Expansive soils owe their characteristics to the presence of swelling clay minerals. As they get wet, the clay minerals absorb water molecules and expand; conversely, as they dry they shrink, leaving large voids in the soil. Swelling clays can control the behavior of virtually any type of soil if the percentage of clay is more than about 5 percent by weight. Soils with smectite clay minerals, s...

Sodium carboxymethyl starch (CMS) was prepared using an extruder as a continuous solvent-less chemical reactor. The effects of NaOH, H2O, temperature, ethanol, sodium mono chloro acetate (SMCA), sodium tripolyphosphate (STPP), citric acid, epichlorohydrin and screw configuration on the degree of substitution (DS) and swelling properties of CMS were studied. Using these factors, CMS with the DS ...

The existence of specific expansive minerals in the clay soil related to the climatological conditions, seasonable variation of rainfall precipitation (wet and dry periods) and fluctuation of water table in Mediterranean countries, has resulted to induce unexpected shrinkage and swelling movements with all the unfavourable consequences. It was observed that light industrial structures and small...

Superporous hydrogels (SPHs), based on poly(2-hydroxyethyl methacrylate) (PHEMA), were prepared by adding minute amounts of an ioncomplexable hydrophilic acrylic acid. PHEMA SPHs are generally strong, but their swelling is minimal. To improve the swelling, different poly(HEMA-coacrylic acid) hydrogels were polymerized and crosslinked, then physically treated with divalent calcium and trivalent ...

A novel thermo-sensitive superabsorbent hydrogel with saltand pH-responsiveness properties was obtained by grafting of mixtures of acrylic acid (AA) and N-isopropylacrylamide (NIPAM) monomers onto kappa-carrageenan, kC, using ammonium persulfate (APS) as a free radical initiator in the presence of methylene bisacrylamide (MBA) as a crosslinker. Infrared spectroscopy was carried out to confirm t...

The chemical environment of bare, excised rabbit corneal stroma was varied to determine the effects of solutes on the swelling pressure. Measurements of changes in the thickness of the stroma are converted to hydration units which are in turn converted to a change in swelling pressure at the initial hydration. The order of effects on swelling pressure are compared to the Hofmeister series for p...