High polymer definition

Deformation and Fracture of High Polymers, Definition and Scope of Treatment... 

The first attempt to formulate a systematic nomenclature for polymers was based on the smallest repeating stmctural unit it was pubHshed in 1952 by a Subcommission on Nomenclature of the lUPAC Commission on Macromolecules (95). The report covered not only the naming of polymers, but also symbology and definitions of terms. However, these nomenclature recommendations did not receive widespread acceptance. Further progress was slow, with a report on steric regularity in high polymers pubHshed in 1962 and updated in 1966 (96). 

Complete fractionation of a high polymer with sufficient precision and enough fractions for even approximate definition of the differential... 

One of the most pressing problems in the radiation chemistry of high polymers is to obtain definite proof of one or the other of the mechanisms proposed for the interoonversion of alkyl and allyl free radicals. Such information might also be of great help in understanding other effects produced by irradiating high polymers. 

It is interesting to compare Dainton s definition of the ceiling temperature with that of Tobolsky. Both have the same mathematical form. Dainton s definition refers to the single process free monomer - —> monomer segment of a high polymer, and takes no account of the... 

RESINS (Synthetic). A manufactured high polymer resulting from a chemical reaction between two (or more) substances, usually with heat or a catalyst. This definition includes synthetic rubbers and silicones (elastomers), but excludes modified, water soluble polymers (often called resins). Distinction should be made between a synthetic resin and a plastic the formei is the polymer itself, whereas the latter is the polymer plus such additives as niters, colorant, plasticizers etc. See also Elastomers and Plasticizers. 

NMR spectroscopic studies have been performed in detail on p-PDA Et, its dimer, oligomer and high polymer19. The dimer and the oligomer of p-PDA Et are prepared by photo-irradiation with a selected wavelength or at a definite temperature (see Sect. III. a.). NMR spectra of the monomer, the dimer, the oligomer and high polymer of p-PDA Et are shown in Fig. 3. 

The ease of migration of small molecules in high polymers has been successfully exploited for gas separations, water purification and controlled release. These topics have been discussed earlier in this review. There is also, however a negative side to the comparative ease of transport in polymers compared with metals and glass. They are obviously not as good gas and vapor barriers and therefore have definite limitations for certain packaging applications. This subject will not be discussed further in this presentation. 

Although simple in its definition, the evaluation of 8 is not always straightforward. In many applications we need to know the effect of temperature and pressure on 8. If in addition the system is not volatile (such as the high polymers), the evaluation of 8 is difficult. The difficulty increases when we further need to know the separate contribution to 8 of intermolecular dispersion forces and of specific forces such as hydrogen bonding. 

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