POS9-1137
Fully Renewable Lignin-graft-Castor Oil Copolymers: Tailoring Properties from Nature's Building Blocks
Topic
S9. Polymer Technology for Sustainability
When and Where
Oct 1, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Jinkee HONG
Ki Su KIM
Presenter(s)
Sundol Kim (Dankook University)
Co-Author(s)
Abstract
Lignin is the second most abundant renewable biomass polymer, offering great potential as a sustainable raw material due to its abundance, low cost, and high aromatic content. However, its complex, poorly-defined chemical structure and excessive reaction sites limit applications. Castor oil, a natural vegetable oil convertible to useful chemicals such as ethylene brassylate, has not previously been used in its pristine form to synthesize a sustainable polymer.
Here, we report the synthesis and structure–property relationships of a novel 100% biomass-based polymer, lignin-graft-castor oil. Natural lignin was chemically modified in a single step with succinic acid and acetic acid: acetic acid caps excess hydroxyl groups on lignin, while succinic acid's carboxylic group provides functionality to link lignin with castor oil. Pristine castor oil, used without modification, was covalently linked to modified lignin via carbodiimide-mediated esterification to form the graft copolymer.
The resulting copolymers exhibited tunable melting temperatures (57–71°C) and glass transition temperatures (39–60°C), enabling thermal processing. Mechanical properties were controlled by crosslinking density and the lignin-to-castor oil mass ratio, achieving a maximum modulus of 228.43 MPa—40% higher than commercial LDPE. Physical properties, including density (0.96–1.14 g mL⁻¹) and water contact angle (70.5°–92.9°), were precisely tuned via the capping agent's mol% and the mass ratio of capped lignin to castor oil.
This fully biomass-based polymer offers a genuine solution to plastic waste, combining 100% renewable content with minimal chemical modification to form readily degradable ester linkages. Its precisely controllable properties enable customized applications across diverse fields.
Here, we report the synthesis and structure–property relationships of a novel 100% biomass-based polymer, lignin-graft-castor oil. Natural lignin was chemically modified in a single step with succinic acid and acetic acid: acetic acid caps excess hydroxyl groups on lignin, while succinic acid's carboxylic group provides functionality to link lignin with castor oil. Pristine castor oil, used without modification, was covalently linked to modified lignin via carbodiimide-mediated esterification to form the graft copolymer.
The resulting copolymers exhibited tunable melting temperatures (57–71°C) and glass transition temperatures (39–60°C), enabling thermal processing. Mechanical properties were controlled by crosslinking density and the lignin-to-castor oil mass ratio, achieving a maximum modulus of 228.43 MPa—40% higher than commercial LDPE. Physical properties, including density (0.96–1.14 g mL⁻¹) and water contact angle (70.5°–92.9°), were precisely tuned via the capping agent's mol% and the mass ratio of capped lignin to castor oil.
This fully biomass-based polymer offers a genuine solution to plastic waste, combining 100% renewable content with minimal chemical modification to form readily degradable ester linkages. Its precisely controllable properties enable customized applications across diverse fields.
