The alkaline hydrolysis of nylons and terylene

Summary The acid hydrolysis of nylons has been carried out quantitatively byHaslam ³ andSchroeder ⁴ using hydrochloric acid solutions. These methods require several hours for complete hydrolysis. The alkaline hydrolysis of nylon 6 has been carried out using barium hydroxide solutions in an autoclave for 24 hours⁵. Although the potassium hydroxide method described is not quantitative, the hydrolysis, isolation, and characterisation of the products can be carried out in 1 to 3 hours.

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Zusammenfassung Die saure Hydrolyse von Nylon wurde vonHaslam ³ undSchroeder ⁴ mit Salzsäurelösungen quantitativ durchgeführt. Diese Verfahren beanspruchen für die vollständige Hydrolyse mehrere Stunden. Die alkalische Hydrolyse von Nylon 6 wurde mit Bariumhydroxidlösung in einem Autoklaven in 24 Stunden durchgeführt⁵. Obwohl das beschriebene Verfahren mit Kalilauge nicht quantitativ ist, kann man die Hydrolyse sowie die Isolierung und Charakterisierung der dabei erhaltenen Produkte in 1 bis 3 Stunden ausführen.

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Résumé Haslam ³ etSchroeder ⁴ ont effectué l'hydrolyse acide quantitative des nylons en utilisant des solutions d'acide chlorhydrique. Ces méthodes exigent plusieurs heures pour l'hydrolyse complète. On a réalisé l'hydrolyse alcaline du nylon 6 en utilisant des solutions d'hydroxyde de baryum, pendant 24 heures dans une autoclave. Bien que la méthode à l'hydroxyde de potassium décrite ne soit pas quantitative, l'hydrolyse, l'isolement et la caractérisation des produits peuvent s'effectuer en 1 à 3 heures.

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The author wishes to express his gratitude to Dr.J. Haslam for helpful discussions and to I. C. I., Ltd., Courtaulds, Ltd., and G. Slack, Ltd., for the gift of samples.     

On quantum electrodynamics of two-particle bound states containing spinless particles

We develop here the general treatment arising from the Bethe-Salpeter equation for a two-particle bound system in which at least one of the particles is spinless. It is shown that a natural two-component formalism can be formulated for describing the propagators of scalar particles. This leads to a formulation of the Bethe-Salpeter equation in a form very reminiscent of the fermion-fermion case. It is also shown, that using this two-component formulation for spinless particles, the perturbation theory can be systematically developed in a manner similar to that of fermions. Quantum electrodynamics for scalar particles is then developed in the two component formalism, and the problem of bound states, in which one of the constituent particles is spinless, is examined by means of the means of the Bethe-Salpeter equation. For this case, the Bethe-Salpeter equation is cast into a form which is convenient to perform a Foldy-Woutyhuysen transformation which we carry out, keeping the lowest-order relativistic corrections to the nonrelativistic equation. The results are compared with the corresponding fermion-fermion case. It is shown, as might have been expected, that the only spin-independent terms that occur for the fermion-fermion system which do not occur for bound scalar particle cases, is the zitterbewegung contribution. The relevance of the above considerations for systems that are essentially bound by electromagnetic interactions, such as kaonic hydrogen, is discussed.     

A simple “market value” bargaining model for weighted voting games: characterization and limit theorems

We offer a bargaining model for weighted voting games that is a close relative of the nucleolus and the kernel. We look for a set of weights that preserves winning coalitions that has the property of minimizing the difference between the weight of the smallest and the weight of the largest Minimum Winning Coalition. We claim that such a set of weights provides an a priori measure of a weighted voter’s bribeworthiness or market value. After introducing our model, we provide a characterization result for this model and show its links to other bargaining model approaches in the literature. Then we offer some limit results showing that, with certain reasonable conditions on the distributions of weights, as the size of the voting body increases, the values of bribeworthiness we calculate will approach both the weights themselves and the Banzhaf scores for the weighted voting game. We also show that, even for relatively small groups using weighted voting, such as the membership of the European Council of Ministers (and its predecessors) 1958–2003, similarities among the usual a priori power scores, bribeworthiness/market value, and the weights themselves, will be quite strong.     

Behavior of Plasma-Treated Elastomeric Polydimethylsiloxane Coatings in Aqueous Environment

Plasma treatment is a useful way of enhancing the wettability of polydimethylsiloxane (PDMS). The subsequent recovery of hydrophobicity in air once treatment is discontinued is well known, but less has been reported about the effect of the storage environment. Water storage is the most relevant, with some reports that this stops the hydrophobic recovery of plasma-treated Medical Grade PDMS elastomer. This is not our experience with a commercial industrial PDMS sealant that had been treated by a helium radio-frequency plasma and stored in pure water and in artificial sea water. Substantial hydrophobic recovery occurs on storage in these environments. The commercial sealant is likely to have more low molecular weight diffusible species and more pre-existing silanol groups than the Medical Grade material. Both of these factors could affect the recovery mechanism by diffusion of untreated polymer chains to the surface or reorientation of polar and non-polar groups in the surface region.     

Trifluoromethyl imidazoles

Some imidazole derivatives with trifluoromethyl substituents have been made, as part of a programme on the synthesis of fluorine-containing annyti-cancer agents. This work is a joint project between ourselves and Professor A.B. Foster's group at the Institute of Cancer Research, Royal Cancer Hospital, London. Imidazole carboxylic acids have been treated with sulphur tetrafluoride to give 2-trifluoromethyl-, 2,4-bis(trifluoromethyl)-, and 2,4,5-tris(trifluoromethyl)-imidazole. Some reactions of these trifluoromethyl derivatives have been studied. Ranges of N-substituted derivatives have been synthesised using the imidazole silver salts and the appropriate alkyl halide derivative. Hydrolytic stabilities of the CF₃ groups in the patent imidazoles have been studied.The 2-trifluoromethyl derivative is the least stable hydrolytically.     

On thermodynamics and intrinsically equilibrated materials

Summary The existence and uniqueness of free energy functions is demonstrated for a class of materials broad enough to contain as special cases those of the theory of finite elasticity, the theory of hypo-elasticity, and the theory of internal state variables for which the path of evolution is invariant under rescalings of time. Dedicated toDario Graffi on his 70th Birthday Entrata in Redazione il 24 giugno 1975. This research was supported by the U. S. National Science Foundation under Grant GP-32951X2.     

A measurement of the charge asymmetry in the decay η → π+π−γ

An experiment has been performed at the Rutherford Laboratory to look for a possible asymmetry in the decay η → π⁺π^?γ. The asymmetry for 34 680 eta decay is measured to be 0.012 ± 0.006, which is consistent with no C-violation in this decay mode.