水性聚氨酯分散体的绿色增稠流变剂——纳米纤维素晶须

涂料助剂的绿色化是涂料绿色化的关键之一,制备并表征水性聚氨酯分散体的新型、绿色增稠流变二合一助剂:纳米纤维素晶须悬浮液.研究纳米纤维素晶须的含量、温度对其悬浮液黏度的影响,考察了悬浮液的Ostwade幂方程模型,发现其具有增稠和触变作用.比较不同条件下在水性聚氨酯分散体中加入纳米纤维素晶须悬浮液后纳米纤维素晶须的含量、温度对混合悬浮液黏度的影响,纳米纤维素晶须的加入能降低混合悬浮液体系的粘流活化能、增加混合悬浮液体系的触变性.研究表明纳米纤维素晶须对水性聚氨酯分散体具有增稠和触变作用,能降低体系粘流活化能,增加触变度,是一种新型的、非石油的、生物高分子的精细化工功能助剂.

Nanocellulose Whiskers as a Green Thickening and Rheological Agent of Waterborne Polyurethane Dispersion

Green coatings additives are the key problems of green coatings. In order to prepare a green thickening and rheological agent of the waterborne polyurethane dispersion, nanocellulose whisker (NCW) suspension was prepared and characterized. The effects of NCW content and temperature on the viscosities of NCW suspension were studied. The Ostwade power equation model of the NCW suspension was investigated. The NCW suspension was found to have the rheological characters of shearing-thinning and thixotropy. The effects of NCW content and temperature on the rheological characters of waterborne polyurethane dispersion that mixed with different content of NCW suspension were compared. When the NCW suspension was added to form a serial of mixed suspensions with the waterborne polyurethane（WPU） dispersion, the viscous flow activation energies of the mixed suspension were reduced, while the thixotropies of the mixed suspensions were increased. Results show that NCW is a thickening agent of the waterborne polyurethane dispersion, because it can reduce the viscous flow activation energy and increase the thixotropic degrees. Thus, the NCW is a new kind of functional additive of waterborne polyurethane dispersion with two functions, non-petroleum, biopolymer and fine chemical.