STUDIES OF DILUTE AND CONCENTRATED SOLUTION PROPERTIES OF NATURAL POLYSACCHARIDES

本文采用光散射法、偏光法、滴定法、量热法和粘度法研究了三链非离子型裂殖藻多糖和双链离子型黄原胶多糖的稀溶液和浓溶液，主要结果和结论如下：1.水溶液中Schizophyllan在侧链构象的有序态和无序态之间进行合作转变，显示出一种明显的同位素特征.黄原胶（NA盐）在0.01 M NaCl水溶液中的双螺旋熔化成二聚线圈。发现水和两种分子量相差很大的裂殖藻多糖样品组成的三元溶液分为三相，两个胆甾相和一个各向同性相.黄原胶的NaCl水溶液也形成胆甾型液晶.将二元半柔性聚合物溶液的各向同性液晶相平衡理论与包括Schizophyllan和Xanthan在内的各种聚合物的相平衡数据进行了比较.本文所建立的光子相关光谱仪能准确测定聚苯乙烯及其胶乳的吸收系数。目前正在对黄原胶溶液进行测量。用自制的磁流变仪测定了各向同性黄原胶溶液的粘度随NaCl和聚合物浓度的变化。发现它们几乎与NAC 1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.