Synthesis and aqueous solution characterization of dihydrophilic block copolymers of methyl vinyl ether and methyl triethylene glycol vinyl ether
Synthesis and aqueous solution characterization of dihydrophilic block copolymers of methyl vinyl ether and methyl triethylene glycol vinyl ether
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DOI：
10.1021/ma9608737
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发表时间：
1996-12-02
期刊：
影响因子：
5.5
通讯作者：
Billingham, NC
中科院分区：
文献类型：
--
作者：
Forder, C;Patrickios, CS;Billingham, NC
采用活性阳离子聚合法合成了甲基乙烯基醚（MVE）和甲基三甘醇乙烯基醚（MTEGVE）的水溶性双亲水AB嵌段共聚物，共聚物的相对分子质量范围为1500 ~ 13900，分子质量分布较窄（M（w）/M（n）< 1.29）。MVE嵌段长度固定为20个单体单元，MTEGVE嵌段长度在2至67个单元之间变化。这些共聚物的水溶液进行了研究，使用动态光散射，染料增溶，和浊度法，以确定温度对胶束化和沉淀的影响。所有嵌段共聚物的光散射数据表明，它们在室温下以单链形式分散在水中，这通过水性SEC实验进一步证实。比浊法实验表明，在将MVE和MTEGVE均聚物的水溶液分别加热至18和83.5 ℃时发生相分离。胶束在加热这些嵌段共聚物的水溶液高于50 ° C时形成，这是由于MVE嵌段在该温度下的疏水性质而预期的。动态光散射研究得到的嵌段共聚物的流体动力学尺寸为8.1至31 nm。变温H-1 NMR光谱（在D2 O中）证实MVE嵌段形成胶束核心，并且胶束化是可逆的。发现通过染料增溶确定的临界胶束化温度在27至41 ℃的相对小的温度范围内随着MTEGVE含量增加。这些共聚物的浊点遵循类似的趋势，并随着MTEGVE含量的增加而增加，覆盖了26至79摄氏度的宽温度范围。
Water-soluble dihydrophilic AB block copolymers of methyl vinyl ether (MVE) and methyl triethylene glycol vinyl ether (MTEGVE) were synthesized by living cationic polymerization, with copolymer molecular weights in the range 1500-13 900 with fairly narrow molecular weight distributions (M(w)/M(n) < 1.29). The MVE block length was fixed at 20 monomer units, and the MTEGVE block length was varied from 2 to 67 units. Aqueous solutions of these copolymers were studied using dynamic light scattering, dye solubilization, and turbidimetry to determine the effect of temperature on micellization and precipitation. The light scattering data for all of the block copolymers indicated that they were dispersed as single chains in water at room temperature, this was further confirmed by aqueous SEC experiments. Turbidimetry experiments showed that phase separation occurred upon heating aqueous solutions of MVE and MTEGVE homopolymers to 18 and 83.5 degrees C respectively. Micelles were formed on heating aqueous solutions of these block copolymers above 50 degrees C, which was expected due to the hydrophobic nature of the MVE block at this temperature. Dynamic light scattering studies gave hydrodynamic sizes of the block copolymers ranging from 8.1 to 31 nm. Variable temperature H-1 NMR spectroscopy (in D2O) confirmed that the MVE block forms the micellar core and that micellization was reversible. The critical micellization temperatures determined by dye solubilization were found to increase with the MTEGVE content over a relatively small temperature range from 27 to 41 degrees C. The cloud points of these copolymers follow a similar trend and increase with the MTEGVE content, covering a wide range of temperatures from 26 to 79 degrees C.