The extraction of polyol for the synthesis of lignin-based polyurethane coatings – a review

• Lignin, with its availability, aromatic structure, and abundant hydroxyl groups, presents a promising source of green bio-based polyols. The environmental implications of oil-derived polymeric materials have sparked interest in renewable biopolymers and composites from natural sources, including polyurethane composites. This review investigates optimal methods for lignin extraction for use in lignin-based polyurethane coatings, scrutinizes alternatives to oil-based polyols, compares existing chemical modification methods of lignin for use in polyurethane coatings and resins, and discusses the control of synthesis and final properties of lignin-based polyurethane, emphasizing the crucial role of the stoichiometric ratio of NCO groups in the isocyanate to the total OH groups in a lignin-based polyol. While numerous studies have focused on polyurethanes with and without isocyanate, this review describes the synthesis of lignin into bio-polyols and its potential as a substitute for petroleum-based polyols, highlighting organosolv and Kraft lignin as optimal choices for replacing oil-based polyols in polyurethanes due to their high purity.

Ämnesord

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Polymerteknologi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Polymer Technologies (hsv//eng)

Nyckelord

Non-isocyanate polyurethane

coatings

wood

Träteknik

Wood Science and Engineering

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