新型环状聚(ε-己内酯-co-γ-三乙基硅氧基-ε-己内酯)的合成

Synthesis of Novel Cyclic Poly( ε-caprolactone- co-γ-triethylsilyloxy-ε-caprolactone)

设计合成了具有精确分子结构的聚合物对深入了解其结构与性能之间的关系起着至关重要的作用。研究了一种合成带有三乙基硅氧侧基的环状无规共聚酯的新方法。功能性单体γ-三乙基硅氧基-ε-己内酯(γ-Et3SiOεCL)和ε-己内酯(ε-CL)在环状引发剂2,2-二丁基-2-锡-1,3-二氧环庚烷(DSDOP)的作用下,进行活性开环聚合反应以制备活性环状无规共聚酯(LCP(εCLcoγEt3SiOεCL))前体,当单体完全转化后,以该活性环状前体作为大分子引发剂,引发反应性单体α-(1-丙烯酰氧乙基)-ε-己内酯(αAEεCL)进行嵌段聚合反应,合成了在活性中心附近带有不饱和双键的功能性环状嵌段共聚酯,即活性环状聚(ε-己内酯-co-γ-三乙基硅氧基-ε-己内酯)-b-(α-(1-丙烯酰氧乙基)-ε-己内酯)。最后该活性环状嵌段共聚酯在紫外光照射下,反应性单体结构单元中的双键发生分子内交联反应,从而制得稳定的不含有机锡的新型环状无规共聚酯cP(εCLcoγEt3SiOεCL)(Mn,NMR=28500)。采用SEC、1H NMR以及DSC等技术手段对聚合物的结构和性能进行表征。该方法的突出特点是能够高效地合成带有功能性侧基的高相对分子质量的环状无规共聚酯。

Design and synthesis of well-defined polymers are of the utmost importance for the reliable establishment of macromolecular structure-properties relationships. This work reports a novel strategy to synthesize cyclic random copolyesters with triethylsilyloxy groups. The ring-opening polymerization of a mixture of 6CL and functional monomer γ-triethylsilyloxy-ε-caprolactone （γ-Et3SiOεCL） was initiated by 2,2-dibutyl- 2-stanna-1, 3-dioxepane （ DSDOP ） to obtain a precursor, i. e. , a living cyclic copolyester （LCP（εCLcoγEt3SiOεCL））. When the comonomers were converted completely, a fresh feed of α-（ 1- acryloyloxyethyl）-ε-caprolactone（αAEεCL） was added to the polymerization medium to achieve a living cyclic block copolyester, poly （ （ εCLcoγEt3 SiOεCL） -b- （αAEeCL） ）. Finally, stable functional cyclic copolyester free of tin dialkoxides, i. e. , cP （ αCLcoγEt3 SiOεCL） （ Mn,NMR = 28500 ） , was synthesized by intramolecular photo cross-linking of acrylic unsaturations in the proximity of the living cyclic chain under the irradiation of ultraviolet light. The structure and properties of the copolymers were characterized by size-exclusion chromatography （SEC）, proton nuclear magnetic resonance spectroscopy（1H NMR）, and differential scanning calorimetry （DSC） technologies. The strategy herein disclosed has been successfully tested for the synthesis of functional cyclic copolyesters with high relative molecular mass in high efficiency.