What factors affect the degradation rate of biodegradable yarn?

Influence of material types
Common raw materials for biodegradable yarns include polylactic acid, polycaprolactone, starch-based polymers, natural fibers and some modified fibers. The molecular structure, degree of polymerization and crystallinity of different materials vary greatly, which affects their identifiability and decomposition difficulty in the microbial environment. For example, some materials with high crystallinity are more difficult to be degraded by microorganisms under natural conditions and the degradation rate is slower, while some natural polymers or modified materials with strong hydrophilicity are more easily degraded under hydrolysis or enzymatic hydrolysis.

Influence of environmental conditions
The environment is an important external factor that determines the decomposition efficiency of biodegradable yarns. Temperature is one of the core variables. High temperature can accelerate the molecular movement and hydrolysis process of yarns, which is conducive to the action of microorganisms. Humidity should not be ignored either. Yarns are more likely to absorb water and swell in a humid environment, increasing the contact area with microorganisms and accelerating the degradation reaction.

Oxygen content and the activity level of microorganisms in the soil also play an important role in degradation. Under aerobic conditions, the degradation of yarns is usually faster, while in anoxic or anaerobic environment, the degradation process will slow down or even stagnate. Differences in microbial species in different soil types can also affect degradation efficiency. For example, more active microbial communities in composting environments can greatly accelerate the degradation process.

Impact of product design and processing methods
The structure of the yarn itself and the textile process can also affect its degradation rate. The thickness, twist and surface treatment of the yarn determine its contact area and degradability in the environment. The finer the fiber, the larger the surface area, which is more conducive to the penetration of water and microorganisms, thereby improving the degradation efficiency. If the yarn is treated with hydrophobicity or anti-degradation additives, it will inhibit the activity of microorganisms and slow down the degradation process.

After the yarn is woven into fabric, the density and structure of the fabric will also affect the overall degradation. Fabrics that are sparse or have good ventilation and water permeability are more conducive to the action of microorganisms and the degradation process is smoother.

Impact of post-use treatment methods
After the biodegradable yarn is used, its treatment method also determines the final degradation performance. For example, the degradation performance of yarn abandoned in natural soil, composting facilities or industrial degradation environments will be very different. Under composting conditions, yarns tend to degrade in a shorter time due to relatively stable temperature, humidity and microbial density. If mixed into traditional landfills, the degradation process may be significantly delayed due to lack of oxygen or closed environment.

The degradation rate of biodegradable yarn is a multi-dimensional and multi-variable process. The nature of the raw materials, the environmental conditions, the processing technology and the subsequent treatment methods all play a key role in it. On the road to promoting green textiles and circular economy, in-depth understanding and reasonable application of these factors will help to achieve the organic unity of material design and environmental protection.