Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine.
Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kyiv 03164, Ukraine.
J Colloid Interface Sci. 2019 Apr 1;541:213-225. doi: 10.1016/j.jcis.2019.01.102. Epub 2019 Jan 24.
Disperse polymethylsiloxane (PMS) alone and in a mixture with highly disperse nanosilica A-300 was studied as a dry powder and a hydrogel located in various dispersion media (air, chloroform alone and with addition of trifluoroacetic acid) using low-temperature H NMR spectroscopy, cryoporometry, thermogravimetry, nitrogen adsorption, microscopy, infrared spectroscopy, and quantum chemistry. The powders of dried PMS and PMS/A-300 can be easily rehydrated upon strong stirring with added water. The slurry properties depend on mechanical treatment features due to stronger compaction of the secondary structures with increasing mechanical loading. The organization of bound water (at a constant hydration degree h = 1 g/g) depends strongly on the dispersion media (because chloroform can displace water from narrow interparticle voids into broader ones or into pores inaccessible for larger CDCl molecules) and mechanical loading reorganizing aggregates of PMS and A-300 nanoparticles (<1 μm in size) and agglomerates (>1 μm) of aggregates. The PMS/nanosilica blends could be of interest from a practical point of view due to additional control of the textural and structural characteristics determining efficiency of sorbents with respect to low- and high-molecular weight compounds depending on the dispersion media that is of importance, e.g., for medical applications.
研究了单独的分散聚甲基硅氧烷 (PMS) 以及与高度分散纳米二氧化硅 A-300 的混合物，它们既作为干粉存在，也作为水凝胶存在于不同的分散介质（空气、单独的氯仿以及添加三氟乙酸的氯仿）中，使用低温 H NMR 光谱、低温渗透压法、热重分析、氮气吸附、显微镜、红外光谱和量子化学进行研究。干燥的 PMS 和 PMS/A-300 粉末在强烈搅拌下加入水后很容易重新水合。悬浮液的性质取决于机械处理的特点，因为随着机械负荷的增加，次级结构的压实程度更强。结合水的组织（在恒定的水合度 h=1 g/g 下）强烈依赖于分散介质（因为氯仿可以将水从狭窄的颗粒间空隙中置换到更宽的空隙中，或者置换到对较大的 CDCl 分子不可进入的孔中）和机械负荷，重新组织 PMS 和 A-300 纳米颗粒（<1 µm 大小）的聚集体以及聚集体的团聚体（>1 µm）。由于可以根据分散介质控制决定对低分子量和高分子量化合物的吸附剂效率的结构和纹理特性，PMS/纳米二氧化硅混合物从实际角度来看可能具有吸引力，例如对于医学应用而言，分散介质非常重要。
