Characterization of Sodium Carboxymethyl Cellulose Aqueous Solutions to Support Complex Product Formulation: A Rheology and Light Scattering Study
Characterization of Sodium Carboxymethyl Cellulose Aqueous Solutions to Support Complex Product Formulation: A Rheology and Light Scattering Study
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DOI：
10.1021/acsapm.8b00110
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发表时间：
2019-03-01
影响因子：
5
通讯作者：
Hunter, Timothy N.
中科院分区：
文献类型：
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作者：
Behra, Juliette S.;Mattsson, Johan;Hunter, Timothy N.
羧甲基纤维素钠（Na CMC）因其增稠和溶胀特性而用于制药、食品、家庭和个人护理应用以及造纸、水处理和矿物加工行业的各种复杂配方产品中。为了设计适用于应用的钠CMC溶液，需要详细了解浓度依赖性流变学和松弛响应。我们在这里解决这个问题，通过调查水钠CMC溶液在很宽的浓度范围内使用流变学以及静态和动态光散射。溶液比粘度η（sp）的浓度依赖性可以使用一组三个幂律来描述，如从聚电解质的标度理论所预测的。或者，可以使用一种更简单的方法，该方法在两个幂律区域之间插值，并且仅引入一个特征交叉浓度。我们解释所观察到的行为作为一个过渡的semidilute非纠缠的纠缠浓度制度，这种过渡行为没有观察到的解决方案的结构，使用静态光散射。动态光散射揭示了三种弛豫模式。两种最快的弛豫被指定为“快”和“慢”弛豫模式，通常在半稀释浓度范围内的无盐或未完全筛选的盐溶液中观察到。第三，典型的弱模式，归因于存在少量溶解不良的纤维素残留物。由于过滤改变了溶液行为，而没有充分去除残留物，因此数据收集和处理适于解释这一点，这有助于对与工业应用相关的原始溶液进行详细的光散射研究。表征快速模式的弛豫时间tau（f）与浓度无关;而慢速模式的弛豫时间tau（s）表现出与比粘度观察到的类似的交叉行为，进一步证明了交叉的动态性质。
Sodium carboxymethyl cellulose (Na CMC) is used for its thickening and swelling properties in a wide range of complex formulated products for pharmaceutical, food, home, and personal care applications, as well as in paper, water treatment, and mineral processing industries. To design Na CMC solutions for applications, a detailed understanding of the concentration-dependent rheology and relaxation response is needed. We address this here by investigating aqueous Na CMC solutions over a wide range of concentrations using rheology as well as static and dynamic light scattering. The concentration dependence of the solution specific viscosities eta(sp) could be described using a set of three power laws, as predicted from the scaling theory of polyelectrolytes. Alternatively, a simpler approach could be used, which interpolates between two power law regimes and introduces only one characteristic crossover concentration. We interpret the observed behavior as a transition from the semidilute nonentangled to the entangled concentration regimes; this transition behavior was not observed in the solution structure, as determined using static light scattering. Dynamic light scattering revealed three relaxation modes. The two fastest relaxations were assigned as the "fast" and "slow" relaxation modes typically observed in salt free or not fully screened polyelectrolyte solutions within the semidilute concentration range. The third, typically weak mode, was attributed to the presence of a small amount of poorly dissolved cellulose residuals. Since filtration altered the solution behavior, without sufficiently removing the residuals, data collection and processing were adapted to account for this, which facilitated a detailed light scattering investigation of the original solutions, relevant for industrial applications. The relaxation time characterizing the fast mode, tau(f), was concentration independent; whereas the relaxation time of the slow mode, tau(s), demonstrated similar crossover behavior as observed for the specific viscosity, further demonstrating the dynamic nature of the crossover.