Biocomposites based on lignin and plasticized poly(L‐lactic acid)

Abstract

In this research work, biocomposites based on a ternary system containing softwood Kraft lignin (Indulin AT), poly-L-lactic acid (PLLA) and polyethylene glycol (PEG) have been developed. Two binary systems based on PLLA/PEG and PLLA/lignin have also been studied to understand the role of plasticizer (i.e., PEG) and filler (i.e., lignin) on the overall physicomechanical behavior of PLLA. All samples have been prepared by melt-blending. A novel approach has also been introduced to improve the compatibility between PLLA and PEG by using a transesterification catalyst under reactive-mixing conditions. In PEG plasticized PLLA flexibility increases with increasing content of PEG and no significant effect of the molecular weight of PEG on the flexibility of PLLA has been observed. Differential scanning calorimetry and size-exclusion chromatography along with FTIR analysis show the formation of PLLA-b-PEG copolymer for high temperature processed PLLA/PEG systems. On the other hand, binary systems containing lignin show higher stiffness than PLLA/PEG system and good adhesion between the particles and the matrix has been observed by scanning electron microscopy. However, a concomitant good balance in stiffness introduced by the lignin particles and flexibility introduced by PEG has been observed in the ternary systems. This study also showed that high temperature reactive melt-blending of PLLA/PEG leads to the formation of a segmented PLLA-b-PEG block copolymer

Production of bacterial nanobiocomposites of polyhydroxyalkanoates derived from waste and bacterial nanocellulose by the electrospinning enabling melt compounding method

“…To enhance its mechanical performance, 5 wt % of PEG was incorporated into PHBV3, giving rise to a significantly increased elongation at break and tensile strength, without affecting the Young's modulus. The same ductility increase was observed for PHB films plasticized with PEG prepared by casting, although in that case, the tensile strength was diminished, probably as a result of the high amount of plasticizer (15 wt % PEG) …”

Thermal Properties of Plasticized Poly (Lactic Acid) (PLA) Containing Nucleating Agent

“…Therefore, all of these components promote crystallinity while they provide a lower cold crystallization temperature. The cold crystallization temperature in ternary system could not be detected probably due to the high degree of crystallinity [12], [13]. Nevertheless, in binary systems the effect of nucleating agent on cold crystallization was not prominent.…”

Thermal properties of lignin in copolymers, blends, and composites: a review

“…50% weight loss of amine-cured lignin took place at 389 °C while the same weight loss temperature for lignin-cured epoxy varied between 345 °C to 363 °C. 193 Kosikova et al studied the sulfur-free lignin derived from the methanol-based organosolv pulping of spruce wood. Increasing the lignin content showed higher onset decomposition temperatures.…”