间位芳纶纤维悬浮液的屈服特性及其与成纸匀度关系的研究

Study on Yielding Properties of Meta-Aramid Fiber Suspensions and Its Relationship with Paper Sheet Formation

关键词:  间位芳纶  压缩屈服应力  剪切屈服应力  成纸匀度

Key Words:meta-aramid fiber  compressive yield stress  shear yield stress  sheet formation

摘要:为探究间位芳纶纤维悬浮液的絮凝特性，本研究从流变学角度出发，分别研究了单一间位芳纶短切纤维和间位芳纶沉析纤维悬浮液及两者共混悬浮液的絮凝浓度、剪切屈服应力和压缩屈服应力，同时通过湿法成形工艺探索间位芳纶纤维悬浮液的屈服流变特性与成纸匀度间的构效关系。结果表明，不同纤维配比间位芳纶纤维悬浮液的凝结点在0.37~0.68 g/L之间，悬浮液的压缩屈服应力和剪切屈服应力与纤维浓度间分别呈线性和指数函数关系；除100%短切纤维悬浮液外，在同一浓度下，间位芳纶纤维悬浮液的压缩屈服应力和剪切屈服应力均随着沉析纤维比例的增大而减小；间位芳纶纤维悬浮液Froude数随着浓度的增大而减小，对特定配比的间位芳纶纤维悬浮液，间位芳纶纸的匀度指数随着悬浮液Froude数的增大而增大。

Abstract:To investigate the flocculation mechanism of meta-aramid fiber suspensions, the critical flocculation concentration, shear and compressive yield stress of the single suspensions of meta-aramid staple fibers and fibrids as well as their mixed suspensionwere examined, and relations between the formation index of the resultant paper and rheological properties could be found based on the rheological theory. The results showed that the flocculation concentration ranged from 0.37 to 0.68 g/L, and the compressive yield stress and shear yield stress of the suspension were depend on the mass concentration complying with a linear and a power-law relationship, respectively. In addition, both the compressive yield stress and the shear yield stress decreased as the proportion of fibrid increased at a certain concentration, with the exception of 100% staple fiber suspensions. Moreover, as the concentration increased, the Froude number decreasd accordingly, and the formation index of aramid paper with a specific staple fiber to fibrid ratio increased with increasing Froude number.