STRUCTURE OF BOUNDARY-LAYERS OF CELLULOSE TRIACETATE ACCORDING TO DATA FROM INFRARED REFLECTION SPECTROSCOPY

The orientation parameter S of cellulose triacetate (CTR) molecules at a liquid-solid phase boundary (the liquid being a solution of CTR in methylene chloride, the solid the material KRS-5) is determined as a f unction of the concentration of CTR on the basis of reflection spectra of CTR boundary layers in the region of valence vibration of carbonyl groups of the polymer nu(C=O), as well as splitting of the complex co ntour of the multiplet nu(C = O) into its individual components 1742, 1730, and 1716 cm-1. The Kramers-Kronig procedure is used in the spect rum study. It is found that S reaches 0.56 (298 K) and 0.28 (308 K) at [eta]0c < 1 (where [eta0]0 is the characteristic viscosity and c is t he concentration of the polymer). It is also determined that [eta]0c = 7S = 0. 1 at both 298 K and 308 K. A model is proposed to describe th e orientation of CTR macromolecules and it is shown that the polymer i n the boundary layer is in the state of a nematic liquid crystal at [e ta0]0c < 1 (298 K).