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Thermosets

Thermosets, also called duroplasts, retain their form even when warming up and, furthermore, the heating of thermosets is part of the production process that hardens them. Also, the hardened thermosets do not melt but are simply destroyed at a certain temperature. As a classical example, the plastic Bakelite belongs to this group. The presence of various reactive groups, that can be used for chemical reactions, carboxyl, aromatic and aliphatic hydroxyl or others, is important for the reactivity and the properties in adhesive applications. Typical thermosets where lignin can be used are phenolic resins, polyurethanes and epoxies.

Lignin is an obvious candidate as a phenol substitute in phenol formaldehyde resins. Recent progresses have been reported with modified lignin powders originating from novel processes (like organosolv pulping and non-wood raw materials). These products can replace up to 50% of the phenol formaldehyde resin in adhesives in the different application fields of phenolic resins. If the phenol is replaced in the resin cooking up to 80% replacement rate is possible.

The use of lignin in polyurethane copolymers is exploiting the presence of hydroxyl groups (aliphatic and aromatic). Lignin can be used without any preliminary chemical modification. It then functions as crosslinker or additive (flame retardant) in polyurethane foam. Moreover, lignin oxypropylation can produce liquid polyol mixtures of lower viscosity that are of great interest in polyurethane.

Epoxy blends are other challenging applications, which have already been extensively studied. The latest was reported by a laboratory of IBM for the production of a printed wiring board that had all the required properties. The composition containing lignin, an epoxy resin and an initiator was utilized to prepare prepregs and then processed by conventional methods.

A big amount of publications is available on these topics (see references and overview in Malherbe – first paper under ‘View All’, pp. 5).

  • Summaries, Overviews and Priority Papers
  • Recent Postings
  • Database

Summaries, Overviews and Priority Papers

  • View All
  • Overviews
  • Resoles
  • Reactivity
  • Fibre Boards
  • Various
  • Epoxies
  • Projects
  • Novolacs
  • PUs

Overviews

Resoles

Reactivity

Fibre Boards

Various

Epoxies

Projects

Novolacs

PUs

CatLignin - Reactive Lignin for phenol replacement in resins

Nordic Wood Biorefinery Conference (NWBC), 2017, Stockholm, Sweden

H. Wikberg, J. Leppävuori, T. Ohra

Lignin in blends with synthetic polymers

ILI Forum 8, Rome 2007

D. Feldman, D.Banu

Isocyanate modified Lignins for formulations of Novolac resins

ILI Forum 7, Barcelona 2005

J. Labidi, A. Tejado, G. Kortaberria, I. Mondragon, J.M. Echeverria

La Biolignine(TM): Structure et Application a l'elaboration de résine époxy

PhD in French, 2011

G.-H. Delmas

Recent Postings

CatLignin - Reactive Lignin for phenol replacement in resins

Nordic Wood Biorefinery Conference (NWBC), 2017, Stockholm, Sweden

H. Wikberg, J. Leppävuori, T. Ohra

Database

  • View All
  • Resoles
  • Various
  • Fibre Boards
  • PUs
  • Reactivity
  • Furans
  • Overviews

Resoles

Various

Fibre Boards

PUs

Reactivity

Furans

Overviews

Rigid polyurethane foams from Lignin-based polyols

Times of Polymers (TOP) and Composites, 2008, Ischia, Italy

Carolina Cateto, Filomena Barreiro

Oxypropylation of Lignins

ILI Forum 8, Rome 2007

C.A. Cateto, M.F. Barreiro, A.E. Rodrigues, M.N. Belgacem

Monitoring of Lignin-based polyurethane synthesis by FTIR-ATR

ILI Forum 7, Barcelona 2005

C.A. Cateto, M.F. Barreiro, A.E. Rodrigues

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