The surface modification of a para-aramid fiber was investigated by graft polymerization of a vinyl monomer having an anionic group onto radicals on the fiber surface that were induced by electron beam (EB) irradiation. Generation of the radicals in the fiber irradiated with EB was evaluated, and it was determined that the radical concentration of the fibers increased with an increase in the dose of radiation. Acrylic acid (AA) was used as the anionic vinyl monomer for graft polymerization. Dyeability was improved for the fabrics that had been graft polymerized with AA because of the formation of ionic bonds between the anionic groups in the grafted chain and the cationic dyes. Furthermore, color fastness to washing was improved for the fabric graft copolymerized with AA and methyl acrylate (MA) compared to that for the fabric grafted with only AA, because the hydrophobic parts of MA in the grafted chains caused a hydrophobic interaction with the dye in addition to ionic bonding.
The current crisis in solid waste management and greenhouse gas emission has focused attention on the development of bio-based biodegradable materials like poly(lactic acid), PLA. New sheath⁄core type of bi-component spunbond fabrics made from poly(butylene succinate) (PBS)⁄PLA have been developed to improve the flexibility of PLA spunbond fabric, and were studied on the biodegradation behaviors in natural environment, such as in soil or in compost, by tensile tests and electron microscopic observations, followed by discussion on the crosslinking effect of the PBS component to improve spinnability. As a result, it was concluded that the crosslinking had a tendency to decrease the rate of biodegradation and the non-crosslinked PBS⁄PLA spunbond fabric has an excellent compostability comparable to conventional PLA one in compost. A SEM photograph of the spunbond fabrics subjected to composting and soil burial showed that a number of fine cracks appeared perpendicular to the fibre axis. It was supposed thathydrolytic degradation occurred preferably in the amorphous regions sandwiched between two crystalline zones of so-called ‘shish-kebab’ structure.
Wool fabrics were modified by pulse corona discharge and enzyme to improve the shrink resistance. The pulse corona treatment alone did not greatly affect the shrink resistance. Thus after the discharge treatment the fabrics were subjected to the treatment with keratinases. The effects of proteases involved in the keratinases on tensile strength were mainly studied. A new type of purified keratinase with a single component was tried. The shrink resistance of pulse corona treated wool was considerably enhanced by the subsequent enzyme application. The shrink proofing, tensile strength, and hand values of primary hand expressions after the dual treatment were investigated. It was found that the single component of keratinase exhibits excellent shrink resistance after the pulse corona discharge. The satisfactory shrink resistance was attained with slight lowering of tensile strength. The primary hand values of the treated fabrics did not change so much after the dual treatment and the good handle of the original wool itself was kept.
Kusakizome is a collective term of Japanese traditional dyeing technologies using naturally-occuring pigments. For green dyeing of a cloth in Kusakizome , two methods have been mainly utilized : (1) the combination of indigo blue and yellowish flavonoids, and (2) chlorophyl green coupled with a copper salt as a color fixative. We have demonstrated useful methods for green dyeing which features the use of anthocyanin blue with alum mordant under the weak basic condition coordinating with natural yellow pigments. Various anthocyanin-containing plants or flowers could be utilized for the green dyeing and the operative simplicity is highly attractive. Some factors for solidity of the green cloth in the method were also evaluated.