Polymers condensation polymers

Synthetic resins form the heart of the paint industry. The tw o main types of synthetic resins are condensation polymers and addition polymers. Condensation polymers, formed by condensation of like or unlike molecules into a new, more complex compound, include polyesters, phenolics.. iniino resins, polyurethane, and epoxies. Addition polymers include polyvinyl acetate, polyvinyl chloride, and the acrylates,... 

Another classification system, first suggested by Carothers in 1929, is based on the nature of the chemical reactions employed in the polymerisation. Here the two major groups are the condensation and the addition polymers. Condensation polymers are those prepared from monomers where reaction is accompanied by the loss of a small molecule, usually of water, for example polyesters which are formed by the condensation shown in Reaction 1.1. 

In 1929 Carothers proposed a generally useful differentiation between two broad classes of polymers condensation polymers in which the molecular formula of the structural unit (or units) lacks certain atoms present in the monomer from which it is formed, or to which it may be degraded by chemical means, and addition polymers, in which the molecular formula of the structural unit (or units) is identical with that of the monomer from which the polymer is derived. Condensation polymers may be formed from monomers bearing two or more reactive groups of such a character that they may condense intermolecu-larly with the elimination of a by-product, often water. The polyamides and polyesters referred to above afford prime examples of condensation polymers. The formation of a polyester from a suitable hydroxy acid takes place as follows ... 

Condensation polymers, which are also known as step growth polymers, are historically the oldest class of common synthetic polymers. Although superseded in terms of gross output by addition polymers, condensation polymers are still commonly used in a wide variety of applications examples include polyamides (nylons), polycarbonates, polyurethanes, and epoxy adhesives. Figure 1.9 outlines the basic reaction scheme for condensation polymerization. One or more different monomers can be incorporated into a condensation polymer. 

Examples of Step-Growth Polymers—Condensation Polymers (30.6)... 

Polyesters are an example of this latter type of polymer. They are also known as condensation polymers. Condensation polymers are formed by the pol)uner-ization of monomers in a reaction that forms a small molecule such as water or an alcohol. Polyesters are synthesized by reacting a dicarboxylic acid and a dialcohol (diol). Notice that each of the combining molecules has two reactive fimctional groups. 

The first step in a step reaction mechanism is the formation of esters or amides from the diols and diacids or diacids and diamines, respectively. From these intermediates, the polymerization reaction (second step) proceeds. Because the first step is a faster reaction than the second, the monomer is used up quickly. During the two steps of the reaction, small molecules such as H2O or CH3OH are eliminated. Water is the most frequent byproduct molecule, for example from the reaction between a diacid and a dialcohol. Unlike addition polymers, condensation polymers, because they incorporate functional groups, generally have noncarbon atoms (heteroatoms) as part of the main backbone chain. Examples are shown in Fig. 3.30. 

For the purpose of this discussion, we will classify polymers into three broad groups addition polymers, condensation polymers, and special polymers. By convention, polymers whose main chains consist entirely of C-C bond are addition polymers, whereas those in which hetero atoms (e.g., O, N, S, Si) are present in the polymer backbone are considered to be condensation polymers. Grouped as special polymers are those products which have special properties, such as temperature and fire resistance, photosensitivity, electrical conductivity, and piezoelectric properties, or which possess specific reactivities to serve as functional polymers. 

Polymers Addition Polymers Condensation Polymers Copolymers Physical Properties Polymers and Additives... 

The Monomer-Polymer Theme I Synthetic Macromolecules Addition Polymers Condensation Polymers... 

Carothers in 1929 made the classical subdivision of polymers into two main groups, condensation and addition polymers. Condensation polymers, are characteristically formed by reactions involving the elimination of a small molecule, such as water, in each step. Polyester formation is a good example of this type of polymerisation. Bifunctional monomers react with each other with the elimination of water as shown in Reaction 6.1. 

Monomer, polymer, addition polymer, condensation polymer... 

---