Materials Literature
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The history of polyolefins actually began in the 1890s with the synthesis of polymethylene from diazomethane. In the 1930s researchers in England discovered that ethylene at high pressure and in the presence of oxygen polymerized to a high molecular weight resin. Further research there and in the United States at stil…
Owing to the large dipole associated with its nitrile bond, 8OCB (cyano-octyloxybiphenyl) tends to associate as antiparallel pairs. The number of pairs, $N$, increases with increasing mole fraction, ${x}_{6\mathrm{OCB}}$, of a shorter homolog, 6OCB (cyanohexyloxybiphenyl). The stability of the nematic and smectic-$A$…
Phase diagram and X-ray studies of mixtures of 8OCB (cyanooctyloxybiphenyl) and 4O8 (butyloxybenzilidene octylaniline)and 8OCB and 6OCB (cyanohexyloxybiphenyl) demonstrate: 1. 4O8 molecules inhibit the pairing of the 8OCB molecules. One 4O8 molecule is attributed with the breakup of one 8OCB pair. 2. The maximum press…
In an attempt to optimize the chemotherapeutic treatment of mouse tumor Sarcoma 180, liposomes containing cis-dichlorodiammineplatinum(II) (PDD), having transition temperatures of few degrees higher than the rectal temperature of mice, were used in combination with local hyperthermia. The uptake of radioactive PDD by…
The effects of temperature and pH on the reversible dimer-tetramer association of concanavalin A were studied by the high-speed sedimentation equilibrium technique. Both commercial and highly purified preparations of concanavalin A were used. Equilibrium constants were analyzed as a Wyman linked function by using trun…
It is shown that electron–electron interaction changes the frequency and temperature dependences of the a.c. conductivity at low temperatures. The result is that the factor kT in the Austin–Mott formula has to be replaced by e 2/κr ω. The effect is similar to the enhancement of the density of states by electron–hole i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCholesteric liquid crystalline phases based on (acetoxypropyl)celluloseSo-Lan Tseng, Agostino Valente, and Derek G. GrayCite this: Macromolecules 1981, 14, 3, 715–719Publication Date (Print):May 1, 1981Publication History Published online1 May 2002Published inissue 1 May 198…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBromination and chlorination of pyrrole and some reactive 1-substituted pyrrolesH. M. Gilow and D. Edward BurtonCite this: J. Org. Chem. 1981, 46, 11, 2221–2225Publication Date (Print):May 1, 1981Publication History Published online1 May 2002Published inissue 1 May 1981https…
Abstract N ‐substituted poly( p ‐phenylene terephthalamide)s (PPTA), such as N ‐alkylated, N ‐aralkylated, and N ‐carboxymethylated poly( p ‐phenylene terephthalamide), were synthesized from PPTA and the corresponding halides by the polymer reaction via the metalation reaction in a solution of sodium methylsulfinylcar…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLanthanide ion luminescence probes. Measurement of distance between intrinsic protein fluorophores and bound metal ions: quantitation of energy transfer between tryptophan and terbium(III) or europium(III) in the calcium-binding protein parvalbuminWilliam DeW. Horrocks Jr. a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolvated electron structure in glassy matrixesLarry KevanCite this: Acc. Chem. Res. 1981, 14, 5, 138–145Publication Date (Print):May 1, 1981Publication History Published online1 May 2002Published inissue 1 May 1981https://pubs.acs.org/doi/10.1021/ar00065a002https://doi.org/1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTObservations by high-resolution carbon-13 nuclear magnetic resonance of cellulose I related to morphology and crystal structureWilliam L. Earl and D. L. VanderHartCite this: Macromolecules 1981, 14, 3, 570–574Publication Date (Print):May 1, 1981Publication History Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSuperconductivity in an organic solid. Synthesis, structure, and conductivity of bis(tetramethyltetraselenafulvalenium) perchlorate, (TMTSF)2ClO4K. Bechgaard, K. Carneiro, F. B. Rasmussen, M. Olsen, G. Rindorf, C. S. Jacobsen, H. J. Pedersen, and J. C. ScottCite this: J. Am.…
We studied the adsorption properties of plasma fibronectin (pFN) on wettable tissue culture (TC) dishes and nonwettable bacteriological (BAC-T) dishes in relationship to its biological activity of promoting fibroblast spreading. The binding of pFN to the dish surfaces was found to be very tight and partially resistant…
Previous research toward more efficient nonlinear optical organic crystals has aimed at increasing the first-order hyperpolarizabilitiy of individual molecular units. We show that the general features derived from these studies (high conjugation, charge transfer, and molecular asymmetry) leave room for the cancellatio…
Accurate core level binding energies for the L and M shells in the metals 22 Ti to 30 Zn have been measured by means of ESCA. Comparisons with previously reported data in many cases show discrepancies of several eV. The spin-orbit splittings of the 2 p subshells have been measured with high accuracy and are compared w…
Abstract The hydrolytic degradation of polyglycolic acid (PGA) was studied by examining the changes of tensile strength and the level of crystallinity of the suture material. It was found that the breaking stress decreased from 6.369 × 10 −1 at 0 day to 3.97 × 10 −3 Newton/Tex at 49 days. The sigmodial shape of the st…
Peaks in the ultrasonic attenuation observed in amorphous materials are almost always explained in terms of a classical, thermally activated, structural relaxation process represented by a symmetric double-well potential with a broad distribution of barrier heights. This model suffers from two drawbacks: a low barrier…
Abstract Ultradrawing of films of high‐molecular‐weight polyethylene (M̄ w = 1.5 × 10 6 ) produced by gelation crystallization from solution is discussed. The influence of the initial polymer volume fraction (ϕ) on the maximum draw ratio (λ max ) of the dried films is examined in the temperature region from 90–130°C.…
Two-dimensional NMR techniques which sep. the chem. shift and heteronuclear dipolar interactions were applied to samples spinning at the magic angle. Because of the inhomogeneous nature of the 2 interactions, rotational echoes were obsd. in the time domain of each dimension. The corresponding Fourier transforms yield…