Poly(1,5-pentylene-co-2,2,4,4-tetramethyl cyclobutylene terephthalate) (PPecBT) random copolyesters glass transition temperature up to 136 °C were synthesized through two-step melting polycondensation of dimethyl terephthalate (DMT) or terephthalic acid (TPA), 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) and 1,5-pentanediol (PeDO). They were characterized and assessed with intrinsic viscosity, ¹H NMR, DSC, TGA, tensile and impact testing as well as melt foaming observation. Using PeDO as a diol comonomer was helpful to depress CBDO sublimation and pipeline blocking, and to reduce the composition and cis-trans ratio deviations between monomer and copolymer. The presence of PeT repeat unit in PPecBT was beneficial to improve the thermal stability of PPecBT and to reduce undesired melt foaming and volume expansion during melt processing. The T_g of these amorphous copolymers is determined by intrinsic viscosity, copolymer composition and cis-cB unit fraction, and a quantitative relationship among them is established. Futhermore, these PPecBTs showed superior tensile ductility as well as strength and modulus.

聚（1,5-戊二烯-co-2,2,4,4-四甲基对苯二甲酸环丁二醇酯）（PPecBT）无规共聚酯玻璃化转变温度高达 136 °C对苯二甲酸 (TPA)、2,2,4,4-四甲基-1,3-环丁二醇 (CBDO) 和 1,5-戊二醇 (PeDO)。通过特性粘度、¹ H NMR、DSC、TGA、拉伸和冲击测试以及熔体发泡观察对它们进行表征和评估。使用PeDO作为二醇共聚单体有助于抑制CBDO升华和管道堵塞，减少成分和顺式-单体和共聚物之间的反式比率偏差。PPecBT中PeT重复单元的存在有利于提高PPecBT的热稳定性并减少熔体加工过程中不希望的熔体发泡和体积膨胀。所述Ť_克这些无定形共聚物的通过特性粘度，共聚体组合物并测定顺式-CB单元分数，和它们之间的定量关系成立。此外，这些 PPecBTs 显示出优异的拉伸延展性以及强度和模量。