Synthese und eigenschaften copolymer polyharnstoffe mit linearer struktur

Abstract

ZUSAMMENFASSUNG:Es wird iiber die Synthese hochmolekularer, thermoplastischer, glasklarer und vorwiegend amorpher Copolyharnstoffe mit periodisch wiederkehrender Harnstoffbindung in der Hauptvalenzkette berichtet. Unverzweigte aliphatische Diamine wurden mit steigenden Mengen von Diaminen cokondensiert, die Atherbriicken oder verschiedene Seitengruppen besitzen, z. B. Methyl-, Nonyl-oder Fluorengruppen. Der E i d u B dieser Substituenten a d Schmelz-und Einfriertemperatur, Kristallisationsverhalten, Wasseraufnahme, Fliellspannung, Bruchdehnung, Kerbschlagzahigkeit und E-Modul wurde untersucht. Die Verarbeitungsmoglichkeiten der neuen Copolyharnstoffe werden kurz angegeben. SUMMARY:High molecular, thermoplastic, optically clear and preferably amorphous copolyureas with periodically recurrent urea-linkages in the main chain are synthesized. Unbranched aliphatic diamines were cocondensatd with increasing amounts of diamines which possess other bridges or various types of substituents as for example methyl-, nonyl-respectivdy fluorene-groups. The inhence of these substituents on melting points, second order transition temperatures, crystallisation behaviour, water absorption, yield stress, elongation at break, notched impact strength, and E-modulus was investigated. The possibilities of processing for the new copolyureas are given.

Long-Chain Aliphatic Polymers To Bridge the Gap between Semicrystalline Polyolefins and Traditional Polycondensates

“…Odd–even effects on the melting behavior of PU-X (blue, adapted from ref ) and for polyureas of the PUa-X type (green, adapted from ref ).…”

Polymers of carbonic acid, 8. Linear polybiurets

“…WAXS powder patterns of A) poly(d0decanebiuret (3d) which is observable in all WAXS patterns obviously represents the distance between neighboring chains. The atomic distances of [12][13][14][15][16] A which are represented by weak reflections below 2 ~9 < 8 " are by 20-30% shorter than the lengths of the constitutional repeating units and do not directly indicate an extended conformation of the chains. However, a detailed X-ray analysis of the crystal lattice was beyond the scope of this work.…”

Isocyanate‐ and Solvent‐Free Route to Thermoplastic Poly(amide‐urea) Derived from Renewable Resources

“…First, increasing the oligomethylene segment length between urea groups in the polyurea backbone markedly reduces polyurea melting temperature . Thereby an even number of methylene groups accounts for higher melting with respect to polyurea containing an odd number of methylene groups . Second, the incorporation of comonomers substantially lowers polyurea melting temperature .…”

“…Thereby an even number of methylene groups accounts for higher melting with respect to polyurea containing an odd number of methylene groups . Second, the incorporation of comonomers substantially lowers polyurea melting temperature . Third, the incorporation of side‐chains with different molecular architectures and variable alkyl chain length impair self‐assembly of polyurea chains and polyurea crystallization .…”

“…Second, the incorporation of comonomers substantially lowers polyurea melting temperature . Third, the incorporation of side‐chains with different molecular architectures and variable alkyl chain length impair self‐assembly of polyurea chains and polyurea crystallization . Hence, the variation of polyurea backbone architectures without short‐chain branching and N ‐substitution represents the method of choice to control thermal, mechanical, and processing properties of polyurea …”