Kraft lignin as filler in PLA to improve ductility and thermal properties
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Date
2015-10Author
Gordobil Goñi, Oihana
Delucis, Rafael
Egüés Artola, Itziar
Labidi, Jalel
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Industrial Crops and Products 72 : 46-53 (2015)
Abstract
[EN] Kraft lignin (KL) and acetylated Kraft lignin (AKL) were used as filler for the elaboration of composites
with poly(lactic acid) (PLA) in different concentrations (0.5, 1, 5, 10 and 20%) by extrusion method at
200 ◦C. Characterization of both lignins has been performed using HPLC, FT-IR, GPC, DSC and TGA. KL
presented only 0.3% of ash content and molecular weight around 2000 g/mol. The esterification increased
the molecular weight and decreases the polydispersity of the lignin (AKL). Also, AKL had lower Tg and
higher thermal stability than unmodified Kraft lignin. Lignin content increased the thermal stability of
PLA, with the addition of both types of lignins. Contact angle was measured to assess the change in the
hydrophobicity of PLA with the addition of lignins. Mechanical properties of different materials were also
investigated in order to know the effect of lignin addition in PLA. Maximum strength was not severely
affected at low concentrations of both lignins, but it decreased dramatically, especially in composites
with 10 and 20% of KL. Elongation at break increased with the addition of low contents of AKL, at high
content of both lignins the material becomes quite brittle