| Abstract: | Two series of amorphous copolyesters, PETGN and PETGS, were synthesized by the copolymerization of 2,6-naphthalene dicarboxylic acid (NDA) (0-40%), succinic acid (SA) (0-40%), 1,3/1,4-cydohexanedimethanol (1,3/1,4-CHDM) (10-50%), ethylene glycol (EG), and terephthalic acid (TPA). The compositions and molecular weights of the copolyesters were determined by <sup>1</sup>H NMR spectroscopy and viscometry, respectively. The thermal behaviors were studied over the entire range of copolymer compositions, using DSC and TGA. The optical characteristics, heat-shrinkable effects and tensile properties of these polymers were also determined. Experimental results indicated that the thermal, optical, tensile, and shrinkage properties of PETGN and PETGS were functions of NDA or SA content. DSC and X-ray analysis demonstrated that both PETGN and PETGS series were amorphous. Incorporating NDA and SA influenced the T<inf>g</inf> values of those polymers, from about 37°C for PETG<inf>30</inf>S <inf>40</inf> to 89°C for PETG<inf>30</inf>N<inf>40</inf>. Furthermore, the shrinkage of these amorphous copolyesters was more than 40% when the heating temperature was higher than the corresponding T<inf>g</inf>. © 2008 Wiley Periodicals, Inc. |
