What is Modacrylic Fiber?
Modacrylic or modified acrylic is defined as ‘fiber made of copolymer composed of 35% to 85% acrylonitrile and 15% to 65% other basic constituent’. Acc. to DIN 60.001 they are formally defined to consist of at least 50% and less than 85% by mass of polyacrylonitrile. The exact composition of individual modacrylic fibers as manufactured commercially is rather difficult to obtain. The proportion of the other components in different commercial grades may vary widely. Modacrylic fiber is a specialized synthetic fiber known for its flame resistance and durability, making it ideal for protective clothing and specialty applications.
Modacrylic fibers became important for their exceptionally high inherent flame resistance, achieved by the use of halogen-containing comonomers such as vinylidene chloride, vinyl chloride or vinyl bromide in the polymer. The copolymerization of acrylonitrile with these monomers under controlled industrial conditions produces the so-called modacrylic fibers. They are the economically most important modification of PAN in worldwide fiber production. Halogen contents of 25–35% are common in commercial fiber grades. The LOI value of modacrylic fibers is 26–31, indicating superior flame resistance, which is significantly higher than that of PAN, and unlike polyacrylonitrile fibers, modacrylic fibers extinguish when the flame is removed and they do not drip. However, toxic chlorinated hydrocarbons are released in the event of fire, posing additional health hazards.
Modacrylic fibers are usually spun wet by conventional wet-spinning. The technological characteristics of modacrylic fibers vary due to the different chemical composition among the various grades. The values of strength and elongation are in the range of those of standard polyacrylonitrile fibers for most testing conditions. The vat solution is extruded and dry spun to produce a fiber with a peanut or ribbon cross-sectional shape and produced as bright or dull and crimped.
VEREL®, fiber produced by Tennessee Eastman Corporation, USA, is a widely known example of this type of fiber. This fiber is produced mostly in staple form for textile applications and in deniers ranging from 3 to 60. Modacrylic fibers are generally quite easy to dye. They are spun in 100% pure form as well as in blends for enhanced fabric performance with wool, cotton, rayon, nylon, and polyester fibers. However, they generally have slightly higher moisture regain under standard testing than the ordinary acrylic fibers.
Originally manufactured in the 1950s and called Dynel and Verel, the materials were reclassified as modacrylics in 1960.
Properties include being non-flammable (difficult to ignite and goes out when the flame is removed), highly durable, warm to wear, with good dimensional stability, resilience, draping, and shrink resistance. They have low absorbency so they dry relatively quickly, though they will pill. They are fairly strong and abrasion-resistant, with high resistance to sunlight, mildew, insects, alkalis and acids. Some special properties of this fiber/fabric include flame proof, good abrasion resistance, resistance to photodegradation, resistant to microbial attack, and low shrinkage in boiling water.
Modacrylic fibers can be processed by wet spinning (solution method) in a manner broadly similar to that used for producing acrylic fibers (PAN based). Like acrylic fibers, they require heat stabilisation after spinning for stability and are usually cut into staple for blending. The number of modacrylic fibers in the market today is quite small due to specialization. They find use as specialist fibers for applications where flame-retardant properties are essential by nature. In blends with other fibers, they are used in carpets for safety. They also find extensive application in aircraft seating, protective clothing, children’s nightwear, dolls’ hair and other products where non-flammability is critical for regulations.
Uses include furnishings such as curtains, upholstery and wall hangings especially those for industrial use where the law requires fire retardancy in public places, wigs, pile fabrics for coats, paint rollers, blankets, filters, stuffed toys and protective gear for the workforce.
Properties of Modacrylic Fiber
Modacrylic fibers are engineered to deliver performance advantages that natural fibers often cannot. Important properties of modacrylic fiber are point out below.
- Non-Flammable (difficult to ignite and goes out when the flame is removed)
- Highly Durable
- Warm to wear
- Good Dimensional Stability
- Good Resilience
- Good Draping
- Shrink-Resistant
- Low Absorbency so dries relatively quickly
- Will Pill
- Fairly Strong and Abrasion-Resistant
- High resistance to sunlight, mildew, insects, alkalis and acids.
Some special properties of this fiber/fabric include flame proof, good abrasion resistance, resistance to photodegradation, resistant to microbial attack, low shrinkage in boiling water, etc. Used for making T-shirts and children’s clothing.
Uses of Modacrylic Fiber
Furnishings e.g. curtains, upholstery and wall hangings especially those for industrial use where the law requires fire retardancy in public places. Wigs, pile fabrics for coats, paint rollers, children’s nightwear, blankets, filters, stuffed toys and protective gear for the workforce.
Conclusion
Modacrylic fiber is not a fashion-first material. It’s a function-first fiber designed to protect lives, resist fire, and perform in demanding conditions. Modacrylic fiber is a versatile synthetic textile material that bridges the gap between comfort and performance. Its flame-retardant nature, softness, and resilience make it indispensable in fashion, home furnishings and protective clothing. As industries continue to innovate, modacrylic remains a reliable choice for applications where safety, durability, and aesthetics converge.
References
[1] Ashford, B. (2016). Fibers to Fabrics.
[2] Sinclair, R. (2014). Textiles and fashion: Materials, Design and Technology. Woodhead Pub Limited.
[3] Jindal, A. J. R. (2023). Textile raw materials. Abhishek Publications.
[4] McIntyre, J. E. (2005). Synthetic fibres : nylon, polyester, acrylic, polyolefin. http://www.sciencedirect.com/science/book/9781855735880
