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Comprehensive insights into lignin oxypropylation reaction
Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Belgacem, N.Polyols resulting from oxypropylation are a mixture of oxypropylated lignin and some low molecular weight products (polypropylene oxide oligomers). Normally these oligomers are left in the final mixture since they constitute useful co-monomers, lowering the Tg and the viscosity of the resulting liquefied lignin. In this work a series of polyols based on Alcell lignin have been produced using L/PO ratios (Lignin...
Polyurethanes as a viable route to valorise lignin
Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Belgacem, M.N.This work presents a study concerning the use of lignin as a macromonomer in polyurethane (PU) synthesis based on four lignin samples (Sarkanda (Granit SA), Indulin AT (MeadWestvaco), Curan 27-11P (BorregaardLigno Tech) and Alcell (Repap Enterprises). They represent three different botanic origins (hardwood, softwood and non-wood), as well as three different pulp processes (kraft, soda and organosolv). The work...
Um processo integrado para produzir compostos fenólicos de elevado valor acresc...
Silva, E.A.B.; Zabkova, M.; Araújo, J.D.; Cateto, C.A.; Barreiro, M.F.; Belgacem, M.N.; Rodrigues, A.E.Neste trabalho, apresenta-se a estratégia que combina a engenharia de reacções e processos de separação para converter lenhina, obtida de licores processuais, em aldeídos de elevado valor acrescentado. O principal resultado é um processo integrado de produção de vanilina a partir de lenhina Kraft. O processo de integração é baseado em três etapas principais. A primeira etapa consiste na oxidação alcalina da len...
Rigid polyurethane foams from lignin based polyols
Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Belgacem, M.N.Rigid polyurethane (RPU) foams were synthesized using lignin-based polyols obtained by an oxypropylation process. Alcell, Indulin AT, Curan 27-11P and Sarkanda lignins have been oxypropylated using formulations deduced from an optimization study with Alcell. L/PO/C (ratio between lignin, PO and catalyst content) of 30/70/2 and 20/80/5 were used to obtain the desired polyols. The resulting RPU foams were charact...
Lignin-based polyurethane materials
Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Belgacem, M.N.Four technical lignins (Alcell, Indulin AT, Sarkanda and Curan 27-11P) were used as macromonomers in the synthesis of polyurethane materials following two global approaches. In the first one Alcell and Indulin AT lignins were used directly as co-monomers in combination with a linear polycaprolactone (PCL) in order to produce polyurethane elastomers where lignin content varied between 10 and 25% (w/w) with respe...
Monitoring of lignin-based polyurethane synthesis by FTIR-ATR
Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.FTIR (Fourier Transform Infrared Spectroscopy), working in ATR (Attenuated Total Reflectance) mode was applied to study the formation of lignin-based polyurethanes. Although some studies related to the use of lignins in polyurethane synthesis, are available in literature, still persist a gap for a systematic study of this kind of systems involving the measurement of kinetic data, optimization and modelling of t...
Bio-based composite materials from olive stone
Sibaja, M.; Alvarado, P.; Jiménez, L.; Rojas, O.; Barreiro, M.F.; Cateto, C.A.; Rodrigues, A.E.; Lopretti, M.The present work describes the methodology used for the preparation and characterization of composite samples prepared by mixing various percentages of olive stone flour in a polyester resin matrix. A study on the chemical-physical properties of the olive stone is reported, as well as, a set of tests to evaluate the mechanical properties of the manufactured products obtained. Biodegradation studies were carried...
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