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To investigate the possibility of using bamboo-bundle laminated veneer lumber (BLVL) as a cooling tower packing material, the water absorption rates, thickness swelling rates, and flexural properties of three different composite materials were studied. The BLVL was combined with either 12% or 24% phenol formaldehyde resin (PF), and the moso bamboo strips were exposed to water baths at three different temperatures (45, 65, and 85 °C) for 30 d. After the aging treatments, the 24%-BLVL samples showed lower water absorption rates and better bending properties than the other two composites. The temperature was found to have a significant effect on the modulus of rupture (MOR), modulus of elasticity (MOE), and the thickness swelling rate. As the temperature increased, the swelling rate and the rate of weight gain increased and the MOE and MOR decreased. According to the activation energies for swelling calculated from the Arrhenius-type plots, compared with the 24%-BLVL (22.95 kJ·mol-1) and the moso bamboo strips (12.69 kJ·mol-1), the effect of temperature on the swelling rate was greatest for the 12%-BLVL (24.15 kJ·mol-1). Results showed that the BLVL material is a promising candidate for a novel cooling tower packing material.

Tensile properties of bamboo fiber (BF)/polypropylene (PP) composites were investigated for different impregnation modification processes. The surface morphology of BF and the fracture morphology of the BF/PP composites were examined by scanning electron microscopy (SEM). Images showed that CaCO3 nanoparticles (nano-CaCO3) adhered to the fiber surfaces. Tension tests of individual bamboo fibers (IBFs) and the BF/PP composites were conducted. The results indicated that the tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EAB) of IBFs increased by 16.0%, 22.2%, and 5.2%, respectively, while those of the BF/PP composites increased by 3.0%, 7.0%, and 15.8%, respectively, compared to the control samples. Various process parameters during the impregnation with nano-CaCO3 had marked effects on the tensile properties of the composites. The optimal conditions for BF-reinforced PP composites by impregnation modification were determined to be a nano-CaCO3 concentration of 1.0×10-2 g/mL, an ethylenediamine tetraacetic acid disodium salt (EDTA-2Na) additive concentration of 8.5×10-4 g/mL, and an impregnation time of 25 min.

The purpose of this study was to investigate the effect of white mud (WM) on mechanical and thermal properties of bamboo plastic composites (BPCs). Bamboo residue fibers (BRFs) and WM were added as the reinforcement, and high-density polyethylene (HDPE) served as the matrix. The lubricating agent and coupling agent were polyethylene wax and maleated polyethylene (MAPE), respectively. The mixture was used to manufacture BPCs using a twin-screw extruder. The crystal structure and thermal properties of BPCs were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the particle size of the WM was 700 nm to 50 μm, which are made mainly of calcium carbonate. BPCs with WM significantly increased the flexural and tensile properties, but the impact strength decreased because of the presence of WM. The flexural and tensile strength of composites with 18 wt% BPF were increased by 36.81% and 6.26%, respectively, while the flexural and tensile modulus were increased by 164.29% and 64.33%, respectively. XRD demonstrated the WM had little effect on the crystal structure of BPCs. Compared to BPCs without WM, the T5% of composites with 22 wt% WM decreased by 27.9 °C. As the WM content increased, the crystallinity of the BPCs decreased initially, then increased with increasing WM content.

The study of viscoelastic and mechano-sorptive creep on bamboo laminated veneer lumber (BLVL) and bamboo/poplar plywood (BPP) is described in this paper. Bending creep tests parallel to the grain were carried out on two bamboo-based composites for a length of 90 days. The specimens measured 500 mm × 20 mm × 12 mm. Based on the experimental data, the creep curves of two boards were evaluated. The results are summarized as follows: (1) the anti-creep property of BLVL was better than that of BPP; (2) two creep curves were successfully approximated using the Burgers model and the power law model. The required experimental term for the creep test to estimate an accurate long-term curve is 2 or 3 years when the power law is used for the estimation; and (3) compared with the creep curve in a constant environment, the creep deformation changed more dramatically under varying environment.

This study inspected the thermal decomposition kinetics of core-shell structured wood-plastic composite material with white mud loading in the shell. The thermal decomposition was studied via thermogravimetric analysis under nitrogen atmosphere. Experiments were performed at different heating rates of 5, 10, 20, 30, and 40 °C/min from ambient temperature to 700 °C. Multivariate linear regression analysis was applied to estimate the activation energy with the Flynn–Wall–Ozawa method, and the thermal aging life equations of composites were obtained as described in ASTM E1877 (2000). The results showed that the combustion characteristic parameters (T5%, Tp1, Tp2, and Tp3) increased at first and then decreased with increased white mud concentration. Accordingly, the average apparent activation energy (Ea) values of thermal decomposition with conversion rates ranging between 20% and 80% were 222 kJ/mol for high-density polyethylene (HDPE) shell layer and the average values of 201, 226, 201, 207, and 223 kJ/mol were achieved with white mud loading of 5, 10, 15, 20, and 25% in the shell layer, respectively. There were no remarkable dependencies among them. The service life tf (min) and the service temperature T (K) of the core-shell structured wood-plastic composites were experimentally determined. [ABSTRACT FROM AUTHOR]

To investigate the possibility of using bamboo-bundle laminated veneer lumber (BLVL) as a cooling tower packing material, the water absorption rates, thickness swelling rates, and flexural properties of three different composite materials were studied. The BLVL was combined with either 12% or 24% phenol formaldehyde resin (PF), and the moso bamboo strips were exposed to water baths at three different temperatures (45, 65, and 85 °C) for 30 d. After the aging treatments, the 24%-BLVL samples showed lower water absorption rates and better bending properties than the other two composites. The temperature was found to have a significant effect on the modulus of rupture (MOR), modulus of elasticity (MOE), and the thickness swelling rate. As the temperature increased, the swelling rate and the rate of weight gain increased and the MOE and MOR decreased. According to the activation energies for swelling calculated from the Arrhenius-type plots, compared with the 24%-BLVL (22.95 kJ·mol-1) and the moso bamboo strips (12.69 kJ·mol-1), the effect of temperature on the swelling rate was greatest for the 12%-BLVL (24.15 kJ·mol-1). Results showed that the BLVL material is a promising candidate for a novel cooling tower packing material. [ABSTRACT FROM AUTHOR]

The study of viscoelastic and mechano-sorptive creep on bamboo laminated veneer lumber (BLVL) and bamboo/poplar plywood (BPP) is described in this paper. Bending creep tests parallel to the grain were carried out on two bamboo-based composites for a length of 90 days. The specimens measured 500 mm × 20 mm × 12 mm. Based on the experimental data, the creep curves of two boards were evaluated. The results are summarized as follows: (1) the anti-creep property of BLVL was better than that of BPP; (2) two creep curves were successfully approximated using the Burgers model and the power law model. The required experimental term for the creep test to estimate an accurate long-term curve is 2 or 3 years when the power law is used for the estimation; and (3) compared with the creep curve in a constant environment, the creep deformation changed more dramatically under varying environment. [ABSTRACT FROM AUTHOR]