The elastic modulus of the crystalline regions in some oriented polymers was determined. An x‐ray diffractometer specially constructed for this purpose was used, and the lattice extension in the direction of the fiber axis was measured under application of a direct load. Usually a meridional reflection was used for the measurement of the lattice extension, but in the case where no strong meridional reflection exists a reflection from planes which are almost perpendicular to the fiber axis of the crystallites was used. The elastic modulus was calculated under the assumption of a simple series model. The values found are as follows: polyvinyl alcohol, 255 × 104 kg./cm.2; polyethylene, 240 × 104 kg./cm.2; polypropylene, 42 × 104 kg./cm.2; polyoxymethylene, 54 × 104 kg./cm.2; cellulose, 137 × 104 kg./cm.2; polyvinylidene chloride, 41.5 × 104 kg./cm.2.

Some experiments were carried out to prove the validity of the assumption of a simple series model for the calculation of the elastic modulus of crystalline regions in oriented linear polymers from X-ray determination of lattice extension. Various specimens such as filaments, fibers, and films were prepared' from polyethylene, polyvinyl alcohol, polypropylene, polyoxymethylenq and cellulose; stress-strain curves constructed under the assumption of a simple series model; and calculated values of modulus compared. In spite of the differences of microstructures of these specimens, nearly the same value for the lattice modulus was obtained for each polymer. A large difference of specimen moduli had no effect on the lattice modulus. Lattice moduli of dry and water-swollen polyvinyl alcohols or cellulose did not differ from each other. These results are a strong support for the above assumption. I Extensibility of various polymer molecules was also discussed. ZUSAMMENFASSUNG:Es wurde eine Reihe von Versuchen durchgefuhrt, um die Giiltigkeit der Annahme eines einfachen Reihen-Modells fur die Berechnung des Elastizitatsmoduls der kristallinen Bereiche in orientierten linearen Polymeren mit Hilfe der rontgenographischen Messungen der Gitterdehnung zu beweisen.Von verschiedenen Proben wie Faden, Fasern und Filmen von Polyithylen, Polyvinylalkohol, Polypropylen, Polyoxymethylen und Cellulose wurden die Kraft-Dehnungskurven unter der obigen Annahme konstruiert und die Werte des Moduls miteinander verglichen. Trotz des Unterschiedes zwischen den Mikrostrukturen dieser Proben erhielt man fast den gleichen Gittermodul bei jedem dieser Polymeren. Die g o -l3en Unterschiede zwichen den makroskopischen Moduln der Proben hatten keinen E i d d auf den Gittermodul. Die Gittermoduln von trockenem und mit Wasser gequollenem Polyvinylalkohol oder auch Cellulose unterschieden sich nicht voneinander. Diese Ergebnisse stellen eine starke Stutze fur die oben erwahnte Annahme dar.Ferner wird die Dehnungsfahigkeit der verschiedenen Polymer-Molekule diskutiert.

SYNOPSISThe force required to stretch a polymer chain by 1% cf value) was calculated from experimental values of elastic moduli E l in the direction of molecular axis and the cross-sectional area of the molecule of 25 well known polymers. The f value is mainly dependent on the conformation of a molecule and almost independent of side groups. The f values of polymers of va_rious types of conformation may be summarized as follows: T type, 4-5 Xdyne;TGTG type, 1.5 X dyne;TG(3/1) type, 1 X dyne;T'G'(7/2) type, 0.58 X lov5 dyne; T'G'(4/1) type, 0.36 X dyne;KTGG type.0.29 X loL5 dyne; where T, G, and E mean tmns, garche and minus guuche, respectively, and the numbers in the parentheses denote helical structures. The reason for an anomalous apparent El value of nylon 6 (&-form) previously reported was elucidated; it was confirmed that El exhibits a value expected for a polymer with a nearly extended zigzag conformation.

A study of the oxidation of poly(vinyl alcohol) (PVAL) by potassium persulfate (KPS) in aqueous solutions showed that the decomposition of KPS was greatly enhanced by the presence of PVAL, its hydroxyl groups being oxidized to ketones in a yield of about one mole of ketone from one mole of KPS. The decomposition rate of KPS was found to be given by the equation, −d[S2O82−]/dt = k[S2O82−] [PVAL]1/2, which was essentially the same as in the oxidation of alcohols of low molecular weight by persulfate ion. The occurrence of gelation of PVAL solutions and graft copolymerization of methyl methacrylate (MMA) onto PVAL in the presence of KPS was evidence for PVAL radical as an intermediate species in the oxidation of PVAL. A characterization study was also carried out for the reaction products of the graft copolymerization of MMA onto PVAL with KPS in dimethyl sulfoxide solution.

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