Film-coating solvents

Air-Suspension Coa.ting. The Wurster process utilizes a cylindrical chamber in which the cores are suspended in a controlled stream of air. Film coatings are appHed by introducing the coating solution into the airstream, where the solvent evaporates quickly. The process is much quicker than film coating however, care must be taken to avoid destmction of the cores by attrition in the air stream. 

Thermosetting epoxy and polyurethane chemically-cured liquid resins can provide, among other characteristics, superior abrasion resistance coatings. Solvent-free formulation applied by hot spray techniques can achieve film thicknesses of up to 5 mm. 

Solid phase extraction (SPE) is a very simple, rapid and reproducible cleanup technique that is now widely accepted as an alternative to the time-consuming liquid-liquid extractions. Additionally, SPE uses relatively small volumes of solvents, and is easy to automate. It is available in a number of different formats, including cartridges, disks, loose material, well plates or SPME using film-coated capillaries. SPE can be considered as an extraction technique when used for isolation and concentration or a cleanup technique when used to remove co-extractives from solvent extracts. The use of SPE for cleanup is discussed later. 

Gas iromatography (GC) Gas-Liquid (GLC) Gas, e.g. N2, H2, He Liquid-film coated on solid support Gases and adequately volatile liquids (mol. wt. <300) of adequate thermal stability, e.g. hydrocarbons and their derivatives, solvents, inorganic gases, essential oils, some steroids and vitamins. 

Condensation polyimides or SP-polyimides from the solvent-phase reaction of an aromatic tetra-acid with a diamine. Despite the thermoplastic form they are infusible and generally insoluble. Consequently, the producer can only mould this type. It is particularly convenient for the manufacture of thin parts and films, coatings... 

Positive photoresist formulations consist of a novolac resin and an appropriate diazonaphthoquinone dissolved in organic solvent. Common solvents include ethyl cellosolve acetate, diglyme, etc. These formulations are spin-coated and then baked to remove the coating solvent. They provide films in which the sensitizer is randomly distributed through the novolac matrix. 

Raman often is evaluated as an alternative to an existing high performance liquid chromatography (HPLC) method because of its potential to be noninvasive, fast, simple to perform, and solvent-free. Raman was compared to HPLC for the determination of ticlopidine-hydrochloride (TCL) [43], risperidone [44] in film-coated tablets, and medroxyprogesterone acetate (MPA) in 150-mg/mL suspensions (DepoProvera, Pfizer) [45] it was found to have numerous advantages and performance suitable to replace HPLC. In an off-line laboratory study, the relative standard deviation of the measurement of the composition of powder mixtures of two sulfonamides, sulfathiazole and sulfanilamide, was reduced from 10-20% to less than 4% by employing a reusable, easily prepared rotating sample cell [46]. 

Solubility Rate Measurements. Solubility rates, Sr, were determined by measuring PBS film thickness as a function of development time. PBS films coated on silicon wafers were broken into several pieces. Each piece was dipped into n-butyl acetate, BuAc, and the development time measured. The film was rinsed in isopropanol and baked at 120 C for 30 minutes to remove residual solvents. Film thickness was measured by interferometry. The temperature of the developer, BuAc, was controlled at 2S C O.OS C and the developer was not stirred or agitated during the deydopment process. Plot of film thickness vs. development time were linear for low Mw films. Films having M, greater than 400,000 g/mole did not completely dissolve in BuAc. 

Amyl formate 638-49-3 Solvent, odorant, Ravoring Films, coating, leather, perfume Rammable toxic by swallowing and breathing skin irritant... 

It is customary to apply these polymers as the poly(amic -acids) and to dehydrate the film, coating, fiber or molded forms by heating to produce the polyimides. Polyimides are insoluble in most solvents hut are attacked by alkalies, ammonia and amines. These heat resistant polymers are used without fillers and with a graphite filler. 

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