Influence Of Water-soluble Polymers Research Articles

Water-soluble polymers in cementitious materials: A comprehensive review of roles, mechanisms and applications

This review paper provides an extensive assessment of the diverse roles played by water-soluble polymers in cementitious materials. It commences with an introduction that provides a thorough overview of the background, objectives and limitations of the review. Subsequently, the various types of water-soluble polymers, encompassing natural, semi-synthetic and synthetic variants, are examined in detail, alongside an exploration of their working mechanisms within cementitious materials. Mechanisms discussed include entanglement and association, adsorption and complexation, as well as bridging. Furthermore, this review delves into the influence of water-soluble polymers on the microstructure, fresh properties, mechanical properties and durability of cementitious materials. A comprehensive analysis of the challenges and opportunities associated with the implementation of water-soluble polymers in cementitious materials is also presented, followed by a summary of the key findings and recommendations for both practical applications and future research endeavors. Overall, this review provides invaluable insights for researchers and practitioners, shedding light on the multifaceted functions of water-soluble polymers in cementitious materials.

Influence of Water-soluble polymers on Epalrestat ternary complexation by kneading

The study reported in this current work objected to demonstrate the formation of binary and ternary inclusion complexes of Epalrestat (EP), a poorly water-soluble acidic type drug, with s-cyclodextrin (CD) and with water-soluble polymers PVP K30 and HPMC E4. The solid systems of EP with s-CD and water-soluble polymers were obtained by kneading and characterized for phase solubility, saturation solubility, dissolution, stability studies. FTIR, DSC, PXRD and SEM data indicated the positive influence of s-CD and hydrophilic polymers on EP solubility and dissolution. Phase solubility studies were carried out to evaluate the solubilizing power of CD, with regards to EP in combination with water-soluble polymers, and to determine the apparent stability constants (Ks) and complexation efficiency (CE) of the complexes. Phase solubility studies showed AL (linear) type of solubility curve for the ternary complexes it also showed amelioration in Ks value for ternary complexes. The CE of s-CD towards EP was promoted by water-soluble polymers signifying its use as a ternary component. The dissolution rate of EP and solubility were undoubtedly improved by complexation with s-CD as compared to model drug EP alone. Ternary complexes incorporated with PVP K 30 and HPMC E4 proved better than binary complex. Hence, the water-soluble carrier could be exploited as a ternary component to improve the solubility of EP via s-CD complexation.

Silicic acid condensation under the influence of water-soluble polymers: from biology to new materials

Silicic acid condensation under the influence of functional polymers is reviewed starting from biology to new materials.

Influence of water-soluble polymers on the in vitro performance of floating mucoadhesive tablets containing metformin

Context: The in vitro performance of floating mucoadhesive metformin tablets was optimized using different polymer ratios of polyvinylpyrrolidone (PVP) tamarind seed gum (TSG) and hydroxypropylmethylcellulose (HPMC).Objective: The objectives of this investigation were to investigate the combinatorial effects of PVP, TSG and HPMC; to study the work of adhesion measured on stainless steel (Wss) and on rabbit gastric mucosa (Wgm); and a comparison of hydrophilic and more hydrophobic tablets.Material and methods: In vitro performance was measured as tablet hardness (H), tablet floating lag time (FLT), time needed to release 60% of drug content (t60%), swelling thickness (S), Wss and Wgm. To compare the effects, a simplex lattice mixture design was used.Results and discussion: H, FLT, Wss and Wgm were found dependent on polymer ratio. H was increased when PVP ratio was increased. FLT, Wss and Wgm were increased when HPMC ratio was increased. The p value for the lack of fit for all models were greater than 0.05. An approximate linear correlation between Wgm and Wss was established (R2 = 0.71). The tablets containing PVP resulted in larger H, shorter FLT and t60%, whereas Wss and Wgm were enhanced.Conclusion: The different in vitro performance of tablets containing different water-soluble polymers could be explained partially by the differences in the hydrophilic properties of the polymers and the ability of PVP to interact with HPMC or TSG. An equation established is used to conclude mucoadhesion based on adhesion measurements on stainless steel.

First experiments at the Swiss Light Source Materials Science beamline powder diffractometer

The Materials Science beamline at the Swiss Light Source saw ‘first light’ in Spring 2001 and is presently undergoing commissioning and pilot experiment operation. In this article we concentrate on one of the three MS beamline stations, the Powder Diffractometer, and report on resolution tests and first experimental results. Using the high-resolution multi-crystal analyzer detector, full widths at half maximum (FWHM) smaller than 0.01° were measured with standard powders and FWHMs smaller than 0.003° were measured with a single Si(111) crystal and a very low-divergent incident beam. With the same detector, first residual stress measurements on low pressure plasma sprayed coatings were performed. Dynamic electric field-induced strain effects in relaxor perovskite crystals and the influence of water-soluble polymers on the early hydration of cement were studied using a fast read-out multistrip solid-state detector.

Influence of Water-Soluble Polymers on the Shear-Induced Structure Formation in Lyotropic Lamellar Phases

The shear-induced structure formation in lyotropic lamellar phases containing water-soluble polymers is investigated. The lyotropic phases consisted of sodium dodecyl sulfate/1-decanol/D2O and were mixed either with poly(n-isopropylacrylamide) (PNIPAM), hydroxyethyl starch (HES), poly(vinyl caprolactame) (PVCa), or poly(ethylenglycol)distearate (PEG-DS). Rheo-optical experiments (flow birefringence and small-angle light scattering, SALS) as well as small-angle neutron scattering (SANS) combined with a commercial rheometer were used to observe structural changes, e.g., layer reorientation or formation of multilamellar vesicles (liposomes). Equilibrium properties of the lamellar phases were investigated using quasi elastic light scattering (QELS) and static SANS, the latter was analyzed using a model proposed by Nallet et al. The polymer addition led to a viscosity increase but the flipping of aligned lamellae from parallel to perpendicular orientation was hardly affected by the polymers. The shear-induced formation of multilamellar vesicles (MLV), however, was strongly influenced by the macromolecules. The addition of small amounts of PNIPAM shifted the region where vesicles are formed to samples with higher decanol contents whereas HES, PVCa, and PEG-DS suppressed the MLV formation in all cases. Results from SANS and QELS indicate a possible correlation between the shear-induced vesicle formation and the viscoelastic properties of the surfactant bilayer.

The Influence of Water-soluble Polymers and pH on Hydroxypropyl-β-Cyclodextrin Complexation of Drugs

AbstractThe effect of water-soluble polymers and ionization of the drug molecules on the cyclodextrin, mainly 2-hydroxypropyl-β-cyclodextrin (HPβCD), solubilization of drugs was investigated. HPβCD has significant solubilizing effect on acetazolamide, prazepam, and sulfamethoxazole in aqueous solutions. All three polymers tested-i.e., hydroxypropyl methylcellulose (HPMC), polyvinylpyrrolidone (PVP), and carboxymethylcellulose-increase the solubilizing effect of HPβCD. The polymers increase the solubilization by increasing the apparent stability constant (Kc of the drug-HPβCD complex. Thus, addition of 0.10% (w/v) HPMC to the aqueous complexation medium results in a 56% increase in K, for the acetazolamide-HPβCD complex and a 200% increase in Kc for the prazepam-HPβCD complex. Addition of 0.25% (w/v) PVP to the complexation medium results in a 138% increase in K for the sulfamethoxazole-HPβCD complex. The HPβCD solubilization of the drugs can also be improved by ionization of the drug molecule through pH a...

Influence of water-soluble polymers and electrolytes on the permeability of weak-filtering dispersed systems

The mechanisms underlying the moisture-conducting properties of the sodium form of clay minerals after the adsorption of various polymers on their surfaces or during the filtration of electrolytes are studied.