Dyne

Abstract: An insulating adhesive tape comprises a base supporting film and an adhesive layer formed on at least one surface thereof, said adhesive layer being formed of a thermoplastic polymer comprising a thermoplastic polyimide. The thermoplastic polymer has a glass transition temperature ranging from 180°C to 280°C and an elastic modulus ranging from 10¹⁰ dyne/cm² to 10¹¹ dyne/cm² at 25°C, said modulus including a value ranging from 10² dyne/cm² to 10⁹ dyne/cm² at a temperature between 250°C and 300°C.

Abstract: The force required to stretch a polymer chain by 1% (f value) was calculated from experimental values of elastic moduli E1 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 various types of conformation may be summarized as follows: T type, 4−5 × 10−5 dyne; TGTG type, 1.5 × 10−5 dyne; TG(3/1) type, 1 × 10−5 dyne; T′G′ (7/2) type, 0.58 × 10−5 dyne; T′G′ (4/1) type, 0.36 × 10−5 dyne; TTGG type, 0.29 × 10−5 dyne; where T, G, and G mean trans, gauche and minus gauche, respectively, and the numbers in the parentheses denote helical structures. The reason for an anomalous apparent E1 value of nylon 6 (α-form) previously reported was elucidated; it was confirmed that E1 exhibits a value expected for a polymer with a nearly extended zigzag conformation.

Abstract: A method is described by which the surface tension of surfaces occurring in the systems copper-hydrogen or argon and copper-lead-hydrogen or argon is determined. At temperatures round 850° C the surface tension between copper grains is 640 dyne/cm. and between copper and the equilibrium lead-copper liquid phase 340 dyne/cm. The surface tension of a copper-gas surface is the same whether the gas is hydrogen or argon, within the limits of precision of the experiment, and has the value 1,800 dyne/cm. When lead vapour is present in the gas atmosphere at a partial pressure of the order of 0.1 mm. Hg the surface tension of the copper-gas surface has the much lower value of 780 dyne/cm It is suggested that the reduction is due to the adsorption of lead at the copper-gas surface The failure of the liquid phase to exhibit a contact angle of zero against solid copper surfaces is thereby understood

Abstract: A theory of the thermal expansion of hexagonal crystals is derived, and shown to account quantitatively for the experimental data on graphite. Certain of the elastic moduli for graphite are estimated, and are at 18°c. approximately: s11+s12= 1.8×10-13 cm./dyne s13=-4.3×10-13 cm./dyne s33= 58.5×10-13 cm./dyne Hence the two linear compressibilities are, at 18°c., approximately: kperpendicular=-2.5×10-13 cm2/dyne; kparallel=50×10-13 cm2./dyne.