Kunze Lena, Tseng Shih-Yu, Schweins Ralf, Sottmann Thomas, Frey Holger
Institute of Organic Chemistry , Johannes Gutenberg University of Mainz , Duesbergweg 10-14 , 55128 Mainz , Germany.
Institute of Physical Chemistry , University of Stuttgart , Pfaffenwaldring 55 , 70569 Stuttgart , Germany.
Langmuir. 2019 Apr 16;35(15):5221-5231. doi: 10.1021/acs.langmuir.8b04265. Epub 2019 Apr 1.
Carbon dioxide (CO) is a renewable carbon source that is easily available in high purity and is utilized as a co-monomer in the direct ring-opening polymerization of epoxides to obtain aliphatic polycarbonates. In this work, degradable aliphatic polycarbonate diblock copolymers (mPEG- b-PBC) are synthesized via catalytic copolymerization of CO and 1,2-butylene oxide, starting from monomethoxy poly(ethylene glycol) (mPEG) as a chain transfer reagent. The polymerization proceeds at low temperatures and high CO pressure, utilizing the established binary catalytic system ( R, R)-Co(salen)Cl/[PPN]Cl. Amphiphilic nonionic diblock copolymers with varying PBC block lengths and hydrophilic-lipophilic balance values between 9 and 16 are synthesized. The polymers are characterized via NMR and Fourier transform infrared spectroscopies as well as size exclusion chromatography, exhibiting molecular weights ranging from 2400 to 4100 g mol with narrow dispersities ( Đ = M/ M) from 1.07 to 1.18. Furthermore, the thermal properties, i.e., T, T, and T, are determined. Surface tension measurements prove that the amphiphilic polymers form micelles above the critical micelle concentration, whereas small-angle neutron scattering shows that they are of nearly spherical shape. Adding small amounts of the synthesized mPEG- b-PBC polymers to different microemulsion systems, we found that the polymers were able to strongly increase the efficiency of medium-chain surfactants to solubilize polar oils.
二氧化碳（CO）是一种可再生碳源，易于获得高纯度产品，并且在环氧化物的直接开环聚合反应中用作共聚单体以制备脂肪族聚碳酸酯。在本工作中，从单甲氧基聚（乙二醇）（mPEG）作为链转移剂开始，通过CO与1,2 - 环氧丁烷的催化共聚反应合成了可降解的脂肪族聚碳酸酯二嵌段共聚物（mPEG - b - PBC）。聚合反应在低温和高CO压力下进行，使用已确立的二元催化体系（R，R）-Co（salen）Cl / [PPN]Cl。合成了具有不同PBC嵌段长度且亲水亲油平衡值在9至16之间的两亲性非离子二嵌段共聚物。通过核磁共振、傅里叶变换红外光谱以及尺寸排阻色谱对聚合物进行了表征，其分子量范围为2400至4100 g/mol，分散度较窄（Đ = Mw/Mn），在1.07至1.18之间。此外，还测定了热性能，即玻璃化转变温度、熔点和热分解温度。表面张力测量证明，两亲性聚合物在临界胶束浓度以上形成胶束，而小角中子散射表明它们近乎球形。向不同的微乳液体系中添加少量合成的mPEG - b - PBC聚合物，我们发现这些聚合物能够显著提高中链表面活性剂增溶极性油的效率。
