Strength of lignin-rich fibers facilitated by surface modification

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master_Khan_Asfar_2025.pdf (1.57 MB)

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School of Chemical Engineering | Master's thesis
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Date

2025-05-26

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Major/Subject

Biomass Refining

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Degree programme

Master's Programme in Chemical, Biochemical and Materials Engineering

Language

en

Pages

77

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Abstract

This thesis explores how surface modification by ozone and oxygen can enhance the strength of lignin-rich high temperature thermomechanical pulp fibers. To evaluate mechanical properties like tensile strength, fiber strength and tearing resistance, as well as compositional changes in cellulose, hemicellulose, lignin, and ash content, a comparative study was carried out. Different ozone and oxygen dose exposure durations were applied to the lignin-rich fibers. Both treatments successfully raised the relative proportion of cellulose, decreased the amount of lignin and ash, and increased surface polarity, evidenced by compositional analysis. By promoting fiber-fiber bonding, moderate ozone dosage greatly increased fiber strength, but high dosages led to degradation. With prolonged exposure, treatment with oxygen at medium consistency has shown a progressive increase in strength. These findings demonstrate that modification at the surface enhances the mechanical performance of lignin-rich fibers, making them potentially suitable for applications they are currently not applicable in.

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Supervisor

Nypelö, Tiina

Thesis advisor

Le, Huy Quang

Keywords

lignin-rich fibers, ozone treatment, oxygen treatment, hydrophilicity, surface modification, mechanical properties, pulping

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https://urn.fi/URN:NBN:fi:aalto-202506104437

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[dipl] Kemian tekniikan korkeakoulu / CHEM