Poly treatment applications

In the development of a reactive non-chrome post-treatment, a variety of phenolic resins were synthesized and commercial phenolic resins evaluated. It was found that phenol-formaldehyde resins, creso1-forma1dehyd e condensates, ortho-novo 1 ak resins, and phenol-formaldehyde emulsions gave positive results when employed as post-treatments over zinc and iron phosphate conversion coatings. The above materials all possessed drawbacks. The materials in general have poor water solubility at low concentrations used in post-treatment applications and had to be dried and baked in place in order to obtain good performance. The best results were obtained with poly-4-vinylphenol and derivatives thereof as shown in the following structure (8,9,10)... 

Water-Soluble Polymers A number of polymers useful for such applications as diaper absorbents, detergents, dispersants, thickeners, and water treatment applications are water soluble and thus may be made by aqueous polymerization processes [61-63]. Poly(methacrylic acid) and its high acid copolymers and salts, as well as poly(V-vinyl pyrrolidone), are some examples. Typically initiators include water-soluble azo compounds, hydroperoxides, persulfates, and redox systems [64]. Often, if the solubility is not complete in water, alcohol solvents are sometimes added. 

Labeled Water Treatment Polymer. Low molecular weight poly(acrylic acid) is used as a dispersant for mineral scale in water treatment applications. The water treatment polymer is added to the aqueous system in a predetermined concentration that is effective to inhibit the formation and deposition of mineral scale. The concentration of the polymer must be monitored over time in order that the amount of polymer present in the system can be maintained at the predetermined concentration. 

Low molecular weight poly(acrylic acid) is difficult if not impossible to detect directly in aqueous solution at the concentrations at which it is employed in water treatment applications. There are, however, many classic colorimetric techniques for the quantitative detection of saccharides down to the ppm level (75). If a poly(acrylic acid) water treatment polymer is prepared with pendent saccharide functionality, detecting the polymer reduces to a problem of detecting the saccharide functionality. With monomers of the type 5 in hand, we were able to explore this strategy for the preparation of a detectable water treatment polymer. 

Poly(maleic anhydride) or the hydrolyzed water soluble polymer has many possible uses, with perhaps the greatest potential application as a detergent builder and scale prevention agent, for water treatment applications. A comprehensive account of MA polymerizations, polymer properties and suggested uses are covered in this chapter. MA-based monomers, such as maleates, fumarates, and maleimides, are also briefly discussed. 

There have been a number of different synthetic approaches to substituted PTV derivatives proposed in the last decade. Almost all focus on the aromatic ring as the site for substitution. Some effort has been made to apply the traditional base-catalyzed dehydrohalogenation route to PTV and its substituted analogs. The methodology, however, is not as successful for PTV as it is for PPV and its derivatives because of the great tendency for the poly(u-chloro thiophene) precursor spontaneously to eliminate at room temperature. Swager and co-workers attempted this route to synthesize a PTV derivative substituted with a crown ether with potential applications as a sensory material (Scheme 1-26) [123]. The synthesis employs a Fager condensation [124] in its initial step to yield diol 78. Treatment with a ditosylate yields a crown ether-functionalized thiophene diester 79. This may be elaborated to dichloride 81, but pure material could not be isolated and the dichloride monomer had to be polymerized in situ. The polymer isolated... 

We discovered another synthetic technique that involves the conversion by direct fluorination of hydrocarbon polyesters to perfluoropolyesters followed by treatment with sulfur tetrafluoride to produce new perfluoropolyethers.42 The first paper in this area ofreasearch reported that conversion of poly(2,2-dimethyl-1,3-propylene succinate) and poly( 1,4-butylene adipate) by using the direct fluorination to produce novel branched and linear perfluoropolyethers, respectively. The structures are shown in Figure 14.6. The second paper concerns the application of the direct fluorination technology base directed toward oligomers, diacids, diesters, and surfactants.43... 

In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp could be introduced by hydrochloric acid treatment and the porosity could be controlled by the pH of the hydrochloric acid solution, the treatment time, and the crystallinity of the HAp particles. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-COL-HAp composites. This material showed potential for keratoprosthesis application. Further study such as a long-term animal study is now required [241]. 

A host of bioadhesive controlled release systems have been proposed in recent years. Among the most commonly studied applications of bioadhesive materials is the area of buccal controlled delivery [408], The buccal delivery of small peptides from bioadhesive polymers was studied by Bodde and coworkers [409], and a wide range of compositions based on poly(butyl acrylate) and/or poly(acrylic acid) gave satisfactory performance. Bioadhesive poly(acrylic add)-based formulations have also been used for oral applications [402,410] for the sustained delivery of chlorothiazide [410] and for a thin bioadhesive patch for treatment of gingivitis and periodontal disease [411]. Other bioadhesive applications of polyelectrolytes include materials for ophthalmic vehicles [412,413], and systems for oral [410,414,415-419], rectal [420,421] vaginal [422] and nasal [423] drug delivery. 

Sorbitan sesquioleate emulsions of petrolatum and wax are used as ointment vehicles in skin treatment. In topical applications, the inclusion of both sorbitan fatty esters and their poly(oxyethylene) derivatives modifies the rate of release and promotes the absorption of antibiotics, antiseptics, local anesthetics, vasoconstrictors, and other medications from suppositories, ointments, and lotions. Poly(oxyethylene(20)) sorbitan monooleate, also known as Polysorbate 80 (USP 23), has been used to promote absorption of ingested fats from the intestine (245). 

Functional derivatives of polyethylene, particularly poly(vinyl alcohol) and poly(acrylic acid) and derivatives, have received attention because of their water-solubility and disposal into the aqueous environment. Poly(vinyl alcohol) is used in a wide variety of applications, including textiles, paper, plastic films, etc, and poly(acrylic acid) is widely used in detergents as a builder, a super-absorbent for diapers and feminine hygiene products, for water treatment, in thickeners, as pigment dispersant, etc (see Vinyl POLYMERS, VINYL alcohol polymers). 

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