As an example of molecular design of new polymers, structures and properties of poly(ethylene thionoterephthalate) (PET[S2]) and the related polymers have been predicted from calculations of ab initio molecular orbital (MO) theory, rotational isomeric state (RIS) scheme, and periodic density functional theory (DFT). The MO calculations were confirmed by NMR experiments and introduced to the RIS scheme for PET[S2] to yield its configurational properties, which are compared herein with those of analogous polyester, polythioester, and polydithioester. Configurational properties of randomly thiono-substituted poly(ethylene terephthalate) (PET), PET[S z O1-z ], were also evaluated as a function of sulfidity (z). On the assumption that the crystal of PET[S2] can be expressed as an isomorphic replacement of the PET crystal, the crystal structure was optimized by a periodic DFT simulation and its Young's moduli in the a-, b-, and c-axis directions were, respectively, evaluated to be Ea = 0.94(7.20) GPa, E b = 19.58(22.26) GPa, and E c = 142.1(182.4) GPa, where the parenthetic values are those of the PET crystal. There is a possibility that properties of PET[S z O1-z ] will be controlled between those of PET and PET[S2] by adjusting the sulfidity. The potential practical applications of the polythionoesters are also discussed herein. By purely theoretical computations, the structures and properties of the not-yet synthesized polymers were predicted quantitatively; that is, the theoretical molecular design of new polymers has been achieved.

中文翻译：

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芳香族聚硫代磺酸酯的分子设计。

作为新聚合物分子设计的一个例子，已经通过计算从头算分子轨道（MO）理论，旋转异构态（RIS）预测了聚对苯二甲酸乙二酯（PET [S2]）和相关聚合物的结构和性能。方案和周期性密度泛函理论（DFT）。通过NMR实验证实了MO的计算，并将其引入到用于PET [S2]的RIS方案中以产生其构型性质，在此将其与类似的聚酯，聚硫酯和聚二硫酯进行比较。还评估了无硫基取代的聚对苯二甲酸乙二醇酯（PET）PET [S z O1-z]的构型性质与硫化度（z）的关系。假设可以将PET [S2]的晶体表示为PET晶体的同构替代物，通过周期性DFT模拟对晶体结构进行了优化，并分别将其在a，b和c轴方向的杨氏模量评估为Ea = 0.94（7.20）GPa，E b = 19.58（22.26）GPa ，并且E c = 142.1（182.4）GPa，其中括号内的值是PET晶体的括号内的值。通过调节硫化度，有可能将PET [S z O1-z]的性质控制在PET和PET [S2]的性质之间。本文还讨论了聚硫代磺酸酯的潜在实际应用。仅通过理论计算，就可以定量预测尚未合成的聚合物的结构和性能。即，已经实现了新聚合物的理论分子设计。评估为Ea = 0.94（7.20）GPa，E b = 19.58（22.26）GPa和E c = 142.1（182.4）GPa，其中括号内的值是PET晶体的值。通过调节硫化度，有可能将PET [S z O1-z]的性质控制在PET和PET [S2]的性质之间。本文还讨论了聚硫代磺酸酯的潜在实际应用。仅通过理论计算，就可以定量预测尚未合成的聚合物的结构和性能。即，已经实现了新聚合物的理论分子设计。评估为Ea = 0.94（7.20）GPa，E b = 19.58（22.26）GPa和E c = 142.1（182.4）GPa，其中括号内的值是PET晶体的值。通过调节硫化度，有可能将PET [S z O1-z]的性质控制在PET和PET [S2]的性质之间。本文还讨论了聚硫代磺酸酯的潜在实际应用。仅通过理论计算，就可以定量预测尚未合成的聚合物的结构和性能。即，已经实现了新聚合物的理论分子设计。本文还讨论了聚硫代磺酸酯的潜在实际应用。仅通过理论计算，就可以定量预测尚未合成的聚合物的结构和性能。即，已经实现了新聚合物的理论分子设计。本文还讨论了聚硫代磺酸酯的潜在实际应用。仅通过理论计算，就可以定量预测尚未合成的聚合物的结构和性能。即，已经实现了新聚合物的理论分子设计。