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Epidural administration: injection into the epidural space of the spinal cord.Epidural, (Greek): situated on or outside the dura mater, from epi- "on top of" + dura mater + -al. Adhesion (Latin) adhēsiōn- for Latin adhaesiōn- (stem of adhaesiō) a clinging, equivalent to adhaes(us), past participle of adhaerēre to adhere + -iōn- -ion.
The same applies to coated items. The adhesive must build adhesion to the coating. The coating in turn must be sufficiently firmly connected to the substrate. Likewise, contaminants, especially those which, due to their low surface tension, counteract wetting by the adhesive (for example, oils, release agents, etc.) hinder the adhesion ...
A number of adhesion promotion methods have been developed to enhance PTFE bond strength. The primary methods currently used in industry are sodium etching and plasma etching. Results of ion beam treatment and laser surface roughening have also been reported in the literature, but do not have a significant presence as commercial processes.
Too low a temperature can cause the polymeric adhesive to enter its glass state becoming very brittle and reducing adhesion. [14] Raising the temperature, on the other hand, causes the polymer to become more fluid and mobile. As the mobility increases, the polymer adhesion is reduced as the polymer starts to flow as opposed to adhere.
There are three major requirements of creating a desirable surface for adhesive bonding of plastics: the weak boundary layer of the given material must be removed or chemically modified to create a strong boundary layer; the surface energy of the adherend should be higher than the surface energy of the adhesive for good wetting; and the surface profile can be improved to provide mechanical ...
Mucoadhesion involves several types of bonding mechanisms, and it is the interaction between each process that allows for the adhesive process. The major categories are wetting theory, adsorption theory, diffusion theory, electrostatic theory, and fracture theory. [5]
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A release agent (also mold release agent, release coating, or mold release coating) is a chemical used to prevent other materials from bonding to surfaces. Release agents aid in processes involving mold release, die-cast release, plastic release, adhesive release, and tire and web release. [ 1 ]