Cast Poly Research Articles

Photodegradation of poly(vinyl esters)—I. Formation and quantitative measurement of volatile products

The high vacuum distillation technique for the analysis of photolysis products has highlighted both the extreme difficulty of removing residual solvent and the slow diffusion of photodegradation products from thin cast poly(vinyl ester) films, even at temperatures 130°C above T g. Very long product collection periods at temperatures just below the onset of thermal degradation were used in order to obtain reliable quantitative data. The distributions of liquid-nitrogen condensable products indicated that a closer relationship exists between the photodegradation of poly(vinyl esters) and the photolysis of low molecular mass esters than previous results had suggested.

A study of the surface characteristics of solvent cast poly(methyl methacrylate)

A study of the surface characteristics of solvent cast poly(methyl methacrylate)

Biaxial stretching of heat‐softened plastic sheets: Experiments and results

AbstractA second‐generation apparatus was built and used to inflate heat‐softened plastic sheets to shapes from hemispheres to large spheroidal bubbles. Three sheet materials, polystyrene, high‐impact polystyrene, and cellulose acetate butyrate, were successfully formed beyond the hemispherical shape at temperatures somewhat below industrial levels. Four others, rigid poly‐(vinyl chloride), an acrylic‐modified PVC, cast poly(methyl methacrylate), and polycarbonate, could not be deformed beyond the hemispherical shape without rupture. Measurements included bubble profiles, thickness distributions and local extension ratios for the final bubbles; two plots of profile growth measured from high‐speed motion pictures; and a continuous record of bubble temperatures and blowing pressure from which the meridional temperature distributions were plotted.Fifteen bubbles were measured and analyzed. Profiles and extension ratios were compared with those computed from the equations of isotropic, isothermal elasticity, using several different strain‐energy functions with constant material parameters. Agreement over all fifteen bubbles on all properties was about ±10.8 percent (absolute) for the best models considered. Bubble growth occurred over periods of 5 to 8 seconds, with about 90 percent of the final area of the larger bubbles being generated in the final 1.5 seconds. The maximum areal elongations obtained were 18,600 percent for clear polystyrene at 238°F, 14,300 percent for high‐impact polystyrene at 224°F, and 1,010 percent for cellulose acetate butyrate at 280°F.

The photodegradation of poly(vinyl chloride) films—IV

The concentration of residual tetrahydrofuran in cast poly(vinyl chloride) films has been varied. It is shown that the amount of tetrahydrofuran present does not affect the extent of degradation but that it does affect the relative concentration of the conjugated polyenes produced. A shift towards shorter polyenes is observed with increasing concentration of residual solvent; this effect is attributed to its ability to act as a plasticizer.

The photodegradation of poly(vinyl chloride) films—II

Cast poly(vinyl chloride) films have been irradiated by ultra-violet light at various intensities and temperatures under a nitrogen atmosphere. The dehydrochlorination reaction is shown to occur in two parts. During the first hour the reaction is dependent on intensity and temperature but later it is independent of these two parameters.

The photodegradation of poly(vinyl chloride) films—I

Cast poly(vinyl chloride) films have been degraded by u.v. light in a nitrogen atmosphere. Degradation is shown to take place only in a thin surface layer.

Isotropic Expansion of Cast Poly(Chlorostyrene) Compositions to Low Density Cellular Products

Isotropic Expansion of Cast Poly(Chlorostyrene) Compositions to Low Density Cellular Products

Hyperfiltration studies XVI: Salt filtration by dynamically formed and cast poly (glutamic acid) and poly (acrylic acid) membranes

Membranes were dynamically formed of poly(glutamic acid) and poly (acrylic acid), and their hyperfiltration (reverse osmosis) properties investigated. Rejections were high in comparison with those of organic polyelectrolytes previously studied. Rejection properties of cast (cross-linked) films were similar. Transmission rates through cast poly(glutamic acid) films were much lower than through those dynamically formed of the same polyelectrolyte, in accord with our usual experience. Cast polyacrylate membranes, however, had extremely high permeation rates for films having comparable rejection made of any material; fluxes were in many cases higher than those of polyacrylate membranes formed dynamically.

Acrylic anhydrides and polymers derived therefrom

AbstractThe free‐radical polymerization of four acrylic anhydrides—methacrylic anhydride, acrylic anhydride, acrylic methacrylic anhydride, and acrylic propionic anhydride—under a variety of conditions has been studied. The polymers and their polyacid and polyester derivatives were characterized by solubility, infrared spectroscopy, and x‐ray diffraction. Methacrylic anhydride could be polymerized in bulk and in hydrocarbon solvents from −50°C. to 80°C. to give soluble, linear cyclopolymers in high conversions. In a polar solvent such as dimethyl sulfoxide, gelation would result at high monomer concentrations and at high conversions. Acrylic anhydride, however, appeared to become crosslinked more readily; soluble polymers could be obtained only by polymerization in nonpolar solvents. Most of the previous and somewhat conflicting results on the cyclopolymerization of these two monomers can now be reconciled by the present findings. The physical properties of cast poly(methacrylic anhydride) suggest that it has a stiff backbone with hindered functional groups and that the monomer itself was perhaps intramolecularly associated. Some improvements in the aqueous hydrolysis of poly(methacrylic anhydride) and in the esterification of the derived polyacid by diazomethane were described. By these refinements, poly(methyl methacrylate), derived from a −50°C. poly(methacrylic anhydride), had previously been shown to possess a novel, mixed syndiotactic and syndioduotactic (++−−++−−) configuration. Acrylic methacrylic anhydride could be cyclopolymerized very much like methacrylic anhydride. The polyacid and polyester derived from this unsymmetrical anhydride are expected to have unique structures; the acrylic or methacrylic units in the derivatives do not occur more than twice in succession. Acrylic propionic anhydride, when homopolymerized, readily changed to a soluble polymer and an unidentified, immiscible liquid. Its soluble copolymer with methyl methacrylate, however, could be crosslinked by heating. An intramolecular and intermolecular disproportionation reaction was postulated to explain these two interesting observations, respectively.