Gola Agnieszka, Niżniowska Aleksandra, Musiał Witold
Department of Physical Chemistry, Pharmaceutical Faculty, Wroclaw Medical University, Borowska 211, 50-556 Wroclaw, Poland.
Nanomaterials (Basel). 2019 Nov 7;9(11):1577. doi: 10.3390/nano9111577.
The thermosensitive polymers of -vinylcaprolactam P1, P2, P3, P4, and P5 were synthesized via the surfactant free precipitation polymerization (SFPP) at 70 °C in the presence of cationic initiator 2,2'-azobis[2-methylpropionamidine] dihydrochloride (AMPA). The influence of various concentrations of initiator AMPA on particle size, aggregation and lower critical temperature solution (LCST) was investigated by dynamic light scattering (DLS) measurement. The conductivity was measured in the course of the synthesis and during temperature decrease of the reaction mixtures. The polymers were characterized by Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), H NMR, and thermogravimetric analysis. Thermal parameters of the degradations process were investigated using thermogravimetric analysis (TGA/DTA) under non-isothermal conditions in N atmosphere. The samples were characterized by powder X-ray diffraction analysis (PXRD).The hydrodynamic diameter (HD), polydispersity index (PDI) and zeta potential (ZP) were measured in aqueous dispersions of the synthesized polymers in temperature 18-45 °C. HD and PDI values at 18 °C were 137.23 ± 67.65 nm (PDI = 0.53 ± 0.18), 83.40 ± 74.46 nm (PDI = 0.35 ± 0.08), 22.11 ± 0.29 nm (PDI = 0.45 ± 0.05), 29.27 ± 0.50 nm (PDI = 0.41 ± 0.04), 39.18 ± 0.57 nm (PDI = 0.38 ± 0.01) for P1, P2, P3, P4, and P5, respectively. The aqueous solutions of the obtained polymers at 18-45 °C had a positive charge. ZP's for P1, P2, P3, P4, and P5 polymers at 18 °C were 11.64 ± 4.27 mV, 12.71 ± 3.56 mV, 3.24 ± 0.10 mV, 0.77 ± 0.28 mV, 1.78 ± 0.56 mV respectively. The LCST range was between 32 and 38 °C. We conclude that the concentration of initiator affects the size of obtained polymeric spheres and theirs LCST.
在阳离子引发剂2,2'-偶氮二[2-甲基丙脒]二盐酸盐（AMPA）存在下，于70℃通过无表面活性剂沉淀聚合（SFPP）合成了聚-乙烯基己内酰胺P1、P2、P3、P4和P5的热敏聚合物。通过动态光散射（DLS）测量研究了不同浓度的引发剂AMPA对粒径、聚集和低临界温度溶液（LCST）的影响。在合成过程中和反应混合物降温过程中测量电导率。通过衰减全反射傅里叶变换红外光谱（ATR-FTIR）、核磁共振氢谱（¹H NMR）和热重分析对聚合物进行表征。在氮气气氛下非等温条件下，使用热重分析（TGA/DTA）研究降解过程的热参数。通过粉末X射线衍射分析（PXRD）对样品进行表征。在18 - 45℃的温度下，在合成聚合物的水分散体中测量流体动力学直径（HD）、多分散指数（PDI）和zeta电位（ZP）。对于P1、P2、P3、P4和P5，18℃时的HD和PDI值分别为137.23±67.65 nm（PDI = 0.53±0.18）、83.40±74.46 nm（PDI = 0.35±0.08）、22.11±0.29 nm（PDI = 0.45±0.05）、29.27±0.50 nm（PDI = 0.41±0.04）、39.18±0.57 nm（PDI = 0.38±0.01）。所得聚合物在18 - 45℃的水溶液带正电荷。18℃时，P1、P2、P3、P4和P5聚合物的ZP分别为11.64±4.27 mV、12.71±3.56 mV、3.24±0.10 mV、0.77±0.28 mV、1.78±0.56 mV。LCST范围在32至38℃之间。我们得出结论，引发剂的浓度会影响所得聚合物球的尺寸及其LCST。
