ISSN:0032-3888    

DOI:10.1002/pen.760020102

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760020103

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractBy following the changes in torsional modulus as a function of time, the kinetics of crystallization of three copolymers of vinylidene chloride containing 10% mole % alkyl acrylate were investigated and the geometrical growth and nucleation constant of the Avrami equation was determined. Isotherms were superimposable within certain temperature ranges while the nucleation constant decreased with a decrease in temperature. Rate of crystallization increased with increase of the alkyl side chain length.

ISSN:0032-3888    

DOI:10.1002/pen.760020104

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractThis paper compares results of four accelerated oxidation tests: the hot milling test, reaction with fuming nitric acid, absorption of oxygen gas at elevated temperature and the redox system—polyethylene—lead peroxide ignition test. The length of the induction period, is a product of antioxidant concentration but not of the inherent oxidizability of the resin. Discrepancies between induction periods as measured by oxygen absorption and hot milling differ because in the former the volume of pure oxygen absorbed is measured and in the latter the electrical consequences of air oxidation. In addition other polymeric degradation occur in milling. Nitric Acid treatment measures the effect of nitric acid upon the specific viscosity and is useful for chain scission comparisons. The ignition tests reflect both inherent oxidizability and presence of antioxidant. All four tests reflect oxidation paramet

ISSN:0032-3888    

DOI:10.1002/pen.760020105

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractThe effects of moisture and rather large doses of reactor radiation (∼4 × 1011ergs/gm) on the dynamic properties of polymerized epoxy resins have been investigated over the temperature range of 80°‐450°K and at frequencies from 200 to 1400 cps. Data are presented for both unfilled and aluminum‐filled systems of a bisphenol A based epoxy, (Epon 828) cured with metaphenylenediamine. Moisture absorption (0.88%) causes a shift of the main glass transition near 440°K to lower temperatures (∼25 degrees for unfilled epoxy). This is similar to the plasticizing action of small molecules absorbed in other polymers such as nylon 6‐6. Irradiation to a dose of 4 × 1011ergs/gm (4 × 109rads) causes a shift to lower temperatures (∼50 degrees) of the onset of the main transition, and, in addition, results in both a shift to lower temperatures and a decrease in maximum height of the damping peak near 250°K. Chain scission, in a loosening of the structure and the breaking up of the partially flexible connecting groups, may be responsible for these

ISSN:0032-3888    

DOI:10.1002/pen.760020106

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractOne of the reasons for purification of low‐pressure polymerization products is the assumed degradation effects of retained catalysts. Degree of degradation was determined from the change in viscosity number. Effects of catalysts on active sights and deactivation were noted along with degradation in the presence of air and oxygen in addition to determining, the effect of antioxidants. Individual components of the catalyst may have the ability to intensify the effect of any antioxidant and affect the rate of degradation where catalyst influence was better defined in the presence of oxyge

ISSN:0032-3888    

DOI:10.1002/pen.760020107

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractA series of thirty‐three phosphites of varied structural variations were tested at 177°C in a vinyl compound utilizing co‐precipitated barium cadmium laurate or a combination of barium nonylphenate and cadmium 2‐ethylhexoate as the primary stabilizer. Best activity was found with mixed alky‐aryl ph

ISSN:0032-3888    

DOI:10.1002/pen.760020108

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractA bibliography of references from 1957 through 1960 was prepared containing the following sub‐headings: Protective Ultraviolet Absorbers, Light Sources, Light Fastness Evaluation, Plastics Degradation and Stabilization Polyesters, Polystyrene, Polyvinylchloride, Polyethylene, Polyacrylo and Methacrylonitrile, Polymethyl Methacrylate, Cellulose Acetate and Nitrate, Polyvinyl alcohol, Polyamides, Wool, Rubber, Silicone Resin, Wood, Dyes and Paint Films, Epoxy, Melamine and Urea Formaldehyde, Oil Films, General Mechanical Degradation, Free Radicals and ESR, Photochemistry, Photochemistry and Spectroscopy at Low Temperatures, Antioxidants and Free Radical Scavengers, Flash Photolysis, Energy Transfer, Phosphorence and the Triplet State, Fluorescenc

ISSN:0032-3888    

DOI:10.1002/pen.760020109

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760020110

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY

摘要:

AbstractA brief description is given of the use of a resonant‐bar type apparatus for measurement of the dynamic elastic modulus and the associated damping or internal friction of a solid polymer. Each different type of polymer is found to exhibit a characteristic internal friction spectrum when explored over the temperature range from liquid nitrogen temperatures to the melting point. These spectra are characterized by the occurrence of one or more peaks in the mechanical loss data centered about certain temperatures, accompanied by an associated drop in dynamic modulus. By variation of polymer composition and of polymer structure, by addition of low molecular weight compounds, and by subjection of samples to irradiation, considerable additional information can be gained that would be helpful in determining the nature of the molecular mechanisms that are responsible for the observed transitions. Dynamic mechanical data are presented and discussed for a series of poly(alpha olefins) with methyl, ethyl, propyl, isopropyl and isobutyl side chains to depict the effects of crystallinity, side chain length and side chain structure on the observed transition

ISSN:0032-3888    

DOI:10.1002/pen.760020111

出版商:Society of Plastics Engineers, Inc.    

年代:1962

数据来源: WILEY