In addition to its good mechanical properties, it is sm […]
In addition to its good mechanical properties, it is smooth and breathable, and it also has biodegradability and biocompatibility which are not found in general chemical fibers. Good performance characteristics in all aspects enable polylactic acid fiber to be widely Woven jacquard fabrics used in many fields such as textile and medical.
Polylactic acid fiber properties
1, mechanical properties
According to tests, the breaking strength of polylactic acid fiber is 3.2~4.9cN/dtex, which is higher than that of natural cotton fiber. The elongation at break in dry state is similar to that of nylon and wool. When it is wet, the elongation increases, indicating polylactic acid fiber. The product has the advantages of high strength, good elongation and the like. However, in order to maintain the good mechanical properties of the polylactic acid fiber, the spinning process and the spinning process parameters must be strictly controlled.
2, heat resistance
PLA has a low glass transition temperature and poor heat resistance. When heated to 140 ° C, shrinkage occurs. Therefore, the temperature of the polylactic acid fiber product during processing cannot be too high. Polylactic acid fiber has a slightly higher heat shrinkage rate than polyester fiber and is slightly inferior in dimensional stability. Poor heat resistance is one of the main drawbacks that hinder the application of polylactic acid fibers.
Polylactic acid fibers and their products are quite stable at normal temperatures and humidity. When in a natural environment with a certain temperature and humidity (such as sand, silt, sea water), polylactic acid is completely degraded by microorganisms into carbon dioxide and water. If the polylactic acid fiber is buried in the soil, the natural degradation time is 2 to 3 years; if the polylactic acid fiber is mixed with organic waste and buried, it will decompose in a few months.
4, taking sex
Drapability: The polylactic acid fiber has a low initial modulus, a small drape coefficient, and a good drapability of the fabric.
Moisture absorption and permeability: Polylactic acid fiber has poor hygroscopicity, but has good gas permeability.
Wrinkle recovery: When the polylactic acid fiber is stretched at 5%, the elastic recovery rate is as high as 93%, so the wrinkle recovery of the pure polylactic acid fiber fabric is very good.
Abrasion resistance and pilling: Polylactic acid fiber wear resistance is slightly better than polyester, but the fabric has pilling phenomenon.
5, flame retardancy
The polylactic acid fiber has poor flame retardancy, and its limiting oxygen index is only 21%. It is UL-94HB grade. When it burns, only a layer of carbon layer which is just visible is formed, and then it liquefies quickly, drops and burns. In the industry, additive flame retardants are often used to improve the flame retardant properties.
6, UV resistance
The molecular structure of polylactic acid fiber contains a large number of C-C and C-H bonds, which generally do not absorb light with a wavelength of less than 290 nm. Therefore, ultraviolet rays irradiated to the earth have little effect on polylactic acid fibers, and polylactic acid fiber products have good properties. UV resistance.
Application field of polylactic acid fiber
Polylactic acid can be completely degraded into water and carbon dioxide in the human body, and the degradation intermediate is also a product of glucose metabolism in the human body, which can be absorbed by the human body. Therefore, polylactic acid fiber is suitable for medical applications such as surgical sutures, dressings and tissues. Engineering brackets, etc.
Polylactic acid fiber surgical suture has strong tensile strength, which can effectively control the degradation rate, and the suture will automatically degrade slowly with the healing of the wound. Since the advent of polylactic acid surgical sutures in 1975, polylactic acid fiber sutures have been favored and favored by medical workers with their unique advantages.
2, disposable hygiene products
The biocompatibility, skin-friendly and breathability of polylactic acid fiber make it particularly suitable for the production of disposable medical and hygiene products with high safety requirements for the human body and environmental hazards, such as sanitary napkins, pads and diapers. , medical gauze, bandages, bed sheets, high-grade antibacterial rags and other products. Polylactic acid fiber can not only solve the bacteriostatic requirements of disposable medical and hygiene products, but also its biodegradability can solve the "white pollution" problem caused by disposable medical and sanitary products.
3, taking fabric
Polylactic acid fiber is very suitable for making underwear, sportswear and high-end clothing fabrics because of its softness, wrinkle resistance, moisture permeability and bacteriostasis. Polylactic acid fiber and cotton fiber blended knit fabric are soft to the touch and can be used to process seamless underwear, ultra-thin sports underwear, baby underwear and so on. Warp-knitted polylactic acid filaments have good wicking properties and can be used to process sportswear fabrics and swimwear fabrics. Polylactic acid fiber woven fabric has a natural and clean appearance, elegant and generous, and can be used as high-grade shirt fabrics and home textile fabrics.
Polylactic acid fiber has high mechanical properties and complete biodegradability, and has great development potential in biomedical fields such as textiles, industrial and agricultural, and tissue engineering. As many countries pay more and more attention to the development of bio-based materials, polylactic acid fiber will become one of the key development products in the field of fabrics and nonwovens in the 21st century.