Polymers as Ophthalmic Lubricating Agents

1987 ◽  
Vol 110 ◽  
Author(s):  
S. Kalachandra ◽  
D. O. Shah
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Polymer Solutions ◽  
Chemical Properties ◽  
Surface Characteristics ◽  
Water Soluble ◽  
Cellulose Derivatives ◽  
Water Soluble Polymer ◽  
The Coefficient Of Friction ◽  
Pmma Surface

AbstractPhysio-chemical properties such as coefficients of friction between low energy surfaces (PMMA/PMMA), surface tension, contact angle and viscosity of various water soluble polymer solutions ( 3–62cp) were measured at ambient temperature. The results showed that the surface tension and the contact angle are independent of viscosity of each polymer. The analysis of the data revealed that the system is operating in a region of “Boundary Lubrication”. It is seen, beyond 30 cp viscosity of almost all polymer solutions, the coefficient friction has been found to be independent of viscosity.Polyvinyl alcohol appears to have better lubricity in the vicinity of 30 cp viscosity or lower values than the cellulose derivatives and dextran. Hydrophobic interaction between PMMA surface and vinyl backbone may be responsible for this observation.It appears that the coefficient of friction of these polymer solutions depends on the structure, conformation and adsorption characteristics of polymers as well as surface characteristics of sliding surfaces, load, speed and viscosity.

scholarly journals Preparation of Lignosulfonates from Biorefinery Lignins by Sulfomethylation and Their Application as a Water Reducer for Concrete

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 841 ◽  
Author(s):  
Caoxing Huang ◽  
Junmei Ma ◽  
Weiyu Zhang ◽  
Guohong Huang ◽  
Qiang Yong
Keyword(s):  
Surface Tension ◽  
Compressive Strength ◽  
Enzymatic Hydrolysis ◽  
Zeta Potential ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Potential Analysis ◽  
Hydrolysis Residue ◽  
Industrial Standards ◽  
Zeta Potential Analysis

Lignosulfonate (LG), a water-soluble polymer from sulfite pulping process of lignocellulosic biomass, has been commercially applied as admixture for concrete. In this work, lignosulfonates were produced from alkaline lignin (AL) and enzymatic hydrolysis residue (EHR) by sulfomethylation and these lignosulfonates as water reducers for concrete were then evaluated. Results showed that 94.9% and 68.9% of lignins in AL and EHR could be sulfonated under optimum sulfomethylation conditions, respectively. The sulfonic groups in lignosulfonates from AL (AL-LG) and EHR (EHR-LG) were 1.6 mmol/g and 1.0 mmol/g, respectively. Surface tension and zeta potential analysis indicated that both AL-LG and EHR-LG can be potentially used to as dispersant for improving the fluidity of the cement paste, similarly to commercial lignosulfonate (CM-LG). Adding 0.2 wt % of AL-LG, EHR-LG, and CM-LG in the concrete, the compressive strength (28 days) of concretes increased from 38.4 Mpa to 41.6, 42.6, and 40.9 Mpa, respectively. These findings suggest that the lignosulfonate from biorefinery lignin by sulfomethylation can meet the industrial standards as water reducers for cement admixtures.

scholarly journals Partially Acetylated Cellulose Dissolved in Aqueous Solution: Physical Properties and Enzymatic Hydrolysis

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1734 ◽  
Author(s):  
Alfassi ◽  
Rein ◽  
Shpigelman ◽  
Cohen
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Enzymatic Hydrolysis ◽  
Cellulose Acetate ◽  
Persistence Length ◽  
Water Soluble ◽  
High Rate ◽  
Cellulose Derivatives ◽  
Molecular Aggregation ◽  
Cellulose Dissolution

Cellulose acetate is one of the most important cellulose derivatives. The use of ionic liquids in cellulose processing was recently found to act both as a solvent and also as a reagent. A recent study showed that cellulose dissolution in the ionic liquid 1-ethyl-3-methylimidazoliumacetate (EMIMAc) mixed with dichloromethane (DCM) resulted in controlled homogenous cellulose acetylation; yielding water-soluble cellulose acetate (WSCA). This research investigated the properties of cellulose acetate prepared in this manner, in an aqueous solution. The results revealed that WSCA fully dissolves in water, with no significant sign of molecular aggregation. Its conformation in aqueous solution exhibited a very large persistence length, estimated as over 10 nm. The WSCA exhibited surface activity, significantly reducing the surface tension of water. Because of the molecular dissolution of WSCA in water, augmented by its amphiphilicity, aqueous solutions of WSCA exhibited an overwhelmingly high rate of enzymatic hydrolysis.

scholarly journals THE STUDY OF PHYSICAL AND CHEMICAL PROPERTIES OF WATER-SOLUBLE POLYMER REAGENTS AND THEIR COMPATIBILITY WITH ANTIBIOTICS

2020 ◽  
Vol 13 (03) ◽  
pp. 1417-1423
Author(s):  
Erzhan Dzhakipbekov ◽  
Saule Sakibayeva ◽  
Nagima Dzhakipbekova ◽  
Botagoz Tarlanova ◽  
Guzaliya Sagitova ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Water Soluble ◽  
Physical And Chemical Properties ◽  
Soluble Polymer ◽  
Water Soluble Polymer ◽  
Physical And Chemical ◽  
And Chemical Properties

scholarly journals Examination of dielectric constant and dynamic surface tension of lubricoolants during the bubbling

2021 ◽  
Vol 26 (4) ◽  
pp. 34-39
Author(s):  
N. Khmil ◽  
◽  
V. Kolesnikov ◽  
S. Khmil ◽  
◽  
...  
Keyword(s):  
Surface Tension ◽  
Dielectric Constant ◽  
Chemical Properties ◽  
Dynamic Surface Tension ◽  
Water Soluble ◽  
Frequency Range ◽  
Dynamic Surface ◽  
Frequency Sweep ◽  
Acoustic Frequency ◽  
Metalworking Industry

Subject and Purpose. The maintenance of physical and chemical properties and biological stability of lubricoolants during downtimes, which are bound to happen sometimes and last long, is a hot problem in metalworking industry. The procedure of bubbling for the lubricoolant mixing, saturation with oxygen and inactivation of anaerobic microflora calls for chemical and biological techniques to monitor the lubricoolant condition during the bubbling and after it. Yet the standard methods lack responsiveness and accuracy of the analysis, implying the further refinement of the output values. In the present work, microwave super-high frequency (SHF) dielectrometry is employed for the examination of the dielectric constant and dynamic surface tension of synthetic, semi-synthetic and organic emulsions during the bubbling. Methods and Methodology. The dielectric constant and dynamic surface tension of 5.7 % water-soluble emulsions are measured at frequency f = 37.7 GHz. A frequency sweep in the acoustic frequency range f = 20…25000 Hz is used, for which purpose the end of the 8-mm waveguide is supplied with a piezo сell. Results. It has been revealed that the dielectric constant and dynamic surface tension of lubricoolants depend on the physicochemical characteristics that the lubricoolants acquire during a month-long downtime and after 10-, 20-, and 30-minute bubblings. The dielectric constant and dynamic surface tension demonstrate that the bubbling improves lubricating properties of all the emulsions examined. For this, a 10-minute bubbling is enough for semi-synthetic lubricoolants, and a 20-minute bubbling is needed for synthetic and organic lubricoolants. Conclusion. The microwave dielectrometry method with a frequency sweep in the acoustic frequency range can be used in metalworking industry as an aid to lubricoolant quality control during the downtime or storage.

scholarly journals Importance of the organic aerosol fraction for modeling aerosol hygroscopic growth and activation: a case study in the Amazon Basin

2005 ◽  
Vol 5 (4) ◽  
pp. 5253-5298 ◽  
Author(s):  
M. Mircea ◽  
M. C. Facchini ◽  
S. Decesari ◽  
F. Cavalli ◽  
L. Emblico ◽  
...  
Keyword(s):  
Surface Tension ◽  
Amazon Basin ◽  
Cloud Condensation Nuclei ◽  
Chemical Properties ◽  
Number Concentration ◽  
Water Soluble ◽  
Hygroscopic Growth ◽  
Wet Season ◽  
Degree Of Dissociation ◽  
Inorganic Species

Abstract. The aerosol in the Amazon basin is dominated throughout the year by organic matter, for the most part soluble in water. In this modeling study, we show how the knowledge of water-soluble organic compounds (WSOC) and the associated physical and chemical properties (e.g. solubility, surface tension, dissociation into ions) affect the hygroscopic growth and activation of the aerosol in this area. The study is based on data obtained during the SMOCC field experiment carried out in Rondônia, Brazil, over a period encompassing the dry (biomass burning) season to the onset of the wet season (September to mid-November, 2002). The comparison of predicted and measured cloud condensation nuclei (CCN) number concentration shows that the knowledge of aerosol WSOC composition in terms of classes of compounds and of their relative molecular weights and acidic properties may be sufficient to predict aerosol activation, without any information on solubility. Conversely, the lack of knowledge on WSOC solubility leads to a high overestimation of the observed diameter growth factors (DGF) by the theory. Moreover, the aerosol water soluble inorganic species describe reasonably well the aerosol hygroscopic behavior at 90% relative humidity, but fail to predict CCN number concentration. In fact, this study shows that a good reproduction of the measured DGF does not result in realistic estimations of CCN concentration if the chemical composition of aerosol, especially that of WSOC, is not appropriately taken into account in the calculations. New parameterizations for the computed CCN spectra are also derived which take into account the variability caused by chemical effects (surface tension, molecular composition, solubility, degree of dissociation of WSOC).

scholarly journals IMMOBILIZATION OF COBALT DISULFOPHTHALOCYANINATE ONTO POLYMETHYLOLACRYLAMIDE

2018 ◽  
Vol 61 (8) ◽  
pp. 73
Author(s):  
Galina V. Osipova ◽  
Nadezhda L. Pechnikova ◽  
Tatiana A. Ageeva
Keyword(s):  
Metal Complex ◽  
Water Solubility ◽  
Electronic Absorption Spectra ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
One Step ◽  
Insoluble Compounds

Different character of usage the porphyrins and their analogs immobilized on carrier polymers stimulates an increased interest in the synthesis and research of physico-chemical properties of porphyrin-polymer immobilizates. In this paper the peculiarities of a synthesis of water-soluble polymer systems containing cobalt disulfophthalocyaninate with the components of a different ratio are described. The methylolation reaction of polyacrylamide to immobilize cobalt disulfophthalocyaninate onto water-soluble carrier polymer has been carried out. It is known that heating polymethylolacrylamide or its solutions leads to the formation of three-dimensional structures with ether and methylene bridges. Therefore, initially the conditions for the preparation of polymethylolacrylamide with preservation of its water solubility were selected. It was found to obtain a water-soluble polymethylolacrylamide, it is necessary that the initial concentration of polyacrylamide in water did not exceed 2% by weight. The immobilization of phthalocyanine metal complex onto the modified polyacrylamide was carried out in two ways. The first is the interaction of the phthalocyanine metal complex with methylated polyacrylamide. The second is functionalization of polyacrylamide and the immobilization of phthalocyaninate metal complex onto the polymer in one-step. The introduction conditions of the cobalt disulfophthalocyaninate introduced influenced the formation of cross-linked structures in the synthesized samples. The introduction of macroheterocycle as a powder was found to promote the formation of insoluble compounds in aqueous media. Therefore, phthalocyanine metal complex was introduced into the system as 1% aqueous solution. The immobilization of the phthalocyanine metal complex onto a carrier polymer has been realized through the formation of hydrogen bonds between the methylol groups of polymethylolacrylamide and sulfo groups of the phthalocyanine metal complex and it was due to coordination interaction between the functional groups of the polymer and metallophthalocyanine as well. The amount of bound cobalt disulfophthalocyanine in the samples was determined by the electronic absorption spectra of the solutions of immobilized phthalocyanine metal complex onto the polymer. The mass content of immobilized cobalt disulfophthalocyaninate onto the polymer in the samples obtained by one-step is greater than in case of the samples obtained in two steps, the ratio of the initial reagents being the same.

scholarly journals The Study of Physical and Chemical Properties of the Water-Soluble Polymer Reagents and their Application as an Ointment

2018 ◽  
Vol 34 (4) ◽  
pp. 1779-1786
Author(s):  
Nagima Dzhakipbekova ◽  
Saule Sakibayeva ◽  
Erzhan Dzhakipbekov ◽  
Didar Ahmet ◽  
Saparkul Rzabay ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Water Soluble ◽  
Physical And Chemical Properties ◽  
Water Soluble Polymer ◽  
Depth Study ◽  
Scope Of Application ◽  
Physical And Chemical ◽  
Expensive Process ◽  
Equal Efficacy ◽  
And Chemical Properties

The creation of new polymer reagents from their synthesis in the laboratory to their industrial production as an ointment is relatively long and expensive process. Therefore, the most promising and justified way is to expand the range of polymer reagents by modifying the already known base samples. We studied MPAA(HP)- hydrolyzed polacrylamide modified with hydrogen peroxide,, MPAA (MEA) - hydrolyzed polycrylamide modified with monoethanolamine, MPAA (TEA) - hydrolyzed polycrylamide modified with three ethanolamine polymers. A more detailed and in-depth study of them will expand the scope of application of low-toxic, affordable reagents that are of equal efficacy to the already existing ones and their application as an ointment. Polymer MPAA-HP polymacrylamide hydrolyzed NaOH with the addition of the H2O2 modifier in the ratio PAA: NaOH: H2O2 = 1: 0.4: 0.2 the hydrolysis reaction is carried out for 1.5-2 hours at temperature of 90-950C. MPAA-MEA polymer polymaracrylamide is hydrolysed with alkali with the addition of monoethanolamine modifier in the ratio of PAA: NaOH: MEA = 1: 0.4: 0.1 the hydrolysis reactions is carried out for 1.5-2 hours at temperature of 90-95°C.

scholarly journals Effect of Polyvinyl Alcohol on the Rheological Properties of Cement Mortar

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 754
Author(s):  
Fang Liu ◽  
Baomin Wang ◽  
Yunqing Xing ◽  
Kunkun Zhang ◽  
Wei Jiang
Keyword(s):  
Polyvinyl Alcohol ◽  
Rheological Properties ◽  
Yield Stress ◽  
Cement Mortar ◽  
Chemical Properties ◽  
Degree Of Polymerization ◽  
Plastic Viscosity ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Hydrolysis Degree

Polyvinyl alcohol (PVA) is a kind of water-soluble polymer, which has been widely used in different industries due to its excellent mechanical and chemical properties. In this paper, the effects of polyvinyl alcohol with different hydrolysis and polymerization degrees on the rheological properties of cement mortar are studied. The results show that the rheological properties of PVA-modified cement mortar can be described by the modified Bingham model. The yield stress of modified cement mortar is less than that of unmodified mortar when the degree of polymerization and the content of PVA are small. With the increase of polyvinyl alcohol content and polymerization degree, the yield stress and plastic viscosity of modified cement mortar increase sharply, which are larger than those of the unmodified cement mortar. However, the effect of hydrolysis degree of PVA on yield stress and plastic viscosity of modified cement mortar is not obvious.

Sign in / Sign up

Export Citation Format

Share Document