Sequences distribution of poly(ethylene terephthalate-isophthalate) copolymers - Experimental TREF study and numerical simulation

The fractionation of a statistical copolyester made of poly(ethylene tereph thalate- isophthalate) has been performed using Temperature Rising Elution Fractionation (TREF). TREF fractions were analyzed by size exclusion chroma tography, thermal analysis, H-1-nuclear magnetic resonance and small angle X-Ray diffractometry. Results show that the fractions exhibit both intercha in and intrachain defect distribution. As the intrachain defect distributio n can not be determined by experimental techniques, a computer simulation b ased on the determination of terephthalic sequences length in a virtual pol ymeric distribution was performed. The simulated chains were constructed us ing a stochastic process. The analysis of the results obtained on the distr ibution of the simulated sequences in the polymer correlates quantitatively well between the new fractionation mechanism proposed for copolyesters and the experimental results.