STUDIES OF DILUTE AND CONCENTRATED SOLUTION PROPERTIES OF NATURAL POLYSACCHARIDES

用光散射法、旋光法、滴定、量热法和粘度计对三链非离子多糖和黄原胶(双链离子)的稀溶液和浓溶液进行了研究，主要结果和结论如下：在水溶液中，裂殖酵母在侧链构象中经历有序和无序状态之间的协同转变，表现出明显的同位素效应。黄原胶(钠盐)在0.01M的NaC_1水溶液中的双螺旋熔化成二异氰酸酯。由水和两个分子量相差很大的裂解液组成的三元溶液被发现分成三个相，两个胆甾相和一个各向同性相。黄原胶的NAC1水溶液也形成胆甾型液体晶体。将二元半柔性聚合物溶液中各向同性-液晶相平衡的理论与不同聚合物的实验数据进行了比较，结果令人满意。本工作建立的光子相关光谱仪给出了聚苯乙烯及其胶乳的准确扩散系数。对黄原胶溶液的测量现在正在进行中。构建了磁流变仪，测量了各向同性黄原胶溶液的粘度随NAC1浓度和聚合物浓度的变化关系。他们被发现几乎与NAC1浓度无关，反映了黄原胶双螺旋固有的高刚性。

DILUTE AND CONCENTRATED SOLUTIONS OF POLYSACCHARIDES, SCHIZOPHYLLAN (TRIPLE-STRANDED, NONIONIC) AND XANTHAN (DOUBLE-STRANDED, IONIC), WERE STUDIED BY LIGHT SCATTERING, POLARIMETRY, TITRATION, CALORIMETRY, AND VISCOMETRY, THE MAIN RESULTS AND CONCLUSIONS ARE AS FOLLOWS.1. SCHIZOPHYLLAN IN AQUEOUS SOLUTION UNDERGOES A COOPERATIVE TRANSITION BETWEEN THE ORDERED AND DISORDERED STATES IN THE SIDE CHAIN CONFORMATION, EXHIBITING A PRONOUNCED ISOTOPE EFFECT.2. THE DOUBLE HELIX OF XANTHAN (NA SALT) IN 0.01 M AQUEOUS NAC1 MELTS INTO A DIMERIZED COIL.3. TERNARY SOLUTIONS CONSISTING OF WATER AND TWO SCHIZOPHYLLAN SAMPLES DIFFERENT LARGELY IN MOLECULAR WEIGHT WERE FOUND TO SEPARATE INTO THREE PHASES, TWO CHOLESTERIC PHASES AND ONE ISOTROPIC PHASE.4. AQUEOUS NAC1 SOLUTIONS OF XANTHAN ALSO FORM CHOLESTERIC LIQUID CRYSTALS.5. THE THEORIES FOR ISOTROPIC-LIQUID CRYSTAL PHASE EQUILIBRIUM IN BINARY SEMIFLEXIBLE POLYMER SOLUTIONS ARE COMPARED FAVORABLY WITH DATA FOR VARIOUS POLYMERS INCLUDING SCHIZOPHYLLAN AND XANTHAN.6. THE PHOTON CORRELATION SPECTROMETER CONSTRUCTED IN THIS WORK GAVE ACCURATE DIFFUSION COEFFICIENTS FOR POLYSTYRENE AND ITS LATEX. THE MEASUREMENT ON XANTHAN SOLUTIONS IS NOW IN PROGRESS.7. A MAGNETIC RHEOMETER WAS CONSTRUCTED AND USED TO MEASURE VISCOSITIES OF ISOTROPIC XANTHAN SOLUTIONS AS A FUNCTION OF NAC1 AND POLYMER CONCENTRATIONS. THEY WERE FOUND TO BE ALMOST INDEPENDENT OF NAC1 CONCENTRATION, REFLECTING THE INTRINSICALLY HIGH RIGIDITY OF THE XANTHAN DOUBLE HELIX.