3o de Montanha (CIMO), Instituto Polit\u00e9cnico de Bragan\u00e7a, Campus de Santa Apol\u00f3nia, 5300-253 Bragan\u00e7a, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,25]]},"reference":[{"key":"ref_1","unstructured":"(2021, January 08). European Commission Green Deal: Commission Adopts New Chemicals Strategy towards a Toxic-Free Environment. Available online: https:\/\/ec.europa.eu\/info\/strategy\/priorities-2019-2024\/european-green-deal_en."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"109977","DOI":"10.1016\/j.rser.2020.109977","article-title":"Circular economy aspects of lignin: Towards a lignocellulose biorefinery","volume":"130","author":"Garlapati","year":"2020","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"117718","DOI":"10.1016\/j.jclepro.2019.117718","article-title":"Social life cycle assessment methodology for evaluating production process design: Biorefinery case study","volume":"238","author":"Cadena","year":"2019","journal-title":"J. Clean. Prod."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"110613","DOI":"10.1016\/j.rser.2020.110613","article-title":"The synergy between stakeholders for cellulosic biofuel development: Perspectives, opportunities, and barriers","volume":"137","author":"Leibensperger","year":"2021","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"645","DOI":"10.3934\/energy.2018.4.645","article-title":"Analysing stakeholders\u2019 perspectives towards a socio-technical change: The energy transition journey in Gela Municipality","volume":"6","author":"Falcone","year":"2018","journal-title":"AIMS Energy"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"565","DOI":"10.3389\/fchem.2019.00565","article-title":"About Making Lignin Great Again\u2014Some Lessons from the Past","volume":"7","author":"Glasser","year":"2019","journal-title":"Front. Chem."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Rodrigues, A.E., Pinto, P.C.D.O.R., Barreiro, M.F., Da Costa, C.A.E., Da Mota, M.I.F., and Fernandes, I. (2018). An Integrated Approach for Added-Value Products from Lignocellulosic Biorefineries. An Integrated Approach for Added-Value Products from Lignocellulosic Biorefineries, Springer International Publishing.","DOI":"10.1007\/978-3-319-99313-3"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1276","DOI":"10.1016\/j.cherd.2009.05.008","article-title":"An integrated process to produce vanillin and lignin-based polyurethanes from Kraft lignin","volume":"87","author":"Zabkova","year":"2009","journal-title":"Chem. Eng. Res. Des."},{"key":"ref_9","first-page":"1223","article-title":"Oxidative Depolymerizaton of Kraft Lignin and its Application in the Synthesis of Lignin-phenol- formaldehyde Resin","volume":"13","author":"Ma","year":"2017","journal-title":"Bioresources"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2385","DOI":"10.1039\/C5GC02876K","article-title":"Hydrolytic liquefaction of hydrolysis lignin for the preparation of bio-based rigid polyurethane foam","volume":"18","author":"Mahmood","year":"2016","journal-title":"Green Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1016\/j.indcrop.2019.02.035","article-title":"Lab-scale structural insulated panels with lignin-incorporated rigid polyurethane foams as core","volume":"132","author":"Zhang","year":"2019","journal-title":"Ind. Crop. Prod."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Alinejad, M., Henry, C., Nikafshar, S., Gondaliya, A., Bagheri, S., Chen, N., Singh, S.K., Hodge, D.B., and Nejad, M. (2019). Lignin-Based Polyurethanes: Opportunities for Bio-Based Foams, Elastomers, Coatings and Adhesives. Polymers, 11.","DOI":"10.3390\/polym11071202"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1186\/s10086-020-01872-5","article-title":"Effect of incorporation of lignin as bio-polyol on the performance of rigid lightweight wood\u2013polyurethane composite foams","volume":"66","author":"Luo","year":"2020","journal-title":"J. Wood Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"111887","DOI":"10.1016\/j.indcrop.2019.111887","article-title":"Fractionation and oxypropylation of corn-stover lignin for the production of biobased rigid polyurethane foam","volume":"143","author":"Li","year":"2020","journal-title":"Ind. Crop. Prod."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Zhang, X., Jeremic, D., Kim, Y., Street, J., and Shmulsky, R. (2018). Effects of Surface Functionalization of Lignin on Synthesis and Properties of Rigid Bio-Based Polyurethanes Foams. Polymers, 10.","DOI":"10.3390\/polym10070706"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2583","DOI":"10.1021\/ie801251r","article-title":"Optimization Study of Lignin Oxypropylation in View of the Preparation of Polyurethane Rigid Foams","volume":"48","author":"Cateto","year":"2009","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1080\/02773813.2011.652795","article-title":"Kraft Lignin-Based Rigid Polyurethane Foam","volume":"32","author":"Li","year":"2012","journal-title":"J. Wood Chem. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"111882","DOI":"10.1016\/j.indcrop.2019.111882","article-title":"Synthesis of thermal insulating polyurethane foams from lignin and rapeseed based polyols: A comparative study","volume":"143","author":"Pinto","year":"2020","journal-title":"Ind. Crop. Prod."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s10965-020-02228-9","article-title":"Production and characterization of rigid polyurethane foam by oxypropylation of organosolv lignin extracted from exhausted olive pomace","volume":"27","author":"Abid","year":"2020","journal-title":"J. Polym. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.eurpolymj.2015.04.030","article-title":"Preparation of bio-based rigid polyurethane foam using hydrolytically depolymerized Kraft lignin via direct replacement or oxypropylation","volume":"68","author":"Mahmood","year":"2015","journal-title":"Eur. Polym. J."},{"key":"ref_21","first-page":"17898","article-title":"Application of Enzymatically Treated Lignin Oligomers as Lignopolyols For A Full Replacement of Commercial Polyols in Polyurethane Foam Formulation","volume":"24","author":"Ihalainen","year":"2019","journal-title":"Biomed. J. Sci. Tech. Res."},{"key":"ref_22","first-page":"137","article-title":"An Overview on the Use of Lignin and Its Derivatives in Fire Retardant Polymer Systems","volume":"Volume 32","author":"Poletto","year":"2018","journal-title":"Lignin-Trends and Applications"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1007\/s10086-018-1701-4","article-title":"Lignosulfonate\/APP IFR and its flame retardancy in lignosulfonate-based rigid polyurethane foams","volume":"64","author":"Lu","year":"2018","journal-title":"J. Wood Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"715","DOI":"10.32604\/JRM.2018.00028","article-title":"Oxypropylation of Brazilian Pine-Fruit Shell Evaluated by Principal Component Analysis","volume":"6","author":"Jo","year":"2018","journal-title":"J. Renew. Mater."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0926-6690(99)00039-4","article-title":"Oxypropylation of sugar beet pulp. 1. Optimisation of the reaction","volume":"12","author":"Pavier","year":"2000","journal-title":"Ind. Crop. Prod."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"112542","DOI":"10.1016\/j.indcrop.2020.112542","article-title":"Analysis of the oxypropylation process of a lignocellulosic material, almond shell, using the response surface methodology (RSM)","volume":"153","author":"Pinto","year":"2020","journal-title":"Ind. Crop. Prod."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Klapiszewski, \u0141., Szalaty, T.J., and Jesionowski, T. (2018). Depolymerization and Activation of Lignin: Current State of Knowledge and Perspectives. Lignin-Trends and Applications, IntechOpen.","DOI":"10.5772\/intechopen.70376"},{"key":"ref_28","first-page":"133","article-title":"Small phenolic compounds production from Kraft black liquor by lignin depolymerization with different catalytic agents","volume":"57","author":"Erdocia","year":"2017","journal-title":"Chem. Eng. Trans."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1016\/j.reactfunctpolym.2007.05.004","article-title":"Methods for polyurethane and polyurethane composites, recycling and recovery: A review","volume":"67","author":"Zia","year":"2007","journal-title":"React. Funct. Polym."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/j.jaap.2016.05.015","article-title":"Thermal degradation study of pure rigid polyurethane in oxidative and non-oxidative atmospheres","volume":"120","author":"He","year":"2016","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_31","first-page":"353","article-title":"Thermal degradation of lignin\u2014A review","volume":"44","author":"Brebu","year":"2010","journal-title":"Cellul. Chem. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1002\/(SICI)1097-0126(199811)47:3<247::AID-PI966>3.0.CO;2-F","article-title":"Thermal degradation of polyurethanes containing lignin studied by TG-FTIR","volume":"47","author":"Hirose","year":"1998","journal-title":"Polym. Int."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/j.biortech.2012.11.081","article-title":"Online evolved gas analysis by Thermogravimetric-Mass Spectroscopy for thermal decomposition of biomass and its components under different atmospheres: Part I. Lignin","volume":"130","author":"Shen","year":"2013","journal-title":"Bioresour. Technol."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Ahmad, Z., Al Dajani, W.W., Paleologou, M., and Xu, C.C. (2020). Sustainable Process for the Depolymerization\/Oxidation of Softwood and Hardwood Kraft Lignins Using Hydrogen Peroxide under Ambient Conditions. Molecules, 25.","DOI":"10.3390\/molecules25102329"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1002\/fam.949","article-title":"Development of fire-retarded materials\u2014Interpretation of cone calorimeter data","volume":"31","author":"Schartel","year":"2007","journal-title":"Fire Mater."}],"container-title":["Energies"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1073\/14\/13\/3825\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:23:58Z","timestamp":1760163838000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1073\/14\/13\/3825"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,6,25]]},"references-count":35,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2021,7]]}},"alternative-id":["en14133825"],"URL":"https:\/\/doi.org\/10.3390\/en14133825","relation":{},"ISSN":["1996-1073"],"issn-type":[{"value":"1996-1073","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,6,25]]}}}