Epoxidation of Kraft Lignin as a Tool for Improving the Mechanical Properties of Epoxy Adhesive

Autor(es)

Gouveia, Julia R. ^[1] ; Garcia, Guilherme E. S. ^[1] ; Antonino, Leonardo Dalseno ^[1] ; Tavares, Lara B. ^[1] ; dos Santos, Demetrio J. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Fed Univ ABC UFABC, Nanosci & Adv Mat Grad Program PPG Nano, BR-09210580 Santo Andre, SP - Brazil

^[2] Fed Univ ABC UFABC, Mat Engn Grad Program PPG Nano, BR-09210580 Santo Andre, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Molecules; v. 25, n. 11 JUN 2020.
• Citações Web of Science: 1

Resumo

Owing to its chemical structure, wide availability and renewable nature, lignin is a promising candidate for the partial replacement of fossil-based raw material in the synthesis of epoxy resins. Its poor compatibility has been reported to be one of the main drawbacks in this domain. On the other hand, a well-established modification method for lignin epoxidation has been used for many years for the improvement of lignin compatibility. However, the extent of the effect of lignin epoxidation on the improvement of bio-based epoxy mechanical properties, applied as adhesives, is still an open question in the literature. In this context, a pristine and industrial grade kraft lignin (AKL) was reacted with epichlorohydrin to yield epoxidized lignin (E-AKL) in this work. Afterwards, AKL or E-AKL were separately blended with petroleum-based epoxy resin at 15 and 30 wt% and cured with a commercial amine. The adhesive curing kinetic was evaluated using a novel technique for thermal transition characterization, Temperature Modulated Optical Refractometry (TMOR); the results showed that the incorporation of AKL reduces the crosslinking rate, and that this effect is overcome by lignin modification. Mechanical tests revealed an improvement of impact and practical adhesion strength for samples containing 15 wt% of E-AKL. These results elucidate the effect of lignin epoxidation on the application of lignin-based epoxy adhesives, and might support the further development and application of these bio-based materials. (AU)

• Processo FAPESP: 19/05460-6 - Adesivo poliuretano termoativado baseado em lignina kraft modificada
• Beneficiário: Leonardo Dalseno Antonino
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 17/22936-9 - Refratometria ótica com modulação de temperatura: uma perspectiva molecular na cinética de cura e separação de fases de poliuretanos a partir de lignina
• Beneficiário: Demetrio Jackson dos Santos
• Modalidade de apoio: Auxílio à Pesquisa - Regular