Final answer:
The main disadvantage of using nylon over natural fiber is its lack of environmental sustainability, as it is made from non-renewable petrochemicals and is not biodegradable. It also emits toxic gases when burnt.
Step-by-step explanation:
What is not an advantage of using nylon over natural fiber is its environmental sustainability. While nylon has many advantages, such as high tensile strength, elasticity, lustre, being wrinkleproof, and resistance to abrasion and chemicals, it is not biodegradable.
Unlike natural fibers, nylon fibers are made from petrochemicals, which are neither renewable resources nor eco-friendly when it comes to disposal and degradation.
Nylon fibers can absorb up to 2.4% of water, which is a disadvantage because this absorption lowers their tensile strength. The production of synthetic fibers like nylon does not require pesticides, unlike cotton, and if made from polypropylene, they can be recyclable.
However, the environmental and safety issues such as flammability and emission of toxic gases when burning are considerable drawbacks.
An advantage of using nylon over natural fiber is that nylon fibers are tough, possessing high tensile strength, elasticity, and lustre. Nylon fibers are also wrinkleproof and highly resistant to abrasion and chemicals such as acids and alkalis.