PLIABILITY

Pliability. (Also see Grindability, Sec. 8.) This is the tendency of the material to break into smaller sizes in the course of handhng. There are quantitative tests specially devised for certain materials such as coal which can be used to estimate this property. Abrasiveness of one ingredient upon another should also be considered. 

Non-medicated moisturizers. Maintaining adequate skin moisture helps to control the scaling associated with psoriasis. Emollients restore skin pliability, reduce skin shedding, reduce pruritus, and help prevent painful cracking and bleeding.2 Non-medicated moisturizers may be liberally applied several times daily to help prevent skin dryness. Fragrance-free products should be selected when available. 

Although much is still to be learned about the factors that contribute to the pliability of the stratum corneum, it is generally accepted that its elasticity is dependent on a proper balance of lipids, hygroscopic,... 

Mineral tanning was probably first practiced in ancient Mesopotamia and then spread to Egypt, the Middle East, and the Mediterranean Sea area (Levey 1958). Mineral-tanned leather is soft to handle, has a velvety texture, and is almost white, a color practically impossible to achieve by other tanning processes. It is, however, very sensitive to humidity and water under wet conditions the alum in the leather is hydrolyzed (decomposed by water), forming sulfuric acid, a very strong acid that attacks the leather and causes its rapid decay. Mineral-tanned leather that has been humid or wet for a more or less extended period of time loses some of its characteristic properties, such as softness, pliability, and strength, and becomes hard, horny, and brittle. 

The first soft contact lenses were also constructed with a polymeric material containing a single monomeric unit. The added pliability of the soft lens was derived from the more hydrophilic nature of the monomer, enhancing the ability of the polymer to absorb water and provide greater comfort to the lens wearer. This monomer is a derivative of MMA known as hydroxyethyl methacrylate (HEMA). A number of hydrophilic monomers are used in soft lenses today these materials are referred to as hydrogels because of their ability to absorb significant amounts of water yet remain insoluble. 

To reduce weight, improve pliability and low-volume storage, and save costs, there are trends to reduce the fabric weight while preserving the properties. 

Proteinases in the Leather Industiy. Protease enzymes are used in the processing of skins and hides into leather, in particular for the removal of hair and wool, and for increasing the pliability (called bating) of leather. 

The skin barrier properties and effect of hand hygiene practices are known to be important in protecting the body. The average adult has a skin area of about 1.75 m2. The superficial part of the skin, the epidermis, has five layers. The stratum corneum, the outermost layer, is composed of flattened dead cells (comeocytes or squames) attached to each other to form a tough, homy layer of keratin mixed with several lipids, which help maintain the hydration, pliability, and barrier effectiveness of the skin. This part of skin has been compared to a wall of bricks (comeocytes) and mortar (lipids) and serves as the primary protective barrier. Approximately 15 layers make up the stratum corneum, which is completely replaced every 2 weeks a new layer is formed almost daily. From healthy skin, approximately 107 particles are disseminated into the air each day, and 10% of these skin squames contain viable bacteria. This is a source of major dirt inside the house and contributes to many interactions. 

Polymerized vinyl chloride as a homopolymer is hard and brittle, making it difficult to work and impractical as a commercial material. In 1926, Waldo Lonsbury Semon (1898—1999) was working for B. F. Goodrich searching for a synthetic rubber that could adhere to metal objects. Semon examined vinyl chloride and found that when polyvinyl chloride powder was mixed in certain solvents, he obtained a stiff gel that could be molded into a plastic material. The material s hardness and pliability depended on the mix of solvent and polyvinyl chloride. Semon... 

Differences in physical properties are also caused by the presence of oil in the wax. Minchin found pure paraffins to be substantially harder than commercial products (70). MacLaren (63) shows the bad effects which relatively small amounts of oil—for example, less than 2%—can have on the desired properties of wax. Even 0.1% of apparent oil is undesirable. The oil segregates between the crystals. This does not improve pliability, but rather makes the product crumbly. 

Amongst tho varieties of fine earthenware may bo classed the peculiar manufacture of day pipes. The clay used in the construction of these requires extreme plasticity, together with a certain amount of porosity upon firing. The plastic clay found in the foyers forming the basis of the clay deposit, is used without the addition of a flux, but to insure tho perfect uniformity and pliability of the mass, great care is taken with the kneading and slapping processes. 

The mechanical properties of LDPE fall somewhere between rigid polymers such as polystyrene and limp or soft polymers such as polyvinyls. LDPF. exhibits good toughness and pliability over a moderately wide temperature range. It is a viscoelastic material that displays non-Newtonian flow behavior, and the polymer is ductile at temperatures well below CLC. Table 2 lists typical properties. 

The SC is also designed to maintain certain degree of flexibility and elasticity under normal conditions so that when skin is flexed, it does not crack. Both proteins and lipids contribute to the overall pliability of the corneum. Water and NMFs maintain the flexibility of the corneocytes27 whereas fluid lipids are thought to maintain the flexibility of the bilayer lipids. 

Boyce, S.T., Supp, A.P., Wickett, R.R., Hoath, S.B., and Warden, G.D. Assessment with the dermal torque meter of skin pliability after treatment of burns with cultured skin substitutes. J. Bum. Care Rehab ll. 2000 21 55-58. 

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