Acrylic fibers physical properties

The sustained commercial success of acrylic fibers over the past 50 years can be attributed largely to their desirable balance of properties. Apparel goods and carpets made from acrylics have appealed to the consumer because they are aesthetically pleasing in comfort and appearance, easy to care for, and reasonably durable. The physical properties of the fiber are by no means remarkable and some obvious deficiencies such as a poor hot-wet strength and only modest tensile strength and abrasion resistance have prevented penetration of acrylic into some markets. 

In this section, we will describe the physical properties of acrylic fibers and, whenever possible, the relationship among structure, properties, and applications will be emphasized. 

Amino resins react with cellulosic fibers and change their physical properties. They do not react with S5uithetic fibers, such as nylon, polyester, or acrylics, but may self-condense on the surface. This results in a change in the stiflftiess or resiliency of the fiber. Partially polymerized amino resins of such molecular size that prevents them from penetrating the amorphous portion of cellulose also tend to increase the stiffness or resiliency of cellulose fibers. 

Diallyl phthlates (DAP) and diallyl isophthlates (DAIP) are the principal thermosets in the allyl family, with DAP used predominantly. They are used for glass-preimpregnated cloth and paper that must undergo a heat, time, and pressure cycle to produce parts. Molding compounds are reinforced with fibers to improve their mechanical and physical properties. Glass fibers impart mechanical performance, acrylic fibers provide improved electrical performance, polyester fibers enhance impact resistance, and other fibers and fillers can impart different performance traits. 

Glass fiber reinforced composites based on epoxy-acrylate modified UPRs were studied [228]. The authors showed that UPRs, endcapped with acrylate groups and diluted with reactive multifunctional acrylic and allylic monomers in the presence of a photoinitiator, can be photocrosslinked with UV radiation as glass fiber laminates in a rapid process. It was found that the physical properties of the photo-crosslinked laminates are well correlated with the molecular weight of the polyester, the amount of multifunctional monomer added, and the glass fiber content. A greater improvement of the tensile and flexural properties of the photocured products was observed for multifunctional acrylate or acrylether monomers added to the UPR (Table 31) than for allylic monomers. 

Acrylic is a fiber made fi om a copolymer composed of at least 85% by acrylonitrile units, -CH -CH(CN)-. Sources Morton, W.E., et. al.. Physical Properties cf Textile Fibres, Fourth Edition, Woodhead Publishing Limited, 2008. Tortora, P.G., Understanding Textiles, Fourth Edition, Macmillian Publishing Company, 1992. ... 

We presently report on a broad search for specific acrylic carbon fiber precursors, which should be stabilized in short time (less than one hour), and yet would give carbon fibers with satisfactory tensile properties. In planning the chemistry of such precursors, it was necessary to take into account the chemical reactions and physical processes going on during the heat treatment. 

Poly(acrylic acid), 260, 265, 278, 381 Poly(acrylic acid-alt-MA), 381, 382, 660 applications, 453, 660 physical and chemical properties, 442 Poly(acrylic acid-co-MA), 278 Poly(acrylic acid-co-maleic acid), applications, 278 Polyacrylonitrile, 444, 445 MA stabilization, 277 MA treated fibers, 505 poly(vinyl acetate-alt-MA) solutions, 441 Poly(acrylonitrile-co-butadiene), MA-grafted, 469 Poly(acrylonitrile-co-MA), 277 Poly(alkyl acrylates), poly(styrene-alt-MA) grafted, 474... 

Vinyl fibers are those man-made fibers spun from polymers or copolymers of substituted vinyl monomers and include vinyon, vinal, vinyon-vinal matrix (polychlal), saran, and polytetrafluoroethylene fibers. Acrylic, modacrylic and polyolefin—considered in Chapters 8 and 9—are also formed from vinyl monomers, but because of their wide usage and particular properties they are usually considered as separate classes of fibers. The vinyl fibers are generally specialty fibers due to their unique properties and uses. AH of these fibers have a polyethylene hydrocarbon backbone with substituted functional groups that determine the basic physical and chemical properties of the fiber. 

Absorbency has both physical and chemical aspects. The unique character of water determines the properties of materials most able to accept, transport, and ultimately retain aqueous solutions. The absorbent process begins at the interface between the incoming fluid and the absorbent structure. With disposable absorbent articles, the coverstock has the responsibility of receiving and transmitting the fluid insult to the underlying absorbent core. The state-of-the-art core is air-laid cellulose fiber mixed with absorbent polymer. The capillary system of the fibrous batt has appreciable physical absorption capacity in addition to the ability to transport fluid to the absorbent polymer. Many water soluble polymers have been made into absorbent compositions, but the industry standard has become lightly crosslinked partially neutralized poly(acrylic acid). 

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