Batch styrene-acrylonitrile

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. 

Figure 2. Styrene-acrylonitrile copolymerization in batch conversion curve for varying sodium laury sulfate contents (( )2g ( + )6g (X)8g))...

Table II - Styrene-Acrylonitrile copolymerization in batch - Effect of monomer initial concentration...

Styrene-acrylonitrile copolymerization in a semi-batch reactor Two cases (a) maximization of monomer conversion and minimization of polydispersity index at the end of reaction, and (b) maximization of monomer conversion at the end of reaction while minimizing polydispersity index at the end of reaction and molar ratio of unreacted monomer in the reactor at any time. NSGA-11 The decision variables for optimization were trajectories of addition rate of a monomer-solvent-initiator mixture and reactor temperature. Nayak and Gupta (2004)... 

ABS resins are produced primarily by grafting styrene and acrylonitrile onto polybutadiene latex in a batch or continuous polymerization process. They may also be made by blending emulsion latexes of styrene-acrylonitrile (SAN) and nitrile rubber (NBR). 

Suspension with large drops 10-1000 pm of insoluble monomer and catalyst suspended in water. free radical addition, styre-nic IX resins, vinyl polymers, PVC, styrene-acrylonitrile, polypropylene batch STR (1-6 kW/m mixei tip speed 6-9 m/s 3-retreated blades at 46-120 rpm heat transfer area = 1-4 tn /m depending on the volume of the reactor with small area associated with large volumes) continuous PVC... 

In the case of styrene-acrylonitrile copolymers, the method of choice for batch suspension polymerization is normally that involving the azeotropic monomer/comonomer composition to minimize copolymer compositional drift. Nevertheless, complications often arise because considerably more acrylonitrile than styrene dissolves in the continuous aqueous phase. As conversion proceeds, acrylonitrile diffuses into the polymer particles and the monomer ratio in the bead changes, causing the composition of the copolymer to change as well [4]. 

Residual amounts of styrene and acrylonitrile monomers usually remain in manufactured batches of styrene-acrylonitrile copolymers. As these copolymers have a potential use in the food packaging field, it is necessary to ensure that the content of both of these monomers in the finished copolymer is below a stipulated level. 

Residual amounts of styrene and acrylonitrile monomers usually remain in manufactured batches of styrene-acrylonitrile copolymers and acrylonitrile-butadiene-styrene terpolymers (ABS), As these copolymers have a potential use in the food packaging field, it is necessary to ensure that the content of both of these monomers in the finished copolymers is below a stipulated level. In a polarographic procedure [9, 10] for determining acrylonitrile (down to 2 ppm) and styrene (down to 20 ppm) monomers in styrene-acrylonitrile copolymer, the sample is dissolved in 0.2 M tetramethylammonium iodide in dimethyl formamide base electrolyte and polarographed at start potentials of -1.7 V and -2.0 V, respectively, for the two monomers. Excellent results are obtained by this procedure. Table 5.3 shows the results obtained for determinations of acrylonitrile monomer in some copolymers by the polarographic procedure. 

The emulsion polymerization process (batch or continuous) is widely used for producing ABS because various grades of ABS resins can be manufactured. In a continuous process, two to six reactors are used in series with rubber latex feed added either to the first reactor or the first two reactors. In a typical ABS emulsion process, the styrene/acrylonitrile copolymer (SAN) and polybutadiene (PBL) are separately prepared by emulsion pro-... 

The mbber latex is usually produced in batch reactors. The mbber can be polybutadiene [9003-17-2] or a copolymer of 1,3-butadiene [106-99-0] and either acrylonitrile [107-13-1] or styrene [100-42-5]. The latex normally has a polymer content of approximately 30 to 50% most of the remainder is water. 

After the mbber latex is produced, it is subjected to further polymerization in the presence of styrene (CgHg) and acrylonitrile (C H N) monomers to produce the ABS latex. This can be done in batch, semibatch, or continuous reactors. The other ingredients required for this polymerization are similar to those required for the mbber latex reaction. 

Example 13.6 The following data were obtained using low-conversion batch experiments on the bulk (solvent-free), free-radical copol)mierization of styrene (X) and acrylonitrile (Y). Determine the copolymer reactivity ratios for this pol5Tnerization. 

FIGURE 13.6 Copolymer composition distribution resulting from the batch polymerization of styrene and acrylonitrile. 

This comprehensive article supplies details of a new catalytic process for the degradation of municipal waste plastics in a glass reactor. The degradation of plastics was carried out at atmospheric pressure and 410 degrees C in batch and continuous feed operation. The waste plastics and simulated mixed plastics are composed of polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile butadiene styrene, and polyethylene terephthalate. In the study, the degradation rate and yield of fuel oil recovery promoted by the use of silica alumina catalysts are compared with the non-catalytic thermal degradation. 9 refs. lAPAN... 

In this work, a comprehensive kinetic model, suitable for simulation of inilticomponent aiulsion polymerization reactors, is presented A well-mixed, isothermal, batch reactor is considered with illustrative purposes. Typical model outputs are PSD, monomer conversion, multivariate distritution of the i lymer particles in terms of numtoer and type of contained active Chains, and pwlymer ccmposition. Model predictions are compared with experimental data for the ternary system acrylonitrile-styrene-methyl methacrylate. 

Applications As the basic process of electron transfer at an electrode is a fundamental electrochemical principle, polarography can widely be applied. Polarography can be used to determine electroreductible substances such as monomers, organic peroxides, accelerators and antioxidants in solvent extracts of polymers. Residual amounts of monomers remain in manufactured batches of (co)polymers. For food-packaging applications, it is necessary to ensure that the content of such monomers is below regulated level. Polarography has been used for a variety of monomers (styrene, a-methylstyrene, acrylic acid, acrylamide, acrylonitrile, methylmethacrylate) in... 

Compositionally uniform copolymers of tributyltin methacrylate (TBTM) and methyl methacrylate (MMA) are produced in a free running batch process by virtue of the monomer reactivity ratios for this combination of monomers (r (TBTM) = 0.96, r (MMA) = 1.0 at 80°C). Compositional ly homogeneous terpolymers were synthesised by keeping constant the instantaneous ratio of the three monomers in the reactor through the addition of the more reactive monomer (or monomers) at an appropriate rate. This procedure has been used by Guyot et al 6 in the preparation of butadiene-acrylonitrile emulsion copolymers and by Johnson et al (7) in the solution copolymerisation of styrene with methyl acrylate. 

Table 1 - Acrylonitrile(AN)-Styrene(S) copolymerization with the "corrected batch process" - Effect of stirring rate...

Example 13.7 A 50/50 (molar) mixture of styrene and acrylonitrile is batch polymerized by free-radical kinetics until 80% molar conversion of the monomers is achieved. Determine the copolymer composition distribution. 

Compositional control in suspension systems can be achieved with a corrected batch process. A suspension process has been described where styrene monomer is continuously added until 75 —85% conversion, and then the excess acrylonitrile monomer is removed by stripping with an inert gas... 

Suspension polymerization is frequently employed as the second stage following a preliminary bulk polymerization, such as in the manufacture of some HIPS and ABS polymers. Polybutadiene or another elastomer is dissolved in liquid styrene, and this monomer or a mixture of styrene and acrylonitrile is polymerized in a batch kettle. The syrup produeed at 30-35% conversion is too viscous for effective mixing and heat transfer. It is therefore dispersed in water, and the polymerization is finished as a suspension reaction. 

Styrene is frequently used as part of some terpolymers with large practical utilization. One such copolymer is acrylonitrile-butadiene-styrene terpolymer (ABS). Usually it is made as poly(l-butenylene-graft-l-phenylethylene-co-cyanoethylene). This form of the copolymer can be made by grafting styrene and acrylonitrile directly on to the polybutadiene latex in a batch or continuous emulsion polymerization process. Grafting is achieved by the free-radical copolymerization of styrene and acrylonitrile monomers in the presence of polybutadiene. The degree of grafting is a function of the 1,2-vinyl content of the polybutadiene, monomer concentration, extent of conversion, temperature and mercaptan concentration (used for crosslinking). The emulsion polymerization process involves two steps production of a rubber latex and subsequent polymerization of styrene and acrylonitrile in the presence of the rubber latex to produce an ABS latex. 

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