TY - JOUR
T1 - Effect of Fatty Acid Esterification on the Thermal Properties of Softwood Kraft Lignin
AU - Koivu, Klaus A.Y.
AU - Sadeghifar, Hasan
AU - Nousiainen, Paula A.
AU - Argyropoulos, Dimitris S.
AU - Sipilä, Jussi
N1 - Funding Information:
This study is part of a multinational project titled High-value products from lignin side-streams of modern biorefineries (ProLignin) coordinated by VTT Technical Research Centre of Finland. Funding from the Academy of Finland is acknowledged. Our gratitude to Stora Enso Oyj, Finland for providing us with the softwood LignoBoost kraft lignin.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/3
Y1 - 2016/10/3
N2 - Esterification of kraft lignin inherently addresses its potential for thermoplastic applications either on its own or as a component of polymer blends. In this effort, we have investigated the selectivity of softwood kraft lignin toward esterification via acylation. LignoBoost kraft lignin was esterified with acetyl (C2), octanoyl (C8), lauroyl (C12), and palmitoyl (C16) chlorides at various molar ratios with respect to the total hydroxyls present. Quantitative 31P NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) were used to evaluate the selectivity and efficiency of these reactions on the various hydroxyl groups present. The C8-C16 acyl chlorides showed distinct enhanced reactivity toward the aliphatic hydroxyl groups, whereas C2 acyl chloride was found to react uniformly with any available OH irrespective of their chemical nature. The effects of long chain acylation on the polymer and material properties were also examined using solution viscosity, thermal, and rheological measurements. Polymer blends were also produced and studied by melt extrusion. The long aliphatic chains when installed on the lignin displayed peculiar association effects in solution and enhanced the melt flow characteristics of the lignin-polymer blends.
AB - Esterification of kraft lignin inherently addresses its potential for thermoplastic applications either on its own or as a component of polymer blends. In this effort, we have investigated the selectivity of softwood kraft lignin toward esterification via acylation. LignoBoost kraft lignin was esterified with acetyl (C2), octanoyl (C8), lauroyl (C12), and palmitoyl (C16) chlorides at various molar ratios with respect to the total hydroxyls present. Quantitative 31P NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) were used to evaluate the selectivity and efficiency of these reactions on the various hydroxyl groups present. The C8-C16 acyl chlorides showed distinct enhanced reactivity toward the aliphatic hydroxyl groups, whereas C2 acyl chloride was found to react uniformly with any available OH irrespective of their chemical nature. The effects of long chain acylation on the polymer and material properties were also examined using solution viscosity, thermal, and rheological measurements. Polymer blends were also produced and studied by melt extrusion. The long aliphatic chains when installed on the lignin displayed peculiar association effects in solution and enhanced the melt flow characteristics of the lignin-polymer blends.
KW - Characterization
KW - Fatty acid esterification
KW - Methylation
KW - Polymer blends
KW - Quantitative P NMR
KW - Softwood kraft lignin
KW - Thermal and rheological properties
UR - http://www.scopus.com/inward/record.url?scp=84989821730&partnerID=8YFLogxK
U2 - 10.1021/acssuschemeng.6b01048
DO - 10.1021/acssuschemeng.6b01048
M3 - Article
AN - SCOPUS:84989821730
SN - 2168-0485
VL - 4
SP - 5238
EP - 5247
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
IS - 10
ER -
