Linear polymers chemical names

In 1967, the Polymer Nomenclature Committee of the American Chemical Society pubHshed proposals for naming linear polymers on the basis of their chemical stmcture (97), which were then introduced into Chemical Abstracts (CA) Indexes and pubHshed in their final form in 1968 (98). 

In the usual chemical formulas written for chain polymers the sue-cessive units are projected as a co-linear sequence on the surface of the sheet of paper. This form of representation fails to convey what is perhaps the most significant structural characteristic of a long polymer chain, namely, its capacity to assume an enormous array of configurations. This configurational versatility is a consequence of the considerable degree of rotational freedom about single bonds of the chain. In the simple polymethylene chain, for example, the conventional formula... 

Table 1.2 Repeating monomer unit, chemical name, abbreviated name and density of some linear polymers...

The fatigue effects are also influenced by the certain structural polymer characteristics, namely the chemical structure of the macromolecular chain, in the case of linearly polyurethane or of the... 

Natural rubber (NR), the most fascinating material known to mankind, is extracted from the latex of Hevea braziliensis. NR is a linear, long-chain polymer chemically known as cis-l,4pdyi P i - Like other high polymers, it is made up of molecules of different sizes with molecular weight ranging from 30000 to about 10 miUion. Polyisoprene exists naturally in the form of two stereoisomers, namely cix-1,4-polyisoprene and tranx-l,4-polyisoprene (Figure 8.1). 

Wang et al. [135] prepared a novel ABB monomer (1-14, Scheme 8), namely 4-[4-(2,4-diaminophenoxy)phenoxy] phfhalic acid 2-methyl ester, which was polymerized to form the precursor polyamic acid monomethyl ester. The direct polycondensation of the ABB monomer was carried out to form polyamic acid monomethyl ester as a precursor and had a M of 12,000 Da. Chemical imidization in the presence of acetic anhydride and pyridine gave hb-PIs with low DB. The DB of the precursor, as determined by the H NMR spectra, was only 7%. They ascribed the low DB to the differences in the reactivities of the amino groups. End modification reactiOTis were accomplished with acetyl chloride, benzoyl chloride, and phthalic anhydride to form end-capped polyimides. The end-group-modified polyimides were soluble in polar aprotic solvents such as DMSO, DMF, and NMP. TGA measurements showed Ta,s% in the range of 400-520°C, and Tg of 200-258°C. The hb-PIs showed film-forming ability, but they were more brittle than analogous linear polymers. 

To characterize a linear polymer, we need to specify the chemical structure of the monomer and the number of monomers per chain. Monomers can be simple chemical units such as in polyethylene (—(CH2) —) or complex structures in itself Polymers are traditionally named according to the monomer from which they are synthesized. For example, polyethylene is synthesized from ethylene (C2H4). lUPAC... 

The term aramid is a portmanteau of the words aromatic polyamide. PA, as you may recall, is the chemical name for the family of materials known as nylon. In organic chemistry, the term aromatic refers not to the way something smells, but to the way in which molecules bond in a ring form, creating strong and stable molecular bonds that are often superior to molecular bonds made in a linear fashion. In polymer chemistry, aromatic polymers typically have performance advantages over linear or cross-linked polymers. This is especially true for aramids (Figures 4.16 and 4.17). 

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