High-polydispersity ratio

Examples of high polydispersity ratios and bimodal distributions have been previously rationalized by heterogeneous reaction conditions. Tirrell et al.(19) found Mw/Mn values well over 2.0 and low molecular weight shoulders in slow, low temperature RIM polymerized urethanes based on polycaprolactone diols. Xu et al. 

The UF-resin itself is formed in the acid condensation step, where the same high molar ratio as in the alkaline methylolation step is used (F/U = 1.8 to 2.5) the methylolureas, urea and the residual free formaldehyde react to form linear and partly branched molecules with medium and even higher molar masses, forming polydispersed UF-resins composed of oligomers and polymers of different molar m.asses. Molar ratios lower than approx. 1.7-1.8 during this acid condensation step might cause resin precipitation. 

Although the majority of the examples in the literature have used viral capsids to nudeate and template inorganic materials, it is also possible to template the formation of organic polymers on their surface. Niu et used the TMV capsid as a scaffold to bind and polymerize pyrrole and aniline into conductive polymer nanowires. Using the capsid as the scaffold allowed for the creation of well-defined constmcts with a low polydispersity, high processability, and a high aspect ratio. 

Accurate correlations for the drag and lift forces in dense collections of nonspherical particles and polydisperse mixtures of particles are needed. For high aspect ratio particles, these correlations should include as a parameter the amount of mutual alignment between the particles. 

Other lignins show different polydispersity as demonstrated by high pressure size exclusion chromatograms (47). The polydispersity of lignosulfates is much greater, with M ratios in the range of 6—8 (48). 

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