33 research outputs found
Biodegradation study of I lignin-based rigid polyrethane foams
Polyurethanes are considered as one of the most versatile polymeric materials offering a wide range of products with applications in diverse sectors. Rigid polyurethane (RPU) foams belong to this class of products and represent a commercially important class of expanded materials. In the present work RPU foams have been prepared from lignin-based polyols (LP) obtained by oxypropylation of two technical lignins (Alcell and Indulin AT) and biodegradability evaluated using respirometry tests in liquid and solid media. A RPU foam produced from a commercial polyether polyol (CP) based on sorbitol (Lupranol® 3323) was used as reference. Lignin biodegradation by P. chrysogenum, T. harzianum, T. reesei, T. versicolor and P. chrysosporium fungi was tested. Respirometry tests (in liquid and solid media) were performed and foam’s biodegradation evaluated based on the produced CO2.FCT (grant SFRH/BD/18415/2004) and the French-Portuguese Scientific Cooperation (actions F-13/06 and F-32/08)
An integrated approach for efficient biomethane production from solid bio-wastes in a compact system
Determination of hydroxyl groups in biorefinery resources via quantitative 31P NMR spectroscopy
The analysis of chemical structural characteristics of biorefinery product streams (such as lignin and tannin) has advanced substantially over the past decade, with traditional wet-chemical techniques being replaced or supplemented by NMR methodologies. Quantitative 31P NMR spectroscopy is a promising technique for the analysis of hydroxyl groups because of its unique characterization capability and broad potential applicability across the biorefinery research community. This protocol describes procedures for (i) the preparation/solubilization of lignin and tannin, (ii) the phosphitylation of their hydroxyl groups, (iii) NMR acquisition details, and (iv) the ensuing data analyses and means to precisely calculate the content of the different types of hydroxyl groups. Compared with traditional wet-chemical techniques, the technique of quantitative 31P NMR spectroscopy offers unique advantages in measuring hydroxyl groups in a single spectrum with high signal resolution. The method provides complete quantitative information about the hydroxyl groups with small amounts of sample (~30 mg) within a relatively short experimental time (~30-120 min)
Applications of lignin in the agri-food industry
Of late, valorization of agri-food industrial by-products and their sustainable utilization is
gaining much contemplation world-over. Globally, 'Zero Waste Concept' is promoted with
main emphasis laid towards generation of minimal wastes and maximal utilization of plantbased
agri-food raw materials. One of the wastes/by-products in the agri-food industry are the
lignin, which occurs as lignocellulosic biomass. This biomass is deliberated to be an
environmental pollutant as they offer resistance to natural biodegradation. Safe disposal of this
biomass is often considered a major challenge, especially in low-income countries. Hence, the
application of modern technologies to effectively reduce these types of wastes and maximize
their potential use/applications is vital in the present day scenario. Nevertheless, in some of the
high-income countries, attempts have been made to efficiently utilize lignin as a source of fuel, as a raw material in the paper industry, as a filler material in biopolymer based packaging and
for producing bioethanol. However, as of today, agri-food industrial applications remains
significantly underexplored. Chemically, lignin is heterogeneous, bio-polymeric, polyphenolic
compound, which is present naturally in plants, providing mechanical strength and rigidity.
Reports are available wherein purified lignin is established to possess therapeutic values; and
are rich in antioxidant, anti-microbial, anti-carcinogenic, antidiabetic properties, etc.
This chapter is divided into four sub-categories focusing on various technological
aspects related to isolation and characterization of lignin; established uses of lignin; proved
bioactivities and therapeutic potentials of lignin, and finally on identifying the existing research
gaps followed by future recommendations for potential use from agri-food industrial wastes.Theme of this chapter is based on our ongoing project- Valortech,
which has received funding from the European Union’s Horizon 2020 research and innovation
program under grant agreement No 810630
Lignin-based rigid polyurethane foams with improved biodegradation
Rigid polyurethane (RPU) foams have been synthesized using lignin-based polyols obtained by oxypropylation of four distinct lignins (Alcell, Indulin AT, Curan 27-11P, and Sarkanda). Polyol formulations with two lignin/propylene oxide/catalyst content (L/PO/C) ratios were chosen (30/70/2 and 20/80/5). RPU foams have been prepared with a polyol component that incorporates the lignin-based one at contents ranging from 25 to 100%. A 100% commercial polyol-based (Lupranol! 3323) RPU foam was also prepared and used as the reference. RPU foams were characterized in terms of density, compressive modulus, and conductivity. Cell morphology and size estimation were accessed by scanning electron microscopy. Moreover, biodegradation of the Alcell- and Indulin AT-based foams was evaluated using respirometry tests in liquid and solid media. The Alcell- and Indulin AT-based polyols together with the 20/80/5 Curan 27-11P-based one led to RPU foams with properties quite similar to those of the reference homolog. Biodegradation seems to be, particularly, favored if using Indulin AT-based polyols mixed with Lupranol! 3323.Portuguese Foundation for Science and Technology (grant SFRH/BD/18415/2004 and project PTDC/CTM/71491/2006_FCOM-01-0124-FEDER- 007156) and the French-Portuguese Scientific Cooperation (actions F-13/06 and F 32/08
Bioactivity evaluation of four technical lignins: Alcell, Indulin-AT, Sarkanda and Curan 27-11P
In what concerns bioactive properties, and due to its phenolic
character, lignin is mostly studied for their antioxidant activity.
In this work four technical lignins (Alcell, Indulin-AT, Sarkanda
and Curan 27-11P) have been evaluated for their antioxidant
activity (DPPH radical scavenging activity, reducing power and
inhibition of β-carotene bleaching) and antitumor potential
against MCF-7, NCI-H460, HCT-15, HeLa and HepG2 cell
lines. Additionally, the toxicity for non-tumour cells (PLP2) was
also evaluated. The obtained results were correlated with the
chemical and structural features of the studied lignins. Based on
the achieved results, lignins of GS type, i.e. lignins rich in
syringyl phenol units and poor in p-hydroxyphenyl ones result in
better antitumor potential
Lignopolyurethanic materials based on oxypropylated sodium lignosulfonate and castor oil blends
Polyurethane Coatings Based on Chemically Unmodified Fractionated Lignin
New
lignin-based thermoset polyurethane (PU) coatings with high
lignin content are presented in this work. These materials were obtained
by extracting a sol fraction from a raw kraft lignin sample with the
bioderived solvent 2-methyltetrahydrofuran (MeTHF), and subsequently
directly cross-linking the MeTHF-soluble lignin fraction with a toluene
diisocyanate (TDI)-based polyisocyanate at different weight ratios.
A thorough characterization of the PU materials highlighted their
improved thermal stability, better film forming ability and higher
hydrophobic character compared with the un-cross-linked lignin precursor.
Additionally, force–distance curve measurements by atomic force
microscopy were employed to determine the elastic modulus of the PU
materials. Finally, the lignin-based PU materials were found to exhibit
high adhesion on different substrates, including glass, wood and metals.
The results of this study demonstrate that the direct reaction of
chemically unmodified fractionated lignin with polyisocyanates represents
an interesting strategy for the development of lignin-based thermoset
PU systems that may find application in the field of high-performance
biobased coatings and adhesives