Acrylonitrile and Acrylonitrile Polymers

Abstract

Acrylonitrile is a versatile and reactive monomer that can be polymerized under a wide variety of conditions and copolymerized with an extensive range of other vinyl monomers because of its polar nature and reactivity. Because of the difficulty of melt processing the acrylonitrile homopolymer, acrylonitrile is usually copolymerized to achieve a desirable thermal stability, melt flow, and physical properties. Acrylonitrile‐containing polymers are used in the areas of textile fibers, carbon fiber percursors, adhesives, binders, antioxidants, medicines, dyes, electrical insulations, emulsifying agents, graphic arts materials, insecticides, leather, paper, plasticizers, soil‐modifying agents, solvents, surface coatings, textile treatments, viscosity modifiers, azeotropic distillations, artificial organs, lubricants, asphalt additives, water‐soluble polymers, hollow spheres, cross‐linking agents, and catalyst treatments. Styrene is the largest volume acrylonitrile comonomer for thermoplastic applications. Styrene–acrylonitrile (SAN) copolymers are inherently transparent plastics with high heat resistance and excellent gloss and chemical resistance. They are also characterized by good hardness, rigidity, dimensional stability, and load‐bearing strength. In general, the styrene component of SAN resins offers clarity, stiffness, and processibility, while the acrylonitrile provides chemical and heat resistance. Because of their inherent transparency, SAN copolymers are most frequently used in clear application. These optically clear materials can be readily processed by extrusion and injection molding, but they lack real impact resistance. SAN resins show considerable resistance to solvents and are insoluble in carbon tetrachloride, ethyl alcohol, gasoline, and hydrocarbon solvents. Polar solvents dissolve SAN. The properties of SAN are significantly altered by water absorption. Commercially, SAN is manufactured by three processes: emulsion, suspension, and continuous mass polymerization. More than 75% of the SAN resin produced is believed to be used captively for acrylonitrile–butadiene–styrene compounding and in the production of acrylonitrile–styrene–acrylate and acrylonitrile–EPDM–styrene weatherable copolymers. SAN resins appear to pose few health problems, and they have been approved by the FDA for direct food contact. Copolymers of acrylonitrile and methyl acrylate and terpolymers of acrylonitrile, styrene, and methyl methacrylate are used as barrier polymers. Acrylonitrile multipolymers containing indene; methyl methacrylate, and α‐methylstyrene are used as poly(vinyl chloride) modifiers for heat distortion temperature and processibility improvement.

Compatibilization of Poly(styrene‐acrylonitrile) (SAN)/Poly(ethylene) Blends via Amine Functionalization of SAN Chain Ends

“…[1,20,21] Poly(styrene-ran-acrylonitrile), SAN, has excellent grease and chemical resistance as well as high gas barrier properties due to the polarity of the acrylonitrile monomer. [22] For this reason it would make an excellent barrier material within a PE blend. However, commercially available SAN made by conventional free radical polymerization does not have inherent functionality making reactive extrusion infeasible.…”

“…Commercially available SAN for barrier applications can have up to 75 mol% acrylonitrile content. [22] However, this high content of acrylonitrile is difficult to achieve in SAN, since the copolymer composition azeotropic point of SAN is close to 40 mol% acrylonitrile. [64] Even with a monomer feed composition of acrylonitrile at 70 mol%, the copolymer composition was found to be only 52 mol%.…”

“…[22] However, due to its high melting point, high melt viscosity and thermal instability, poly(acrylonitrile) is seldom homopolymerized for practical applications and thus acrylonitrile is almost always copolymerized with another monomer. [22] Its most common comonomer is styrene. Poly(styrene-ran-acrylonitrile) (SAN) keeps many of the excellent barrier properties of PAN, but the styrene contributes to improved processability.…”

“…Poly(styrene-ran-acrylonitrile) (SAN) keeps many of the excellent barrier properties of PAN, but the styrene contributes to improved processability. [22] Conventional free radical polymerization of SAN gives polymers with broad polydispersities ~2, and poorly defined microstructure. [40,52] Controlled radical polymerization (CRP) can be used to create useful SAN copolymers with low polydispersity and controlled microstructure, such as segmented block copolymers.…”

Superporous IPN hydrogels having enhanced mechanical properties

“…10 PAN molecules synthesized in SPH are expected to form a network by physical crosslinks, resulting in IPN. The properties of the synthesized SPIHs were significantly dependent on the amount of the initiator pair.…”