Repellency, applications conditioned

In commercial use, easy-care and durable press finishes are frequently combined with other finishes to provide additional properties such as water and oil repellency, flame retardancy, soil release and the like. Often the combination of another finish with the cellulose crosslinking finish will result in a more durable effect from the first finish. Combination with pigment printing is very common because of similar chemistry to cellulose crosslinking agents and binders and the similar application conditions. 

Some bird repellents are composed of viscous, sticky materials that birds dislike having on their feet (17). These compounds, eg, Tanglefoot, Roost-No-More, and TackTrap, are often based on incompletely polymerized isobutylene and thinned with aromatic solvents. They should be formulated to have the proper blend of tackiness and viscosity for the weather, method of application, and pest species. They are applied to leave sticky residues on perching locations in buildings and roosts in trees. Because these materials do not have an obnoxious odor, the birds must land on and learn its location in order to avoid it, as there are no long-range cues in the treatment itself for conditioning. 

A frequent concern about the use of monomeric silanes is their volatility, which increases at high temperatures and also in windy conditions. In such cases, evaporation occurs after application before they are converted into the non-volatile water-repellent substance. Comprehensive and systematic investigations have shown that evaporation losses can be overcome by correct choice, to maximise the chances of success. Incorporation of catalysts accelerates the formation of active substances on the treated surface so that there is no appreciable loss from evaporation. 

The simplest treatment is an application by brush or spray. Although penetration across the grain is minimal, some penetration along the grain is possible. The additional life obtained by such treatments over that of untreated wood will be affected greatly by the conditions of service, e.g. just brushing untreated wood with a simple wax water-repellent is surprisingly effective for rustic joinery (Feist and Mraz, 1978 Feist, 1984). 

Most silicone polymers act as very good insulators. Polarity of the slloxane backbone apparently is shielded by methyl groups. In addition, the hydrophobic nature of the surface helps to repel water (and dissolved ionic contaminates) which assures the retention of insulation properties under difficult conditions. One application where these properties have found recent importance has been for insulator sheds. Even after repeated exposure to salt fog and high voltage stress, the materials retain their resistance to conductive and arc failure (33). 

One of the most promising innovations in recent years is the development of hydrophobic Sacrificial Pretreatment Technology (SPT), in conjunction with hydrophobic cold-cure epoxies, to enable underwater bonding(70,83). The energetically-favourable conditions for bonding are established underwater by the application of a water-repellant preferred contaminant to a cleaned or blasted steel... 

Transportation Emulsions. Some emulsions are made to reduce viscosity so that an oil can be made to flow. Emulsions of asphalt, a semi-solid variety of bitumen dispersed in water, are formulated to be both less viscous than the original asphalt and stable so that they can be transported and handled. In application, the emulsion should shear thin and break to form a suitable water-repelling roadway coating material. Another example of emulsions that are formulated for lower viscosity with good stability are those made from heavy oils and intended for economic pipeline transportation over large distances. Here again the emulsions should be stable for transport but will need to be broken at the end of the pipeline. It is desirable for the dispersion to possess poor stability under static conditions to permit easy separation of the oil and water. In addition, the oil that has undergone separation is often re-emulsified for further treatment/application. 

Ayurveda has described Ocimum sanctum to have insecticide and pest repellent activities, and for this reason it is grown in most gardens. It is particularly said to act as a repellent against anopheles mosquitoes. The leaves are the most commonly used part and are applied locally on wounds. Topical application is believed to improve blood circulation. It has been prescribed for ear-ache. The juice of the leaves is also described as having digestive, laxative and antihelminthic properties. Apart from having a cardiotonic activity, its actions on the respiratory tract have made it a popular constituent of most therapies for respiratory infections. It also has antipyretic effects and has been prescribed for skin conditions such as leprosy [36]. 

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