Vinyl sponge

There are many expansion joint materials. The general practice is to leave the mortar out of the joint. Then partially fill with a vinyl sponge rod as a back-up. 

Sintering has been used to produce a porous polytetrafluoroethylene (16). Cellulose sponges are the most familiar cellular polymers produced by the leaching process (123). Sodium sulfate crystals are dispersed in the viscose symp and subsequently leached out. Polyethylene (124) or poly(vinyl chloride) can also be produced in cellular form by the leaching process. The artificial leather-tike materials used for shoe uppers are rendered porous by extraction of salts (125) or by designing the polymers in such a way that they precipitate as a gel with many holes (126). 

Poly(vinyl butyral), prepared by reacting poly(vinyl alcohol) with -butyraldehyde, finds wide appHcation as the interlayer in safety glass and as an adhesive for hydrophilic surfaces (161). Another example is the reaction of poly(vinyl alcohol) with formaldehyde to form poly(vinyl formal), used in the production of synthetic fibers and sponges (162). 

Thermosetting Reactive Polymers. Materials used as thermosetting polymers include reactive monomers such as urea—formaldehyde, phenoHcs, polyesters, epoxides, and vinyls, which form a polymerized material when mixed with a catalyst. The treated waste forms a sponge-like material which traps the soHd particles, but not the Hquid fraction the waste must usually be dried and placed in containers for disposal. Because the urea—formaldehyde catalysts are strongly acidic, urea-based materials are generally not suitable for metals that can leach in the untrapped Hquid fractions. Thermosetting processes have greater utiHty for radioactive materials and acid wastes. 

Type AD-G is used in an entirely different sort of formulation. The polymer is designed for graft polymerisation with methyl methacrylate. Typically, equal amounts of AD-G and methyl methacrylate are dissolved together in toluene, and the reaction driven to completion with a free-radical catalyst, such as bensoyl peroxide. The graft polymer is usually mixed with an isocyanate just prior to use. It is not normally compounded with resin. The resulting adhesive has very good adhesion to plasticised vinyl, EVA sponge, thermoplastic mbber, and other difficult to bond substrates, and is of particular importance to the shoe industry (42,43). 

This paper describes a method for improving hydrophilicity by using radiation-induced grafting of flexible polyurethane (polyether) foam with polar vinyl monomers. By this procedure, the normally hydrophobic material can be converted into a remarkably water-wettable sponge. 

The main applications for PVA are in textile sizing, adhesives, polymerization stabilizers, paper coating, poly(vinyl butyial), and PVA fibers. In terms of percentage, and omitting the production of PVA not isolated prior to conversion into poly(vinyl butyral), the principal applications are textile sizes, at 30% adhesives, including use as a protective colloid, at 25% fibers, at 15% paper sizes, at 15%, poly(vinyl butyral), at 10% and others, at 5%, which include water-soluble films, nonwoven fabric binders, thickeners, slow-release binders for fertilizer, photoprinting plates, sponges for cosmetic, and health care applications. 

Vinyl sulfones were prepared from PhS02Na and vinyl iodinium salts C=C—I Ph BF4 Sulfinate esters (RS(=0)0R were prepared from alcohols and sulfinyl chlorides, in the presence of Proton Sponge . " ... 

Now let us look at a complete synthesis.28 The natural product pleraplysillin-1 199 is found in a marine sponge and in the nudibranch (a kind of apparently defenceless shell-less mollusc) that eats it. It has a defensive role - the nudibranch is rapidly rejected as a food source by carnivorous fish .29 Pleraplysilin-1 has a diene joined to a furan at the difficult 3-position. Disconnection between the two double bonds suggests a vinyl triflate 201 from a cyclic alkene, as we can make that regioselectively from the corresponding ketone, and a vinyl stannane from the furan half 200. 

Pyrinodemin A was reported in 1999 as a cytotoxic pyridine alkaloid isolated from the sponge Amfhimedon sp. collected in Okinawa. The planar structure of this alkaloid was composed of a unique cyclopent[r]isoxazo-lidine connected with a bis-3-alkylpyridine based on the MS and NMR data. Location of the Z olefin [5c 129.3 (2C), C-16 and C-17 ] was assigned from the chemical shift of the two vinyl carbons (C-15 and C-18, ... 

Actafoam . [Unitoyal] Fatty acid salts disperskxi acdvatcx -stabUizer fc vinyl foams, sponge rubbo gas release accelerator. 

FIceHk [ hering Berlin Pdymets] Azo-dicarbonamide chemical blowing i ent to sponge rubber, cushion vinyl fkxning and fabrics, profiles r sealants, structural foam mdding, wire and cd)Ie insulatkm, films. 

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