AB copolymer

Acrylonitrile-butadiene-styrene (ABS) copolymer Poly(vinylidene chloride)... 

Among the preformed polymers cured by minor additions of aHyl ester monomers and catalysts followed by heat or irradiation are PVC cured by diallyl fumarate (82), PVC cured by diallyl sebacate (83), fluoropolymers cured by triaHyl trimeUitate (84), and ABS copolymers cured by triaUyl trimeUitate (85). 

The homopolymers, which are formed from alkyl cyanoacrylate monomers, are inherently brittle. For applications which require a toughened adhesive, rubbers or elastomers can be added to improve toughness, without a substantial loss of adhesion. The rubbers and elastomers which have been used for toughening, include ethylene/acrylate copolymers, acrylonitrile/butadiene/styrene (ABS) copolymers, and methacrylate/butadiene/styrene (MBS) copolymers. In general, the toughening agents are incorporated into the adhesive at 5-20 wt.% of the monomer. 

Figure 12.2 Cliromatograms of an ABS copolymer sample (a) microcolumn SEC ti ace (b) capillaiy GC trace of peak x . Peak identification is as follows 1, C,4 alkanes 2, C,5 alkanes 3, C 8 alkanes 4, nonylphenol 5, palmitic acid 6, styrene-acetonitrile firmer 7, stearic acid 8, styrene-acetonitrile trimer 9, Irganox 1076 10, fiinonylphenyl phosphate 11, Ethanox 330. Reprinted with permission from Ref. (12).

Triarylamines have been employed in arylene vinylene AB copolymers 38 by Horhold et al. using a Homer polycondensation route of aldehydes and ketones 36 with fois-phosphonate 37 (Scheme 1-12) 164]. Phenylamines have remarkably low redox potentials and their charge transport properties have been investigated extensively [65]. EL devices comprising triarylamines have demonstrated low driving voltages. 

In the case of copolymers the heterogeneity parameters need to be considered in the analysis. If we assume an AB-copolymer the heterogeneity parameters are given by... 

Investigations on a series of miktoarm-star AB copolymers of PS and poly(2-methyl-l,3-pentadiene), PS(P2MP)3, indicate a different morphological behaviour [113] (Fig. 37), as predicted by Milner s theory [111] (Fig. 38). The discrepancies near the boundaries between different morphologies when compared with corresponding PS/PI systems on the one hand and to theoret-... 

Furthermore, Hirschler (32) has investigated the smoke-reducing ability of a number of metal hydroxides and oxides, at incorporation levels of up to 40 phr in acrylonitrile-butadiene-styrene (ABS) copolymer. At the lowest additive level studied (10 phr), SnO gave a higher degree of smoke suppressancy (viz. 58%), than any of the other compounds, and loadings of at least 30 phr were found to be necessary to achieve comparable performance with either A1(0H) or Mg(0H). 3... 

In this section, we would like to briefly describe the micellization behavior of hybrid AB copolymers, leading to remarkable structures with new potential applications. By hybrid AB block copolymers we mean copolymers in which at least one of the constituent blocks is not a classical poly-... 

The copolymer obtained from acrylonitrile, butadiene and styrene is termed as an ABS copolymer. It is a terpolymer. Two methods are used for preparing ABS copolymers such as blending and grafting. These two process produce the copolymers which are different in nature. 

By this method, the ABS copolymers are obtained by polymerising acrylonitrile and styrene in the presence of polybutadiene latex at 50°C in the presence of initiator and transfer agent. 

ABS copolymers obtained by this method consists of a mixture of polybutadiene, polybutadiene grafted with acrylonitrile and styrene and styrene-acrylonitrilecopolymer. The graft copolymer gets cross-linked. 

ABS copolymers have high strength and softening points. They are used extensively in cars, panels, switches, shoe heels, domestic appliances, etc. In recent years, their manufacture has started in India. 

Copolymers of styrene, especially with acrylonitrile, also attained increasing importance both in the unmodified form (30) and modified with rubber as ABS copolymers. The first products of this kind were blends of nitrile rubber and SAN (31). However, these only had mediocre mechanical properties because the interfacial compatibility was insufficient. The breakthrough came when nitrile rubber was replaced by a polybutadiene rubber which was grafted in emulsion with styrene and acrylonitrile... 

Similar to the branches in copolymer stars and miktoarms, the grafted chains in brushes can be of different chemical compositions. Brown et al. [223] studied the microphase separation of grafted mixtures of homopolymer chains composed of immiscible A and B units and also [224] of diblock AB copolymers. In the former case, the brushes expand laterally and then experience lateral microphase separation. In the latter case, however, monomers segregate vertically to the surface forming a three layer structure. 

Rigid PVC is representative of hard and soft polymers. These polymers have a high modulus of elasticity and high yield strength. The curve for hard and tough polymers, such as ABS copolymers, shows moderate elongation before the yield point followed by nonre-coverable elongation. 

Azdel Fibrous glass-reinforced ABS copolymer sheet Azdel... 

Urea-formaldehyde resins ABS copolymer Rigid insulation polyurethane Cellulose acetate butyrate Polyesters (PBT, PCT, PET) PE emulsions PS... 

Compatibilizer Polymers. ABS copolymers that are functionalized may act as a compatibilizer for other polymer blends. These types are grafted in the same way as polymers dealt with above. 

Compatibilizer ABS copolymers have been prepared via an emulsion polymerization process. These copolymers have been functionalized with glycidyl methacrylate (GMA). The functionalized copolymers are blended PBT. Characterization by thermal mechanical analysis indicates that PBT is partially miscible with ABS and the glycidyl grafted ABS (48). 

Since glassy polymers tend to become plasticized by C02, it is important to determine the magnitude to which CO2 effects plasticization. This is achieved in monitoring nonlinear effects of gas permeability of mixtures containing CO2. CO2 shows a higher sorption than expected. This is attributed to the presence of acrylonitrile moieties in the ABS copolymer. 

Mixed matrix membranes have been prepared from ABS and activated carbons. The membranes are intended for gas separation. A random agglomeration of the carbon particles was observed. A close interfacial contact between the polymeric and filler phases was observed. This morphology between inorganic and organic phases is believed to arise from the partial compatibility of the styrene/butadi-ene chains of the ABS copolymer and the activated carbon structure. A good permeability and selectivity for mixtures of carbon dioxide and methane has been reported (91,92). 

In general, polymerization reactions have to be to performed with care. Based on the fact that Taiwan has the largest ABS copolymer production in the world, a group originating from there has presented a study on possible hazards that might arise in the course of the polymerization process (112,113). The prevention of unexpected exothermic reactions and related emergency relief hazard is essential in the safety control of ABS emulsion polymerization. Various scenarios were verified from abnormal conditions, including (113) ... 

J. Abenojar, R. Torregrosa-Coque, M.A. Martinez, and J.M. Martin-Martinez, Surface modifications of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) copolymer by treatment with atmospheric plasma, Surf. Coat. Technol, 203(16) 2173-2180, May 2009. 

M. Anson, J. Marchese, E. Garis, N. Ochoa, and C. Pagliero, ABS copolymer-activated carbon mixed matrix membranes for CO2/CH4 separation,. Membr. Sci., 243(l-2) 19-28, November 2004. 

M. Brebu, T. Bhaskar, K. Murai, A. Muto, Y. Sakata, and M.A. Uddin, The individual and cumulative effect of brominated flame retardant and polyvinylchloride (pvc) on thermal degradation of acrylonitrile-butadiene-styrene (ABS) copolymer, Chemosphere, 56(5) 433 440, August 2004. 

---