Sensitivity of bamboo fiber longitudinal tensile properties to moisture content variation under the fiber saturation point

Wang, Hankun; Tian, Guohui; Li, Wanju; Ren, Dan; Zhang, Xuexia; Yu, Yan

doi:10.1007/s10086-015-1466-y

Cited by 25 publications

(10 citation statements)

References 20 publications

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“…Stress relaxation refers to the fact that at a fixed strain, the stress resistance against deformation diminishes or relaxes on increasing time. WPCs are a kind of viscoelastic material and, therefore, exhibit a time‐dependent mechanical behavior, such as stress relaxation under deformation within the elastic region . Previous literature shows that the stress relaxation approach has been mainly used as a technique to investigate the interaction between wood and wood‐modifying chemicals , as well as the interface properties of natural fiber–plastics composites .…”

Section: Introductionmentioning

confidence: 99%

Thermal stability of organo‐montmorillonite‐modified wood flour/poly(lactic acid) composites

2015

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In this research, wood flour (WF) was modified using sodium-montmorillonite (Na-MMT) at four different concentrations (0.5, 1.0, 2.0, and 4.0 wt%, respectively) and didecyl dimethyl ammonium chloride (DDAC) in a twostep process to form organo-montmorillonite (OMMT) inside the WF or attached to the WF surface. The thusmodified WF was then mixed with poly(lactic acid) (PLA) to produce WF/PLA composites. The thermal stability of these composites with respect to their resistance against both thermal deformation and thermal decomposition was characterized by stress relaxation, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. Besides, the activation energies for thermal decomposition of the composites were calculated. The results showed the following: (1) The modification of WF by OMMT improved the resistance against thermal deformation of the composites at appropriate OMMT loadings (lower than 1 wt% in this study). However, after introducing excessive OMMT, the enhancements in thermal stability diminished. Composite containing WF modified by 0.5 wt% of OMMT showed the optimal thermal deformation stability in this study, reflected in the highest values of thermal properties such as the glass transition temperature, melting temperature, crystallization temperature, and slowest stress relaxation rate. (2) OMMT showed a negative effect on the resistance against thermal decomposition. Namely, OMMT accelerated the thermal decomposition of the composites, probably by the easier degradation of the organic surfactant used for the WF modification. However, this behavior might be favorable for achieving fire retardancy. POLYM. COMPOS., 00:000-000, 2015.

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Section: Introductionmentioning

confidence: 99%

Thermal stability of organo‐montmorillonite‐modified wood flour/poly(lactic acid) composites

2015

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“…previous study [14], namely, MAPP loading of 2% gives the optimal mechanical properties as well as the longterm stress relaxation.…”

mentioning

confidence: 67%

“…However, with the continuous increase of MAPP loading from 2 to 8%, the relaxation strength did not decrease further, which means that excessive MAPP is not helpful in restricting the reorientation of methylol groups in wood flour. Wang et al [14,15] also found by stress relaxation approach that excessive MAPP molecules may have had a negative effect on compatibility between wood flour and PP because excessive MAPP resulted in weaker hindrance for the methylol groups to reorient by conglomerating together leading to weaker bonding between MAPP and PP, or MAPP molecules themselves. It indicates that the optimal loading level for MAPP is 2% in composites, at which the most methylol groups are restrained and correspondingly the compatibility between wood and PP was the best.…”

Section: Cole-cole Plots Of Wood Flour/pp Composites With Different Mmentioning

confidence: 99%

“…Among those, MAPP is one of the mostly widely used types because MAPP is a very effective coupling agent for wood flour and polymer to improve the interfacial adhesion. The interfacial coupling mechanism between MAPP, wood flour and polymer was analyzed by various methods such as dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), scanning electron microscope (SEM), environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and the thermogravimetric analysis (TGA), etc [6][7][8][9][10][11][12][13][14][15]. It was indicated that the MAPP, which contains both polar groups and nonpolar groups, might produce a molecular bridge between wood and polymers by forming physical or/and chemical bonds and benefit the dispersion and aggregation of wood flour in polymer, which finally results in lower interfacial tension between wood and PP.…”

Section: Introductionmentioning

confidence: 99%

“…It was indicated that the MAPP, which contains both polar groups and nonpolar groups, might produce a molecular bridge between wood and polymers by forming physical or/and chemical bonds and benefit the dispersion and aggregation of wood flour in polymer, which finally results in lower interfacial tension between wood and PP. Some investigations [7,12,[14][15][16] further pointed out that there is an optimal loading level of MAPP to provide the best mechanical properties of the composites. These methods still can not quantitatively evaluate the interfacial compatibility of wood flour/polymer composites, but only provide some information on the compatibility of the interface.…”

Section: Introductionmentioning

confidence: 99%

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Effect of MAPP on interfacial compatibility of wood flour/polypropylene composite evaluated with dielectric approach

et al. 2013

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To quantitatively evaluate the effect of maleic anhydride grafted polypropylene (MAPP) as a coupling agent on interfacial compatibility between wood and polymer in wood/polypropylene (PP) composite, the dielectric constant and dielectric loss factor were measured for poplar (Populus tomentasa Carr.) wood flour/polypropylene (PP) composites prepared with six MAPP loading levels (0.5, 1.0, 1.5, 2.0, 4.0, and 8.0%), and the Cole–Cole plots, the dielectric relaxation strength, the distribution of relaxation time and the activation thermodynamic quantities of the dielectric relaxation based on the reorientation of the methylol groups (CH2OH) in the amorphous region of wood cell wall were further analyzed. The results showed that the dielectric relaxation strength decreased with the MAPP loading and dropped to the lowest at MAPP loading of 2.0%, after which it kept almost constant. It suggested that the internal bonding between wood and PP molecules was the strongest at 2.0% MAPP, therefore the reorientation of the methylol groups in wood became very difficult under the strong hindrance from the long‐chained PP molecules and the physical or/and chemical bonds between MAPP, wood flour, and PP in the composites. The activation free energy ΔE could be served as the indicator to quantitatively evaluate the effect of MAPP on interfacial compatibility of the wood/PP composites. ΔE of 2.0% MAPP modified composites showed the maximal value among all the tested conditions, which was 33.52 kJ mol−1; while the values for 1.5 and 4.0% MAPP modified were 23.35 and 21.75 kJ mol−1. Therefore, excessive MAPP was not beneficial to improve the internal compatibility of wood/PP composites, but had negative effect. POLYM. COMPOS., 35:489–494, 2014. © 2013 Society of Plastics Engineers

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Water absorption and mold susceptibility of wood flour/polypropylene composites modified with silane‐wax emulsions

Chen

Peng

et al. 2017

Polymer Composites

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Wood plastic composites can absorb water in exterior applications due to the hygroscopicity of wood flour (WF). The cycle of adsorption and desorption process causes damage to the interfacial bonding between WF and polymer matrix, which benefits the fungal attack. In this study, WF was, respectively, immersed with silane, wax emulsion, and their compound systems for modification at different concentrations (1, 2, and 4%, respectively). Then, the modified WF was mixed with polypropylene (PP) to produce WF/PP composites at mass ratio of 6:4. The water absorption and mold susceptibility of the composites against Aspergillus niger were investigated. The results showed that silane can improve the interfacial adhesion between WF and PP. The water uptake of WF/PP composites treated with 4% silane decreased by 6% compared with the control, and the average mold growth rating decreased from level 4 (mold covering of 75-100%) to level 1 (mold covering of 0-25%). The strong hydrophobicity of wax had a negative effect on the interfacial adhesion of the composites. Thus, composites modified with wax and silane-wax compounds showed higher water uptake than the control. However, the mold resistance of composites was improved in these groups. POLYM. COMPOS., 00:000-000,

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Sensitivity of bamboo fiber longitudinal tensile properties to moisture content variation under the fiber saturation point

Cited by 25 publications

References 20 publications

Thermal stability of organo‐montmorillonite‐modified wood flour/poly(lactic acid) composites

Thermal stability of organo‐montmorillonite‐modified wood flour/poly(lactic acid) composites

Effect of MAPP on interfacial compatibility of wood flour/polypropylene composite evaluated with dielectric approach

Water absorption and mold susceptibility of wood flour/polypropylene composites modified with silane‐wax emulsions

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