羧甲基羟丙基纤维素溶液流变性质的研究

用旋转粘度计研究了羧甲基羟丙基纤维素(CMHPC)复合醚水溶液在25～80℃温度范围内的热稳定性,以及水溶液和盐溶液的流变性质。借助阿氏(Arrheaius)方程得到的CMHPC粘流活化能介于离子型羧甲基纤维素醚(PAC)和非离子型纤维素醚(HEC)之间。研究发现,CMHPC体系中羧甲基含量较高时流动曲线类似PAC,符合Ostwad-Der Waele幂律模型,而羟丙基含量较高时,流动曲线类似HEC,偏离幂律模型。在CMHPC水溶液中加入小分子电解质时,羧甲基受屏蔽,流变行为主要受羟丙基的影响,曲线将发生偏离。本文还考察了CMHPC溶液的抗盐能力。     

羧甲基纤维素水溶液流变性的研究 Ⅰ.牙膏型羧甲基纤维素的流变行为

用旋转粘度计研究了牙膏型羧甲基纤维素水溶液流变性质,考查了该材料对时间、温度的依赖关系。通过幕律模型表征了材料的均勻性,测定了盐粘比。探讨了流变性与取代均匀性的依赖关系。     

羧甲基羟丙基纤维素溶液流变性质的研究

用旋转粘度计研究了羧甲基羟丙基纤维素(CMHPC)复合醚水溶液在25-80℃温度范围内的热稳定性,以及水溶液和盐溶液的流变性质.借助阿氏方程得到的CMHPC粘流活化能介于离子型羧甲基纤维素醚(PAC)和非离子型羟乙基纤维素醚(HEC)之间.研究发现,CMHPC体系中羧甲基含量较高时流动曲线类似PAC符合Ostwad-Der Waele幂律模型,而羟丙基含量较高时,流动曲线类似HEC,偏离幂律模型.在CMHPC水溶液中加入小分子电解质时,羧甲基受屏蔽,流变行为主要受羟丙基影响,曲线将发生偏离.本文还考察了CMHPC溶液的抗盐能力.     

Synthesis and Crystal Structure of Cobalt(II) Complex [Co(H2O)2(bpe)(OAc)2](4,4''-dpdo

The reaction of Co(OAc)2 with bpe and 4,4'-dpdo in an aqueous-alcohol solution affords the formation of red crystals of [Co(H2O)2(bpe)(OAc)2](4,4'-dpdo (bpe = trans-1,2-bis(4- pyridyl)ethylene, 4,4'-dpdo = 4,4'-dipyridyl N,N'-oxide). The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P with a = 7.6146(9), b = 8.6691(11), c = 10.344011 A, α = 88.311(3), β = 76.992(3), γ = 75.809(3)°, V = 644.7613 A3, Z = 1, C26H28CoN4O8, Mr = 583.45, Dc = 1.503 g/cm3, μ = 0.724 mm-1, F(000) = 303, T = 223(2) K, the final R = 0.0477 and wR = 0.1177 for 3199 observed reflections with I > 2σ(I). In the crystal the cobalt atom is six-coordinated by oxygen atoms from two carboxylic molecules, two nitrogen atoms from the bpe ligands and two water molecules, completing an octahedral geometry. The structure of the title complex consists of neutral chains containing cobalt(II) ions bridged by mutually trans bpe molecules. The adjacent chains are connected through weak hydrogen bonds to form a two-dimensional structure.