Macromolecular concept

It is now a common feeling that our world cannot survive as it is without plastics [1]. Starting from 1930, when the macromolecular concept started to gain acceptance in the scientific community [2], the advances in polymer science have been so striking that plastics have invaded almost every aspect of modern human life, both as daily materials and as sophisticated substrates able to cover high-tech applications [3]. A very easy and simple way to check this assertion is to visit the The Macrogalleria web site (1st floor) [4] where an extensive exemplification of the most common and important plastic applications in different fields is provided in a really immediate and impressive way. 

Yet as the many sided debate went on, Wallace Carothers started a series of investigations in 1928 which would eventually establish the macromolecular concept. His objective from the beginning was to prepare polymers of known structure through the use of established reactions of organic chemistry (85). In the brilliant years before his untimely death in 1937, he studied the preparation and properties of polyesters, polyanhydrides, polyamides, and polychloroprene (28). 

There is an increased awareness of the place in history of science, particularly polymer science where many of those who contributed the basic building blocks are still alive. Ray Seymour is doing a series on the Pioneers of Polymer Science for Polymer News. Fred Eirich has been asked by the Journal of Chemical Education to write a history of the development of the "macromolecular concept." (As a side comment, those associated with the Journal of Chemical Education such as Tom Lippincott, have been "friendly" towards polymer chemistry and have assisted in the attempt to bring polymer chemistry into the mainstream of material presented to both the teaching staff and chemistry students alike). 

X HE SCIENCE AND TECHNOLOGY of polymers have had a profound influence on the quality of life in the 20th century. Indeed, the utility of polymeric materials was widely appreciated long before scientists understood the molecular basis of this class of materials. Early telephone handsets, for example, were made from a condensation polymer of formaldehyde and phenol, but it was many years later before the macromolecular concept of a polymer molecule was proposed, much less accepted. 

Cellulose represents an important polymer, which is most abundant in nature, and serves as a renewable resource in many applications, e.g., fibers, films, paper, and as a composite with other polysaccharides and lignin in wood. Cellulose derivatives will also be used as films and fibers, food additives, thermoplastics, and construction materials, to name just a few. Cellulose and cellulose derivatives have played an important role in the development of the macromolecular concept. So far, little use has been made of the fact that cellulose represents a chiral material except, e.g., in a rare case as stationary material in liquid chromatography for the separation of chiral compounds. Nature ifself uses the chirality of cellulose occasionally, and twisted structures of cellulose molecules are found in cell walls. 

Finally, I would like to put emphasis on the importance of macromolecular concepts. The characteristics of macromolecules are usually summarized in two points one is a linearity and length of the molecule having many sites of property, functionality, and sensibility, and the other is flexible... 

Investigations on macromolecular concepts are very analogous to those on brain mechanisms, in which the relation between polymer and brain is more important ... 

The macromolecular concept was proposed in 1917 by Staudinger, who received the Nobel Prize for chemistry in 1953. His theory was supported by the work of other researchers. Mark described the relationship between the viscosity of a polymer solution and its molecular weight (i.e. the Mark-Houwink-Sakurada relationship), demonstrating that cellulose was made of giant molecules. Carothers demonstrated the existence of synthetic macromolecules, and his researches led to the invention of the famous Nylon 6-6. 

Other investigators in the nineteenth century including Emil Fischer, reported unusually high molecular weights for natural polymers. Nevertheless, confusion between concepts of colloids, the association theory and that of macromolecules continued to retard progress until Nobel Laureate Hermann Staudinger championed the true macromolecular concept in the early 1920 s. 

By the end of the 1920 s Staudinger s efforts to prove the macromolecular concept by chemical reactions with polymers and by improved x-ray stodies on < llulose, silk rubber and chitin, by systematic measurements with the ultracentrihige and, perhaps most of all by the brilliant synthetic work of W.H. Carothers in the laboratories of the DuPont company, he succeeded in preparing polyesters and polyamides in the macromolecular range and determined their molecular weight by exact and reprodudble end group analysis. 

Verlag Springer in Berlin it summarized on a broad front, the origin of the macromolecular concept and its emergence as a new branch of organic chemistry. 

About a decade after, Schulten and Schnitzer (1993) published the HA molecular structure shown in Figure 10.19. Clearly, a macromolecular concept is implied here, which would require necessarily extensive coupling reactions of degradation fragments from plant residues. Another humic structure proposed was a polymeric one. 

If a student is asked about the formula of indigo during an examination and replies that he believes that A. von Baeyer s formula is the right one, this would not be enough to pass the examination. He surely would be asked how the formula was proved. Similarly, it is necessary to know exactly the proofs for the macromolecular structure of cellulose and many other natural products, as well as those of synthetic products, if one intraids to wrak with them on the basis of this macromolecular concept. 

Staudinger s self-confident predictions proved to be correct the macromolecular concept stimulated material research and really did lead to an industrial boom soon afterwards ... 

From purely empirical optimisation of materials to molecular material design — this, in a nutshell, is the most tangible progress that has been made thanks to Staudinger s macromolecular concept and that is highlighted when tribute is paid to Staudinger s historical achievements. His concept [...] that was revolutionary at the time paved the way for the molecular design of functional and decorative polymer materials, the property profiles of which are customised for specific applications via the molecular architectures [24, p. 1072]. 

Keywords Appreciating the essence of Japanese culture Lectures on macromolecular concept Short reunion Staudmger effect Visiting Emperor Hirohito... 

Crystallinity in polymers was first observed by X-Ray Diffraction even before these materials were understood to be polymers. Prominent examples were polysaccharides, especially cellulose (Herzog et al. 1920) and stretched natural rubber (Katz 1925). This was before Staudinger s macromolecular concept was widely accepted (Morawetz 1995). By the time synthetic crystalline polymers such as polyethylene (in 1933) and nylons (in 1935) were developed, it was generally acknowledged that the unit cell of a polymer crystal was based on repeating monomer units, rather than on the whole molecules. 

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