Example for poly

The SnAt reactions were first successfully used in the synthesis of high-molecular-weight poly(arylene etherjs by Johnson et al.4,5 This reaction represents a good example for poly(ether sulfonejs in general, either in laboratory -or industrial-scale preparations. In this procedure, the bisphenol A and sodium hydroxide with an exact mole ratio of 1 2 were dissolved into dimethyl sulfoxide (DMSO)-chlorobenzene. The bisphenol A was converted into disodium bisphenolate A, and water was removed by azeotropic distillation. After the formation of the anhydrous disodium bisphenolate A, an equal molar amount of 4,4,-dichlorodiphenyl sulfone (DCDPS) was added in chlorobenzene under anhydrous conditions and the temperature was increased to 160°C for over 1 h... 

Experimental values of the molar mass exponent close to 2 have been obtained. For example, for poly(methyl methacrylate), a value of 2.45 has found (see P. Prentice, Polymer, 1983, 24, 344—350). As with values of selfdiffusion coefficient, this has been regarded as close enough to 2 for reptation to be considered a good model of the molecular motion occurring at the crack tip. 

Other variants that are used in lubricating oils are sulfurized olefin compositions (69). An example for poly(isobutyl-l,2-dithiol-e-4-cyclopentene-3-thione) compounds is shown in Figure 6.10. 

As an example, for poly(methyl methacrylate), the radical transfer reaction may take place as follows ... 

Some polymers containing heterocycles can be included in resins following further condensation. This is possible, for example, for poly(furfuryl alcohol), which can condense with formaldehyde, phenol, melamine and urea. Furfuryl alcohol-formaldehyde copolymer can be synthesized in the reaction of furfuryl alcohol with formaldehyde in the presence of oxalic acid as catalyst. 

The poly(stannane-co-germane) and poly(stannane-co-silane) materials exhibit kmax between those of the respective homopolymers. However, increasing the stannane contents in the copolymers results in a red shift of the UV absorption probably due to the effective overlap of orbitals ascribed to the increased atomic radius of tin over Ge(Si). As an example, for poly(di-n-butylstannane-ct -di-n-butylsilane) with an Sn Si ratio of 43 57, kmax = 375 nm, as compared to 314 and 384 nm for poly(di-n-butylsilane) and poly(di-n-butylstannane), respectively. 

The problem appears somewhat more complicated in the case of nanocapsules, where one deals with at least three different structural elements a continuous liquid phase, the solid phase represented by the capsule walls and the encapsulated liquid domain All techniques mentioned so far only allow for the differentiation of the solid phase from the two liquid phases. An example for poly-w-butylcyanoacrylate nanocapsules in aqueous dispersion is shown in Figs. 15 and 16. 

FIGURE 12.7 Monomer conversion vs. polymerization time for two initiator concentrations. (Example for poly(NIPAM) particles polymerization temperature T = 70°C, [NIPAM] = 48.51 mmoles, [MBA] = 3 mmol,... 

The exponent a of the [riJ-M-relationship increases with the solvent quality. In a good solvent, a coil has its so-called perturbed dimensions. In a good solvent the exponent a can reach a theoretical value of 0.76 according to the mean-field theory [47]. Slopes between 0.5 and 0.76 are also experimentally observed, for example for poly(acrylamide) in H2O at 25 °C in Fig. 6.7. Exponents a greater than 0.76 are experimentally not observed for flexible coils in good solvents [47]. Therefore, exponents a greater than 0.76 are not solely caused by the solvation of the polymer chain. In these cases, the coil expansion is also determined by the chemical structure of the polymer chain as shown in the following. 

The lubricating effect depends on the structure. For example, for poly(vinyl chloride) (PVC), dimethyl phthalate acts as solvent, whereas dioctyl phthalate acts as plasticizer. Eventually, distearyl phthalate acts as lubricant. 

A number of linear polymers are soluble in organic solvents that are able to be eliminated rapidly (through evaporation) after the adhesive has been deposited. This is the case, for example, for poly(fi-pinene) (O Fig. 14.5) which, dissolved in methyl ethyl ketone, has for a long time been the basis of universal glues Scotch by 3M). 

J.K. Kruger I think that there are certainly striking similarities between several quantities like density, viscosity, etc. for 7// and T . Are there any materials which show both transitions For example, for poly(4-methyl pentene-1) discussed by Prof. Geil, [P.H. Geil, contribution in this volume], does it show a 7/ We have found what we call 7 in this material. Is there a 7//, in addition, or not ... 

In the majority of cases, the polymer was named according to its structure, particularly when the CRU was composed of two or more subunits following each other in a regular fashion. An example is poly(ethylene terephthalate). With more complicated structures, the CRU was divided into its possible subunits, each of which was treated as a bivalent radical and so named. One of the subunits was treated as the parent compound, for example, the terephthalic acid of the above example. For poly(amides) and poly(esters), the acid was chosen as the parent compound for poly(urethanes) it was the isocyanate. 

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