Radical copolymerization of maleic acid with allyl amine or diallyl amine derivatives results in regular polyampholytes which are completely or to high extent soluble in water. With equimolar amounts of both comonomers the rate of the alternating copolymerization runs through a minimum. The copolymers are thermally relatively stable and can be changed to water insoluble products by tempering.

331Besides the surface activity of the amino resins used, the electrostatic interactions between the protonated amino resin and the negatively charged organic phase can be considered as driving force. Thereby the reaction rate of the polycondensation in the boundary phase is increased contrary to the volume phase with the result of capsule wall formation.These conceptions are supported by the fact t h a t in the presence of other non-reactive tensides no microcapsules will be formed. These tensides occupy the phase boundaries and prevent the enrichment of polycondensation active b u t less surface active amino resins.A detailled discussion of the mechanism of capsule formation will be given in connection with the discussion of surface activity of amino resins [Is]. The preparation of microcapsules is also possible with unmodified, nonetherified $IF-resins. In this case the suitable reaction conditions have to be evaluated by preliminary tests. Under t h e applied reaction conditions, pure urea-formaldehyde resins were not capable of wall formation.Results of biological testing of MP-microcapsules will be published elsewhere [ 2 4 ] .

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Der Einfluß von Kristallviolett auf die Strukturbildung von PVDF‐Filmen aus DMSO‐Lösungen wird mittels IR‐Spektroskopie untersucht. In Abhängigkeit von der Kristallviolett‐Konzentration entstehen Filme mit bevorzugter α‐, γ‐ oder β‐Modifikation. Bei einem hohen Anteil des Additivs werden unorientierte PVDF‐Filme mit reiner β‐Struktur erhalten

Durch säurektalysierte Polykondensation hergestellte feinverteilte Harnstoff‐Formaldehyd‐Feststoffe wurden infrarotspektroskopisch untersucht. In Abhängigkeit von der Zusammensetzung wurden drei verschiedene Strukturen gefunden. Bei einem Molverhältnis F/H < 1,25 wurden lineare kristalline Methylenharnstoffe erhalten, bei F/H > 1,25 Dimethylenetherstrukturen und nur unter stark sauren Bedingungen cyclische Strukturen (Urone).