engleski

Structural Ordering in Homopolymers and Copolymers of N-substituted Maleimides, with Special Regard to Polymers with Benzo-15-crown-5 Substituent

X-ray diffractograms of powdered N-substituted maleimide (MI) homopolymers and alternating copolymers with alpha-methylstyrene (alpha-MS) show the presence of two diffraction maxima. The interplanar spacing of the second diffuse maximum d2 is independent of the length of the N-substituent and has values between 0,40... 0,54 nm. These spacing values correspond to the periodic distance of side chains along the macromolecules. At a lower angle, both homopolymers and copolymers of N-substituted maleimides show a diffuse diffraction maximum which, with the increasing length of N-substituent, becomes narrower and shiffs to smaller diffraction angles, i.e., its interplanar spacings dl value increases. These results indicate an obvious tendency of the smectic type of mesogenic ordering with the increasing length of the side chain. Smectic Sc structures with tiited side chains could explain smaller experimental than theoretical interchain distance values. The introduction of alpha-methylstyrene as an alternating copolymer unit in the main chain disturbs the smectic order. Lower spacing values d1 for copolymers indicate the possibility of more significant tilting of side chains with the greater distance between them. Such disturbance of structural ordering with the introduction of a-methylstyrene in the main chain occurs also in the case of large lateral N-substituents, such as benzo-15-crown-5. Besides these two maxima (dl and d2), diffractograms of homopolymer and copolymer with benzo-15-crown-5 moiety in the side chain contain also a third diffuse maximum, thus indicating that the presence cf 31-helix cannot be ruled out.

alternating copolymers; benzo-15-crown-5; maleimide polymers; N-substituted maleimides; smectic order; X-ray diffraction

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