Percentage Swelling Research Articles

The effect of magnesium chloride solution on the engineering properties of clay soil with expansive and dispersive characteristics

Because expansive and dispersive soils damage engineering structures, extensive studies on using additives to ameliorate the effects of these soils have been conducted. In this study, the effect of magnesium chloride (MgCl2) solution on the engineering properties of clay soils was evaluated. Previous studies on this subject have shown that MgCl2 is more commonly used as an anti-icing agent on roads than as a soil stabilizer. MgCl2 is also used to control dust and humidity on roads and to reduce the scattering of coarse particles from road surfaces. However, as the use of MgCl2 becomes more common, its potential to improve the geotechnical properties of problematic soils will receive increasing attention.To this end, the variation in the engineering properties of expansive and dispersive clay soil samples as functions of the added MgCl2 content was investigated. First, the physical and chemical properties of the soil sample were determined. Next, the swell percentage, swell pressure, crumb, pinhole and unconsolidated undrained (UU) triaxial compression tests were performed at different curing times on samples with and without the additive by compressing the sample to achieve particular compaction characteristics. Scanning electron microscopy (SEM) analyses were performed to observe the microstructures in the sample without the additive and with the amount of additive that most strongly improved the expansive and dispersive qualities of the clay. The results show that dispersive and expansive clay soils can be effectively improved using an additive MgCl2 solution.

Response surface methodology and optimized synthesis of guar gum-based hydrogels with enhanced swelling capacity

Guar gum based hydrogel was optimally synthesized using a response surface methodology (RSM) approach for enhanced swelling capacity. Maximization of the water absorption capacity of the synthesized hydrogel was achieved through sequential experimental design based optimization. A fractional factorial screening (Resolution-IV) approach was used to screen significant process variables for maximization of percentage swelling in phase-1. Studied reaction parameters were: (i) monomer concentration, (ii) initiator concentration, (iii) cross linker concentration, (iv) polymerization time, (v) reaction temperature, (vi) vacuum level, and (vii) pH of reaction mixture. A Pareto chart indicated monomer concentration, pH and initiator concentration as significant process variables which were further optimized using full factorial design (23) in phase-2. RSM based center composite design (CCD) was applied to maximize the percentage swelling for the two most significant variables (pH and initiator concentration) in phase-3. Statistical modeling using ANOVA predicted a near neutral range for pH (∼7.0) and an initiator concentration of 21–23 × 10−6 mol L−1 as optimum operating conditions for maximizing the percentage of swelling (5307%). Hydrogels were found to be highly pH sensitive and should be kept in a narrow range for maximization of percentage swelling. Thus, the sequential experimental design was helpful in achieving two fold increases in percentage swelling in a systematic way. Synthesized super absorbent polymers can be used as effective water-saving materials for horticultural and agricultural applications.

Experimental investigation and modeling of the anti-cancer drug delivery from poly(N-isopropylacrylamide-co Acrylic acid) copolymeric hydrogels

The diffusion mechanism of a model anti-cancer drug in cross-linked poly(N-isopropylacrylamide/acrylic acid) (P(NIPAAm/AA) copolymeric hydrogels was studied. The crosslinking ratiowas constant but acrylic acid ratio ranged from 10:1 to 10:3. P(NIPAAm/AA) copolymeric hydrogels were synthesized by redox-initiated free radical polymerization in water at room temperature The presence of poly(ethyleneglycol) in the hydrogel formulation resulted the higher mechanical strength. Use of acrylic acid resulted in higher hydrogel swelling. Drug size was also found to be a significant factor. 5-FU is used as amodel anti-cancer drug. The effect of 5-FU solution on swelling characteristics P(NIPAAm/AA) copolymeric hydrogels have also been studied. The percent swelling, equilibrium swelling, diffusion constant values are evaluated for P(NIPAAm/AA) copolymeric hydrogels at 1.5% of 5-FU solution at room temperature Based on the release kinetic of the 5-FU drug, the hydrogels displayed a non-Fickian diffusion mechanism. According the diffusion kinetic data in hydrogels became clear that diffusion kinetic data were best described by Peppas model. Permeation from P(NIPAAm/AA) copolymeric hydrogels followed a Super Case II transport mechanism, most likely driven by macro molecular chain relaxation and swelling of hydrophilic polymers.

A PRELIMINARY INVESTIGATION OF GYPSUM BONDED MOULDS BY THREE DIMENSIONAL PRINTING

Gypsum is used as binder in traditional moulding sand system for non-ferrous casting. New Zealand silica sand is the best sand as near white, high purity (silica 99.32%) can be used for foundry application. An attempt has been made to use this material system in 3DP systems to study the behaviour and suitability to print moulds for non-ferrous casting with and without coating application at various baking conditions. The result shows that the importance of the calcination and the relation between the density and porosity, when density increases the mould strength increases but the porosity decreases and it is understood that the baking temperature and the type of coating influence the surface roughness. The dimensional error result shows the percentage swelling and shrinkage errors which is non-linear, but the result shows 0.5 % shrinkage in lateral axis, 1% in horizontal axis, and 5% in vertical axis. Based on the volume the average error is been drastically reduced from 64.5% to 6.5%. These result shows that the mould shrinkage can be reduced by further optimizing the baking condition and or adding suitable additives. There were no casting defects like mould wash, mould burn or distortion, and etc. It shows that the gypsum bonded mould have enough mould strength for casting at various conditions. In general surface roughness is the main concern in sand casting, it can be improved by adding suitable additives and coatings. Compare with two bench marked values the tensile strength value is higher and it’s proved that the locally available material system used to print moulds by 3DP is not an inferior with commercially available material system.

Waste Silicon Carbide as Filler for Natural Rubber Compounds

This work studied possibilities of using waste silicon carbide (SiC) particles from abrasive industry as alternative filler in natural rubber (NR) compounds. The rubber was prepared by using natural rubber grade STR 5L and waste silicon carbide loading of 0, 10, 20, 30 and 40 phr. Firstly, the rubber were compounded by using two roll mill and then using Oscillating Disc Rheometer for studying cure time at one hundred and fifty degree Celsius. Then, shear viscosity and extrudate swell of the compounded natural rubber were characterized by using capillary rheometer at 100°C. The result showed that the apparent shear viscosity increased slightly with increasing waste silicon carbide loading and the percentage of extrudate swell was found to be a decreasing function of the filler loading. Then, test tensile by using the prepared samples for studying tensile modulus, tensile strength and elongation at break. The result showed that tensile modulus and tensile strength increased with increasing waste silicon carbide. On the other hand, the elongation at break of the filled natural rubber decreased with increasing waste silicon carbide. Finally, bring the sample to test hardness by using shore A. Results indicated that waste silicon carbide direct variation with the indicator of hardness.

Environmentally sensitive hydrogels: N‐isopropyl acrylamide/Acrylamide/ Mono‐, Di‐, Tricarboxylic acid crosslinked polymers

Environmentally sensitive hydrogels responsive to various stimuli such as temperature, pH, ionic strength of the medium and the solvent were prepared by using N‐isopropyl acrylamide (NIPAM), acrylamide (AAm) and monomers that have various number of carboxylic acid (XA) functionality using N,N′‐methylene bisacrylamide (Bis) as crosslinker. Hydrogels were prepared via free radical polymerization reaction in aqueous solution. P(NIPAAm‐co‐AAm) and p(NIPAAm‐co‐AAm)/XA hydrogels that contain monoprotic crotonic acid (CA) exhibit a lover critical solution temperature (LCST) at 28°C, whereas p(NIPAAm‐co‐AAm)/IA (IA:itaconic acid), and P(NIPAAm‐co‐AAm)/ACA (ACA:acotonic acid) hydrogels exhibit a lover critical solution temperature at 30.7°C and 34.4°C, respectively. Spectroscopic and thermal analyses were performed for the structural and thermal characterizations of the prepared hydrogel. The swelling experiments as equilibrium swelling percentages by gravimetrically were carried out in different solvents, at different solutions temperature, pH, and ionic strengths to determine their effects on swelling characteristic of hydrogels. POLYM. ENG. SCI., 55:843–851, 2015. © 2014 Society of Plastics Engineers

Synthesis and biodegradation studies of gamma irradiated electrically conductive hydrogels

Abstract Poly(acrylamide-aniline)-grafted gum ghatti [Gg-cl-poly(AAm)] conducting hydrogel was prepared via 60 Co γ-irradiation using N, N′-methylene-bis-acrylamide as a cross linker. The effects of the reaction conditions (viz. gamma dose, monomer, solvent and cross linker concentration) were investigated on the degree of swelling of Gg-cl-poly(AAm). Results showed that optimum reaction conditions for maximum percentage swelling were 10 ml of solvent, 1.08 mol/L of monomer concentration, 0.324 × 10 −1 mol L −1 of crosslinker concentration and 1.5 kGy of total dose. The semi-interpenetrating network (Semi-IPN) was converted into an IPN through the impregnation of poly(aniline) chains followed by doping with HCl. The influence of dopant concentration on the conductivity of synthesized hydrogel was investigated. Different physical properties of the synthesized hydrogel were also studied. The candidate polymers were characterized using different techniques such as X-ray diffraction and thermogravemetric analysis techniques. The mechanism of graft copolymerization via 60 Co irradiation was discussed. Biodegradation studies of the synthesized hydrogels were carried out using a soil burial test. IPN showed better degradation efficiency than semi-IPN. Weight loss of semi-IPN and IPN was 68% and 78%, respectively, in 60 days. Different degradation stages were studied using FTIR and SEM techniques.

Swelling Characteristics of Saudi Tayma Shale and Consequential Impact on Light Structures

Expansive soils in Saudi Arabia have received wide attention in recent decades, following the rapid urbanization of rural and agricultural parts of the country. Tayma expansive shale inflicted serious damages to light structures, roads and boundary walls. This research is aimed at studying the engineering characteristics of the shale at this area including the basic geotechnical parameters as well as swelling behavior under oedometric loading conditions. The engineering properties were determined and compared to the local and international characterization charts. Mineralogy study using x-ray diffraction was conducted to investigate clay minerals present. The swell percent and the swelling pressure of the shale were investigated for samples prepared at different initial moisture contents and various dry densities. A close-up view of damages caused by the expansive shale in the town is highlighted and measures to reduce the risk of potential swelling distress for future constructions are presented.

Prediction of the Vertical Swelling Percentage of Expansive Clays Using a Two-Stage Artificial Neural Networks Methodology

Abstract Artificial Neural Networks (ANN), which are used in many different areas, have been applied to predict the vertical swelling percentage of expansive clays. In contrast to previous models that estimated ANN Models in a single phase, this paper proposes an alternative analysis in based on the following two-stage operation: (a) conducting an ANN analysis on the swelling-pressure test results (i.e., the ASTM 4546 Method C test results) to obtain the swelling-pressure model for any given clay characteristics, and (b) performing an additional ANN analysis on the swelling-percentage test results (i.e., the ASTM 4546 Method B test results), including the former ones, with the given independent variables of the clay characteristics. This second stage includes a defined expression containing the given surcharge pressure and the predicted value of the swelling pressure as obtained from the model of the previous stage. Two final ANN Models, each with a different arrangement of the given independent variables, were derived from this two-stage procedure. Their statistical fit was clearly found to be superior in comparison to previous models estimated with the same data set. Furthermore, one of these two models exhibited the expected geophysical behavior. As this new ANN Model yields higher predicted swelling-percentage values, it can definitely be regarded as a preferable one in the sense of enlarging the safety margin in heave calculations.

Water retention and dye adsorption behavior of Gg-cl-poly(acrylic acid-aniline) based conductive hydrogels

Investigation on water retention and dye adsorption behavior of Gg-cl-poly(acrylic acid-aniline) conducting hydrogel has been studied. In this study, a novel poly(acrylic acid-aniline)-grafted gum ghatti based conducting hydrogel were synthesized by a simple two-step method. Initially, superabsorbent copolymers based on acrylic acid and gum ghatti was prepared using N,N′-methylene-bis-acrylamide and ammonium persulfate as a cross linker-initiator system under microwave irradiation. Optimum reaction conditions affording maximum percentage swelling were: solvent=10ml, acrylamide=0.291×10−3 molL–1, ammonium peroxydisulfate=0.291×10−3 molL–1, N, N′-methylene bisacrylamide=0.324×10−1 molL−1, reaction time=55s, microwave power=100% and pH=7.0. The effect of different reaction parameters on the swelling capacity was investigated. In the final step, polyaniline was entrapped within a crosslinked hydrogel followed by doping with hydrochloric acid (HCl), which led to the formation of conducting hydrogel. The IPN has been observed to exhibit as much as 2032% swelling in aqueous solution. Synthesized hydrogels were analyzed using FTIR, XRD, SEM and TGA. Application of hydrogels to improve the water retention properties of different soils was studied and found that the IPN hydrogel can improve the moisture retention capacity of soil for cultivation. Finally, synthesized hydrogels was studied for dye removal from waste water. It has been found that IPN hydrogel shows better adsorption behavior than semi-IPN.

Engineering Properties of Bentonite Stabilized with Lime and Phosphogypsum

The paper presents the engineering properties such as compaction, unconfined compressive strength, consistency limits, percentage swell, free swell index, California bearing ratio and consolidation of bentonite stabilized with lime and phosphogypsum. The content of lime and phosphogypsum was varied from 0 to 10% to check the improvement in the engineering properties. The results of this study reveal that the dry unit weight and optimum moisture content of bentonite + 8% lime increased with the addition of 8% phosphogypsum. The dry unit weight and optimum moisture content of bentonite + 8% lime increased with the addition of 8% phosphogypsum. The percentage swell increased and free swell index decreased with the addition of 8% phosphogypsum to the bentonite + 8% lime mix. The unconfined compressive strength of the bentonite + 8% lime increased with the addition of 8% phosphogypsum as well as increase in curing period up to 14 days. Beyond a phosphogypsum content of 8%, the unconfined compressive strength decreased. The liquid limit and plastic limit of bentonite + 8% lime increased where as the plasticity index remains constant with the addition 8 % phosphogypsum. The California bearing ratio, modulus of subgrade reaction, secant modulus increased for the bentonite stabilized with lime and phosphogypsum. The coefficient of consolidation of bentonite increased with the addition of 8% lime and no change with the addition of 8 % phosphogypsum. The improved behaviour of the bentonite-lime-phosphogypsum mixture will boost the construction of road pavements on such problematic soils.

Deregulation of inflammatory response in the diabetic condition is associated with increased ischemic brain injury.

BackgroundAlthough elicited inflammation contributes to tissue injury, a certain level of inflammation is necessary for subsequent tissue repair/remodeling. Diabetes, a chronic low-grade inflammatory state, is a predisposing risk factor for stroke. The condition is associated with delayed wound healing, presumably due to disrupted inflammatory responses. With inclusion of the diabetic condition in an experimental animal model of stroke, this study investigates whether the condition alters inflammatory response and influences stroke-induced brain injury.MethodsC57BL/6 mice were fed a diabetic diet (DD) for 8 weeks to induce an experimental diabetic condition or a normal diet (ND) for the same duration. Gene expression of inflammatory factors including monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), CCR2, and CD36 was assessed in the peripheral immune cells and brains of normal and diabetic mice before and after focal cerebral ischemia. The expression of these factors was also determined in lipopolysaccharide (LPS)-treated cultured normal and diabetic macrophages. Ischemic outcome was assessed in these mice at 3 days post-ischemia.ResultsDD intervention in mice resulted in obesity and elevated insulin and glucose level in the blood. The peritoneal immune cells from the diabetic mice showed higher MCP-1 mRNA levels before and after stroke. Compared to normal mice, diabetic mice showed reduced MCP-1, IL-6, and CCR2 gene expression in the brain at 6 h post-ischemia. LPS-stimulated inflammatory responses were also reduced in the diabetic macrophages. The diabetic mice showed larger infarct size and percent swelling.ConclusionsThese results showed that diabetic conditions deregulate acute inflammatory response and that the condition is associated with increased stroke-induced injury. The study suggests that interventions aimed at restoring appropriate inflammatory response in peripheral immune cells/macrophages may be beneficial in reducing stroke-induced brain injury in subjects with chronic inflammatory conditions.

The effect of different types of water on the swelling behaviour of expansive clays

In the design of foundations of structures, especially light buildings, on clayey soils, the main soil behaviours to be considered are swelling properties and surface heave. Therefore, determination of swelling properties by means of swell percent and maximum swell pressure as well as estimation of the surface is very important in the investigation of such soils and light structures on them. In order to obtain the swelling parameters of clayey soils, experimental laboratory tests were carried out and standardised. Distilled water is generally used during these experimental tests; however, the soil in situ interacts with different types of water having different water chemistries. Therefore, the swelling behaviour of expansive soils tested with distilled water would naturally be different from the behaviour of expansive soils tested with different water types and chemistries. For this reason, it was anticipated that determination of the realistic swell behaviour in laboratory experiments requires the use of the same water as in the in situ condition. In this article, the effect of the water type and chemistry on the swelling behaviour of the clays was investigated by testing the clay samples with eight different types of water collected from the sea, river, lake and different rock formations. The main result of this research was that the anticipated clay swell percentages and pressures for different types of water were lower than for the distilled water routinely used in testing.

Ultraviolet-induced free radical reactions in ENR50/alkyd blend leading to significant increase in cross-linking

In this work, the potential of palm stearin alkyd as a cross-linking agent for rubber compounding was investigated. Alkyd carrying pendent –COOH groups was blended with epoxidised natural rubber (ENR50) via solvent casting technique at ambient temperature. Spectroscopic characterisations show that ENR50 and alkyd have interacted with each other via chemical reaction involving the epoxide of the rubber and –COOH of alkyd. Consequently, notable increase in the glass transition temperature ( Tg) and gel content of the blend was observed. In addition to the epoxide ring-opening reaction, the extent of cross-linking in the blend was further increased by means of ultraviolet (UV) curing. As a result, the UV-cured blends experienced lower percentage of swelling, produced higher percentage of gel, have higher cross-link density and higher Tg. The cross-link density in the rubber/alkyd blend has increased from 3.0 × 10−6 mol cm−3 to 2.0 × 10−4 mol cm−3 after UV curing. This is clearly evidenced from the swelling test results, where ENR and alkyd are completely soluble in the solvent, but upon blending and subsequent UV irradiation, the blend produced >90% of gel and swelled by 318%. Findings from this work show that sustainable material such as vegetable oil could be utilised in development of cross-linking agent for rubber. Significant increase in the cross-link density of the UV-cured blend suggests that environment friendly compound such as alkyd has great potential to serve as an alternative to conventional compounds in rubber vulcanisation.

Caractérisation minéralogique et géotechnique des argiles marneuses gonflantes de la région de Médéa, Algérie

This paper presents the approach followed for the geological, mineralogical, and geotechnical characterization of swelling marly clays in the Medea region. This investigation is conducted in order to estimate the swelling potential of this marly clay layer. The studied sites, located at about 80 km south of Algiers, Algeria, cover an area of approximatively 400 hectares. Five sites are considered. In the first step, the geological, tectonic, climatic, and hydrological contexts of the region are described. According to the geological map of Medea, most of the formations encountered in the area are composed of Miocene layers represented by marly clays (Fig. 2). This region is characterized by its high and low temperature in summer and winter, respectively, and variable humidity (Fig. 3). In a second step, the results of geotechnical studies, X-ray diffraction tests, chemical analyses, and scanning electron microscope (SEM) observations are presented (Figs. 3, 4, 5, 6, 7, 8, 9). The soils contain quartz (20–26 %), calcium carbonates (11–55 %), kaolinite (8–13 %), illite (6–14 %) and Montmorillonite (18–26 %). The study of their microstructure by means of SEM indicates that these soils are formed by a compact marly clay matrix that is relatively homogeneous and oriented in the dip direction of bedding. A grain size analysis shows that the clay content varies between 17 and 70 %. The water content of all samples varies between 8 and 30 %. The values of the liquidity limit (LL) and plasticity index (PI) vary between 28–76 % and 16–36 % respectively, indicating a highly plastic soil; this is also confirmed by a specific surface varying between 99 and 179 m2/g. The dry density γd varies between 15 and 19 kN/m3. The swelling potential of the marly clay samples is evaluated firstly using various indirect methods. In literature, a number of empirical classifications are proposed by different authors (BRE 1980; Chen 1988; Komornik and David 1969; Seed et al. 1962; Snethen 1984; Vijayvergiya et Ghazzaly 1973 et Williams and Donaldson 1980). The swelling potential is related to certain physical properties of soils, such as consistency limits, clay content, methylene blue value, etc. In general, these methods indicate that all the tested soils have a high swelling potential, which confirms the results of mineralogical analysis. Secondly, direct measurements of swelling parameters are performed. Swelling tests are carried out using a standard slaved one-dimensional odometer using two methods: free swell and constant volume, according to standard ASTM D 4546-90 and AFNOR (1995). The swell pressure, the swell percentage and the swell index are given in Fig. 16. It is noted that the soils develop very significant swell pressures which vary between 25 and 900 kPa. This is in agreement with the results obtained by empirical methods. This investigation clearly shows that the marly clays of the Medea region have a high swelling potential. Therefore, taking into account the phenomenon of soil swelling in structure design is essential.

Effects of sodium hydroxide treatment on the properties of low‐density polyethylene composites filled with chicken feather fiber

The effects of alkali treatment with sodium hydroxide on the tensile properties, morphology, thermal degradation, and mass swell of low‐density polyethylene (LDPE)/(chicken feather fibers (CFF)) composites were studied. The LDPE/CFF composites were prepared by using a Z‐Blade mixer at 180oC and a rotor speed of 50 rpm. The LDPE/CFF‐Treated composites exhibited higher tensile strength, Young's modulus, and final decomposition temperature but had lower mass swell percentage and elongation at break than the LDPE/CFF composites. An SEM morphology study showed that the CFF treatment could significantly improve adhesion at the interface and lead to ingress of the fiber into the LDPE phase. Thermogravimetric analysis indicated that the LDPE/CFF‐Treated composites had higher thermal stability than the LDPE/CFF composites. J. VINYL ADDIT. TECHNOL., 20:36–41, 2014. © 2014 Society of Plastics Engineers

Microwave Assisted Synthesis of Poly (Acrylamide-co-2-Hydroxyethyl Methacrylate)/Poly(Vinyl Alcohol) Semi-IPN Hydrogel

In this study, microwave irradiation technique is used to synthesize poly (acrylamide-co-2-hydroxyethyl methacry-late) / poly(vinyl alcohol) (P(AM-co-HEMA)/PVA) semi-IPN hydrogels, which are separately synthesized by using one-pot polymerization and two-step polymerization techniques. Semi-IPN hydrogels were crosslinked by glutaraldehyde (GA) using ammonium persulfate (APS) as an initiator. The first step, (P(AM-co-HEMA) network was synthesized in PVA aqueous solution, then followed by glutaraldehyde crosslinking reagent, it formed to semi-IPN structured. The presence of function groups in the structure of hydrogel films were confirmed using Fourier transform infrared spectroscopy (FT-IR). Swelling behaviors of the hydrogel were measured gravimetrically in distilled water at the temperature of 27°C. The results showed that the hydrogel prepared by one-pot polymerization technique exhibited the highest swelling ratio (the percentage swelling has higher than 900%), comparing with the hydrogels prepared by two-step polymerization technique. Therefore, the one-pot polymerization is the suitable technique to prepare the P(AM-co-HEMA)/PVA) semi-IPN hydrogels due to less synthesis time and providing acceptable swelling ratio.

Changes Caused by Heat Treatment in Color and Dimensional Stability of Beech (Fagus sylvatica L.) Wood

Thermal modifi cation of wood permanently alters several of its chemical and physical properties. Beech wood is one of the most important hardwoods in Central and Eastern Europe and is extensively used in furniture production. In this study the effects of thermal modifi cation of beech wood (Fagus sylvatica L.) on hygroscopic properties were examined and the color changes of the treated wood were determined. Beech wood has been subjected to a heat treatment at the temperature of 180 °C for fi ve different durations ranging from 2 to 10 h. A more intense, gradual color change of the treated samples was observed after 4-h treatment, whereas in some other cases the recorded alterations were less intense. The most pronounced color differentiations compared to untreated samples occurred in 8-h and 10-h treatments. Dimensional stability and absorption were measured after 1-h, 3-h, 6-h, 1 day and 3 days immersion in water. The 8-h treatment duration exhibits the greatest reduction of swelling and absorption percentage.

Gum ghatti based novel electrically conductive biomaterials: A study of conductivity and surface morphology

Gum ghatti-cl-poly(acrylamide-aniline) interpenetrating network (IPN) was synthesized by a two-step aqueous polymerization method, in which aniline monomer was absorbed into the network of gum ghatti-cl-poly(acrylamide) and followed by a polymerization reaction between aniline monomers. Initially, semi-IPN based on acrylamide and gum ghatti was prepared by free-radical copolymerization in aqueous media with optimized process parameters, using N,N!-methylene- bis-acrylamide, as cross-linker and ammonium persulfate, as an initiator system. Optimum reaction conditions affording maximum percentage swelling were: solvent (mL) =12, Acrylamide (AAm) (mol·L -1 ) = 1.971, Ammonium peroxydisulfate (APS) (mol·L -1 ) = 0.131·10 -1 , N,N!-methylene-bis-acrylamide (MBA) (mol·L -1 ) = 0.162·10 -1 , reaction time (min) = 210, temperature (°C) = 100 and pH = 7.0. The resulting IPN was doped with different protonic acids. The effect of the doping has been investigated on the conductivity and surface morphology of the IPN hydrogel. The maximum conductivity was observed with 1.5N HClO4 concentration. The morphological, structural and electrical properties of the candidate polymers were studied using scanning electron micrscopy (SEM), Fourier transform infrared spectroscopy FTIR and two-probe method, respectively.

DURABILITY OF EXPANSIVE SOIL USING ADVANCED NANOCOMPOSITE STABILIZATION

This article describes the effect of creating nanocomposite materials on the long -term durability of expansive soil. A series of tests were performed to examine the effect of induced nanocomposites on the durability behaviors of the expansive clay. Tests w ere carried out at different polymer contents and curing time. The nano-structure was examined to confirm the occurrence of nanocomposites through the stabilized samples. The results showed that the curing time can be modified the consistency state of stabilized samples. The induced nanocomposites within the swelling clay can be attributed to non -plastic properties and acted as a hydraulic binder with lesser swelling potential. After long term curing time 28 days, the use of 15% polymer content reduced the swell percent by 90% and increased the stiffness by 4.5 time of its initial value. The improving factor in its unconfined strength was found to be 220%. This can be tended to improve the long term durability and increased the resistance to immersion whic h confirmed the produced durable hydrophobic material.