Intratree Variation in Viscoelastic Properties of Cell Walls of Masson Pine (Pinus Massoniana Lamb)

Shaoxiang Cai,Yuliang Guo,Yanjun Li

doi:10.32604/jrm.2022.016260

Abstract

In this study, Pinus massoniana Lamb at different heights, across the annual rings, and between earlywood and latewood was measured by X-ray diffraction and the chemical composition was analyzed by chemical treatment. Results indicated that the microfibril angle (MFA) decreased and the chemical composition changed little with the increase in height from 1 m to 9 m. In the radial direction, the MFA decreased and the chemical composition changed little with an increase in annual rings. The cellulose content of latewood was higher than that of earlywood. The viscoelastic changes of wood cell walls at different heights, across the annual rings by the method of quasi-static nanoindentation and dynamic modulus mapping techniques. Results indicated that the wood cell walls’ elastic modulus increased, and the creep rate and creep compliance decreased with the increase in height; The elastic modulus and hardness increased with the annual rings. The cell walls’ storage modulus increased and the loss modulus gradually decreased with an increase in height; the storage modulus gradually increased and the loss modulus decreased with the annual rings.

Highlights

Masson pine (Pinus massoniana Lamb.) is an important resource widely distributed in China’s southern provinces [1]
Several studies have shown that the microfibril angle (MFA) in the annual rings near the young timber of the medullary heart is usually large, and it tends to decrease with the increase in tree age, and remains relatively stable [23,24,25]
The results showed that the static mechanical properties of cell walls were better with increasing annual rings

Summary

Introduction

Masson pine (Pinus massoniana Lamb.) is an important resource widely distributed in China’s southern provinces [1]. The Masson pine plantation wood is an important raw material for construction, polymer composites, and pulp and paper due to the beautiful grain pattern, suitable for planting in temperate and tropical climates, and the period of growing into useful timber is short [2,3]. Studying the mechanical properties of wood fibers is of great significance for pulping and papermaking. In the past few decades, scientists have done extensive research on the intratree variations in wood mechanical properties. Wood physical properties have been expanded from density and tracheid morphology to anatomical parameters, microfibril angle (MFA), chemical composition, and micromechanical properties. Researchers have investigated the macroscopic mechanical properties and the anatomical variations in the wood. Compared with Pinus sylvestris, the dry density of Masson pine wood was 0.48–0.53, which was higher than that of Pinus sylvestris; And its relative cellulose content is larger, cell wall microfibril angle is smaller; The average elastic modulus and hardness of Masson pine wood cell wall are larger [4,5,6]

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Conclusion