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Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator. The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate.
Superabsorbent polymers are now commonly made from the polymerization of acrylic acid blended with sodium hydroxide in the presence of an initiator to form a poly-acrylic acid sodium salt (sometimes referred to as sodium polyacrylate). This polymer is the most common type of SAP made in the world today.
During solution polymerization, monomers are dissolved in a solvent that contains a catalyst to induce polymerization. [5] Solution polymerization in water utilizes water as the solvent which means that the end product formed from the reaction is soluble in water. Inverse emulsion polymerization requires water, monomers, and a surfactant.
Step-growth polymers increase in molecular weight at a very slow rate at lower conversions and reach moderately high molecular weights only at very high conversion (i.e., >95%). Solid state polymerization to afford polyamides (e.g., nylons) is an example of step-growth polymerization. [8]
The polymerization is obtained with a broad molecular weight distribution due to the high viscosity and lack of good heat transfer. very high molecular weights are obtained. Gel effect. For reducing the disadvantages of bulk polymerization, the process can be carried out in a solution. This is known as solution polymerization. [2]
The simplest case refers to the formation of a strictly linear polymer by the reaction (usually by condensation) of two monomers in equimolar quantities. An example is the synthesis of nylon-6,6 whose formula is [−NH−(CH 2) 6 −NH−CO−(CH 2) 4 −CO−] n from one mole of hexamethylenediamine, H 2 N(CH 2) 6 NH 2, and one mole of adipic acid, HOOC−(CH 2) 4 −COOH.
Flory–Huggins solution theory is a lattice model of the thermodynamics of polymer solutions which takes account of the great dissimilarity in molecular sizes in adapting the usual expression for the entropy of mixing. The result is an equation for the Gibbs free energy change for mixing a polymer with a solvent. Although it makes simplifying ...
Suspension polymerization is divided into two main types, depending on the morphology of the particles that result. In bead polymerization, the polymer is soluble in its monomer and the result is a smooth, translucent bead. In powder polymerization, the polymer is not soluble in its monomer and the resultant bead will be porous and irregular. [5]