Steric hindrance effect on thermoresponsive behaviors of pyrrolidone-based polymers
Steric hindrance effect on thermoresponsive behaviors of pyrrolidone-based polymers
复制标题
位阻效应对吡咯烷酮基聚合物热响应行为的影响
DOI：
10.1039/c2py20773g
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发表时间：
2013-01
影响因子：
4.6
通讯作者：
Zhang, Hailiang
中科院分区：
文献类型：
--
作者：
Liu, Peng;Xiang, Liangbo;Tan, Qian;Tang, Haoyu;Zhang, Hailiang
研究了吡咯烷酮类水溶性聚合物的空间位阻效应对温敏行为的影响。采用自由基聚合法合成了两种含不同吡咯烷酮侧基的聚合物聚N-（1-甲基-2-丙烯酰氧基乙基）吡咯烷酮（PMEP）和聚N-（2-丙烯酰氧基丙基）吡咯烷酮（PAPP）。通过凝胶渗透色谱法证实了PMEP和PAPP具有近似的分子量和多分散性。利用动态光散射（DLS）和变温1H NMR研究了它们在水介质中的温敏相变行为。PMEP和PAPP的浊点随浓度的增加呈指数下降而非线性下降。在相同质量浓度下，PMEP的浊点低于PAPP。PMEP和PAPP都表现出溶剂同位素效应，因为它们在氧化氘（D2 O）中的浊点低于在氧化氢（H2O）中的浊点。我们还注意到，在20.0 mg ml−1时，D2 O中的ΔCP [CPPAPP − CPPMEP]为5.2 °C，H2O中为4.2 °C。此外，PAPP在温度升高过程中表现出更明显的质子共振信号强度变化。PMEP和PAPP的温敏相变行为的差异是由于它们的侧基的空间位阻效应。
This paper describes the steric hindrance effect on thermoresponsive behaviors of pyrrolidone-based water-soluble polymers. Two polymers, poly[N-(1-meth-2-acryloyloxyethyl)pyrrolidone] (PMEP) and poly[N-(2-acryloyloxypropyl)pyrrolidone] (PAPP) with different pyrrolidone-based side groups were synthesized via conventional free-radical polymerization. PMEP and PAPP with approximate molecular weights (MW) and polydispersities were confirmed by gel permeation chromatography. Their thermoresponsive phase transition behaviors in aqueous media were studied using dynamic light scattering (DLS) and temperature-variation 1H NMR. The cloud points of PMEP and PAPP decreased exponentially rather than linearly with the increase in concentration. PMEP exhibited a lower cloud point than PAPP at the same mass concentration. Both PMEP and PAPP showed a solvent isotopic effect, as their cloud points in deuterium oxide (D2O) were lower than those in hydrogen oxide (H2O). We also noted that the ΔCP [CPPAPP − CPPMEP] was 5.2 °C in D2O and 4.2 °C in H2O at 20.0 mg ml−1. In addition, PAPP showed more noticeable changes in proton resonance signal intensities during the temperature elevation. The differences in thermoresponsive phase transition behaviors between PMEP and PAPP resulted from the steric hindrance effect of their side groups.
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影响因子：
5.5
作者：
S. Sugihara;S. Kanaoka;S. Aoshima
通讯作者：
S. Sugihara;S. Kanaoka;S. Aoshima
影响因子：
6.2
作者：
W. He;K. Gonsalves;J. H. Pickett;C. Halberstadt
通讯作者：
W. He;K. Gonsalves;J. H. Pickett;C. Halberstadt
影响因子：
16.6
作者：
Haba, Yasuhiro;Kojima, Chie;Kono, Kenji
通讯作者：
Kono, Kenji
影响因子：
5.5
作者：
V. Boyko;S. Richter;I. Grillo;E. Geissler
通讯作者：
V. Boyko;S. Richter;I. Grillo;E. Geissler
影响因子：
5.5
作者：
OTAKE, K;INOMATA, H;SAITO, S
通讯作者：
SAITO, S