Jinsong Shen

The Use of Proteolytic Enzymes to Reduce Wool-fibre Stiffness and Prickle

Carefully controlled treatments with proteolytic enzymes were used to reduce the buckling load and collapse energy of wool yarns. These treatments are shown to improve the softness and reduce the subjectively perceived prickle of fabrics knitted from the treated yarns. A new yarn-bundle compression test was used to quantify changes in the fibre-buckling properties. The method discriminates between wool samples that differ by about 1.0 mm in mean fibre diameter.

Direct 3D printing of polymers onto textiles: experimental studies and applications

– The purpose of this paper is to investigate the adhesion of polymer materials printed directly onto fabrics using entry-level fused deposition modelling (FDM) machines. A series of functional and decorative parts were designed to explore the limitations and to identify potential applications. , – A series of shapes and structures were designed as 3D computer-aided design (CAD) solids to determine whether complex parts could be printed directly onto the surface of fabrics. The structures were fabricated using an entry-level FDM printer with acrylonitrile butadiene styrene, polylactic acid (PLA) and nylon on eight different types of synthetic and man-made woven and knit fabrics. The results were recorded according to four parameters – the warp, bond, print quality and flex – before comparing the data sets. , – Among the three polymers, PLA showed the best results when printed on the eight different types of fabrics, having extremely good adhesion with little warp, yet displaying a high quality of print with good flexural strength. For the fabrics, woven cotton, woven polywool and knit soy had excellent adhesion when the three polymers were deposited. , – Future work should cover a wider range of polymers and textiles and incorporate more functional features for testing. Other aspects include modifying the fibre surface through mechanical or chemical means to achieve a more efficient adhesion with the fibre and examining the deposition process in terms of temperature, pressure and build density. Future work should also investigate the feasibility for large-scale production. , – This paper supports work on wearable electronics by integrating comfortable textiles with hard wearing parts without compromising on quality and fit and combining additive manufacturing processes with textiles to maintain the drape characteristics of the fabric. Polymer–textile deposition will contribute to new applications and functional products such as orthopaedic braces for medical use or for decorative features such as buttons and trimmings for garments. , – This paper has contributed to new knowledge by providing a better understanding of polymer materials being printed directly onto fabrics using entry-level FDM machines.

New Enzyme-based Process Direction to Prevent Wool Shrinking without Substantial Tensile Strength Loss

In this paper a new enzymatic process direction is described for obtaining machine washable wool with acceptable quality. In general, application of protease enzyme technology in wool processing results in considerable loss of tensile strength by diffusion of the enzyme into the interior of wool fibers. To overcome this disadvantage enzymatic activity has been more targeted to the outer surface of the scales by improving the susceptibility of the outer surface scale protein for proteolytic degradation. This has been realized by a pretreatment of wool with hydrogen peroxide at alkaline pH in the presence of high concentrations of salt.

Modification of Esperase by covalent bonding to Eudragit polymers L 100 and S 100 for wool fibre surface treatment.

The protease Esperase® was modified by covalent bonding with two grades of a reversible soluble-insoluble co-polymer of methacrylic acid and methyl-methacrylate, namely Eudragit® L 100 and Eudragit® S 100. The optimum reaction conditions and washing protocol were investigated and it was found that Esperase® modified with Eudragit® L 100 showed greater activity than if modified with Eudragit® S 100. This should be expected as there is a greater quantity of active sites, namely carboxyl groups, per mass of Eudragit® L 100 in comparison with Eudragit® S 100 to interact with the enzyme. Gel filtration confirmed that Eudragit® L 100 covalently bonded to Esperase®. Treatment of the modified Esperase® on wool showed that the enzyme modified with Eudragit® L 100 had greater activity towards the wool and appeared more effective in shrink resistant finishing.

Surface modification of wool with protease extracted polypeptides

Polypeptides were extracted from wool protein fibres using the serine type protease Esperase 8.0L (EC 3.4.21.62), a subtilisin from Bacillus sp., in a reducing solution. The extracted polypeptides, in aqueous liquor, were then applied to modify the fibre surface of wool fabric with or without additional protease. The treated wool fabric was subsequently treated with the cross-linking agent, glycerol diglycidyl ether, and then underwent a curing process to affix the polypeptide to the fibre. The resulting knitted fabric showed a very high level of shrink-resistance to machine washing, without excessive fibre damage. Shrinkage of 1-2% could be achieved after 5 times 5A washes with minimal (<1%) weight loss due to washing and a burst strength of 317 kPa.

An ethoxylated alkyl phosphate (anionic surfactant) for the promotion of activities of proteases and its potential use in the enzymatic processing of wool

Pretreatments of wool fabrics with cationic, anionic or non-ionic surfactants were investigated to reduce surface tension and improve the wettability of the fibres in order to promote protease activity on the fibres in subsequent processes. Results showed that an ethoxylated alkyl phosphate (specific anionic surfactant) as well as the widely used non-ionic surfactant was compatible with proteases in the enzymatic treatment of wool. There is therefore a potential for using specific anionic surfactants to achieve efficient enzymatic scouring processes.

Synthesis of silicone-containing epoxide and its application on silk crease-resist finishing

A silicone-containing epoxide named as EPSIB was prepared For silk crease-resist finishing. The major influence parameters for the synthesis of EPSIB were discussed. These treatments are shown to improve significantly both dry and wet resiliencies of silk with a good laundering durability. The shrinkage of finished silk by EPSIB was also improved. Other properties such as breaking strength, abrasion resistance and moisture regain remain almost constant. The results obtained in this study indicated that EPSIB may be suitable for commercial exploitation for silk finishing.

The removal of lipid from the surface of wool to promote the subsequent enzymatic process with modified protease for wool shrink resistance

Abstract When treated with modified protease, wool shows shrink resistance without significant damage to the fiber. It was considered that if wool fiber was pre-treated to make it more hydrophilic, the subsequent treatment with modified protease would be more efficient. After wool was pre-treated with cetyltrimethylammonium bromide (CTAB) under alkaline conditions, the fiber became very hydrophilic due to the removal of surface lipid. After CTAB treatment, it was found that residual CTAB on the fiber significantly decreased enzyme activity. Therefore prior to enzyme treatment, CTAB was washed off the fiber with anionic surfactant under acidic conditions. It was found that the activity of modified protease towards wool improved if wool had been pre-treated with CTAB then washed with anionic surfactant. It was concluded that pre-treatment of wool with CTAB under alkaline conditions followed by washing with anionic surfactant improves the wettability of wool and therefore promotes more efficient treatment with modified protease, achieving improved levels of shrink resistance with no effect on strength of the fiber or coloration properties.

Enzymatic treatment of wool and silk fibres

Abstract: In this chapter, the major enzymes used as bio-catalysts for protein fibre processes in the textile industry are described and the protein structure of wool and silk fibres is explained. Recent developments are presented in the application of enzymes in wool scouring and finishing processes to achieve a variety of finishing effects including softness, reduction of prickle and shrink-resistance. Recent developments in the application of enzymes in silk degumming and finishing are also reviewed.

The influence of woven stretch fabric properties on garment design and pattern construction

Tensile properties of various woven stretch fabrics were measured. The extension, residual extension and elastic recovery under repeated tests were evaluated. The measurement of a female body was taken in five different postures and five patterns produced. These were combined to produce one pattern which allows for optimum movement. This pattern was then modified by taking into account the extension and recovery properties of the stretch woven fabric. Garments produced using a traditional method of pattern production and the new modified pattern for both woven and woven stretch fabrics were compared by 40 experienced fashion and textile designers with regard to appearance and visual fit during movement.