Assessing the Efficiency of Open-System Densification on Chemically Treated Dendrocalamus asper Bamboo

André Luiz Pereira de Godoy Junior ¹, Marzieh Kadivar ^1,2, Leo Maia do Amaral ¹

⁰Research Center on Materials for Biosystems (BioSMat), Materials Science and Engineering Graduate Program, University of São Paulo, Pirassununga 13635-900, SP, Brazil.

Materials (basel, Switzerland) +

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June 27, 2025

View abstract on PubMed

Summary

Modifying bamboo with delignification and densification improves its properties but requires process adjustments. Optimized densification for natural bamboo is not directly transferable to delignified bamboo, necessitating further research for enhanced material performance.

Area Of Science

Materials Science
Wood Science
Chemical Engineering

Background

Natural bamboo's variability and moisture sensitivity hinder construction applications.
Densification and delignification are promising modification techniques for wood and bamboo.
Improving bamboo's structural integrity is crucial for sustainable construction.

Purpose Of The Study

To investigate the transferability of optimized densification parameters from natural bamboo to delignified bamboo.
To assess the impact of alkali-based delignification on bamboo's physical and mechanical properties.
To evaluate the effectiveness of an open thermo-mechanical press system for densifying delignified bamboo.

Main Methods

Two-step treatment: delignification (NaOH and Na2SO3 at 25°C or 100°C) followed by drying.
Open thermo-mechanical pressing at 160°C and 6.7 mm/min to achieve 50% thickness reduction.
Evaluation of compression stress, flexural properties (MOR, LOP, MOE), water absorption, and thickness swelling.

Main Results

Delignification facilitated densification, reducing required compression stress (7-13.4 MPa vs. 17 MPa for untreated).
Flexural properties (MOR, LOP, MOE) decreased in alkali-treated, densified bamboo.
Physical properties like water absorption and thickness swelling remained unchanged after delignification.

Conclusions

Optimized densification parameters for natural bamboo are not directly applicable to delignified bamboo.
Alkali treatment increases free space in bamboo, requiring higher densification degrees for optimal results.
Further research is needed to adjust densification processes for chemically modified bamboo to maximize its potential.

Keywords:

bamboo delignification densification process optimization