Migration behavior of anionic polyurethane dispersion during infiltration and redistribution in sand

Zang, Yunxiao; Xie, Hao; Gong, Wei; Du, Zechuan; Liu, Bailing; Chen, Hualin

doi:10.1039/c6ra02764d

Cited by 6 publications

(2 citation statements)

References 32 publications

(28 reference statements)

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“…4(b), the precipitated nutrient connected two adjacent particles and the outline of particles was unobstructed. This is similar to SEM images given by Zang et al (2016), which studied the precipitation of organic polymers in sand.…”

Section: Gas Permeability At Different Degrees Of Saturationsupporting

confidence: 87%

Effects of biofilm on gas permeability of unsaturated sand

Coo

et al. 2019

Géotechnique

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Microbial activities may sustainably improve earthen structures such as landfill covers. Typically, after consuming nutrient, bacteria produce hydrated exopolysaccharide to form a biofilm, which may cause bio-clogging in soil. Previous studies have mainly focused on the combined effects of biofilm and nutrient on the water permeability of saturated sand. The present study investigates biofilm effects on gas permeability of unsaturated sand at different degrees of saturation using a flexible wall permeameter. Soils with water (‘Water’), nutrient only (‘Nutrient’) and a mixture of bacteria and nutrient (‘Combined’) were examined with three replicates. Statistical analysis and scanning electron microscopy (SEM) were adopted for further interpretation. Compared to ‘Water’, the gas permeabilities of ‘Combined’ and ‘Nutrient’ were consistently lower. The differences increase with decreasing saturation. At around 5% degree of saturation, the gas permeability of the ‘Combined’ and ‘Nutrient’ cases was 22% and 14% lower than the ‘Water’ case, respectively. Statistical analysis reveals that the gas permeability reductions in ‘Combined’ and ‘Nutrient’ cases were significant at a significance level of less than 0·05 (probability > 95%). The reduction was attributed to pore clogging by nutrient precipitation (for ‘Nutrient’) or both biofilm and nutrient precipitation (for ‘Combined’), as evident from the SEM results. The effects of biofilm on reducing soil gas permeability can be overestimated if nutrient effects are ignored.

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Section: Gas Permeability At Different Degrees Of Saturationsupporting

confidence: 87%

Effects of biofilm on gas permeability of unsaturated sand

Coo

et al. 2019

Géotechnique

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“…It is necessary to harness desertification for curbing the development trend of desertification. At present, there are three ways for combating desertification by sand fixation: engineering sand fixation, vegetal sand fixation, and chemical sand fixation . Among them, the first one is effective and the second is environment‐friendly, but both have the disadvantages such as high cost, difficult construction, and some unlivable environmental factors .…”

Section: Introductionmentioning

confidence: 99%

Inner relationship between the damping property and the sand‐fixing durability of polymer materials

Xie

Liu

Chen

et al. 2018

J of Applied Polymer Sci

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This article for the first time reveals the impact of the damping property of materials on its sand‐fixing durability. Based on the turbulence of wind, it could be regarded as a kind of periodic mechanical force. So, when polymers are used to fix sand, they would constantly perceive a periodic force of wind. And, this force would give rise to yielding fracture and fatigue of polymer, so that the sand‐fixing durability of material could be weakened significantly. To impair the periodic force of wind and extend the durability of sand‐fixation polymer materials, we, for the first time, introduce the designing principle of macromolecular damping material, that can transform external mechanical force into own thermal energy, into the preparation of sand‐fixing materials. In this work, poly(vinyl acetate) (PVAc) emulsions with different dangling chain have been synthesized successfully in order to improve their damping properties. The effects of the prepared PVAc with gradually growing dangling chain length have been investigated on their damping properties, on the sand stabilization strengths and sand‐fixing durability. And the relationship between the damping property and the sand‐fixing property of PVAc was built by simulating wind tunnel test. The experimental results show that, introducing the dangling chain could significantly improve the damping temperature range and extend the anti‐wind erosion time of PVAc. It has to be noticed that, introducing the dangling chain, will provide a double effects for the sand stabilization strength of materials, i.e., it can improve both the flexibility of the side‐chain and the internal friction of the molecular chains. Wind tunnel test verified that introducing the dangling chain can raise the damping performance of material and convert more periodic force of wind into the friction heat of molecular chain, and thus impair the damage of wind on the materials and improve their anti‐wind erosion properties. These findings suggest that the damping material applied in sand fixation is a bright idea and successful method for improving the sand‐fixing durability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47208.

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Effects of different segments in polyurethane on the performance of sand stabilization

Zang

Gong

Liu

et al. 2018

J of Applied Polymer Sci

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Synthetic polymers have recently drawn increasing attention to chemical sand stabilization (CSS). The relationship between the molecular structure and the fixing effect, however, is rarely reported aside from the performance. In this article, different segments of waterborne polyurethane dispersions (PUDs) are discussed with respect to their influence on stabilizing sand. We prepared five PUDs by controlling parameters including the diisocyanate‐to‐polyol ratio (R) and the molecular weight and characterized them with Fourier transform infrared spectroscopy and laser particle analysis. The unconfined compressive strength (UCS), a key criterion in CSS, was used to evaluate the performance of the PUDs. We found that a bigger R gave the polyurethane (PU) film a higher strength than the smaller R but did not do the same to the sand mold. This indicated that homogeneity was a primary property of the sand mold. Taking the details of the crushed sand molds and the PU films into account, we concluded that the soft segments played a major role in the homogeneity. Force analysis showed that four modes of breaking occurred at the interface of the sand and cured PU. We concluded that whereas the hard segments in PU determined the ceiling of the UCS, the soft segments determined the floor by benefiting adsorption. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47267.

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Migration behavior of anionic polyurethane dispersion during infiltration and redistribution in sand

Abstract: The migration behavior of anionic polyurethane (APU) dispersion (APUD) was investigated by using a newly established method, which is based weight measurement.

Cited by 6 publications

References 32 publications

Effects of biofilm on gas permeability of unsaturated sand

Effects of biofilm on gas permeability of unsaturated sand

Inner relationship between the damping property and the sand‐fixing durability of polymer materials

Effects of different segments in polyurethane on the performance of sand stabilization

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