Finite element modeling reveals that microfibril angle drives moisture swelling in conifer branch wood, indicating structural orientation outweighs chemical differences.
Key Points
To determine the structural and molecular mechanisms that drive differences in moisture-induced swelling between conifer compression wood and opposite wood.
Developed a finite element model of the predominant cell wall S2 layer incorporating nanoscale structural and mechanical data of cellulose, hemicellulose, and lignin.
Performed parametric sensitivity investigations to assess the effects of biopolymer composition, lignin hygroexpansion coefficients, and microfibril angles on cell wall swelling.
Microfibril angle exerted a significantly stronger influence on hygroexpansion behavior in compression and opposite wood than the relative composition of cell wall biopolymers.
Variations in the hygroexpansion coefficient of chemically distinct lignin had a minimal effect on overall swelling compared to the microfibril angle.