Poly heptene

The Tg-value of poly(1-heptene), for example, is then calculated as follows ... 

For historical reasons, unbranched chains are called linear chains, since it was originally thought that such chains would occur fully extended in space. In fact the random distribution of microconformations dictates that an isolated chain of this type adopts a random coil shape, which also occurs in the amorphous state. Regularly recurring substituents such as in poly(heptene-l),... 

There is, in fact, room for some variation of the frequencies to which the experiments are sensitive measurements of the spin-lattice relaxation time can, as a practical matter, be shifted over a range of one or two decades in frequency [iO —ii]. Moreover, variation of the radiofrequency field strength affords a range in the spectrum for Tip [4,5]. Fig. 2 shows how the spin-lattice relaxation processes are shifted to progressively higher temperatures, in poly(heptene-l), as the frequency of the measurement is increased [ii]. 

Fig. 2. Temperature dependence of the spin-lattice relaxation time in poly(heptene-l) measured...

The polymers of the optically active and racemic 4-methyl-1-hexene and the poly-(S)-5-methyl-l-heptene have isotactic structure (115) the same structure seems probable also in the case of the other polymers prepared till now from optically active or racemic a-olefins. 

The X ray spectra of the optically active and optically inactive polymers seem identical in the case of poly-4-methyl-l-hexene but different in the case of poly-5-methyl-l-heptene and poly-3-methyl-1-pentene (80,96). 

I. R. spectra of polymers of optically active and racemic monomers (12) having similar stereoregularity are identical in the case of poly-5-methyl-l-heptene, but slightly different in the case of poly-3-methyl-l-pentene and poly-4-methyl- 1-hexene. A very characteristic crystallinity band has been found in the I. R. spectrum of poly-5-methyl-l-heptene at 12.06 fi bands which seem connected with stereoregularity have been found in the I. R, spectrum of poly-4-methyl-l-hexene at 10.06 fi the nature of these bands has been proved when preparing a practically atactic sample by hydrogenation of poly-4-methyl-l-hexyne (24). 

The optical activity has been evaluated in some cases also in the solid state (112), and for the poly-(S)-5-methyl-l-heptene it appears of the same order of magnitude as in the liquid state and in solution (110). 

Considering the polymers in which the side chain asymmetric carbon atom is in the y-position with respect to the main chain, a remarkable difference in molar rotation has been found between the monomeric units of the polymers and the model compounds in the case of poly-(S)-5-methyl-l-heptene but not in the case of poly-[(S)-2-methyl-butyl]-vinyl-ether or in the case of poly-(S) l.3-dimethyl-butyl methacrylate. The discrepancy might be related both to conformational and to electronic (113 a) factors. 

Two of the substances detected, pentamethyl heptene and tetramethyloctene were considered as substances known to contribute to the odour of extrusion film coatings. The fact that these substances could transfer from the film to the gas phase supported the potential for these substances to give rise to odour problems in foodstuffs. They also impregnated a filter paper with octanal and placed it in the test cell in contact with paperboard laminated to various films including PE, PP, poly(ethylene terephthalate) (PET) and aluminium/PE (Al/PE) (with PE on the outer surface). They monitored transfer of octanal across the material held at 30 °C for 8-10 hours. Transfer was most rapid through uncoated paperboard. Octanal was shown to transfer across PE film laminated to the paperboard within ten minutes. There was no transfer of octanal through PP, Al/PE and PET over ten hours. 

Several poly(fluorinated olefins) are used in practice. These include poly(vinyl fluoride), poly(vinylidene fluoride), poly(trifluoroethylene), poly(tetrafluoroethylene), and other fluorinated polyolefins such as poly(perfluoro-heptene) or poly(perfluoro-propylene). Poly(vinyl fluoride) with the general formula [-CH2CHF-]n and CAS 24981-14-4 is less common than its chlorinated analog, but still has numerous practical applications, mainly in coatings. Upon heating, the polymer begins losing HF at about 350° C with formation of double bonds in the carbon chain. At about 450° C the backbone of the polymer... 

In these isotactic polymers, the optical purity of the monomer affected the optical activity via the relationship to the excess helical sense of the polymer (Figure l).47 In the case of isotactic poly[(5)-4-methyl-1-hexene] (2) and poly[(A)-3,7-dimethyTl-octene] (3), an increase in the optical purity of the monomers resulted in an increase in the optical activity of the polymers in a nonlinear fashion the optical activity of the polymers leveled off when the optical purity of the monomer reached ca. 80%. In contrast, in the case of isotactic poly[(5)-5-methyl-l-heptene] (4), the... 

A large number of dibasic acids and anhydrides are used in the preparation of poly(ester amide)s. These include terephthalic acid, phthalic anhydride, isophthalic acid, endic endo-cis bicyclo(2,2,10-5)-heptene-2,3-dicarboxylic] anhydride, hydrogenated endic anhydride, maleic anhydride, fumaric acid, dichloromaleic anhydride, itaconic acid, brassylic acid, dimer acid, adipic acid, sebacic acid, succinic acid, trimeUitic anhydride, pyrromellitic anhydride and ethylenediamine tetraacetic acid (EDTA). However, tri- and poly-functional compounds are used only partially and are combined with bifunctional derivatives, or derivatives of previously prepared multifunctional compounds which are subsequently polymerised with bifunctional compounds. 

Figure 4-21. Molar optical rotation per monomeric unit [< )] as a function of optical purity % of the monomer for poly[(S)-4-methyl-l-hexene] (top curve) poly[(S)-5-methyl-l-heptene], and poly[(R)-3,7-dimethyl-l-octene] (bottom curve) (after P. Pino, F. Ciardelli, G. Montagnoli, and O. Pieroni).

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