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首页> 外文期刊>Journal of Applied Polymer Science >Preparation and characterization of polycarbonates from 2,4,8,10-tetraoxaspiro[5,5]undecane-3-one (DOXTC)-trimethylenecarbonate (TMC) ring-opening polymerizations
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Preparation and characterization of polycarbonates from 2,4,8,10-tetraoxaspiro[5,5]undecane-3-one (DOXTC)-trimethylenecarbonate (TMC) ring-opening polymerizations

机译：由2,4,8,10-四氧杂螺[5,5]十一烷-3-一（DOXTC）-三亚甲基碳酸酯（TMC）开环聚合制备和表征聚碳酸酯

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The new cyclic carbonate monomer 2,4,8,10-tetraoxaspiro[5,5]undecane-3-one (DOXTC) was prepared in > 80% yield by the reaction of 1,3-dioxane-5,5-dimethanol with ethyl chloroformate in tetrahydrofuran (THF). DOXTC homopolymerization and copolymerizations with trimethylene carbonate (TMC) were carried out using aluminoxanes (methyl and isobutyl) as catalysts. The copolymer yields normally exceeded 90%. Carbon-13 (C-13) nuclear magnetic resonance (NMR) at 62.5 MHz resolved copolymer dyad sequences. Comparison of the fraction of dyad sequences determined by C-13-NMR and calculated assuming a Bernoullian distribution showed that propagation statistics were approximately random for copolymerizations carried out at both 90 and 140 degrees C. Studies by differential scanning calorimetry (DSC) showed that the DOXTC homopolymer, as well as the copolymers with high DOXTC content (F-DOXTC to F-TMC greater than or equal to 7 : 3), were semicrystalline. The DOXTC homopolymer had a peak melting temperature of 202 degrees C, enthalpy of fusion of 75 J/g, and a glass transition temperature of 36 degrees C. For copolymers with F-DOXTC to F-TMC greater than or equal to 9/1, crystallization exotherms were observed both during the second heating, as well as cooling (10 degrees C/min) DSC scans. The relationship between the copolymer glass transition and composition was in agreement with that predicted by the Fox equation. Comparison of the wide-angle X-ray scattering (WAXS) patterns of the DOXTC homopolymer with F-DOXTC to F-TMC Of 7 : 3 and 9 : 1 showed that the former sample had more pronounced and better resolved crystalline reflections. These results suggest that the DOXTC homopolymer has well-ordered crystalline domains and high sample crystallinity. By increasing the molar content of 1,3-dioxane side groups in DOXTC-TMC copolymers from 0 to 50%, the water uptake by the corresponding films was increased from 5.1 to 19% (w/w). (C) 1998 John Wiley & Sons, Inc. [References: 28]
机译：新的环状碳酸酯单体2,4,8,10-四氧杂螺[5,5]十一烷-3-酮（DOXTC）是通过1,3-二恶烷-5,5-二甲醇与1,3-二恶烷的反应制备的，产率> 80％。四氢呋喃（THF）中的氯甲酸乙酯。使用铝氧烷（甲基和异丁基）作为催化剂进行DOXTC均聚和与碳酸三亚甲基酯（TMC）的共聚。共聚物的产率通常超过90％。碳13（C-13）核磁共振（NMR）在62.5 MHz解析的共聚物二元序列。比较通过C-13-NMR测定并假设伯努利分布的二倍体序列分数，结果表明，在90和140℃下进行的共聚反应，传播统计近似随机。通过差示扫描量热法（DSC）进行的研究表明， DOXTC均聚物以及具有高DOXTC含量（F-DOXTC到F-TMC大于或等于7：3）的共聚物是半结晶的。 DOXTC均聚物的峰值熔融温度为202摄氏度，熔融焓为75焦耳/克，玻璃化转变温度为36摄氏度。对于F-DOXTC至F-TMC的共聚物，其均大于或等于9/1在第二次加热以及冷却（10摄氏度/分钟）DSC扫描期间均观察到结晶放热。共聚物玻璃化转变与组成之间的关系与Fox方程所预测的关系一致。 DOXTC均聚物与F-DOXTC与F-TMC的7：3和9：1的广角X射线散射（WAXS）模式的比较表明，前一个样品具有更明显和更佳的分辨晶体反射。这些结果表明，DOXTC均聚物具有良好的晶域结构和较高的样品结晶度。通过将DOXTC-TMC共聚物中1,3-二恶烷侧基的摩尔含量从0增加到50％，相应薄膜的吸水率从5.1增加到19％（w / w）。 （C）1998 John Wiley＆Sons，Inc. [参考：28]

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