Styrene acrylonitrile copolymer, characteristics

The valuable characteristics of polyblends, two-phase mixtures of polymers in different states of aggregation, were also discussed in the previous chapter. This technique has been widely used to improve the toughness of rigid amorphous polymers such as PVC, polystyrene, and styrene-acrylonitrile copolymers. 

A first indication of the composition of the present sample was obtained from the contour plot in Fig. 32. Component 3 shows typical absorption peaks of a phenyl benzotriazole and can be identified as a UV stabilizer of the Tinuvin type. Component 2 exhibits absorption peaks which are characteristic for nitrile groups (2237 cm x) and styrene units (760,699 cm-1), while component 1 shows a strong ester carbonyl peak around 1740 cm"1 and peaks of styrene units. In agreement with the peak pattern of literature spectra, component 2 can be identified as a styrene-acrylonitrile copolymer. Component 1 is either a mixture of... 

Kim, J.W. Jang, L.W. Choi, H.J. Jhon, M.S. Physical and electroresponsive characteristics of the intercalated styrene-acrylonitrile copolymer/ clay nanocomposite under applied electric fields. J. Appl. Polym. Sci. 2003, 89, 821-827. 

Chemistry Polyurethane is produced by the reaction of a polyol with an diisocyanate (or in some instances a polyisocyanate) in the presence of catalysts. The polyols of choice are poly(propylene glycol), block copolymers of ethylene oxide (10-15%) with propylene oxide, or the newer polymer polyols (based on polymers such as polystyrene or styrene-acrylonitrile copolymer). Polyester diols such as polycaprolactone diol can be used in place of the polyether polyol in this reaction. The isocyanate of choice is a mixture of the 2,4 and 2,6 isomers of tolylene di-isocyanate in the ratio of 80 20, generally referred to as 80 20TDI. Other isocyanates such as diphenylmethane di-isocyanate (MDI), hexamethylene di-isocyanate (HMDI), and isophorone di-isocyanate (IPDI) are also used. A tin-based or amine catalyst is used to promote the reaction. Given the wide choice of reactants available, the reaction can yield foams with a range of different mechanical and thermal characteristics. 

ABS comprises the dispersed phase of styrene/acrylonitrile copolymer grafted on polybutadiene rubber and the continuous phase of styrene/acry-lonitrile copolymer. The use of SAN grafted on polybutadiene rubber provides high impact strength, processability, chemical resistance, staining property, etc., as the characteristics peculiar to ABS resins. 

Such improvement cannot, however, be taken for granted. No improvement in fire retardancy characteristics was observed when a wide range of filler/reinforcing agents were incorporated into non-fire retardant polycarbonate, polybutylene terephthalate, polyethylene terephthalate, polyamide 6,6, or styrene acrylonitrile copolymer. 

This work studied the mechanical characteristics of amorphous plastic styrene acrylonitrile copolymer (SAN). Nanodiamond powder particles (2.5, 5, and 10%) were added to copolymer granules and mixed in a microextruder-type mixer (auger diameter, 9 mm 2rpm, 200°C, mixing time 5 min). Samples of the mixture as extrudates were tested at room temperature on an Instron testing machine. 

The principal use of acrylonitrile since the early 1950s has been in the manufacture of so-called acrylic textile fibers. Acrylonitrile is first polymerized to polyacrylonitrile, which is then spun into fiber. The main feature of acrylic fibers is their wool-like characteristic, making them desirable for socks, sweaters, and other types of apparel. However, as with all synthetic textile fibers, fashion dictates the market and acrylic fibers currently seem to be in disfavor, so this outlet for acrylonitrile may be stagnant or declining. The other big uses for acrylonitrile are in copolymers, mainly with styrene. Such copolymers are very useful for the molding of plastic articles with very high impact resistance. 

We will describe its use for controlling the styrene-acrylonitrile emulsion copolymerization system. Results concerning copolymer compositions, molecular characteristics and particle sizes will be compared to the corresponding ones from batch or semi-continuous processes. 

Table 3.3 Morphological characteristics of macroporous styrene (S)-DVB, styrene-acrylonitrile (AN)-DVB, and acrylonitrile-DVB copolymers... 

Acrylonitrile-butadiene-styrene (ABS) copolymers are produced by three monomers acrylonitrile, butadiene, and styrene. The desired physical and chemical properties of ABS polymers with a wide range of functional characteristics can be controlled by changing the ratio of these monomers. They are resistant... 

In this paper we will discuss evidence for the existence of CTC s of styrene and acrylonitrile and the resultant differences in the copolymer produced from them. We will also report the preparation of copolymers with block copolymer characteristics from poly(styrene-co-acrylonitrile) macroradicals prepared in tert-butyl alcohol. This solvent is a poor solvent for the macroradical and exhibits a very low chain transfer constant (28). The copolymers reported in this paper were prepared in the absence and presence of zinc chloride (ZnCU), and the effect of ZnClz on the reactivity of the macroradical will be discussed. 

ABS copolymer is a popular engineering thermoplastic because of its unique properties, which include an excellent mechanical response, chemical resistance, fine surface appearance, and easy processing characteristics. Its unique properties. It consists of a styrene-acrylonitrile (SAN) continuous phase partially grafted onto a dispersed polybutadiene phase of an elastomeric nature. ABS resin is its inherent flammability and lower thermal stability when it is exposed to heat, mechanical stress, and ionizing or ultraviolet radiation in the presence of oxygen because of the formation of reactive intermediates such as free radicals and hydroperoxides. 

The characteristic properties of ABS resins are strongly affected by molecular characteristics of the styrene/acrylonitrile (SAN) copolymer forming the elastomeric phase and the matrix. 

Styrene-acrylic copolymers were analyzed via NIR for styrene content using the 2100 nm aromatic C—H combination band [65]. Spectral characteristics of these blends are so distinct that no special sample preparation technique is required. NIR has also been applied for the compositional analysis of styrene-acrylonitrile (SAN), styrene-MMA, styrene/butadiene [15], AS in polyvinylchloride [66], and styrene-acrylic copolymers. 

When the polymer was prepared by the suspension polymerization technique, the product was crosslinked beads of unusually uniform size (see Fig. 16 for SEM picture of the beads) with hydrophobic surface characteristics. This shows that cardanyl acrylate/methacry-late can be used as comonomers-cum-cross-linking agents in vinyl polymerizations. This further gives rise to more opportunities to prepare polymer supports for synthesis particularly for experiments in solid-state peptide synthesis. Polymer supports based on activated acrylates have recently been reported to be useful in supported organic reactions, metal ion separation, etc. [198,199]. Copolymers are expected to give better performance and, hence, coplymers of CA and CM A with methyl methacrylate (MMA), styrene (St), and acrylonitrile (AN) were prepared and characterized [196,197]. 

Table 6.7 Experimental values of composition and microstructure parameters of copolymer of styrene with acrylonitrile prepared in bulk at T = 60 °C. Composition was determined by two techniques NMR-spectroscopy and elementary nitrogen analysis [215, 282]. Characteristic coefficients were calculated via Eqs. (6.15), (6,2) according to the experimental data adduced in Refs. [215, 282]... 

MABS polymers (methyl methacrylate-acrylonitrile-butadiene-styrene) together with blends composed of polyphenylene ether and impact-resistant polystyrene (PPE/PS-I) also form part of the styrenic copolymer product range. Figure 2.1 provides an overview of the different classes of products and trade names. A characteristic property is their amorphous nature, i.e. high dimensional stability and largely constant mechanical properties to just below the glass transition temperature, Tg. 

As occurs in natural rubber, only the 1,4-cis isomer exhibits elastomeric characteristics. The most important synthetic diene rubbers are polychlor-oprene (neoprene) and rubbers derived from butadiene such as styrene-butadiene and acrylonitrile-butadiene copolymers. 

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