1,4-Polybutadiene behavior, elastic

The stress relaxation properties of a high molecular weight polybutadiene with a narrow molecular weight distribution are shown in Figure 1. The behavior is shown in terms of the apparent rubber elasticity stress relaxation modulus for three differrent extension ratios and the experiment is carried on until rupture in all three cases. A very wide rubber plateau extending over nearly 6 decades in time is observed for the smallest extension ratio. However, the plateau is observed to become narrower with increasing extension... 

Kraus,G., Moczygemba,G.A. Chain entanglements and elastic behavior in polybutadiene networks. J. Polymer Sci. Part A 2,277-288 (1964). 

With a Raman instrument, measurement of these low lying bands is fairly straightforward. If the elastic Rayleigh scattering can be removed (for example the use of iodine gas filters (56) to selectively absorb the Rayleigh line), very low frequency vibrations in the range of a few cm can be observed. Based on the imit cell parameters of polyethylene, a set of Raman active lattice vibrations has been observed for polyethylene and paraffins (57). Rotatory modes are seen in traras-l,4-polybutadiene (49). With analysis of these low lying vibrations in a quantitative fashion, a correlation between molecular and macroscopic properties such as heat capacity, thermal pressure, thermal expansion, P-V-T relations, and stress-strain behavior can all be established (58). 

Stadler and coworkers have made important contributions to the field of supramolecular polymer chemistry through their studies of polybutadienes derivatized with hydrogenbonding phenylurazole derivatives (Figure 2). Lightscattering experiments, optical measurements, and thermal analysis were used to probe the formation of thermoplastic elastomers and elastomeric blends at lower temperatures, hydrogen bonding contributes to network formation and elastic behavior, whereas at higher temperatures these... 

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