支化聚乙烯醇水溶液的流变行为

Rheological Behaviors of Aqueous Branched Polyvinyl Alcohol Solution

以线型聚乙烯醇为参照,研究了支化程度不同的2组聚乙烯醇水溶液的稳态和动态流变行为。稳态流变结果表明,在相同条件下,聚乙烯醇(PVA)水溶液的表观黏度随主链支化程度的提升而下降,随剪切速率(10^(-1)～10~2 s^(-1))增加而下降,呈现出剪切变稀的非牛顿流体特性。同时,支化程度增加,PVA水溶液表观黏度的剪切敏感性上升。动态流变结果表明,PVA水溶液的复数黏度和松弛时间与PVA主链支化程度密切相关,提升主链支化程度,有助于降低PVA水溶液的复数黏度及松弛时间。

The steady and dynamic rheological behaviors of the aqueous solutions of linear polyvinyl alcohol (PVA) and two types of branched PVA with different branched degree were investigated. The steady rheological results show that the apparent viscosity of PVA aqueous solution decreases with the increase of branched degree of PVA under the same conditions. And the rheological measurements also reveal that the aqueous solutions of branched PVA are non-Newton fluids with a shear thinning characteristic, and the shear-thinning effect increases with the branched degree of PVA. Dynamic rheological results show that the complex viscosity and molecular chain relaxation time of PVA aqueous solution are sensitive to the branched degree. Increasing the branched degree leads to the decrease of complex viscosity and molecular chain relaxation time.