Tears, lubricating properties

The lubricating properties of tears are an important feature in normal blinking. Kalachandra and Shah measured the coefficient of friction of ophthalmic solutions (artificial tears) on polymer surfaces and found no correlation with viscosity, surface tension or contact angle [58]. The coefficient of friction appears to depend on the structure of the polymer surfaces and decreases with increasing load and sliding speed. 

An erodible insert developed as a potential ocular drug-delivery system is marketed as a prescription drug for the lubricant properties of the polymer base. Lacrisert is a sterile ophthalmic insert used in the treatment of moderate to severe dry eye syndrome and is usually recommended for patients unable to obtain symptomatic relief with artificial tear solutions. The insert is composed of 5 mg of hydroxypropylcellulose in a rod-shaped form about 1.27 mm diameter by about 3.5 mm long. No preservative is used, since it is essentially anhydrous. The quite rigid cellulose rod is placed in the lower conjunctival sac and first imbibes water from the tears and after several hours forms a... 

Uses Emulsifier, solubilizer, antistat and lubricant for textiles solubilizer for essential oils raw material for no-tears shampoo Properties Liq. 100% cone. 

The even-numbered carbon alpha olefins (a-olefins) from through C q are especially useful. For example, the C, C, and Cg olefins impart tear resistance and other desirable properties to linear low and high density polyethylene the C, Cg, and C q compounds offer special properties to plasticizers used in flexible poly(vinyl chloride). Linear C q olefins and others provide premium value synthetic lubricants linear 145 olefins are used in... 

Uses In polyvinyl acetate to improve fiber-tear properties plasticizer for polystyrene in epoxy resins and polyvinyl acetate to improve adhesion and resistance to chemical attack as an insulator fluid for electric condensers and as an additive in very high pressure lubricants. In fluorescent and high-intensity discharge ballasts manufactured prior to 1979 (U.S. EPA, 1998). 

The revolatilization of condensable vapors will decreases vacuum potential by replenishing the vapors in the system you were just trying to remove. This can create an artificially high maximum limit on the pump s potential vacuum. In addition to the backstreaming of vapors, the pump itself is affected when condensable vapors contaminate the pump s oil. Not only will this decrease the vapor pressure of the pump oil, but the condensed vapors can cause a reduction of lubrication and sealing properties of the oil and lead to an eventual corrosion of the pump s internal parts.16 Other condensed liquids (such as hydrocarbons) can mix, emulsify, and/or break down the pump oil. They can also directly destroy a pump by chemical attack, or indirectly, by poor pump performance, they can cause extra wear and tear on the pump parts. 

SOFTENER 2945 is a silicone-based softener or lubricant which is useful in fabric finishing to give softer hand, higher tear strength and better sewing properties. It may be used on all types of fibers. 

Textiles are made from a very limited list of a dozen or so structural fibers. From these, products must be made with millions of different specific end-use properties. In many cases the inherent properties of the fiber itself and substrate structure do not inherently impart the desired properties of comfort and func-tionahty, for example, water repellent, stain block, soil release, crease resistant, flame refardant, antifungal, rot resistant, stiff, soft, antistatic, stretch, recovery, antiseam slippage, and enhanced tearing strength. Thus, fabrics must be finished either to overcome the inadequacies of design or to fine tune the attributes of fabrics, not only for the end uses noted above but also for facilitating cut-and-sew operations (e.g., needle lubrication, anticurl). 

The part may need to be in contact with service fluids such as mineral and vegetable based oils. The selection of the correct polymer depends on the exact nature of the fluid and the service temperature. For mineral oils a polychloroprene or acrylonitrile -butadiene copolymer based compound may be appropriate but small variations in lubricant constituents make it worthwhile to measure the changes that can occur at operating temperatures to properties such as modulus and tear resistance. For solvents it may be more viable to use a physical sheath of an impervious material such as polytetrafluoroethylene. Swelling or shrinkage is strongly influenced by the nature of fillers and oils used to compound the rubber. 

Non-ionic polymer softener Prill-type concentrated softener which yields lubricating type, bulky soft hand feel with anti-static properties. Imparts anti-static, strong hydrophilicity and superior anti-tear, anti wear strength to treated fabrics. 

Although the fluids most often considered in biofluid mechanics studies are blood and air, other fluids such as urine, perspiration, tears, ocular aqueous and vitreous fluids, and the synovial fluid in the joints can also be important in evaluating tissue system behavioral responses to induced chemical and physical stresses. For purposes of analysis, these fluids are often assumed to exhibit Newtonian behavior, although the synovial fluid and blood under certain conditions can be non-Newtonian. Since blood is a suspension it has interesting properties it behaves as a Newtonian fluid for large shear rates, but is highly non-Newtonian for low shear rates. The synovial fluid exhibits viscoelastic characteristics that are particularly suited to its function of j oint lubrication, for which elasticity is beneficial. These viscoelastic characteristics must be accounted for when considering tissue therapy for joint injuries. 

---