Preparation of ultra-porous UPM/PHBV nanofibres using solvent-etching technology and drug-loading efficiency

In this study, ultra-porous fibres have been produced by partly washing out poly(3-hydroxybutyrateco-3-hydroxyvalerate) (PHBV) from the heat-crosslinked electrospun unsaturated polyester macromonomers/poly(3-hydroxybutyrateco-3-hydroxyvalerate) (UPM/PHBV) fibrous composite using chloroform. Tetracycline hydrochloride has been used as the module drug to test the drug-loading efficiency of porous fibres. Field emission scanning electron microscope images show that the etched UPM/PHBV fibres have lost the original smooth surface. The result demonstrates that the PHBV is successfully washed by chloroform, but most of UPM is remained because of the heat-crosslinking. Furthermore, with the increase of PHBV ratio in composite fibres, the etched fibres show much rougher surface. The drug absorption behavior also varies with the different PHBV ratios

Fuzzing mechanism and fibre fatigue of wool knit

The fibre fatigue fibrillation and even fracture of knitted wool fabric under the rubbing force have been studied using scanning electron microscopy. The fatigue fracture sections, involved in the process of abrasion, show that loop hairs predominantly participate in fuzzing and the free ends exist in either pills formation or wearing-off. The major form of failure consists of the bend fatigue which is about 70 - 80% of the total failure and cracks. Fibrils occur in torsional fatigue (10 - 18%) and fibrillation head-ends comprise both bending and twisting

Automatic pattern segmentation of jacquard warp-knitted fabric based on hybrid image processing methods

This paper reports an automatic pattern separation approach for jacquard warp-knitted fabric, which includes bilateral filter, pyramidal wavelet decomposition and improved fuzzy c-means (FCM) clustering. First, jacquard warp-knitted fabric images are captured and digitized by a scanner in gray mode, and then the bilateral filter is adopted to smoothen the fabric textures formed by various lapping movements of jacquard fabric and to reduce the noise appearing in capturing process. Next, multi-scale wavelet decomposition is applied to lessen calculation burden and to shorten computation time. Finally, the modified FCM clustering is proposed, in which the Mercer Kernel function is used to make some features prominent for clustering, and a weight function is proposed to measure the similarity between the data and the clustering center. The experimental results reveal that this hybrid method can achieve fast and accurate pattern segmentation. It is proved that this study is suitable for the pattern separation of jacquard warp-knitted fabric

Predictive algorithm for run-in value of warp knitting based on weave matrix

To predict the run-in values of single-needle-bar warp-knitted fabrics, three-dimensional weave matrixes have been established by considering main parameters of shogging movement, take-up density and total bar number. Length of a stitch has been deduced from the parameters in weave matrixes, and a new predictive algorithm model is developed. Moreover, to validate the accuracy of the proposed predictive algorithm, 30 samples with different parameters are knitted on HKS4-EL warp-knitting machine, and the predicted run-in values and measured run-in values of the samples are compared. It can be deduced from the comparison that the predictive algorithm model can provide high prediction accuracy with a relative error of < 4.26%

PATTERN RELATED ISSUES IN THE MODELLING OF DEFORMED OVER SURFACE WARP KNITTED STRUCTURES WITH LONGER UNDERLAPS

The yarn level modelling of warp knitted structures is a complex process. For structures placed on the plane, it is well investigated and there are a few software solutions and papers reported. This paper considers the simulation of warp knitted structure, deformed in the 3D space. Especially the modelling of the areas of high curvature are detailed observed. Underlaps with longer lengths makes an unreal visualization for simulation results. Different pattern with different length of the underlaps are modelled with original algorithm developed by the authors. Modelling and visualization problems in the areas with long underlaps are discussed and possible solutions are proposed