Acrylonitrile-styrene-maleic anhydrid

Modifications of epichlorohydrin elastomers by radical-induced graft polymeri2ation have been reported. Incorporated monomers include styrene and acrylonitrile, styrene, maleic anhydride, vinyl acetate, methyl methacrylate, and vinyHdene chloride (81), acryHc acid (82), and vinyl chloride (81,83,84). When the vinyl chloride-modified epichlorohydrin polymers were used as additives to PVC, impact strength was improved (83,84). 

Other blends of polycarbonate have limited markets so far. The most significant blends are with polyurethanes, polyetherimides, acrylate—styrene-acrylonitrile (ASA), acrylonitrile—ethylene—styrene (AES), and styrene—maleic anhydride (SMA). 

A commercially important example of the special case where one monomer is the same in both copolymers is blends of styrene—acrylonitrile, 1 + 2, or SAN copolymers with styrene—maleic anhydride, 1 + 3, or SMA copolymers. The SAN and SMA copolymers are miscible (128,133,144) so long as the fractions of AN and MA are neatly matched, as shown in Figure 4. This suggests that miscibility is caused by a weak exothermic interaction between AN and MA units (128,133) since miscibility by intramolecular repulsion occurs in regions where 02 7 can be shown (143) by equation 11. 

Fig. 4. Miscibihty map for blends of styrene—acrylonitrile copolymers (SAN), with styrene—maleic anhydride copolymers (SMA).

Styrene readily copolymerizes with many other monomers spontaneously. The styrene double bond is electronegative on account of the donating effect of the phenyl ring. Monomers that have electron-withdrawiag substituents, eg, acrylonitrile and maleic anhydride, tend to copolymerize most readily with styrene because their electropositive double bonds are attached to the electronegative styrene double bond. Spontaneous copolymerization experiments of many different monomer pair combiaations iadicate that the mechanism of initiation changes with the relative electronegativity difference between the monomer pairs (185). 

Most of the surface sizes used in North America are modified styrene maleic anhydride (SMA) copolymers. Commercially available materials include Scripset (Monsanto/Hercules Inc.), Cypres (Cytec), Sursize (Akzo Nobel), MSA (Morton), NovaCote (Georgia Pacific), and HTl (Hopton Technologies). Styrene acrylate emulsions that are commonly used include Jetsize and Unibond (Akzo Nobel), Basoplast (BASF), and Cypres (Cytec). Other materials used as surface sizes include acrylonitrile acrylate copolymer (Basoplast, BASF), stearylated melamine resin (Sequapel, Sequa), polyurethane (Graphsize, Vining Chemicals), and diisobutylene maleic anhydride copolymers (Baysynthol, Bayer). 

Styrene acrylonitrile Styrene butadiene Styrene maleic anhydride Styrene methyl methacrylate Thermoplastic urethane, rigid... 

Polycarbonate is blended with a number of polymers including PET, PBT, acrylonitrile-butadiene-styrene terpolymer (ABS) rubber, and styrene-maleic anhydride (SMA) copolymer. The blends have lower costs compared to polycarbonate and, in addition, show some property improvement. PET and PBT impart better chemical resistance and processability, ABS imparts improved processability, and SMA imparts better retention of properties on aging at high temperature. Poly(phenylene oxide) blended with high-impact polystyrene (HIPS) (polybutadiene-gra/f-polystyrene) has improved toughness and processability. The impact strength of polyamides is improved by blending with an ethylene copolymer or ABS rubber. 

An appropriate formalism for Mark-Houwink-Sakurada (M-H-S) equations for copolymers and higher multispecies polymers has been developed, with specific equations for copolymers and terpolymers created by addition across single double bonds in the respective monomers. These relate intrinsic viscosity to both polymer MW and composition. Experimentally determined intrinsic viscosities were obtained for poly(styrene-acrylonitrile) in three solvents, DMF, THF, and MEK, and for poly(styrene-maleic anhydride-methyl methacrylate) in MEK as a function of MW and composition, where SEC/LALLS was used for MW characterization. Results demonstrate both the validity of the generalized equations for these systems and the limitations of the specific (numerical) expressions in particular solvents. 

In this paper a generalized approach is presented to the derivation of H-H-S equations for multispecies polymers created by addition polymerization across single double bonds in the monomers. The special cases of copolymers and terpolymers are derived. This development is combined with experimental results to evaluate the numerical parameters in the equations for poly(styrene-acrylonitrile ) (SAN) in three separate solvents and for poly(styrene-maleic anhydride-methyl methacrylate) (S/HA/MM) in a single solvent. The three solvents in the case of SAN are dimethyl formamide (DMF), tetrahydrofuran (THF), and methyl ethyl ketone (MEK) and the solvent for S/HA/HH is HER. 

PS PSF PSU PTFE PU PUR PVA PVAL PVB PVC PVCA PVDA PVDC PVDF PVF PVOH SAN SB SBC SBR SMA SMC TA TDI TEFE TPA UF ULDPE UP UR VLDPE ZNC Polystyrene Polysulfone (also PSU) Polysulfone (also PSF) Polytetrafluoroethylene Polyurethane Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) poly(vinyl butyrate) Poly(vinyl chloride) Poly(vinyl chloride-acetate) Poly(vinylidene acetate) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl fluoride) Poly(vinyl alcohol) Styrene-acrylonitrile copolymer Styrene-butadiene copolymer Styrene block copolymer Styrene butadiene rubber Styrene-maleic anhydride (also SMC) Styrene-maleic anhydride (also SMA) Terephthalic acid (also TPA) Toluene diisocyanate Ethylene-tetrafluoroethylene copolymer Terephthalic acid (also TA) Urea formaldehyde Ultralow-density polyethylene Unsaturated polyester resin Urethane Very low-density polyethylene Ziegler-Natta catalyst... 

Zeng W and Shirota Y (1989) Studies on alternating radical copolymerization analysis of microstructures of styrene-maleic anhydride, styrene-acrylonitrile, and styrene-methyl methacrylate copolymers by fluorescence spectroscopy. Macromolecules 22 4204-8. 

The tendency to alternation increases as the r V2 product nears zero, as long as both r and T2 are less than unity. Such copolymerizalions occur in free-radical systems when the two monomers have opposite polarities (Section 7.10.2). The styrene maleic anhydride copolymers mentioned in Chapter I are an example of a purely alternating system (ri = V2= 0), while styrene (Mi)-acrylonitrile (M2) copolymers have a pronounced tendency to alternate monomer residues (ri = 0.4, Y2 = 0). 

Osmometry has been applied to a variety of copolymer systems such as vinyl-chloride-vinyl acetate (67, 68), acrylonitrile vinyl-ether copolymers (69) styrene-acrylonitrile (70), styrene-maleic anhydride (71) and for a series of styrene copolymers (72). 

PP, polypropylene PS, polystyrene HDPE, high-density poylethylene EVA, ethylene vinyl acetate ABS, acrylonitrile-butadiene-styrene SMA, styrene maleic anhydride LDPE, low-density polyethylene LLDPE, linear low-density polyethylene. (From Ref. f)... 

A group of new, fully miscible, polymer blends consisting of various styrene-maleic anhydride terpolymers blended with styrene-acrylonitrile copolymer and rubber-modified versions of these materials have been prepared and investigated. In particular the effects of chemical composition of the components on heat resistance and the miscibility behavior of the blends have been elucidated. Toughness and response to elevated temperature air aging are also examined. Appropriate combinations of the components may be melt blended to provide an enhanced balance of heat resistance, chemical resistance, and toughness. 

Blends of copolymers of styrene and acrylonitrile and butadiene and acrylonitrile called ABS plastics which are more ductile than polystyrene, are now used at an annual rate of almost 500 thousand tons. Terpoljrmers of styrene, acrylonitrile and maleic anhydride (Cadon) have heat deflection points above lOOOC.Q)While the physical properties of both ABS and the maleic anhydride terpolymers are superior to polystyrene, the improvements are not sufficient to classify them as high performance plastics. 

New macroradicals have been obtained by proper solvent selection for the homopolymerization of styrene, methyl methacrylate, ethyl acrylate, acrylonitrile, and vinyl acetate, and by the copolymerization of maleic anhydride with vinyl acetate, vinyl isobutyl ether, or methyl methacrylate. These macroradicals and those prepared by the addition to them of other monomers were stable provided they were insoluble in the solvent. Since it does not add to maleic anhydride chain ends, acrylonitrile formed a block copolymer with only half of the styrene-maleic anhydride macroradicals. However, this monomer gave excellent yields of block polymer when it was added to a macroradical obtained by the addition of limited quantities of styrene to the original macroradical. Because of poor diffusion, styrene did not add to acrylonitrile macroradicals, but block copolymers formed when an equimolar mixture of styrene and maleic anhydride was added. 

The difference between the solubility parameter of acrylonitrile and the styrene-maleic anhydride macroradical is 0.5 hildebrand unit. The formation of block copolymer was thus rapid, and the weight of these macroradicals increased by 86 percent in 24 hours in the presence of acrylonitrile (Figure 3). 

Figure 3. Rate of addition of acrylonitrile monomer to a styrene-maleic anhydride macroradical in benzene at 50°C...

Dead copolymers, as noted, were obtained when large amounts of styrene monomer were added to styrene-maleic anhydride macroradicals. However, macroradicals were obtained when the amount of styrene added equalled less than 30% of the weight of the macroradical. For example, block copolymers were obtained when styrene and maleic anhydride or acrylonitrile were added to styrene-co-maleic anhydride-b-... 

For example, the styrene-maleic anhydride copolymer is soluble in acetone, and polyacrylonitrile is insoluble in acetone but soluble in dimethylformamide. Yet, the block copolymer obtained by addition of acrylonitrile to the styrene-maleic anhydride macroradical is soluble neither in acetone nor in dimethylformamide. Pyrolysis gas-chromatography, though, shows that this acetone and dimethylformamide-insoluble product contains styrene, maleic anhydride, and acrylonitrile. The relative area of the acrylonitrile peak was related to the amount of acrylonitrile added to the original macroradical. 

Recently, products composed of styrene, acrylonitrile, and maleic anhydride have been introduced as improvements over the older ABS materials. These products exhibit superior heat resistance and thermal stability in comparison to conventional ABS materials. In addition, the impact resistance of styrene-acrylonitrile-maleic anhydride terpolymers can be improved by the addition of or by grafting onto appropriate elastomers. The product also exhibits desirable rheological behavior due to polar interaction of anhydride groups during processing and drawing. 

NBR nitrile rubber poly(butadiene-co-acrylonitrile) SMA styrene-maleic anhydride poly(styrene-co-maleic anhydride)... 

Styrene-maleic anhydride copolymer (SMA) and terpolymers with methyl methacrylate (SMA-MMA) and acrylonitrile (SMA-AN)... 

---