Polymer Class Terms

CLAIMS COMPREHENSIUE (subscriber access only) further enhances the UNITERM indexing from 1964 with roles for aH iadexed compounds and polymer class terms and with links and negation codes for the fragment terms describiag chemical compounds (94). 

STN International, Registry File Polymer Class Terms, Chemical Abstracts Service, Jan. 1993 (Publication CAS6009-1192). 

Organic Polymers, Work is in progress on the algorithmic generation of 1. Polymer class term. 

Each example below illustrates the assignment of polymer class term to the monomer-based registration, derivation of corresponding monomeric units, and generation of the complete SRU whenever applicable. 

STN International. Registry File Polymer Class Terms . Chemical Abstracts Service. January, 1993 (Publication CAS6009-1192). Note this reference lists 42 classes an up-to-date list may be viewed by entering CAS Registry File online and executing the command expand A/PCT. 

The multicomponent systems require the retrieval of Registry Numbers of every component as a first step, using the field Chemical Name (CN) and, as a second step, their conversion into Component Registry Numbers (CRN) (Fig. 92). For a polymer class search the field Polymer Class Terms (PCT) should be used ... 

When the Registry Numbers of polymers are retrieved in the Registry File using the field Polymer Class Term (PCT) (Sect. 7.1.4.3), a supplementary Basic Index and abstract (search field lA) search should be conducted (Fig. 121). 

Dendrons and dendrimers are the most intensely investigated subset of dendritic polymers. In the past decade over 2000 literature references have appeared on this unique class of structure controlled polymers. The term dendrimer was coined by Tomalia, et al. over 15 years ago in the first reports on poly(amidoamine) (PAMAM) dendrimers [75, 76]. It is derived from the Greek words dendri-(branch tree-like) and meros - part of). Poly(amidoamine) dendrimers constitute the first dendrimer family to be commercialized and undoubtedly represent the most extensively characterized and best understood series at this time. In view of the extensive literature information in this area, much of the remaining overview will focus on PAMAM dendrimers and will... 

An interesting class of polymer matrices widely employed for CSE consists of temperature-dependent, viscosity-adjustable polymer solutions that are filled into the capillary at one temperature at low viscosities and are used in separation at another temperature at entanglement threshold concentrations and higher viscosities. Such viscosity-adjustable polymers are termed thermoresponsive... 

Polyhydroxy Aldehydes and Ketones Carbohydrates are a class of organic biopolymers which consist of polyhydroxy aldehydes and ketones, their derivatives and polymers. Other terms for carbohydrates include sugars and saccharides. A single monomer unit is called a monosaccharide several units are referred to as an oligosaccharide larger polymers are called polysaccharides. The simplest carbohydrates are glyceraldehyde and dihydroxyacetone. 

Research Center [292]. With an oxygen permeability of 370 Barrer and an O2/N2 selectivity of 4.0 the PIM-1 shows an extraordinary behavior as a gas-separation polymer. However, long-term measurements revealed a physical aging of PIM-1 analogous to PTMSP, which resulted in reduced permeabilities. When the aging problems can be solved, the PIMs will be a highly interesting polymer class for fabrication of gas-separation membranes. 

More recently, nontraditional polymerization strategies have evolved to produce a fourth new major polymer architectural class, now referred to as dendritic polymers. This new architectural polymer class consists of four major subsets, namely (a) random hyperbranched, (b) dendrigrafts, (c) dendrons, and (d) dendrimers. Dendrimers, the most extensively studied subset, were discovered by the Tomalia group while at The Dow Chemical Company laboratories (1979). They represent the first example of synthetic, macro-molecular dendritic architecture [33,34]. First use of the term dendrimer appeared in preprints for the 1st SPSJ International Polymer Conference held in Kyoto, Japan (1984). The following year, a full article Polymer Journal, Vol. 17, No. 1, pp. 117-132 (1985)) (see article abstract. Fig. 42.7) described the first preparation of a complete family of... 

Deoxyribonucleic acid (DNA), on the other heind, may be thought of as a simpler host polymer in terms of primary and higher order structures.3 So it is interesting to compare its binding behavior with those of another class of polymers, since the interactions of DNA with various kinds of ligands are biologically and medically important. l ... 

The growth in polymer-made biomedical devices has in part been made possible thanks to the discovery of a new class of materials bioresorbable polymers. The term bioresorbable has become a common expression, used in order to qualify this type of macromolecules. A scientifically accepted definition for such materials is the following a material for which the degradation is mediated, at least partly, from a biological system (Ottenbiight and Scott, 1992). This statement shows one of the most important features of these materials. Devices made of bioresorbable polymers are subjected to degradation in the human body which means they do not need to be removed. 

In contrast, for many polymer classes, especially those that result from considerable chemical transformation of starting materials, it is more useful to represent them by structure than in terms of the source materials used to prepare them. 

A final remark concerns the application of poly (acetylene) in electrical storage batteries. It is now quite clear, that poly(acetylene) is an example of yet another redox-polymer - a term first used by H. G. Cassidy many years ago - to describe a class of polymers which can be reversibly oxidized and reduced and may thus be used as exchange resins etc. The prototype polymer of this class is poly(vinylhydroquinone) which can be reversibly oxidized to poly(vinylquinone) the semi-quinone radical being an intermediate. 

All the polymers mentioned in the above subsections, fall in the class termed homopolymers. Simply considering the repeating units, a polymer gets classified as a homopolymer or a copolymer. 

MERISATION. Chemical terms are seven-digit alphanumeric Du Pont accession numbers or C-Numbers, and each represents an individual chemical substance, including polymers. A C-Number is assigned sequentially to each unique substance entered into the system, and it links a series of files used for identification, document referencing, and classification of substances. Non-polymeric organic compounds are stored as compact connection tables based on topology descriptors, which resemble chemical fragments, are also part of the record. Polymeric substance records consist of C-Numbers of component monomers as well as polymer class descriptors where applicable. 

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