Supporting Information Sulfonated Poly(hexamethylene terephthalate) Copolyesters: Enhanced Thermal and Mechanical Properties Mayka Bautista, Antxon Martínez de Ilarduya, Abdelilah Alla, and Sebastián Muñoz-Guerra Universitat Politècnica de Catalunya, Departament d´Enginyeria Química, ETSEIB, Diagonal 647, Barcelona 08028, Spain TABLE 1S Number-average sequence lengths and randomness of PHTxSIy copolyesters.a Dyads (mol%) Number-Average Sequence Lengths Randomness Copolyester THT THSI SIHSI nT nSI R PHT95SI5 91.6 8.4 0 22,8 1.0 1.04 PHT90SI10 82.8 15.7 1.6 11.5 1.2 1.08 PHT80SI20 66.2 27.7 6.1 5.8 1.4 0.86 PHT70SI30 52.9 34.5 12.6 4.1 1.7 0.82 PHT60SI40 42.6 43.9 13.9 2.9 1.6 0.95 PHT50SI50 27.2 46.8 26.1 2.2 2.1 0.93 a Experimental values were obtained by Lorentzian deconvolution of 13C NMR spectra in the region of oxymethylene peaks. Number average sequence lengths and randomness were calculated using ref. 23. TABLE 2S Powder X-ray diffraction data of PHT and PHTxSIy copolyesters. d a (Å) Copolyester PHT 12.6 6.2 5.5 4.9 4.1 3.9 3.7 3.4 (m) (s) (m) (w) (s) (vw) (vw) (vw) (vw) (vw) (vw) 12.5 5.5 4.9 4.3 4.1 3.7 (w) (w) (w) (w) (s) (w) (s) PHT95SI5 PHT70SI30 (w) 3.3 3.2 3.0 2.7 2.6 4.3 (m) a Bragg spacings measured in powder diffraction patterns for samples coming from synthesis. Intensities visually estimated as follows: m, medium; s, strong; w, weak; vw, very weak. 1 40 PHT60SI40 PHT70SI30 30 PHT80SI20 Tension (MPa) PHT95SI5 PHT PHT90SI10 20 10 0 0 50 100 150 200 250 300 350 400 450 500 550 600 Deformacion (%) FIGURE 1S Stress-strain curves of PHT and PHTxSIy copolyesters with the indicated compositions. 2