Chemical and Rheological Characteristics of Thermally Stable Kraft Lignin Polycondensates Analyzed by Dielectric Properties

Le Dai Duong, Luong Nguyen Dang, Nguyen Thi Thanh Binh, In Kyung Park, Seong Hoon Lee, Dea Sik Kim, Yong Sang Lee, Young Kwan Lee, Byung Woo Kim, Kwang Ho Kim, Ho KyuYoon, Ju Ho Yun, Jae Do Nam*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review


In light of the difficulties and disagreements in determining the property-processing structure relations of lignin-based polymers, dielectric analysis was used to identify the thermal and rheological characteristics of a lignin-based polycondensate and the pristine lignin. Using dielectric analysis, the pristine lignin with M-w=6000 g/mol, was clearly identified as giving the wet glass transition temperature (T-g,T-wet) and the evolution of gases (i.e., burning) at around 80 degrees C to 125 degrees C followed by subsequent cross-linking reactions over 150 degrees C to give the dry glass transition temperature (T-g,T-dry) of lignin at around 130 degrees C to 140 degrees C. Connecting the lignin macromers using sequential condensation reactions with caprolactone and sebacoyl chloride, the lignin based polycaprolactone (LigPCL) polycondensates were synthesized as a thermoplastic polymer composed of lignin macromers and aliphatic polyester chains with M-w=10500 g/mol. The synthesized LigPCL presented good thermal stability and rheological melting behavior without evolving odor or fumes. In particular, the T-2% (defined at 2% of weight loss) of the LigPCL and pristine lignin were 200 degrees C and 80 degrees C, respectively. The melt viscosity was measured at 10(3)Pa.s at 120 degrees C, ensuring facile melt-blending processing with various commodity polymers to be used in eco-friendly polymer composite development.

Original languageEnglish
Pages (from-to)4518-4532
Number of pages15
Issue number3
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed


  • Lignin
  • Polycondensate
  • Polycaprolactone
  • Biodegradable polymer
  • Eco-friendly
  • CURE


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