The structural and rheological properties of aqueous suspensions of spray-dried cellulose nanocrystals (CNCs) were investigated and compared to those of freeze-dried. The cellulose nanocrystals were obtained from sulfuric acid hydrolysis of wood pulp. Ultrasonication was used to disperse cellulose nanocrystals in Milli-Q water and the power applied during ultrasonication was shown to be the controlling parameter for their dispersion, more than total energy. Dynamic light scattering measurements showed a decrease of the average hydrodynamic diameter down to the same limiting value, i.e. ∼75 nm, for both spray and freeze-dried cellulose nanocrystals. Since the same maximum dispersion state was reached for both CNC types, it indicated that the spray drying process did not limit dispersion, provided that sufficient ultrasonication was provided. Moreover, no desulfation occurred during ultrasonication at ambient temperature. Strong ultrasonication also caused a decrease of intrinsic viscosity, along with an increase in maximum packing concentration. These properties were correlated to agglomerates break-up, which released both ions and water in suspension. The ionic strength increase may lead to a thinner electrostatic double layer surrounding the cellulose nanocrystals, reducing their apparent concentration.

研究了喷雾干燥的纤维素纳米晶体（CNC）的水悬浮液的结构和流变性能，并将其与冻干的进行了比较。纤维素纳米晶体由木浆的硫酸水解获得。超声处理用于将纤维素纳米晶体分散在Milli-Q水中，超声处理过程中施加的功率是其分散的控制参数，超过了总能量。动态光散射测量显示平均流体动力学直径减小到相同的极限值，即喷雾和冷冻干燥的纤维素纳米晶体均约为75 nm。由于两种CNC类型都达到了相同的最大分散状态，因此表明只要提供足够的超声处理，喷雾干燥过程就不会限制分散。而且，在环境温度下的超声处理期间没有发生脱硫。强大的超声处理还会导致特性粘度的降低，以及最大填充浓度的增加。这些性质与附聚物的分解有关，附聚物的分解在悬浮液中释放了离子和水。离子强度的增加可能导致围绕纤维素纳米晶体的更薄的静电双层，从而降低其表观浓度。