Effect of Glow-Discharge Plasma Treatment on Contact Angle and Micromorphology of Bamboo Green Surface

Xuehua Wang,Kenneth J Cheng

doi:10.3390/f11121293

Abstract

The inner and outer surfaces of bamboo stems are usually removed prior to the manufacture of bamboo panels because the surfaces are hydrophobic and difficult to bond with glue. Hence, the recovery and utilization ratio of bamboo during processing is low. This study focused on using glow-discharge plasma to treat green bamboo surfaces to make them less hydrophobic. The effects of plasma treatment on green bamboo stems were examined using contact goniometry (wettability), non-contact confocal profilometry and scanning electron microscopy (SEM). Confocal profilometry and SEM revealed that the morphology of green bamboo surfaces varied between 3 different stems. Plasma was able to etch bamboo green surfaces, and make them rougher and more powdery. Plasma treatment was effective at converting green bamboo surfaces from hydrophobic (initial contact angle >110°) to hydrophilic (contact angle <20°). However, this effect was temporary and contact angle increased with time and recovered approximately 30% of its original value after 24 h. Based on our findings, we conclude that plasma treatment can alter parameters such as surface energy and roughness that could improve glue bonding of green bamboo, but delays between plasma treatment and further processing would need to be minimized.

Highlights

As primary forest area declines, fast growing bamboo is becoming more important as a source of biomaterials especially for forest-deficient countries, such as India, China, and so on
Plasma treatment had the temporary effect of making green bamboo surfaces hydrophilic than 110°
Plasma treatment etched green bamboo surfaces resulting in roughness increases and changes in surface morphology including creation of a powdery layer

Summary

Introduction

As primary forest area declines, fast growing bamboo is becoming more important as a source of biomaterials especially for forest-deficient countries, such as India, China, and so on. The bamboo industry supplies earnings, food, and fibre for more than 2.2 billion people; half the world’s population is involved in using and trading bamboo products. Manufactured bamboo is widely used in many fields, such as furniture, buildings, musical instruments, and so on. Bamboo has the advantage of fast growth, low energy consumption during processing and much higher strength compared with other herbaceous plants. Some of its mechanical properties compare favourably with those of wood. Yang et al studied three species of eucalypt wood Deane & Maiden) Maiden, E. regnans F. Muell.), with Modulus of Elasticity (MOE) of

Methods

Discussion

Conclusion