Hong Xianze, Edirisinghe Mohan, Mahalingam Suntharavathanan
Department of Mechanical Engineering, University College London (UCL), London WC1E 7JE, UK.
Department of Mechanical Engineering, University College London (UCL), London WC1E 7JE, UK.
Mater Sci Eng C Mater Biol Appl. 2016 Dec 1;69:1373-82. doi: 10.1016/j.msec.2016.07.071. Epub 2016 Jul 28.
This work focuses on forming bead on string poly(caprolactone) (PCL) by using gyration under pressure. The fibre morphology of bead on string is an interesting feature that falls between bead-free fibres and droplets, and it could be effectively controlled by the rheological properties of spinning dopes and the major processing parameters of the pressurised gyration system which are working pressure and rotating speed. Bead products were not always spherical in shape and tended to be more elliptical, therefore both their width and length were measured. The average bead width and length produced spanned a range 145-660μm and 140-1060μm, respectively. The average distance between two adjacent beads (i.e. inter-bead distance) and the bead size (width and length) are shown to be a function of processing parameters and polymer concentration. An interesting morphology i.e. beads with short fibre was observed when using a high polymer concentration. Bead on string structure agglomeration was promoted by a low polymer concentration. Formation of droplets or agglomerated bead on string is promoted below 5wt% polymer concentration, and beads with short fibre were present in the microstructure beyond a polymer concentration of 20wt%.
这项工作聚焦于通过在压力下进行旋转来形成串珠状聚己内酯（PCL）。串珠状纤维形态是介于无珠纤维和液滴之间的一个有趣特征，它可以通过纺丝原液的流变性能以及加压旋转系统的主要加工参数（工作压力和转速）进行有效控制。珠状产物并非总是球形，而是更倾向于椭圆形，因此对其宽度和长度都进行了测量。所生产的珠状产物的平均宽度和长度分别在145 - 660μm和140 - 1060μm范围内。相邻两个珠子之间的平均距离（即珠间距）以及珠子尺寸（宽度和长度）显示为加工参数和聚合物浓度的函数。当使用高聚合物浓度时，观察到一种有趣的形态，即带有短纤维的珠子。低聚合物浓度会促进串珠状结构的团聚。聚合物浓度低于5wt%时会促进液滴或团聚串珠的形成，而聚合物浓度超过20wt%时，微观结构中会出现带有短纤维的珠子。
