Moisture Content Of Bamboo Research Articles

Multi-Scale Analysis of Changes in Crack-Free Flattened Moso Bamboo After Saturated Steam Treatment and Flattening Process

ABSTRACTIn this study, Moso bamboo was firstly softened by saturated steam and then pressed flat by a machine. The modification effect (high-temperature saturated steam) was characterized by FTIR, XRD, SEM, and wet chemistry. The dynamic mechanical analysis (DMA) was used to investigate the effects of three variables (temperature, time, and moisture content) on the thermal-mechanical properties of Moso bamboo. The results indicated that high-temperature saturated steam can effectively soften bamboo cells under high pressure at high temperature. As expected, in comparison with reference samples, the content of hemicellulose and cellulose decreased, while that of relative lignin increased. The results of the changes in main chemical composition were further confirmed by FTIR, which showed that the intensity of the main peak belongs to hemicellulose decreased, so the polysaccharide such as hemicellulose went through the process of hydrolysis and pyrolysis. An increase in the moisture content of bamboo led to a decrement in storage modulus value, which can be attributed to the plasticizing effect. Both temperature and time had a positive effect on the reduction in glass transition temperature. This conclusion not only helps to understand the relationship between bamboo and water, but also provides guide for the utilization and production process of crack-free flattened bamboo board and its products in the construction and building fields.

Factors affecting the temperature increasing rate in arc-shaped bamboo pieces during high-frequency heating

In the process of applying the high-frequency heating technology to bamboo heat treatment, controlling the material temperature has a great influence on the quality of bamboo forming. Therefore, research on the heat transfer mechanism of high-frequency heating of arc-shaped bamboo pieces is of great importance. In this paper, the influence of different moisture content, chord length, and plate voltage on the heating rate of arc-shaped bamboo pieces under high-frequency electric field were studied. The moisture content of bamboo had the most remarkable effect on the heating rate. With increased moisture content, the temperature rose faster. The selection of the plate voltage had an obvious influence on the heating. If the voltage was low, the heating rate was too slow, the heating time was long, or the voltage was high, it was easy to cause electric field breakdown and damage the bamboo pieces. As the chord length decreased, the heating rate gradually increased. When the radian of the arc-shaped bamboo pieces could be ignored, the heating rate was the fastest. The results showed that under certain conditions, the arc-shaped bamboo pieces showed a good heat treatment effect in a high-frequency electric field.

Flexural behavior of sprayed lightweight composite mortar-original bamboo composite beams: Experimental study

To study the flexural behavior of a composite beam, original single and double bamboo beams (SBBs and DBBs, respectively) and sprayed lightweight composite mortar-original bamboo composite beams (SCBs and DCBs) were designed and subjected to a four-point bending test based on the moisture content of the original bamboo. The failure modes, bearing capacity, and initial flexural rigidity of all of the beams were analyzed. Also, the strengthening effect of the lightweight composite mortar on the flexural behavior was studied. The results showed that a higher moisture content in the bamboo degraded the anti-slip property of the bond interface between the lightweight composite mortar and bamboo. The moisture content of the bamboo should be kept at approximately 20% before spraying. The initial flexural rigidity and bearing capacity of the DBBs were approximately 2.5 times and twice that of the SBBs, respectively. The initial flexural rigidities of the SCBs and DCBs were approximately 3.8 and 5.7 times that of the SBBs and DBBs, respectively. The ultimate load bearing capacity of the composite beams was approximately 1.5 times that of the original bamboo beams. It was shown that the lightweight composite mortar had a remarkable strengthening effect on the flexural behavior of the original bamboo.

Bamboo Conditions for Processing Bamboo Fiber with Combing Method

The bamboo fibre is a new kind of natural fibre from bamboo with machine method, and is in the frontier of bamboo timber processing, new composite and textile research field. The combing method is mainly one in processing bamboo fiber. The plasticity and strength of bamboo were required in processing bamboo fiber by machine method. The aim of this work is to explore changes of mechanical properties -lengthways tensile properties of bamboo after alkali treatment and focuses on a relation between lengthways tensile properties of alkali treated bamboo and the moisture content. Mechanism of plastic deformation of bamboo was initially revealed in this paper. Experiment shows that: above fibre saturation point, the lengthways tensile strength and elasticity modulus of bamboo decreased with increase of moisture content with 2.5%NaOH soaking for 24h, and bamboo plasticity is better when its moisture content is between 40% and 90%. According to the principle of bamboo fiber processing by combing, the moisture content of bamboo should be controlled from 50% to 70% after 24h soaked with 2.5%NaOH. Bamboo fiber processing test shows that the conclusion is correct.

Temperature inside mats of high-frequency, hot pressed, glued and laminated bamboo

To obtain variation in the temperature law for glued and laminated bamboo （GLB）, mats were hot pressed during two phases: fast heating and slow heating, with high-frequency at different moisture contents and amount of spreads. A statistical analysis on temperature variation inside the mats was conducted by Microsoft Excel software using ANOVA two-factor with replication analysis at a 95% confidence level. Results showed that when moisture content increased from 6% to 18%, the amount of spread increased from 200 to 300 gm－2, during the first phase, temperature inside the mats increased slowly with increasing moisture content below 12%, amount of spread below 250 gm－2, and pressing time, and increased sharply with moisture content above 12% and amount of spread above 250 gm－2; whereas, during the second phase temperature influence on moisture content and amount of spread inside the mats was very small at all conditions. Also during the second phase, the heating rate of the core layer decreased with an increase in pressing time. Optimum high-frequency hot pressing technological parameters for GLB manufacturing were as follows: amount of spread--300 gm－2, moisture content of bamboo splits--12%, and pressing time--7 min. It mean that temperature inside the mats are satisfactory, is necessary to make high quality of GLB in order to improve the performance of GLB.［Ch, 3 fig. 4 tab. 18 ref.］