Styrenics
Thermoplastics > Styrenics
Styrenics | ||||||||
Types of styrenics | ||||||||
Styrenic plastics covers a broad class of polymeric materials of which a major part is styrene. Styrenic copolymer and terpolymer products: Styrenic block copolymers (SBC: elastomers of styrenic block copolymers (SBC TPE-S) and styrene-butadiene (HS-SBC) high rigid copolymer resins in styrene Styrene-acrylic ester Ion exchange resins (IER, styrene-divinylbenzene) Styrenic copolymers weather (acrylonitrile styrene acrylate [ASA] and acrylonitrile-EPDM-styrene [AES]) Methacrylate-butadiene-styrene (MBS) Styrene-maleic anhydride (SMA) Chlorinated polyethylene-styrene with acrylonitrile (ACS) Styrene is also known as vinylbenzene. Styrene polymers have some unique properties such as transparency, processability, thermal stability, low cost, which make suitable in a wide range of applications. A very important feature is that polystyrene is singular solid below 100 ° C. Above this temperature, commonly called glass transition temperature (Tg), polymer chains (on a molecular level) have rotational freedom which allows mobility long chain segments.Styrene / acrylonitrile may be subdivided into transparent and non-transparent plastics. Among the first group are SAN, PS and MABS; among the second group, ABS, ASA, PC / ABS, PC / ASA and PA / ABS. | ||||||||
Polimerization | ||||||||
Used as polystyrene, acrylonitrile butadiene styrene (ABS), styrene acrylonitrile (SAN), the addition of monomer methyl methacrylate (MMA) in the rigid phase is SAN obtine a polymer with high transparency (MABS). The introduction of an elastomer in grafted acrylic ester copolymerization reaction between styrene and acrylonitrile, generates acrylonitrile styrene acrylate (ASA). The monomer incorporation polybutadiene (PB) in the rigid phase PS a polymer high impact (HIPS) is obtine. The copolymerization of styrene with maleic anhydride creates a copolymer called styrene maleic anhydride (SMA). SMA has a transition higher than polystyrene and is chemically reactive temperature due to the active functional groups. In this way, SMA polymers are often used in blends or composites where interaction or reaction of the maleic anhydride provides desirable interfacial effects. Moreover, the styrenic block copolymer or SBC, is a commercially important thermoplastic elastomer. | ||||||||
No transparent | ||||||||
The mechanical property of copolymers of styrene are not transparent; good or high impact, good thermal and HDT Vicat. The weather resistance and thermal aging is another important property of these plastics. Both ASA and PC / ASA are excellent in resistance to UV radiation and thermal aging, as the n-butyl acrylate rubber contains almost no residual double bonds. In contrast, the rubber phase ABS contains about residual double bond per monomer unit. As a result, radicals can be generated more easily by heat or ultraviolet radiation.
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Transparent | ||||||||
The mechanical property of copolymers of styrene are transparent; low impact, low thermal and HDT as vicat. It does not have a lot of resistance to weathering and thermal aging. In crystalline polymers such as polystyrene, many microcracks appear. Have been given this name does not correspond to reality, since they are not real cracks, these entities also called "crazes" grow normal to the direction of stress of greatest tension, reflect light, and fracture usually it is possible if enough tensing.
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