Ostwald Viscometer Research Articles

Effect of the different chain transfer agents on molecular weight and optical properties of poly(methyl methacrylate)

Investigation of molecular weight and optical properties of poly(methyl metacrylate) (PMMA) polymerized in house with different chain transfer agents was studied. Isopropyl alcohol (IPA), n-butyl mercaptan (nBMC) and pentamethyl disilane (PMDS) were used as chain transfer agents. The molecular weight (Mw) of PMMA samples were measured by Ostwald viscometer. Mw of bulk polymer samples were decreased with increase the concentration of chain transfer agents (CTA). Since reactivity of used CTAs is not same, molecular weights of samples which were produced with different type of CTA but same concentration of CTA was varied. Higher concentration of n-BMC showed higher scattering. Transmission of samples could not be correlated with different concentration of CTA. Refractive index of samples was not affected by concentration of CTA nevertheless higher molecular weight of CTA showed higher refractive index.

DETERMINATION OF SOME PHYSICAL AND CHEMICAL PROPERTIES OF PECTIN SUBSTANCES FROM THE SOLVENT CAKE OF TAGETES PATULA L. INFLORESCENCES

Big molecular weight conditions are responsible for some properties, which are absent in low molecular compounds. Therefore, its determination allows revealing of some physical and technological properties of biopolymers and prediction of the possibility of their practical application. The aim of this work was to determine an average molar weight, to study the superficial properties at the border of “solution-air” phases, and to establish an isoelectric spot of water solutions of pectin substances (PS), isolated from a solvent cake of Tagetes patula inflorescences. Materials and methods. Polysaccharide complexes were isolated from the solvent cake of Tagetes patula inflorescences of Carmen species which was left after a raw material extraction with ethanol 40% with the method of Kochetkov and M. Sinnera. The time of water and PS solutions flow out was measured by the use of a capillary Ostwald viscosimeter; different types of viscosity were calculated. The density of solutions was determined by using a picnometric method, however due to the closeness of density of the analyzed solutions and water, they were not considered in the calculation of the relative viscosity. Series of solutions with 0.01 to 0.5% concentrations were prepared from 1% PS water solutions to determine a surface activity. Monometric liquid tension variations were set in Rehbinder’s apparatus in the moment of an air bubble appearance on the surface of PS solution. Isoelectric spot (IES) of PS was determined in acetate buffer solution with pH within 3.2 to 6.2 by using the viscometer method. Results and discussion. Fractioning of the obtained polysaccharide complexes showed that efficiency of the pectin substances amounted to 2.2%. Calculation shows that an average molar weight of PS amounted to 45272 g/mol. About the degree of interaction between macromolecules of polymer and solvent, structural properties of macromolecule, the degree of its branching can be judged by the value of Huggins test. The value was found to be 1.46, which proves the low solubility of PS in water. Apparently, a biopolymer chain has been branched which worsen the solubility of macromolecules and further may promote the formation of gel condition. PS, isolated from the solvent cake of Tagetes patula, belong to the group of the surface active substances. Due to a big cross section of a molecule (S) and the high average molar weight, (45272 g/mol) molecules occupy a big volume at the surface of phase separation. We have established that macromolecule is in the isoelectric state at pH = 4.7. Conclusion. In the result of the studies using viscometer method, we have determined a molar weight of PS equal to 45272 g/mol. Huggins constant (1.46) which is connected to a low solubility of PS in water has been determined. We have established that PS, isolated from the solvent cake of Tagetes patula, are surface active. We have shown that PS macromolecule is in the state of polyamphion at pH = 4.7.

Blood viscosity increases the degree of coronary stenosis in coronary heart disease

Background<br />Endothelial dysfunction and associated increased blood viscosity (BV) play an important role in the formation of atherosclerosis during inflammatory processes. C-reactive protein (CRP) is a biomarker of inflammation with an active role in endothelial dysfunction and development of atherosclerosis that is marked by degree of coronary stenosis (CS). The purpose of this study was to determine the relationship of BV and CRP with varying degrees of CS among coronary heart disease (CHD) patients.<br /><br />Methods<br />This cross-sectional study involved 24 subjects taken consecutively among patients with CHD who underwent angiography. Blood viscosity levels were determined using an Ostwald viscometer, with reference limits of 1.5 to 1.72 (cP). C-reactive protein was determined by turbidimetric immunoassay, with a normal reference value of <3 mg/L. Degree of CS was examined with angiography, where 0% = no stenosis; <50% = nonsignificant stenosis; > 50% = significant stenosis. Data was analyzed using non-parametric Spearman correlation test.<br /><br />Results<br />There were 17 male and 7 female subjects, with mean age of 55.96 ± 7.29 years. The angiography results were: non-significant stenosis in 2 subjects (8.3%), significant stenosis in 22 subjects (91.7%) and none with normal stenosis. Statistical analysis of the relationship of BV with degree of CS found a moderate significant positive relationship (r=0.549; p=0.005). A poor significant positive relationship was found between CRP and degree of CS (r=0.481; p=0.017).<br /><br />Conclusion<br />Blood viscosity increased the degree of CS in CHD patients. Therapy should target both BV-associated risk and angiographically evident stenosis.

Effect of Solvents on the Ultrasonic Velocity and Acoustic Parameters of Polyvinylidene Fluoride Solutions

Ultrasonic studies provide a wealth of information in understanding the molecular behavior and intermolecular interaction of polymer solvent mixtures. Attempts were made to measure ultrasonic velocity, density, and viscosity for the mixture of polyvinylidene fluoride (PVDF) in acetone and dimethylformamide (DMF) of various stoichiometric ratios at 300 K using crystal controlled ultrasonic interferometer (Mittal make), pyknometer (specific gravity bottle), and Ostwald viscometer, respectively. The acoustic parameters adiabatic compressibility (β), intermolecular free path length (Lf), acoustic impedance (Z), relative association (RA), ultrasonic attenuation (α/f2), and relaxation time (τ) have been estimated using experimental data with well-known techniques. The variation of these acoustic parameters is explained in terms of solute-solvent molecular interaction in a polymer solution.

Hydrophobisation effectiveness of building ceramics, polymeric inorganic ultrasound integrated with the addition of fillers

The article describes the studies of efficacy of ceramic brick surface hydrophobisation by preparations based on silicones (micropolymer). The different series of specimens were subjected to a process of surface hydrophobisation by immersion for 15 s using the hydrophobizing formulations, whose structure was further sonificated by power of 400 W. In order to determine the average absorption of polymer by specimens in respective series, before the hydrophobisation samples were dried to a constant weight and weighed. Then, after 14 days of their immersion in the formulation, specimens were weighed again in order to determine the percent change in the sample weight to the weight of the dried sample. The impact of ultrasonic energy on the viscosity of the polymer (measured by Ostwald viscometer) and on the surface tension (measured by stalagmometer) was determined. The hydrophobic properties of the resulting nanofilm created on the surface of the ceramic brick were determined on the basis of the measurement of surface free energy γs (SFE) by using Owens – Wendt method measuring the sample surface contact angles with distilled water (highly polar liquid) and diiodomethane (a polar liquid) to determine the dispersive γsd and polar γsp components (expressed in mJ/m2). Based on the results, the effect of sonification on some adhesive and physico. – mechanical properties of the tested material surface was determined.

Anodic behavior of neodymium in acidic AlCl3-1-ethyl-3-methyl-imidazolium chloride ionic liquid

The anodic behavior of neodymium in acidic AlCl3-1-ethyl-3-methyl-imidazolium chloride (AlCl3-EMIC) ionic liquid was investigated by conducting linear sweep voltammeter and chonopotentiometry. The viscosity of Nd dissolved ionic liquid and the surface morphologies of Nd were characterized using an Ostwald viscometer and a scanning electron microscope, respectively. The chemical composition of Nd surface was indentified by Raman spectra. The results showed that dissolution of Nd under anodic polarization occurred after the breakdown of oxide films. A viscous layer formed at the interface of Nd/ionic liquid during the galvanostatic process of 5 and 20 mA/cm2. The formation of viscous layer was attributed to the accumulation of Nd dissolved AlCl3-EMIC ionic liquid, which had high viscosity. The oxide films could be removed thoroughly and the surface of Nd was homogeneous without etching pits, when viscous layer formed in the anodic process. Otherwise, the surface showed a pitting morphology.

Effects of Metal Ions on Viscosity of Aqueous Sodium Carboxylmethylcellulose Solution and Development of Dropping Ball Method on Viscosity

This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the colloidal size of CMC aggregations is changed mainly by the metal cation charge. The improvised apparatus was introduced to high school students in a lesson on viscosity and intermolecular interaction where the students could examine the viscosity of several solutions and compare it with an aqueous sodium CMC solution. Although there are some limitations, the results show that the apparatus can be useful in helping high school students to understand the concept of viscosity.

Viscosity of endodontic irrigants: Influence of temperature

The aim of this study was to assess the influence of temperature on the viscosity of different endodontic irrigants. The measurements of viscosity of 3% hydrogen peroxide, 0.9% sodium chloride, aqueous solution of 0.2% chlorhexidine (CHX) and 0.2% cetrimide, 5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) at different temperatures (22°C, 30°C, 40°C, 50°C and 60°C) were obtained using Mohr balance and Ostwald viscometer. The Shapiro-Wilk test and Mann-Whitney U-tests were used for the statistical analysis. (α = 0.05). No significant differences were recorded at each temperature among 3% hydrogen peroxide, 0.9% sodium chloride and aqueous solution of 0.2% CHX and 0.2% cetrimide. 5% NaOCl and 17% EDTA showed the higher values. Viscosity statistically decreased with increasing temperature. Within the limitations of this study, 5% NaOCl and 17% EDTA are significantly viscous at room temperature and their viscosity reduces with elevating temperature.

Anodic behavior of Mg in acidic AlCl3–1-ethyl-3-methyl-imidazolium chloride ionic liquid

In this paper, anodic behavior of Mg in acidic AlCl3–1-ethyl-3-methyl-imidazolium chloride (AlCl3–EMIC) ionic liquid was investigated by conducting linear sweep voltammetry, chronoamperometry and chonopotentiometry. The viscosity of Mg dissolved ionic liquid and the surface morphologies of Mg were characterized using an Ostwald viscometer and a scanning electron microscopy, respectively. The results showed that the oxide film on the surface of Mg had great effects on the anodic behavior. The dissolution of Mg under anodic polarization occurred after the breakdown of oxide film. A viscous layer was observed forming at the interface of Mg/ionic liquid during the dissolution process. The formation of viscous layer was attributed to the accumulation of Mg dissolved AlCl3–EMIC ionic liquid at the interface, which was of high viscosity. With a viscous layer formed in the anodic process, the etched surface of Mg anode was homogeneous and flat without any etching pits. Otherwise, the Mg showed a morphology of pitting on the surface.

Modification of Starch with Allopurinol and Ampicilline as Sulfonamide Derivatives

The available hydroxyl groups on the starch chains potentially exhibit reactivity specific for alcohols which were modified with chlorosulfonic acid at zerooC to yield starch sulfonic acid P1, then substitution of P1 to its corresponding drug derivatives such as with allopurinole or ampicilline P2 and P3 respectively. The new prepared starch derivatives were characterized byFT.IR and UV. Spectroscopy. The physical properties were studied. Thermal analyses were recorded and swelling % were studied, Controlled drug release were measured at different pH values at 37oC. Intrinsic viscosities were measured using Ostwald viscometer at 30oC. This technique through which stomach drug targeting can be achieved as timed released system.

Preparation of Poly (N-4-Antipyrinyl or Procainyl Methyl Nadamic Acids) as Drug Polymers

Two new monomers of N-4-antipyrinyl methyl nadamic acid M1 and N-Procaienyl methyl nadamic acid M2 were synthesized from reaction of 4-Aminoantipyrine or procaine with methyl nadic anhydride at room temperature with dioxane as a solvent.
 The prepared monomers M1 and M2 were polymerized free radically with AIBN as initiator to corresponding polyamic acids P1 and P2, Which were converted to their sodium salt polymers P3 and P4 to enhanced their solubility's in water.
 The physical and chemical properties were studied for monomers and polymers, also FT-IR ,1H-NMR and UV. Spectroscopy was characterized of M1or M2. The intrinsic viscosity was measured by Ostwald viscometer at 30 0C .The swelling %was measured and the controlled release rates of drug polymers were studied in different pH values at 37 0C.

Comparative Ultrasonic and Conductometric Studies of Aqueous Sodium Chloride and Potassium Chloride Solutions

Densities (ρ), viscosities (η), ultrasonic velocities (u) and conductivities (κ) have been measured by using specific gravity bottle, Ostwald's viscometer, single frequency ultrasonic interferometer (6 MHz frequency) and conductivity meter respectively for aqueous solutions of sodium chloride and potassium chloride at different concentrations (w/w). Various acoustical parameters viz. adiabatic compressibility (βad), intermolecular free length (Lf), acoustical impedance (Z), relaxation time (τ), rao's constant (RM), wada's constant (W), free volume (Vf), absorption coefficient (α/f 2 ), gibb's free energy (∆G), relative association (RA) and available volume (Va) were calculated from these experimental data. The results are interpreted in terms of molecular interactions between components of solutions.

Poly-Condensation of CDTA with Some Diamines

In this research, new condensed polymers (A1-A8) were prepared by poly condensation between 1, 2-cyclohexyl diamine tetraacetic acid CDTA with different diamines such as 1, 6-Diamino hexane, Melamine, 3,3-,5,5--Tetramethyl benzidine, Benzidine and Cystine. These prepared chelate polymers could be used to remove heavy metals and toxic metal ions in many industrial processes as well as acting as sequestrate for metal ions. The all prepared polymers were characterized by 1H-NMR and FT-IR spectra. The thermal analyses (TGA, DSC) were studied, the intrinsic viscosities were calculated at 30 ˚C using Ostwald viscometer, and all physical properties were measured.

Nature of pectin–protein–catechin interactions in model systems: Pectin–protein–catechin interactions

Apple pectins, proteins and catechins were combined in model systems, and the resulting hazes were measured by spectrophotometric method, a zeta potential and particle size analyzer and Ostwald viscosimeter. The amount of hazes formed depends on the concentrations of both protein and pectin. The cooperative hydrogen bonding between the numerous hydroxyl groups of pectins and hydrone and the gel-like structure developed by pectin induced the solvation or solubilization of polymers, and the protein molecule has a fixed number of polyphenol binding sites. The influence of pectin relative molecular mass and degree of esterification on the formation of suspended particles is prominent, and this makes the number of hydroxyl groups and charge of pectin which is concerned with combining protein and catechin to change a lot. More haze was observed when model systems were heated, suggesting that hydrophobic groups of protein are beneficial to their binding with phenols and pectins. The pH value affects the charged state of the protein and pectin, which influences the combination of pectin-gliadin-catechin.

Oral Health Status , Salivary Physical Properties and Salivary Mutans Streptococci among a Group of Mouth Breathing Patients in Comparison to Nose Breathing

Background: Mouth breathing can lead to introduce cold, dry unprepared air that insults the tissue of oral cavity, nasopharynx and lung, leading in turn to pathological changes in oronasal cavity, nasopharyngeal and other respiratory tissue, mouth breathing associated with nasal obstruction may lead to many health problems, in particular oral health problems such as inflammation of gingiva, oral dryness, change in oral environment that may decrease pH, salivary flow rate and increase bacteria and dental caries.Aims of the present study were to assess the oral health condition among mouth breather associated with nasal obstruction, including dental caries, oral cleanliness and gingival health condition as well as to evaluate the changes in salivary physical characteristics and salivary mutans streptococci counts, and their relation to oral variables in comparison to a control group. Materials and Methods: Thirty patients with mouth breathing associated with nasal obstruction (15 females and 15 males) were selected as a study group with an age range (18-22) years old, all subjects were examined by ENT specialist to confirm mouth breathing. A 30 gender and age matched healthy looking subjects without nasal obstruction were selected as control. The diagnosis and recording of dental caries was according to severity of dental caries lesion through the application of D1_4MFS(Manji et al., 1989). Plaque index of (Silness and Loe, 1964) was used for plaque assessment; gingival index of (Loe and Silness, 1963) was used for gingival health condition assessment. Stimulated salivary samples were collected according to (Tenovuo and Lagerlof, 1996) and the following variables were recorded: microbiological analysis included the salivary counts of mutans streptococci, salivary flow rate, salivary pH (potential of hydrogen) and then measurement of salivary viscosity by using Ostwald's viscometer. Results: Results of the present study showed that the mouth breathing group had statistically highly significant, higher plaque and gingival indices than nose breathing group (P<0.01) with a positive highly significant correlation between them in mouth breathing and nose breathing groups (r=0.56, r= 0.64, respectively).The salivary flow rate was lower among mouth breathing with highly significant difference than nose breathing (P<0.01), also salivary pH was lower among mouth breathing but with significant differencecompare to nose breathing (P<0.05); statistically a negative highly significant correlation was recorded among mouth breathing group between salivary flow rate with gingival index (r= -0.56). It has been found that salivary viscosity was not statistically significant difference between mouth breathing group and nose breathing group. The salivary viscosity was found to be inversely significantly correlated with salivary flow rate among mouth breathing group (r= -0.38). While it was positively not significantly correlated with plaque index, gingival index and counts of mutans streptococci among mouth breathing group. Data analysis of the present study showed that salivary mutans streptococci counts among mouth breathing group were higher than that among nose breathing group, difference was statistically highly significant (P<0.01). Conclusion: Mouth breathing associated with nasal obstruction may have an effect on oral health status, leading to an increase in periodontal disease and changes in dental caries.

Preparation of Poly (N-Cephalexin Amic Acids) as Drug Polymers

In this work new monomers have been prepared such as N-Cephalexin maleamic acid M1 and N-Cephalexin citriconamic acid M2 , from reaction of Cephalexine with maleic anhydride and citraconic anhydride at room temperature using dioxane as a solvent.The new prepared monomers M1and M2 were polymerized free radically with AIBN as initiator to their corresponding poly amic acids P1 and P2. Whichwere converted to their sodium salt polymers P3 and P4 to enhance their solubility in water.The physical and chemical properties were studied; the prepared monomers and polymers were characterized by FTIR, 1H-NMR and UV. Spectroscopy, theintrinsic viscosity was measured by Ostwald viscometer at 30 0C with DMF as a solvent; the drug release rate was studied. Experimental results showed that the hydrolysis of Cephalexin in alkaline medium was higher than acidic medium.&#x0D; The softening point of the prepared P1 drug polymer was 130.23-138.350C with-190.17mJ as used in softing point,and softening point of the prepared P2 was 207-2200C

Comparison tests for plasma viscosity measurements

The present study measured plasma viscosity using three different viscometers: Ostwald capillary-tube viscometer, Brookfield rotating viscometer, and scanning capillary-tube viscometer (SCTV). The plasma viscosity data obtained using Ostwald viscometer at 37°C with the conversion constant provided by its manufacturer were in good agreement with those obtained using Brookfield viscometer at 37°C. In addition, the plasma viscosity data obtained using SCTV were in excellent agreement with those from Brookfield viscometer. However, when the Ostwald viscometer is used for plasma viscosity measurements at the room temperature, one should be cautioned because the conversion constant provided by manufacturers may not be applicable to the room temperature as the surface tension of plasma depends on temperature, affecting the accuracy of the plasma viscosity measurement.

Molecular interaction study of glycine in aqueous galactose solution and effect of sodium chloride at 298 to 318 K

Sound speed, density and viscosity of glycine in aqueous galactose solution at varying concentrations from 0.1035 to 1.0345 m at 298, 308 and 318 K have been determined. Density, viscosity and sound speed have been measured by using pre-calibrated bicapillary pycnometer, Ostwald's viscometer and single-frequency ultrasonic interferometer at 2 MHz frequency, respectively. The derived acoustic parameters like free volume (Vf ), adiabatic compressibility (β), hydration number (nH ) and Gibbs free energy for activation (ΔG) acoustic impedance (Z), intermolecular free length (Lf ) and relative association (RA ), internal pressure (πi ), Rao's constant (R), Wada's constant (W) have been calculated from experimental data. All the measurements have been carried out in a thermostatic water bath having PT-100 sensor with circulating medium with an accuracy of ± 0.1°C. Solute–solvent interactions dominate over solute–solute interactions and, the solute–solvent interactions increase with temperature.

The determination of cellulase activity by viscometry.

Abstract The enzymatic activity of cellulase has been estimated by the decrease of viscosity of a hydroxyethylcellulose solution as a function of incubation time. This decrease is a function of the applied shear stress. It is proposed that the viscosity be measured in an ordinary Ostwald viscometer under conditions where the viscosity is Newtonian, that is, the decrease of viscosity by enzymatic activity is independent on the shear stress.

Pathophysiology of Waldenstrom's macroglobulinemia

Sixty-five years ago, Jan Waldenstrom described two patients presenting with oronasal bleeding and lymphadenopathy.[1][1] Both had manifestations of hyperviscosity syndrome, which was documented with an Ostwald viscometer. One had a cryoglobulin. Waldenstrom recognized that these patients had a