Improvement of Internal Stability of Alluvial Clay from Famagusta Bay, Cyprus, Using Copolymer of Butyl Acrylate and Styrene

2019 ◽  
Vol 25 (4) ◽  
pp. 289-300 ◽  
Author(s):  
Mohammad Reza Golhashem ◽  
Eris Uygar
Keyword(s):  
Butyl Acrylate ◽  
Erosion Resistance ◽  
Polymer Chains ◽  
Stability Test ◽  
Internal Stability ◽  
Actual Behavior ◽  
Clay Particles ◽  
Aqueous Polymer ◽  
Curing Period ◽  
Alluvial Clay

ABSTRACT The internal stability of alluvial clays may be significantly compromised during a heavy rainfall due to infiltration of surface water causing sudden inundation, softening, and loss of erosion resistance or mechanical strength. Most of the available stabilization methods for clay soils employ pozzolanic or other cementitious binders, creating a chemically bound clay-admixture matrix. These admixtures commonly require a curing period after placement and compaction. Alternatively, aqueous polymers can be used in diluted form without any need for a curing period. Aqueous polymers can form agglomerations of clay particles enclosed in a matrix of polymer chains, held together by electrostatic and hydrogen bonding, improving erosion resistance. In this research, an aqueous polymer, namely, copolymer of butyl acrylate and styrene (CBAS), is mixed with alluvial clay sampled from Famagusta Bay, Cyprus, and the clay stability test is performed as a basis for assessing the degree of improvement on erosion resistance. A time-dependent approach for the evaluation of test results is followed to increase the accuracy of the analysis of the actual behavior observed during the test. A significant improvement in the erosion resistance is observed in treated test specimens. The mode of collapse of specimens during the clay soil stability test when aqueous polymer is used also changed from being gradual cracking and slaking to explosive. The swelling behavior and the effect of drying on the erosion resistance are also observed in the testing program. X-ray diffraction analysis and Fourier transform infrared spectroscopy are performed for observation of the effect of CBAS on microstructural interactions, such as electrostatic bonding and changes in soil fabric.

Morphology, Crystalline Structure and Isothermal Crystallization Kinetics of Polybutylene Terephthalate/Montmorillonite Nanocomposites

2005 ◽  
Vol 13 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Defeng Wu ◽  
Chixing Zhou ◽  
Xie Fan ◽  
Dalian Mao ◽  
Zhang Bian
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Polymer Chains ◽  
Isothermal Crystallization Kinetics ◽  
Clay Particles ◽  
Nucleation Sites ◽  
Kinetics Of ◽  
Montmorillonite Nanocomposites

The melt intercalation method was employed to prepare poly(butylene terepathalate)/montmorillonite nanocomposites, and their microstructure was characterized by wide angle X-ray diffraction and transmission electron microscopy. The XRD results showed that the crystalline plane such as (010), (111), (100) was smaller than that of pristine PBT, which indicates that the crystallite size of PBT in the nanocomposites could be diminished by adding clay. Moreover, the isothermal crystallization kinetics of PBT and PBT/MMT nanocomposites was investigated by differential scanning calorimetry (DSC). During isothermal crystallization, the development of crystallinity with time was analysed by the Avrami equation. The results show that very small amounts of clay dramatically increased the rate of crystallization and high clay concentrations reduced the rate of crystallization at the low crystallization temperatures. At low concentrations of clay, the distance between dispersed platelets was large so it was relatively easy for the additional nucleation sites to incorporate surrounding polymer, and the crystal nucleus was formatted easily. However, at high concentrations of clay, the diffusion of polymer chains to the growing crystallites was hindered by large clay particles, despite the formation of additional nucleation sites by the clay layers. At the higher crystallization temperature, the crystallization of the nanocomposites was slower than that of the pure PBT under the experimental conditions, which means that with the increase in chains mobility at the high crystallization temperature, the crystal nuclei are harder to format, and the hindering effect of clay particles on the polymer chains was stronger than the nucleating effect of the layers. In addition, the activation energies of crystallization for PBT and its nanocomposites were calculated by the Arrhenius relationship, and the results showed that the nanocomposites with a low clay content had the lower activation energy values than PBT, while high amounts of clay increased the activation energy of PBT.

scholarly journals Synthesis and Characterization of a Lignin-Styrene-Butyl Acrylate Based Composite

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1080
Author(s):  
Daniel López Serna ◽  
Perla Elizondo Martínez ◽  
Miguel Ángel Reyes González ◽  
Antonio Alberto Zaldívar Cadena ◽  
Erasto Armando Zaragoza Contreras ◽  
...  
Keyword(s):  
Contact Angle ◽  
Butyl Acrylate ◽  
Raw Materials ◽  
Positive Influence ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Polymerization Process ◽  
Oh Groups ◽  
Water Measurement

In recent years, the pursuit of new polymer materials based on renewable raw materials has been intensified with the aim of reusing waste materials in sustainable processes. The synthesis of a lignin, styrene, and butyl acrylate based composite was carried out by a mass polymerization process. A series of four composites were prepared by varying the amount of lignin in 5, 10, 15, and 20 wt.% keeping the content of butyl acrylate constant (14 wt.%). FTIR and SEM revealed that the –OH functional groups of lignin reacted with styrene, which was observed by the incorporation of lignin in the copolymer. Additionally, DSC analysis showed that the increment in lignin loading in the composite had a positive influence on thermal stability. Likewise, Shore D hardness assays exhibited an increase from 25 to 69 when 5 and 20 wt.% lignin was used respectively. In this same sense, the contact angle (water) measurement showed that the LEBA15 and LEBA20 composites presented hydrophobic properties (whit contact angle above 90°) despite having the highest amount of lignin, demonstrating that the interaction of the polymer chains with the –OH groups of lignin was the main mechanism in the composites interaction.

The Effect of Clay Content on PMMA-Clay Nanocomposite Foams

2005 ◽  
Vol 24 (2) ◽  
pp. 49-70 ◽  
Author(s):  
Allan R. Manninen ◽  
Hani E. Naguib ◽  
A. Victoria Nawaby ◽  
Xia Liao ◽  
Michael Day
Keyword(s):  
High Pressure ◽  
Clay Content ◽  
Polymer Chains ◽  
Nanocomposite Films ◽  
Compression Moulding ◽  
Clay Particles ◽  
Nanocomposite Foams ◽  
Cell Structures ◽  
Nanoclay Content ◽  
Co Precipitation

In this study the CO2 sorption at 45 °C in PMMA nanocomposite films containing 2 wt.% of nanoclay has been measured using an in-situ gravimetric technique. The films examined were prepared by compression moulding material obtained by dry-blend and solvent co-precipitation techniques. The CO2 diffusion coefficients were found to be higher for the dry-blended nanocomposite due to the larger agglomerations of the organoclay agglomerations, which prevented the polymer chains from fully wetting and intercalating the clay particles. The Tg-p profile for PMMA nanocomposite containing 2 wt.% nanoclay in the presence of CO2 was also measured using high-pressure DSC. The glass transition phase envelope was shifted vertically by approximately 10 °C when compared to the value reported in the literature for neat PMMA. This result suggests that the nanoclay affects the plasticization behaviour of PMMA under high-pressure CO2 conditions. The cellular morphologies obtained for these PMMA nanocomposite foams produced by batch processing with subcritical CO2 are strongly dependent upon the clay content and the dispersion of the nanoclay in the material. In the case of intercalated nanocomposites, most clay particles exist as agglomerated stacks of silicate sheets. On foaming the cells tend to form around the clay particles causing either irregular-shaped cells or layers to be produced. As a result, the cell density increases and the mean cell size decreases in the foamed nanocomposite on increasing the nanoclay content. Accordingly, the resulting cell structures are highly non-uniform and show large variations in cellular morphologies throughout the foam.

Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand

1973 ◽  
Vol 31 ◽  
pp. 212-213
Author(s):  
John M. Wehrung ◽  
Richard J. Harniman
Keyword(s):  
United States ◽  
Surface Water ◽  
Direct Observation ◽  
Controlled Study ◽  
Clay Particles ◽  
Organic Debris ◽  
Rock Formations ◽  
Water Tables ◽  
Permeable Rock ◽  
Natural Means

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.

Freeze-etch TEM of aqueous polymer gel network morphology

1986 ◽  
Vol 44 ◽  
pp. 796-797
Author(s):  
J. A. N. Zasadzinski ◽  
R. K. Prud'homme
Keyword(s):  
Metal Ion ◽  
Polymer Network ◽  
Polymer Gels ◽  
Polymer Gel ◽  
Deformation History ◽  
Crosslinked Polymer ◽  
Aqueous Polymer ◽  
History Of ◽  
Gel Network ◽  
Network Morphology

The rheological and mechanical properties of crosslinked polymer gels arise from the structure of the gel network. In turn, the structure of the gel network results from: thermodynamically determined interactions between the polymer chain segments, the interactions of the crosslinking metal ion with the polymer, and the deformation history of the network. Interpretations of mechanical and rheological measurements on polymer gels invariably begin with a conceptual model of,the microstructure of the gel network derived from polymer kinetic theory. In the present work, we use freeze-etch replication TEM to image the polymer network morphology of titanium crosslinked hydroxypropyl guars in an attempt to directly relate macroscopic phenomena with network structure.

Solvent-assisted osmium staining of butyl acrylate and ethylene-propylene-diene in a styrene acrylonitrile matrix

1993 ◽  
Vol 51 ◽  
pp. 900-901 ◽  
Author(s):  
Gudrun A. Hutchins
Keyword(s):  
Butyl Acrylate ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Staining Procedure ◽  
Reactive Site ◽  
Ethylene Propylene ◽  
Minimal Distortion ◽  
Styrene Acrylonitrile ◽  
Engineering Polymers ◽  
Effective Reaction

In order to optimize the toughening effect of elastomers in engineering polymers, it is necessary to characterize the size, morphology and dispersion of the specific elastomer within the polymer matrix. For unsaturated elastomers such as butadiene or isoprene, staining with osmium tetroxide is a well established procedure. The residual carbon-carbon double bond in these materials is the reactive site and forms a 1,2-dilato complex with the OsO4. Incorporation of osmium tetroxide into the elastomer not only produces sufficient contrast for TEM, but also crosslinks the elastomer sufficiently so that ultramicrotomy can be accomplished at room temperature with minimal distortion.Blends containing saturated elastomers such as butyl acrylate (BA) and ethylene propylene diene monomer (EPDM) cannot be stained directly with OsO4 because effective reaction sites such as C=C or -NH2 are not available in sufficient number. If additional reaction sites can be introduced selectively into the elastomer by a chemical reaction or the absorption of a solvent, a modified, two-step osmium staining procedure is possible.

The internal stability of an elastic solid

2000 ◽  
Vol 80 (12) ◽  
pp. 2827-2840 ◽  
Author(s):  
J. W. Morris Jr, C. R. K Renn
Keyword(s):  
Elastic Solid ◽  
Internal Stability

What Can We Learn From Factorial Surveys About Human Behavior?

Methodology ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Knut Petzold ◽  
Tobias Wolbring
Keyword(s):  
Social Sciences ◽  
Behavioral Intentions ◽  
Actual Behavior ◽  
Full Time ◽  
Factorial Survey ◽  
Survey Experiment ◽  
Intended Behavior ◽  
The Social ◽  
Survey Experiments ◽  
High Level

Abstract. Factorial survey experiments are increasingly used in the social sciences to investigate behavioral intentions. The measurement of self-reported behavioral intentions with factorial survey experiments frequently assumes that the determinants of intended behavior affect actual behavior in a similar way. We critically investigate this fundamental assumption using the misdirected email technique. Student participants of a survey were randomly assigned to a field experiment or a survey experiment. The email informs the recipient about the reception of a scholarship with varying stakes (full-time vs. book) and recipient’s names (German vs. Arabic). In the survey experiment, respondents saw an image of the same email. This validation design ensured a high level of correspondence between units, settings, and treatments across both studies. Results reveal that while the frequencies of self-reported intentions and actual behavior deviate, treatments show similar relative effects. Hence, although further research on this topic is needed, this study suggests that determinants of behavior might be inferred from behavioral intentions measured with survey experiments.

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