Monomer containing carboxylic acid groups

A terpolymer rubber was introduced by Du Pont in 1975 (Vamac). This is based on ethylene, methyl acrylate and a third, undisclosed, monomer containing carboxylic acid groups to act as the cure site (see Section 11.9). 

More recently, in 1975, Du Pont introduced a terpolymer (Vamac) based on ethylene, methyl acrylate and a third monomer of undisclosed composition which contained a carboxylic acid group to provide a cure site for use with peroxides or amines. Both types of rubber exhibit good heat, oxygen and ozone resistance. 

Ionomer-type elastomers, containing small amounts (less than 5%) of metal carboxylate or sulfonate groups, have potential as a new class of thermoplastic elastomers. Carboxylic acid groups are introduced into polymers such as polybutadiene by copolymerization with a monomer such as acrylic or methacrylic acid. 

Of particular importance in describing the difference between these two families of resins are the locations of die reactive unsaturation. In the polyester resin, these groups are located along the backbone of die polymer with terminal hydroxyl or carboxylic acid groups. The vinyl ester resins contain no significant acidity but terminate in reactive vinyl ester groups. Because of the location of these reactive sites, the vinyl ester resins will homopolymerize as well as coreact with various vinyl monomers. 

Besides addition polymerization, the other general way to prepare polymers is known as condensation polymerization or step growth polymerization. Much of the pioneering work on condensation polymerization was conducted by Wallace Carothers while he was employed by DuPont. He recognized that many natural polymers are formed from monomers with two reactive functional groups. For example, proteins are polymers of amino acids, which contain both amine and carboxylic acid groups. The formation of amide bonds is used to connect one monomer to another. Carothers s attempts to imitate nature led to a whole industry based on condensation polymerization. 

Nafion-perfluorinated membranes are manufactured from copolymers of tetrafluoroethylene and perfluorinated monomers and contain sulfonic groups on one side and carboxylic acid groups on the other. The membranes, originally designed for use in... 

Consider synthesis of nylon-6,10 from stoichiometric amounts of hexamethy-lene diamine, H2N(CH2)eNH2, and sebacic acid, HOO(CH2)8COOH. At 98% conversion of carboxylic acid groups, determine (a) and of the product, and (b) the sum of the mole fractions and that of the weight fractions of species containing 1 through 6 (inclusive) monomer units. 

Amino acid The monomer that forms the protein polymers. They contain an amine functional group and a carboxylic acid group separated by a carbon. 

Because of polymerization problems with the ketone monomers (II and III) and with monomers containing free carboxylic acid groups (IX), simple derivatives such as (X to XII) were synthesized instead. 

Tphe phenomenon of ion clustering in polymers containing ionic co-monomers has received considerable attention recently, primarily in materials based on styrene, ethylene, or butadiene backbones containing a small concentration of pendant carboxylic acid groups randomly distributed along the chain. These materials have been reviewed in two... 

Appropriate telechelic polymers produced from a variety of monomers may be incorporated as reactive components in a variety of applications such as sealants, elastomers, foams, and fibers. Such telechelic polymers may impart almost any desired characteristic such as hydrophilic properties, elastomeric properties, dyeability, and solvent resistance. A dihydroxy telechelic polymer may be reacted with a telechelic polymer containing two carboxylic acid groups to produce a condensed polyester. Accordingly, from these telechelic entities one may produce block copolymers that will have alternating addition polymer residues of like or unlike repeat units. In addition, block copolymers can be produced by modifications of this procedure in which addition polymers are alternated with condensation polymer units. 

Nylon is the common name of a synthetic polyamide. Nylon 6 is an example of a step-growth polymer formed by a monomer with two different functional groups. The carboxylic acid group of one monomer reacts with the amino group of another monomer, resulting in the formation of amide groups. Stmcturally, the reaction is similar to the polymerization of a-amino acids to form proteins (Section 23.7). This particular nylon is called nylon 6 because it is formed from the polymerization of 6-aminohexanoic acid, a compound that contains six carbons. 

Step-growth Polymerization The simplest scheme of this polymerization involves the reaction of a difunctional monomer AB, which contains both functional groups A and B in the molecule. For example, A can be an amine and B a carboxylic acid group. Another scheme involves the reaction between two difunctional monomers of the type AA and BB. In any case, each polymer linkage will have involved the reaction of the functional groups A and B coming from two molecules (monomers or chains). Some examples of polymers synthesized by this mechanism are polyurethane, polyamide, and polyester. 

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