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SynopsisThe radiation-initiated solution polymerization of vinylidene fluoride was examined in an effort to determine the effect of polymerization conditions on the head-to-head content of the resulting poly(viny1idene fluoride). No appreciable change was observed in the head-to-head content when this new type of polymerization was utilized. However, the polymers which resulted had melting points 10-15°C higher than those of the suspensionpolymerized poly(viny1idene fluoride), higher crystallinity, and, when trifluoroacetic acid was used as a solvent, a higher molecular weight.

A detailed study of high-pressure-crystallized poly(viny1idene fluoride) has indicated that a mixture of low-melting phase II and high-melting phase I is present, rather than a new crystalline phase (phase 111) as originally suggested.The relative amounts of phase I and phase I1 resulting from crystallization under pressure a r e a function of pressure and the degree of supercooling. Pressure crystallization at 285°C and 5500 atm results in samples which were pure phase I with an increased melting point of 187°C.

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1. Es wurden die Dihalogenide des Europiums dargestellt.

1. Durch DEBYE‐SCHERRER‐Aufnahmen konnten folgende Strukturen ermittelt werden: Europiumdifluorid besitzt Fluoritstruktur, Kalziumbromid hat Kalziumchloridstruktur. Im Bleichlorid‐Typ kristallisieren: Bariumchlorid, ‐bromid, ‐jodid, Samarium‐ und Europiumdichlorid. Ytterbiumdijodid besitzt Kadmiumjodidstruktur, Ytterbiumdichlorid möglicherweise eine verzerrte Flußspatstruktur.