Polymers amide group containing

New heat-resistant polymers containing -iiitrophenyl-substituted quinoxaline units and imide rings as well as flexible amide groups have been synthesi2ed by polycondensation reaction of a dianainoquinoxaline derivative with diacid dichlorides (80). These polymers are easily soluble in polar aprotic solvents with inherent viscosities in the range of 0.3—0.9 dL/g in NMP at 20°C. AH polymers begin to decompose above 370°C. 

In addition to the commercial aromatic polyamides described above many others have been prepared but these have not achieved commercial viability. There are, however, a number of other commercial polymers that contain amide groups such as the polyamide-imides. The latter materials are discussed in Section 18.14. 

STRATEGY (a) Look at the backbone of the polymer, the long chain to which the other groups are attached. If the atoms are all carbon atoms, then the compound is an addition polymer. If ester groups are present in the backbone, then the polymer is a polyester and the monomers will be an acid and an alcohol. If the backbone contains amide groups, then the polymer is a polyamide and the monomers will be an acid and an amine, (b) If the monomer is an alkene or alkvne, then the monomers will add to one another a Tr-bond will be replaced by new cr-bonds between the monomers. If the monomers are an add and an alcohol or amine, then a condensation polymer forms with the loss of a molecule of water. 

Nylons are classified into two categories AB and AABB polymers. Molecules of the AB type consist of repeat units that contain a single amide group, such as nylon 6, which is illustrated in Fig. 23.2 a). Molecules of the AABB type consist of repeat units that contain two amide groups, such as nylon 66 (pronounced nylon six six ), which is illustrated in Fig. 23.2 b). Type AB nylons are made from a single monomer, such as caprolactam, which is shown in Fig. 23,3 a). We make type AABB nylons from diamines and diacids, such as adipic acid and hexamethylene diamine, which are shown in Fig. 23.3 b) and c), respectively. 

Nylon molecules contain short, non-polar, polymethylene sequences and polar amide groups. The ratio of the polar to non-polar components strongly influences the properties of the polymer. We can envisage a vast number of polymers that fall into the class of nylons, but... 

Hydrolysis of amide groups to carboxylate is a major cause of instability in acrylamide-based polymers, especially at alkaline pH and high temperatures. The performance of oil-recovery polymers may be adversely affected by excessive hydrolysis, which can promote precipitation from sea water solution. This work has studied the effects of the sodium salts of acrylic acid and AMPS, 2-acrylamido-2-methylpropanesulfonic acid, as comonomers, on the rate of hydrolysis of polyacrylamides in alkaline solution at high temperatures. Copolymers were prepared containing from 0-53 mole % of the anionic comonomers, and hydrolyzed in aqueous solution at pH 8.5 at 90°C, 108°C and 120°C. The extent of hydrolysis was measured by a conductometric method, analyzing for the total carboxylate content. 

Polymide polymers contain amide group NH CO in the main chain. The most important are linear aliphatic Polyamides. These are known as nylons. Polyamides are also used as adhesives, coatings and in engineering applications. 

It should not be taken for granted that all polymers that are defined as condensation polymers by Carothers classification will also be so defined by a consideration of the polymer chain structure. Some condensation polymers do not contain functional groups such as ester or amide in the polymer chain. An example is the phenol-formaldehyde polymers produced by the reaction of phenol (or substituted phenols) with formaldehyde... 

POLYAMIDE RESINS. These are synthetic polymers that contain an amide group, —CONH-. as a recurring part of the chain. Poly-alpha-aminoacids, i.e., proteins, whether natural or synthetic, are not normally included in this classification. 

Polymer IX illustrates that it is possible to include a limited proportion, for example 20 moles %, of amide linking groups into this type of copolymer without destroying the thermotropic property. In this case the melting point of the copolymer containing 60 moles % of 2,6-oxynaphthoyl units and 20 moles % each of p-oxybenzoyl and p-iminobenzoyl units is only 277 °C 43>, similar to that just noted for the copolymer with ester instead of amide groups. 

Amides are compounds with the C -N functional group. Without amides, there would be no life. As we ll see in the next chapter, the amide bond between nitrogen and a carbonyl-group carbon is the fundamental link used by organisms for forming proteins. In addition, some synthetic polymers such as nylon contain amide groups, and important pharmaceutical agents such as acetaminophen, the aspirin substitute found in Tylenol and Excedrin, are amides. 

Ring-opened polyethyloxazoline Polymer-containing amide groups... 

A first approach was to consider amorphous polymers with quite different chemical structures, either containing side groups responsible for the /> transition (PMMA and its copolymers), or only a chain backbone without side chains (BPA-PC, aryl-aliphatic copolyamides) in which the ft transition results from motions of some of the main-chain units (typically phenyl ring, carbonate, or amide groups). 

Materials and Film Preparation. The molecular structure of the polymerized lipid referred to as CO-1.5 is shown in Figure 1. The material is a co-polymer of a double 18-carbon alkyl chain lipid with a side-group spacer and five main-chain spacer groups. The purpose of the spacer chains is to allow more free volume for the lipid chains to orientationally order normal to the polymer backbone. The lipid chain contains an amide, and the main-chain spacer groups contain tertiary amines. The polymer was synthesized following the general procedures given by Laschewsky et al. (10). 

Polyamides are polymers that contain the amide group and are produced, by, for example, polymerization reaction of adipic acid and hexamethyl-enediamine (HMDA). Nylon 6,6 (so-called because each of the raw material chains contains six carbon atoms) was the first all-synthetic fiber made commercially. 

Besides the above examples, the influence of dipole-dipole interactions between polar side chains (containing a heteroatom in the y position) and backbone amide groups has been shown for polymers such as poly-L-serine (Birshtein and Ptitsyn, 1967). In such eases, the jS-strueture is energetically more favored than the a-helix. 

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