Textile fibres can be classified into natural fibres and man-made fibres according to ISO/TR 11827. The biodegradation of petroleum-based fibres is relatively slow compared to biology-based or natural fibres due to the chemical structure.
ISO 21701 specifies a test method for the determination of the biodegradability of the hydrolysate of textile materials obtained after accelerated hydrolysis under controlled composting conditions by measurement of the amount of evolved carbon dioxide with gas chromatography.
ISO 21701 can be applied to petroleum-based man-made biodegradable textile materials which are manufactured from polyethylene terephthalate succinate, polycaprolactone, polypropylene carbonate, polybutylene succinate, or copolymer using them.
ISO 21701 on accelerated hydrolysis of textile materials is useful for:
Some man-made fibres manufactured from organic materials are biodegradable and can be divided into three major categories based on their origin, i.e., natural material base, biology base, and petroleum base. The representative bio-based, man-made biodegradable fibre is polylactide, and petroleum-based, man-made biodegradable fibres are manufactured from polyethylene terephthalate succinate, polycaprolactone, polypropylene carbonate, polybutylene succinate, or copolymer using them.
The rate of biodegradation of textile materials such as fibres and yarns can also be affected negatively by high molecular weight, degree of crystallinity, and orientation that occurred during the spinning. Therefore, it is difficult to determine the biodegradation of petroleum-based textile materials using the existing standards available for natural fibres, biology-based fibres or plastic materials used for packaging. To overcome these difficulties, ISO 21701 discusses a new test method that uses a combination of accelerated hydrolysis and biodegradation using instrument analysis for analysis of evolved carbon dioxide.
For the composting of textile materials; both mechanisms, abiotic and biotic processes, operate together and the microorganisms eventually remove the hydrolysate in a synergistic process. ISO 21701 walks you through the process wherein the rate and extent of molecular weight loss are measured as indicative of losses in physical properties from accelerated hydrolysis and then the biodegradability of hydrolysate is estimated by direct measurement of evolved carbon dioxide with a gas chromatograph.
ISO 21701 discusses the terms and definitions, principles, reference materials, apparatus, and procedure which involves preparation of test material, preparation of the inoculum, accelerated hydrolysis test (abiotic test), biodegradation test (biotic test) of hydrolysate, and gas chromatographic analysis.
ISO 21701 describes the calculation process and expression of the results which involves the amount of carbon dioxide in grams, the percentage of biodegradation, validity of the results. ISO 21701 is a step towards making man-made fibres more environment friendly.
ISO 21701