Polystyrene swelling

Actually, it is known8 that polystyrene swells a little more in benzene than in toluene, and this fact agrees with our interpretation. 

For example, hypercrosslinked polystyrene swells significantly in non-solvents for the equivalent linear polymer (e.g. water, methanol [21]) and, conceivably, can... 

Copolymers of Styrene and Divinj benzene, Rubber Chem. Tech. 40, 476 (1967). Homo-IPNs of polystyrene and polystyrene. Swelling and mechanical behavior. 

Since polymer swelling is poor and the aqueous solubiUty of acrylonitrile is relatively high, the tendency for radical capture is limited. Consequentiy, the rate of particle nucleation is high throughout the course of the polymerization, and particle growth occurs predominantiy by a process of agglomeration of primary particles. Unlike emulsion particles of a readily swollen polymer, such as polystyrene, the acrylonitrile aqueous dispersion polymer particles are massive agglomerates of primary particles which are approximately 100 nm in diameter. 

Lightly crosslinked resins are less robust but have greater ability to swell in appropriate solvents. Typically a 1-2% crosslinked divinyl benzene polystyrene resin is employed in organic synthesis. 

In addition to monomers and the initiator, an inert liquid (diluent) must be added to the monomer phase to influence the pore structure and swelling behavior of the beaded resin. The monomer diluent is usually a hydrophobic liquid such as toluene, heptane, or pentanol. It is noteworthy that the namre and the percentage of the monomer diluent also influence the rate of polymerization. This may be mainly a concentration or precipitation effect, depending on whether the diluent is a solvent or precipitant for the polymer. For example, when the diluent is a good solvent such as toluene to polystyrene, the polymerizations proceed at a correspondingly slow rate, whereas with a nonsolvent such as pentanol to polystyrene the opposite is true. 

A macroporous polystyrene-divinylbenzene copolymer, produced by copolymerizing a mixture of styrene and divinylbenzene, is dissolved in an organic liquid such as t-amyl alcohol or isooctane, which is a solvent for monomers. This solvent is unable to substantially swell the resulting copolymer. Macroporous cation-exchange beads are also produced from these macroporous copolymers (25,26). 

Monosized macroporous polystyrene-divinylbenzene particles have been prepared in a multistep swelling process, in which particles of different sizes... 

Step II Swelling of polystyrene seed particles with CDD... 

A typical scanning electron micrograph of the uniform macroporous polystyrene-divinylbenzene particles is given in Fig. 20. First studies on the synthesis of macroporous uniform particles were started by Ugelstad et al. [109]. They used a two-step activated swelling method to obtain macroporous uniform particles in the... 

Expanded polystyrene. The plastic is formed into beads containing an expanding agent. When placed in a mould and heated they swell and stick together. The blocks are then cut into thicknesses as required. 

If the swelling effects in the polymeric phase are considered, the evaluation of the adsorbed macromolecules as a monolayer seems to be too approximate. The mean-square end-to-end distance of the polystyrene coil (M = 10000) in... 

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