Vaezi Khashayar: Role of lignin in high-yield fiber property formation:5000 eur ( 2025)

Role of lignin in high-yield fiber property formation 

By: Khashayar Vaezi 

With the support of the Walter Ahlström grant, my doctoral research at the University of Oulu is advancing sustainable, high-yield fiber development and emission-free pulping technologies with strong relevance to the Finnish pulp and paper industry. The funding has enabled parallel progress in chemical pulp modification and advanced microscopic characterization, accelerating both experimental development and industrial applicability. 

A key achievement has been the successful thiourea-based treatment of various wood pulps under mild conditions. Elemental analysis confirmed effective chemical modification while high material yields (72–94%) demonstrated that fiber carbohydrates were largely preserved. This approach enhances fiber strength without extensive lignin removal, which is critical for maintaining high yield and reducing energy and chemical demand. Mechanical testing of laboratory hand sheets showed a clear improvement in tensile strength and stiffness, highlighting strong potential for cost-efficient, high-performance pulp products. In parallel, the project pioneers the use of fluorescence-lifetime imaging microscopy (FLIM) to investigate lignin structure and distribution in pulp fibers. Initial results indicate changes in lignin chemistry after treatment, offering new microscale insight into fiber modification mechanisms. The grant has also facilitated international collaboration with research partners and exploration of complementary lifetime-imaging techniques, strengthening the scientific impact and industrial applicability of the work. 

In the short term, these developments can reduce operational costs through lower energy

use, chemical savings, and improved material efficiency. Over the next 5 years, scaling emission free pulping concepts could significantly reduce carbon emissions, align Finnish production with EU sustainability targets, and strengthen the global competitiveness of Finland’s pulp and paper industry.