G. Allan Stahl

Preparation of Block Copolymers of Vinyl Acetate in. Viscous Poor Solvents

Abstract Stable macroradicals of poly(vinyl acetate) were produced by heating vinyl acetate (VAC) and 2% tert-butyl peroxypivalate at 50° C for 96 hr in silicone oil. Block copolymers were produced from these macroradicals by adding a second vinyl monomer and heating at 50° C for an additional 72 hr. The formation of these macroradicals was monitored by yield, dilatometric rate data, and scanning electron micrographs. Poly(vinyl acetate-b-methyl methacrylate), polyvinyl acetate-b-acrylic acid), polyvinyl acetate-b-acrylonitrile), poly(vinyl acetate-b-vinylpyrrolidone), poly(vinyl acetate-b-styrene), and polyvinyl acetate-b-methyl methacrylate-b-styrene) were characterized by yield, selective precipitation, pyrolysis gas chromatograph, and differential scanning calorimetry (DSC).

Recording capacitance dilatometer

A capacitance dilatometer is described which automatically records the height of a mercury column as a function of time. Changes as small as 10−4 ml have been detected, with an instrumental stability allowing experiments of several days’ duration. The technique is based on the measurement of the capacitance of an aluminum foil‐covered, precision bore, glass column containing Hg. The dilatometer has been used to measure coefficients of expansion and rates of polymerization and hydrolysis.

The Reaction of Vinyl Monomers with “Trapped Free Radicals”

Abstract Previous attempts to prepare copolymers by the reaction of vinyl monomers, such as styrene, with “trapped free radicals” such as acrylonitrile macroradicles has been unsuccessful because of the large differences in solubility parameters between the liquid and the solid. However, acrylonitrile will react with styrene macroradicals in the absence of oxygen, and yield block copolymers. Block copolymers may be produced from other vinyl monomers and other macroradicals when the difference in the solubility parameter of the monomer and macroradicals is less than 3.2H.

History of Vinyl Chloride Polymers

Abstract In 1926 Semon tried to dehydrohalogenate high molecular weight poly(vinyl chloride) (PVC) in a high boiling solvent to get an unsaturated polymer which might bond rubber to metal. Unexpectedly, he obtained plasticized PVC, a flexible product inert both electrically and chemically. This discovery opened the door to the commercialization of PVC, a plastic with an annual United States production now exceeding 6 billion pounds. Special PVCs and PVC products have been developed taking advantage of the many favorable properties. Rigid structural products from house siding to pipes are becoming of increasing importance. Two main types of polymers have been utilized: 1) one prepared by suspension polymerization, and 2) a special variety prepared by colloidal polymerization and spray drying. This latter material has been especially useful for making plastisols. Plasticizers and stabilizers were developed to maximize useful and nontoxic properties. Vinyl chloride monomer (VCM) production and co-polymeriza...

Giulio Natta a Pioneer in Polypropylene

Giulio Natta, who shared the Nobel Prize in chemistry with Karl Ziegler, was an Italian crystallographer who used the “Ziegler catalyst” to produce polypropylene. His wife, Rosita, coined the tacticity terms after Giulio had shown that stereoregular polymers could be produced by the polymerization of alpha substituted ethylenes.

PREPARATION AND PROPERTIES OF CELLULOSE BLENDS IN DIMETHYLSULFOXIDE SOLUTION

ABSTRACT Solutions of cellulose where prepared via the in situ formation of cellulose methylols by heating mixtures of dimethylsulfoxide (DMSO), paraformaldehyde (PF) and Whatman Filter paper. These 1.0 percent stock solutions of cellulose were used to prepare homogeneous blends of other DMSO soluble polymers with cellulose. Clear homogeneous solutions of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP) and Poly(vinyl alcohol) (PVA) were prepared as 0.3, 1.0 and 3.0 percent solutions in 1.0 percent solutions of cellulose dissolved in DMSO:PF, These solutions were characterized using Brookfield viscometry and used to cast cellulose films containing various amounts of PAN, PVP and PVA. These films were characterized physically and found to exhibit tensile strengths ranging between 130 and 540 kg/cm2 as a function of the cellulose polyblend composition. The films were characterized morphologically via scanning electron microscopy (SEM) and the cellulose/PVA films were found to be porous. The average pore diameter varied between 5.0 and 80.0 microns as a function of film composition.

William Joseph Sparks Co-Inventor of Butyl Rubber

William J. (“Bill”) Sparks, disdainful of the tradition synthetic rubbers made from C4 to C6 dienes, selected other raw materials for making rubberlike polymers. In 1937 Sparks, and colleague R.M. Thomas, chemists with Standard Oil of New Jersey, invented the now-famous butyl rubber, made by copolymerizing isobutylene with small proportions of butadiene or isoprene. While a research supervisor (1939–1940) at USDA’s Northern Regional Research Center (Peoria, IL), Spark’s rubber expertise helped initiate research that eventually transformed vegetable oils into the elastomer called Norepol. Yielding to attractive offers, Sparks returned in 1940 to the Esso Research & Engineering Co., where he remained- (Director of Chemical Research, until his retirement in 1967. Spark’s creative genius, which was not limited to polymers, led to numerous patents on various materials, e.g., new fuels, gasoline additives, propellents, encapsulated oxidants, asphalt additives, and food-wrapping films. Born in 1904 and a graduate of Indiana University and the University of Illinois (Ph.D., 1936), Sparks received many honors. He advocated creativity and enhanced status for inventors. Active in professional societies (President, American Chemical Society, 1966), Sparks served both chemistry and chemists with distinction. He and Mrs. Meredith Pleasant Sparks (Ph.D., chemistry, and law degree) parented four children. William J. Sparks died October 23, 1976, in his home in Coral Gables, Florida.

Modern Pioneers in Plastics, Fibers, Inorganic Polymers, Elastomers and Engineering Polymers

While some polymer chemists are better known for their accomplishments, few excelled Herman Alexander Bruson in ingenuity and productivity. Herman, who was the son of Samuel J. and Rebecca Arnowitz Bruson, was born in Middleton, OH on July 20, 1901. After receiving the B.S. degree from MIT in 1923, he enrolled in Zurich’s Federal Technical University where he was awarded the Ph.D. degree in 1925.

J.C. Patrick Father of American Synthetic Elastomers

While he was not a chemist, Dr. Joseph Cecil Patrick invented America’s first synthetic rubber in the early 1920’s when few scientists recognized the existence of polymers. Unlike his contemporaries, he didn’t discard the brown insoluble gum that was produced when he attempted to hydrolyze ethylene dichloride with sodium polysulfide. He named this product Thiokol after the greek words for sulfur and gum. He solved commercial production problems by inventing the suspension polymerization process and solved the compounding problems by degrading the high molecular weight polymer to a low molecular weight liquid polymer. The latter is now the principal binder for solid propellants.

Maurice Loyal Huggins a Pioneer in Solution Theory

While Maurice Huggins spent much of his career in industry, he was more interested in basic research than in practical investigations. his major contributions to polymer science were related to entropy of mixing and the viscosity of dilute solutions. He died in California in December 1982.