Study On The Knittability Of Basalt Fiber Yarns On A Computerized Flat Knitting Machine

At present,in the background of a serious shortage of the carbon fiber in the world,the basalt fiber can be a good substitute for it to a certain extent due to its excellent performance and high cost-effective.However, to make the basalt fibers have a broader application prospects in the field of composite materials.Its knittability is one of the problems to be solved. Over the last decades,although a lot of investigations have been done to study the relationship between the performance of high-modulus fiber yarns and their knittability at home and abroad,most of them are focused on the glass fiber yarns.Only few literature related to the systematic study on the kittability of high modulus yarns have been reported.Besides,these studies are not deep enough.Particularly,for this new material——basalt fiber yarns,such related investigation has not been initiated.This thesis aims to study the knittability of basalt fiber yarns on a computerized flat knitting machine and its unique loop shape.The glass fiber yarns and the wool-acrylic blended yarns were selected as a contrast of the basalt fiber yarns,and the performance of these three yarns was tested and analyzed,including the tensile breaking strength, bending rigidity,knotted strength,friction coefficient,etc.in order to understand the special characters of the basalt fiber yarns.Using the knitting experience of the glass fiber yarns on a computerized flat knitting machine,reasonable knitting parameter scopes were determined for the basalt fiber yarns.Jersey and 1x1 rib fabrics were produced on a computerized flat knitting machine with different knitting parameters(yarn input tension,cam setting and take down force).The influences of these parameters on the fiber damage degree,the loop length and fabric appearances were mainly analyzed.At the same time,the differences of these three yarns on the knittability were compared,and the emphasis was focused on the basalt fiber yarns to determine its optimum knitting parameters.As the basalt fiber yarns have the similar problem like the glass fiber yarns to make knitting elements more easily damaged than the Ordinary yarns during knitting process,damage of knitting elements (needles,sinkers,middle pieces and needle selections) was also analyzed. In addition,various geometrical parameters of the fabrics knitted above were measured,and the relations between fabric densities and loop lengths were mainly analyzed.In this way,the dimensions of the fabrics can be predicted before knitting.Both the studies on the knittability of basalt fiber yarns and the analysis on the dimensional properties of jersey and 1x1 rib fabrics in this work can not only provide a reliable knitting parameter changing ranges for the production of basalt fiber weft knitted fabrics with reducing the fiber damage and knitting elements damage,but also improve the quantity and performance of fabrics.Furthermore,this work makes a realization of the basalt fiber weft knitted fabric composites can be designed,produced, and it has a more important theoretical and practical significance for the research and development of new materials.