Polymer connectivity

Figure 6.7 displays the SANS data obtained from the PEP-PEE triblock, where a label was placed at the polymer-polymer connection point (sample VII)... 

Since it is generally viewed that coniferous lignin has almost 40% of its linkages connected via 0-O-4 bonds, these aforementioned results suggest that a lignin polymer connected primarily via such linkages should... 

It is remarkable that the predictions of classical nucleation theory without any consideration of polymer connectivity are borne out in experiments. At higher supercooling, deviations are expected because of temperature dependence of the nucleation rate prefactor. 

The McMurry reagent can also be applied for the synthesis of polymers connected by olefmic double bonds... 

Polymers Connected with Bivalent Hydrogen Bonds... 

Spin diffusion Domain sizing e.g. polymers, connectivity Caravatti et al. (1983), (1982)... 

The extended method was then used as the foundation of a scheme of predictive techniques and correlations for the calculation of the physical properties of polymers. Connectivity indices were correlated either with experimental data or with tables of group contributions. For example, there is a sufficient amount of reliable experimental data for the molar volume or the... 

More recent views (17) of the origin of stereospecificity in the synthesis of isotactic polymers connect this origin with the ability of the catalyst-growing polymer chain system, that is, the catalytic center, to discriminate between the two prochiral faces of the a-olefin. The catalytic system must possess one or more chirality centers (Figure 4). 

Fig. 10.18. Vertices with m legs (here m = 1,2,3,4) each vertex represent a polymer or a set of polymers connected with one another in an irreducible way.

The molecular mass of a polymer incr ses during crosslinking and this is directly interrelated with the change of properties sample deformability. The crosslinking leads to an increase of viscosity of the polymer melt, increase of the tensile strength [154], improvement of creep properties [155, 15Q, increase of the resistance against environment stress cracking [157], etc. 

A lot of molar mass dependencies can be described by eq. (4.1.4). Most of the thermodynamical properties of polymers, e.g. T, Tg, depend on M . Often, the limiting value is attained aheady at molar masses below the real molar mass range of a polymer. Then, no dependence of the characteristics can be observed from the molar mass. Properties of bulky polymers connected with large deformations, e.g. melt viscosity, solution viscosity, are determined by M . Viscoelastic properties, e.g. melt elasticity, depend on M. ... 

Table 5.5.2 CAS Registry Numbers of polymers (connectives are explained in Table 5.9.1)...

All polymers are yellow or orange powders with yields of 15 to 80%. NMR spectra of the polymers were observed in order to clarify how the silicon atoms in the polymers connect with each other. Hexyl-silicon polymer exhibited a very broad resonance peak at -61ppm, which suggests the presence of silicon atoms having three silyl substituents. 

The polymer-analogous cyclization is accompanied by a remarkable change in the absorption properties. The colorless intermediate is converted to the deep yellow planar ladder polymer connected with this is a distinct bathochromic shift of the longest wavelength absorption maximum. The polymer possesses an absorption band with well-defined vibrational fine structure and a sharp absorption edge of the 0-0 transition (see Table 14.4 and Fig. 14.3). 

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