Staudinger effect

The timing was superb. Their visit brought a sort of Staudinger effect oti the polymer activities just taking off in Japan (see Sect. 6). According to the remaining documents, the following account is why and how it happened. 

Staudinger also found that diacetates of polyoxymethylenes with a degree of polymerisation of about 50 were less stable. Truly high molecular weight polyoxymethylenes (degree of polymerisation -1000) were not esterified by Staudinger this was effected by the Du Pont research team and was found to improve the thermal stability of the polymer substantially. 

Staudinger concept of polymer structure 1-2 stereoelectronic effects... 

The fact that mbber shows mbber elasticity was discovered more than 100 years earlier than professor H. Staudinger s proposal. The memory effect acquired by vulcanization, so-called Gough-Joule effect, and its thermodynamic explanation were the great achievements in the nineteenth century. As seen in many textbooks, this thermodynamic approach was the easiest one to gain consistency between ever-performed experiments and theory. In fact, thermodynamics of mbbery material can be treated in parallel with thermodynamics of gas. One could show experimentally that... 

In the following four years Mark successively reported on the viscosity and molecular weight of cellulose (40), Staudinger s Law (41), high polymer solutions (42), and the effect of viscosity on polymerization rates (43). Confident of his findings, he proposed (at the same time as R. Houwink) the general viscosity equation now known as the Mark-Houwink Equation (44, 45). 

Ultrasonic waves also bring about a reduction in the viscosity of nitrocellulose. The effect is more marked the higher the initial viscosity, and thus the longer the nitrocellulose chains (Sollner [93] Schmidt and Rommel [94]). For instance, nitrocellulose with a molecular weight of 123,000, estimated by means of Staudinger s viscosity equation, subjected in solution form to the action of ultrasonic waves suffered a degradation to a molecular weight of 70,000-80,000. 

More recently Staudinger and Dreher [96] have confirmed these observations, by determining the effect of the time of pulping nitrocellulose in a colloid mill on its molecular weight as determined by viscosity measurement. They further established that owing to intensive milling a partial denitration of nitrocellulose took also place, as seen in Table 56. 

The blue PVA-Iodine complex was first found by Herrmann et al [5] who first synthesized PVA, and by Staudinger et aL [6] as early as 1927. Since then, the complex has attracted the interest of many researchers, and many studies have been done from different points of view. Some studied the complex formed in PVA solutions, while others studied the complex formed in bulk (film and fibers) PVA. Some concentrated their attentions on the effects of the PVA molecular structure on the complex formation, i.e. the 1,2 glycol hetero structure content of the chain backbone [10-12], the stereoregularity [10,11,13-15], the degree of saponification [16-18] and the chemical modification such as formalization [18-20]. 

Staudinger, J. J. P. The effect of cross-linking in vinyl-polymer resins in P. Morgan Plastics Progress Papers and Discussions at the Brit. Plastics Convention 1951, 13. London Iliffe Sons 1951. 

The experimental techniques available to determine AWPCs and their limitations have been discussed by Staudinger and Roberts [2]. These authors also evaluated the effects of pH, compound hydration, compound concentration, cosolvent, cosolute, and salt effects, suspended solids, dissolved organic matter, and surfactants. The experimental data have been compiled by a number of different authors [2-11]. 

The first probable values for the molecular size of the native pectins from apple and sugar beet were obtained by Schneider and co-workers.71 These workers prepared the nitro- and acetyl-derivatives in order to avoid the anomalous behavior due to charge effects which occurred using the unsubstituted polysaccharides. From osmotic and viscometric measurements on the nitrate, values for the molecular weight of 30,000-100,000 were found, the constant Km in Staudinger s equation being 6(10)-4. Viscometric measurements indicated that there was little difference in size between the two derivatives. 

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