Lipatov Yuri, Chornaya Valentine, Todosijchuk Tamara, Menzheres Galina
Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, 48 Kharkov Shaussee, Kiev 02160, Ukraine.
J Colloid Interface Sci. 2006 Feb 15;294(2):273-80. doi: 10.1016/j.jcis.2005.07.039. Epub 2005 Sep 22.
Adsorption from solutions of mixtures of polymers which considerably differ by the parameter of thermodynamics flexibility (sigma) has been studied at various components ratio. Initial and equilibrium concentrations of solutions were determined, surface coverage (theta) and energy of adsorption interaction (Q, kJ/mol of segments) were estimated by means of IR spectroscopy. The objects of investigation were: cis-1,4-polybutadiene rubber (PB) and cellulose triacetate (CTA). Aerosil (fumed silica) was used as an adsorbent. Analysis of the experimental data testifies that polymer polarity and its affinity to the surface have the decisive influence on the adsorption. Polar stiff chain CTA has greater affinity to the surface of adsorbent and correspondingly has greater adsorption activity as compared with flexible, but nonpolar PB. The values of energy of adsorption interaction and surface coverage obtained under the adsorption from polymer systems first of all depend on whether the stiff chain polar component or flexible chain nonpolar component prevails in the system. Increase of concentration of the nonpolar PB flexible chain in the system results in diminishing of summary energy of adsorption interaction, but its great flexibility at the same components ratio provides the maximal values of surface coverage. The greater values of the surface coverage under the adsorption from the solutions of polymer mixtures in comparison with the individual solutions are explained by the simultaneous adsorption of both components for all concentration intervals.
在不同的组分比例下，对热力学柔性参数（σ）差异很大的聚合物混合物溶液的吸附进行了研究。测定了溶液的初始浓度和平衡浓度，通过红外光谱法估算了表面覆盖率（θ）和吸附相互作用能（Q，kJ/摩尔链段）。研究对象为：顺式-1,4-聚丁二烯橡胶（PB）和三醋酸纤维素（CTA）。使用气相二氧化硅（气相法白炭黑）作为吸附剂。对实验数据的分析表明，聚合物的极性及其对表面的亲和力对吸附具有决定性影响。与柔性但非极性的PB相比，极性刚性链CTA对吸附剂表面具有更大的亲和力，相应地具有更大的吸附活性。从聚合物体系吸附过程中获得的吸附相互作用能和表面覆盖率的值首先取决于体系中刚性链极性组分还是柔性链非极性组分占主导。体系中非极性PB柔性链浓度的增加导致吸附相互作用总能量的降低，但其在相同组分比例下的高柔性提供了最大的表面覆盖率值。与单一溶液相比，聚合物混合物溶液吸附时表面覆盖率更高，这是由于在所有浓度区间两种组分同时吸附所致。
