Theses and Dissertations

ORCID

https://orcid.org/0009-0000-8698-9443

Advisor

Zhang, Jilei

Committee Member

Kim, Yunsang

Committee Member

Street, Jason

Committee Member

Mlsna, Todd

Committee Member

Yan, Qiangu

Date of Degree

5-15-2026

Original embargo terms

Embargo 2 years

Document Type

Dissertation - Open Access

Major

Forest Resources (Sustainable Bioproducts)

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Forest Resources

Department

Department of Sustainable Bioproducts

Abstract

Lignin, a carbon-rich biomass, represents a promising precursor for graphene-based carbon nanomaterials. Our previous studies have employed iron catalysts to convert Kraft lignin into graphene under elevated temperatures; however, these efforts were limited by low yields and the formation of thick, multi-layered graphene (30+ layers), which hindered its potential applications. Since the number of graphene layers is strongly influenced by carbon solubility, optimizing the manufacturing procedure of lignin-derived graphene and synthesizing fewer graphene layers, copper (Cu) was explored as an alternative in this dissertation to iron (Fe) due to its lower carbon solubility and potential to generate fewer layers of graphene. In this dissertation, the effects of graphitization temperature, Cu loading, and precursor solvents were systematically investigated using a modified tube furnace system. The results demonstrated that fewer-layer graphene can be obtained under optimized conditions. Moreover, the applications of carbon nano- and micro-scaled materials in cement-based composites were explored. The synthesized lignin-derived graphene (LG) alongside the industrial-grade graphene nanoplatelets (GNP), as reinforcement additives for cement-based composites were investigated. The findings revealed that LG improved 28-day compressive strength by 6.9%, while GNP achieved enhancements of up to 20.7%. The primary mechanism of strength improvement was attributed to providing heterogeneous nucleation sites, with the specific surface area (SSA) playing a critical role. Although LG exhibited enhancement potential, its SSA requires further optimization. Biochar (BC), a micro-scale carbon material, was also investigated for its reinforcing effects in cement-based composites. The results suggest that BC primarily contributed through water retention with a particle size of approximately 20 μm under optimized mix method and curing condition.

Sponsorship (Optional)

Forest Products Laboratory (FPL)

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