Acrylonitrile-EPDM-styrene copolymer

After the examination of the PS photooxidation mechanism, a comparison of the photochemical behavior of PS with that of some of its copolymers and blends is reported in this chapter. The copolymers studied include styrene-stat-acrylo-nitrile (SAN) and acrylonitrile-butadiene-styrene (ABS). The blends studied are AES (acrylonitrile-EPDM-styrene) (EPDM = ethylene-propylene-diene-monomer) and a blend of poly(vinyl methyl ether) (PVME) and PS (PVME-PS). The components of the copolymers are chemically bonded. In the case of the blends, PS and one or more polymers are mixed. The copolymers or the blends can be homogeneous (miscible components) or phase separated. The potential interactions occurring during the photodegradation of the various components may be different if they are chemically bonded or not, homogeneously dispersed or spatially separated. Another important aspect is the nature, the proportions and the behavior towards the photooxidation of the components added to PS. How will a component which is less or more photodegradable than PS influence the degradation of the copolymer or the blend We show in this chapter how the... 

AES (acrylonitrile-EPDM-styrene) is a blend of SAN and EPDM. SAN is a statistic copolymer of styrene and acrylonitrile. EPDM is an elastomeric terpo-lymer of ethylene, propylene and a nonconjugated diene. The diene studied here was 5-ethylidene-2-norbomene. The total content of EPDM was 34mole% [6]. The diene represented 8 mole% of the EPDM and the SAN phase was composed of 80 mole% of styrene and 20 mol% of acrylonitrile. The AES films were irradiated at / > 300 nm at 60 °C in the presence of oxygen. The photoproducts resulting from the photooxidation of each components of AES were identified by FTIR spectroscopy coupled with the same chemical and physical treatments as mentioned above for the previous studies. As pointed out in the literature [17], the EPDM component is more reactive than the copolymer SAN towards photooxidation. 

MGE copolymers are also efficient reactive precursors to compatibihze PBT/AES blends. Since AES (acrylonitrile-ethylene-styrene copolymer) is itself a two-phase blend, consisting of EPDM grafted to SAN, it is likely that MGE can promote coalescence suppression in PBT/AES through a mechanism similar to that found in PBT/ABS/MGE blends. In fact. Figure 7.8 shows that the incorporation of MGE leads... 

The isoprene units in the copolymer impart the ability to crosslink the product. Polystyrene is far too rigid to be used as an elastomer but styrene copolymers with 1,3-butadiene (SBR rubber) are quite flexible and rubbery. Polyethylene is a crystalline plastic while ethylene-propylene copolymers and terpolymers of ethylene, propylene and diene (e.g., dicyclopentadiene, hexa-1,4-diene, 2-ethylidenenorborn-5-ene) are elastomers (EPR and EPDM rubbers). Nitrile or NBR rubber is a copolymer of acrylonitrile and 1,3-butadiene. Vinylidene fluoride-chlorotrifluoroethylene and olefin-acrylic ester copolymers and 1,3-butadiene-styrene-vinyl pyridine terpolymer are examples of specialty elastomers. 

Examples of such compatibilized systems that have been studied include EPDM/PMMA blends compatibilized with EPDM- -MMA, polypropylene/polyethylene blends with EPM or EPDM, polystyrene/nylon-6 blends with polystyrene/nylon-6 block copolymer, and poly(styrene-co-acrylonitrile)/poly(styrene-co-butadiene) blends with butadiene rubber/PMMA block copolymer. 

Acrylic resin Acrylonitrilefbutadiene/styrene copolymer Bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite Butadiene/acrylonitrile copolymer EthyleneA/A copolymer Methoxyethyl acrylate Methyl methacrylate butadiene styrene terpolymer Polyethylene elastomer, chlorinated 2-Propenoic acid, 2-methylmethyl ester, polymer with 1,3-butadiene and butyl 2-propenoate impact modifier, PVC rigid EVA/PVC graft polymer impact modifier, recycled polyamides EPDM, maleated impact modifier, thermoplastics Butadiene/acrylonitrile copolymer impact strength modifier PEG-6 trimethylolpropane impact-resistance lights Polyester carbonate resin impact-resistance, lights Polyester carbonate resin impeller... 

PP poly(propylene), PS poly(styrene), MAH maleic anhydride, MA methacrylic acid, S styrene, PE poly(ethylene), PPE poly(phenylene ether), LDPE low-density PE, EPDM ethylene-propylene-diene terpolymer, SAN styrene-acrylonitrile copolymer, EPR ethylene-propylene copolymer, NMAC A -methacrylyl caprolactam, GMA glycidyl methacrylate, FA fumaric acid, AEFO anhydride and epoxide functionalized olefin copolymer, SEBS styrene/ethylene-butylene/styrene copolymer, HDPE high-density PE, AN acrylonitrile, and S-MAH-MMA styrene-maleic anhydride-methyl methacrylate copolymer. 

To this group of blends belong mixtures of PP with st)oene-elastomer copolymers, styrene-diene blocks styrene-butadiene-st)a ene (SBS), sty-rene-ethylene/butylene- t30 ene (SEBS), st)rrene-isoprene-styrene (SIS), with acrylonitrile-butadiene-styrene terpol)nners (ABS), acrylonitrile-styrene-acrylate (ASA), or with EPR/EPDM grafted with styrene and acrylonitrile (AES or AXS). The first blends of this type date from the early 1960s. In these systems, PP is either the main component to be modified, or an additive to enhance performance of the styrenic matrix. 

The major types of impact modifiers are acrylics, styrenics including methacrylate-butadiene-styrene (MBS) copolymers and Acrylonitrile-Butadiene-Styrene Polymers, chlorinated polyethylene (CPE), EVA copolymers, and the ethylene-propylene copolymers and terpolymers (EPR and EPDM respectively). The major market for impact modifiers is in PVC, although they are used in a wide range of other polymers such as polyolefins and engineering polymers. 

Abbreviations-. EPDM, ethylene-propylene-diene monomer (a copolymer elastomer) CTBN, carboxy-terminated butadiene nitrile (an elastomer prepolymer) ABS, acrylonitrile-butadiene-styrene (a complex latex structure used both independently and to toughen other polymers) SBR, styrene-butadiene rubber (an elastomer). 

Abbreviations HIPS, high-impact polystyrene ABS, acrylonitrile-butadiene-styrene graft copolymer EPDM, ethylene propylene-diene copolymer CTBN, carboxyl terminated butadiene nitrile telomer M = 5000 g/mol) PC, polyearbonate SBS, styrene-butadiene-styrene triblock copolymer SIS, styrene isoprene styrene tribloek copolymer SEBS, SBS with hydrogenated center block PU, segmented (block copolymer) polyurethanes PDMS, poly(dimethyl siloxane) FIFE, polytetralluoroethylene. 

There are many other commercial examples of polymer blends. Polycarbonate can be blended with an acrylonitrile-butadiene-styrene terpolymer to give a PC-ABS blend. Polypropylene impact can be improved by the addition of ethylene-propylene copolymers, which are sometimes called ethylene-propylene-rubber (EPR). Ethylene, propylene, and a diene monomer (EPDM), such as ethylidene norbomene, is also used to impart impact and flexibiUty to polypropylene. 

Impact modifiers are added to many formulations. As the name implies, they impart toughness to the polymer article or film. Many of them are butadiene copolymers that disperse in the polymer matrix. One type - the so-called core shell modifiers - has a rubbery core surrounded by a harder acrylate layer. They have been compared to an egg soft on the inside and hard on the outside. The outer shell also has some adhesion to the matrix so that the modifier can be dispersed. Other impact modifiers include methacrylate-butadiene-styrene copolymers or EPDM, ethylene-propylene-diene monomer copolymers. Acrylonitrile-butadiene-styrene (ABS) and ethylene-vinyl acetate (EVA) are also used. 

Over 5.5 billion pounds of synthetic rubber is produced annually in the United States. The principle elastomer is the copolymer of butadiene (75%) and styrene (25) (SBR) produced at an annual rate of over 1 million tons by the emulsion polymerization of butadiene and styrene. The copolymer of butadiene and acrylonitrile (Buna-H, NBR) is also produced by the emulsion process at an annual rate of about 200 million pounds. Likewise, neoprene is produced by the emulsion polymerization of chloroprene at an annual rate of over 125,000 t. Butyl rubber is produced by the low-temperature cationic copolymerization of isobutylene (90%) and isoprene (10%) at an annual rate of about 150,000 t. Polybutadiene, polyisoprene, and EPDM are produced by the anionic polymerization of about 600,000, 100,000, and 350,000 t, respectively. Many other elastomers are also produced. 

Styrene-acrylonitrile copolymer (SAN) and its impact modified versions, viz., ABS (polybutadiene rubber grafted SAN), ASA (acrylate rubber grafted SAN), AES (EPDM rubber grafted SAN)... 

Elastomers or rubbers are flexible materials that are mainly used in tires, hoses, and seals as adhesives or as impact modifiers of thermoplastics. They exhibit high resistance to impact, even at low temperatures at which materials increase their rigidity. Eor some of the applications (e.g., tires or hoses), these materials have to be slightly crosslinked once they are formed into the desired shape in order to impart them dimensional stability, since otherwise they tend to slowly flow. Elastomers are polymers that are used above their glass-transition temperature (Tg). Some examples of common elastomers are polybutadiene, which is used as an impact modifier of rigid plastics SBR (copolymer of styrene and butadiene), mainly used in tires EPDM (copolymer of ethylene, propylene, and a diene monomer, usually norbornene) NBR (copolymer of acrylonitrile and butadiene) and so on. 

Considerable quantities of styrene are used in producing copolymerisates and blends, as, for example, in the production of copolymers with acrylonitrile (SAN), terpolymers from styrene/acrylonitrile/butadiene (ABS polymers) or acrylonitrile/styrene/acrylic ester (ASA), etc. The glass transition temperature of poly (styrene), 100 C, can be increased by copolymerization with a-methyl styrene. What are known as high impact poly (styrenes) are incompatible blends with poly(butadiene) or EPDM, which are consequently not transparent, but translucent. For this reason, pure poly (styrenes) are occasionally called crystal poly (styrenes). 

Dow has prepared a compatibilized blend of PC and linear PE. The compati-bilizer used was EPDM grafted with SAN. The product has high impact strength and good melt processability. Polymer alloys with S-AMS copolymer and PP with styrene-grafted polyolefin copolymer have been reported. Triax 1000 of Monsanto is a blend of nylon and ABS compatibilized with styrene-acrylonitrile and glycidyl methacrylate terpolymer. The compatibilizer often improves the property balance of an immiscible blend. Reactive compatibilization is an emerging technique. 

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