Materials Literature
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In laboratory trials on samples from individual fleeces solvent degreasing has shown a higher yield than aqueous alkaline scouring. Differences of 0.5% to 1.4% of clean dry fiber are found when solvent degreasing is compared with traditional soap-soda scouring. Evidence is presented showing that the difference in yiel…
Abstract Extensive fatigue tests of vulcanizates of natural rubber and SBR were carried out using a cycle of alternate stretching in two perpendicular directions. It is shown that the data can be best handled statistically by assuming a lognormal distribution or by the use of extreme probability techniques. Illustrati…
Samples of polydivinylbenzene (PDVB) and of copolymers of styrene with divinylbenzene (DVB) and with trivinylbenzene (TVB) were pyrolyzed in a vacuum in the temperature range of 346 to 450 °C. The volatile products were collected in two fractions: A heavy fraction volatile at the temperature of pyrolysis and a light f…
Abstract Neoprene vulcanizates crystallize most rapidly at —12° C. The temperature at which a vulcanizate is crystallized determines the minimum temperature at which it will thaw, the thaw point being approximately 15° C higher than the crystallization temperature over the range studied. Brittleness temperature is not…
Previous investigations on the solution properties of sodium carboxymethylcellulose (CMC) have led to the conclusion that crystalline cellulose regions, remaining after processing act as binding or crosslinking sites for the establishment of a fraction comprised of swollen gels or aggregates in solution. The present p…
The assumptions used in theoretical predictions of the tensile properties of twisted continuous-filament yarns are critically discussed. A modified theory, based on constant yarn volume during extension, is derived, and theoretical and experimental values of modulus are compared. Expressions for yarn extension and bre…
As a preliminary to the investigation of the ternary systems Li 2 O‐B 2 O 3 ‐P 2 O 5 and Li 2 O‐SiO 2 ‐P 2 O 5 the existence of the previously reported lithium ortho‐, pyro‐, and metaphosphate compounds was confirmed. A rapid, reversible inversion takes place in Li 4 P 2 O 7 at 630°C. New data on the melting points, o…
The optical absorption properties of Co60-irradiated fused silica and crystalline quartz have been studied in the vacuum-ultraviolet region. The most prominent absorption band found in both materials has a maximum at 7.6 ev (1620 A). Optical and thermal bleaching experiments indicate that this band is not necessarily…
Abstract The mechanical properties of rubberlike composite propellants and similar filled elastomers are determined largely by the volume fraction of filler, the visco-elastic properties of the binder, and the interactions between the binder and filler particles. The ratio of the quasi-equilibrium modulus of the compo…
The dielectric relaxation in two polyamides has been studied over a temperature range from -100 to 175 °C and a frequency range from 50 c/s to 10 Mc/s. The effects of various thermal treatments on the relaxation behavior and density, X-ray diffraction, and intrinsic viscosity have been studied. The polyamides were pol…
The glass-transition temperatures Tg of various copolymers of acrylonitrile and vinyl acetate were measured by observing the linear expansion of molded discs. For vinyl acetate contents of 0 to 27 wt-.% the glass temperature is constant at 87°C. This value agrees with the results of Kolb and Izard for pure polyacrylon…
An hochgereinigtem 4,4′-Di-methoxy-azoxybenzol (p,p′-Azoxyanisol) wurden die Hauptdielektrizitätskonstanten ε 1 und ε 2 und die dielektrische Anisotropie Δε der nematischen kristallinflüssigen Phase bei 0,10; 0,26; 0,65 und 1,60 MHz gemessen. Die Ergebnisse werden mit der in einer früheren Veröffentlichung entwickelte…
The macroscopic physical properties of a partially crystalline polymer become anisotropic when the polymer is `drawn', i.e. when the polymer undergoes a large permanent deformation from its isotropic state. The anisotropy of refractive index, X-ray scattering etc. has been investigated by many workers. In this paper t…
In the present paper we collect the available evidence from work-hardening curves, slip-line observations, and ferromagnetic measurements on the easy glide region of f.c.c. metals and alloys and the low-temperature work-hardening of hexagonal metals. New experimental results are reported on copper single crystals defo…
Copper single crystals subjected to a neutron dose of 3×1018 nvt (total flux) at pile temperature have been examined after deformation by the following experimental techniques: (a) observation of the load-extension relationships, (b) investigation of the slip-line structure with the electron microscope, and (c) diffra…
The results of the postirradiation examinations on UC compounds having nominal compositions of 4.6, 4.8, and 5.0 w/o C continue to be encouraging after irradiation to approximate burnups of from 1000 to 15,000 MWD/Ton of U. Density changes were small varying from a minimum of 0.7% to a maximum of about 2.5%. Cracking…
Abstract The experimental data collected on the interaction of active centers of carbon black with the rubber on the one hand and of the active centers of carbon black with the sulfur and accelerators, and also with the antioxidants, on the other hand, provide a sound basis for belief that the problem of reinforcement…
Treatment of unaccelerated natural rubber–sulfur vulcanizate networks with triphenylphosphine in benzene at 80°C. effects the removal of part of the combined sulfur, the proportion removed decreasing with increasing cure time. This partial desulfurization of the network is attributed, on the basis of the mode of inter…
Studies have been made of the emission spectra (3000 to 6000 A) obtained from low-pressure atomic oxygen-acetylene flames diluted with varying amounts of molecular oxygen and molecular nitrogen. Added molecular oxygen greatly increased the OH emission while reducing CH and C2 emission. It also had an effect on the rot…
Abstract On the basis of previous work, a model for the structure of cellulose fibers is proposed. The effect of degree of polymerization (DP), lateral order, and orientation on tensile properties is discussed in the light of this model. A program was set up to determine separately the effects of the different factors…