SAXS investigations of the influence of the length of methylene chain on supermolecular structure of poly(alkylene phosphates)

Abstract
The influence of the number of CH₂ groups and the evennes of this number on the lamellar arrangement of macromolecules of poly(alkylene phosphates) PPhn were investigated by SAXS method. The results indicate that deviations from the ideal lamellar model for the polyphosphates with asymmetric mers (n-odd number) are generally larger and qualitatively different as compared with that for the polyphosphates with symmetric mers (n- even number). The heterogeneity of phases were measured by the ratio of the mean square electron density fluctuations calculated from the SAXS curves before and after background subtraction. It was found that the heterogeneity of the PPh8 polyphosphate is smallest. Besides, a linear relationship between the weight average long period L_w and the molecular mass of the PPhn polyphosphates was confirmed.