Linear polymers, discovery

After the discovery of the photopolymerization of 2,5-DSP crystals, several types of photoproducts were found, not only the linear polymers, but some other derivatives, e.g. the V-shaped dimer or cyclophane (Hasegawa and Hashimoto, 1992). The photopolymerization occurs in a step-growth mechanism by cyclobutane formation between the excited olefin and the olefin in the ground state. 

In the laboratories of Natta in Milan it was found that the Ziegler catalysts could polymerize (besides ethene) propene, styrene, and several a-olefins to high linear polymers. These polymers appeared crystalline when examined by X-ray diffraction techniques and were able to give oriented fibers. In less than one year since the preparation of the first polymer of propene, Natta was able to communicate, in the meeting of the Accademia dei Lincei of December 1954 in Rome, that a new chapter had been disclosed in the field of macromolecular chemistry, due to the discovery of processes to obtain polymers with an extraordinary regularity in their structure in terms of both chemical constitution and configuration of the successive monomeric units along the chain of each macromolecule. 

The next breakthrough came with the discovery of how to make almost linear polymers with just a few crosslinked connections between molecules. These materials will not flow after crosslinking, and they become elastomers. A final type is the heavily crosslinked polymers such as epoxy and urea-formaldehyde, which are processed as monomers and then crosslinked at a suitable time and rate to make paints, adhesives, and very hard and durable plastic materials. 

Nylon 6. Poly[imino(l-oxo-l, 6-hexanediyl)] poty(imlnocarboaylpeMamethytene) Caprolan Enkalon Grilon Kapron Mirton Perlon Phrilon Ami Ian. Linear polymer obtained by polymerization of e-caprolactam, q.v. Schlack, US. pat. 2,241,321 (1941 to I. G. Farbenind.). The importance of this fiber increased with the discovery that caprolactam can be produced by the nitrosation of cyclo-hexanecarboxylic acid Muench et al, U.S. pats. 3,022,291 and 3,108,896 (1962, 1963, both to Snia Viscosa). Review R. W- Moncrieff, Man-Made Fibres (John Wiley Sc Sons, New York, 1963) pp 335-355 H. K. Reimschuessel, J. Polym. Sci, Macromol Rev. 12, 65-139 (1977). 

Design of mechanophore for nonlinear topologies. As we mentioned in the previous section, the development of polymer mechanochemistry in the last decade is largely promoted by the discovery of mechanophores. The current design of mechanophores in linear polymers is not perfect. We have proposed several adequate positions for mechanophores in nonlinear topologies. These designs are based on the computer simulations of CST and can be tested in the future. 

Recently, the investigation of polymer brushes has been focused on the synthesis of new tethered polymer systems primarily through surface-initiated polymerization (SIP). Previously, the term polymer brushes has been limited to the investigation of block copolymers (qv) or end-functional linear polymers that have been physically or chemically adsorbed to surfaces, respectively (3,4). Recent synthetic efforts using different polymerization mechanisms have resulted in the discovery of many novel properties of polymer brushes. This has been aided no less than the use of innovative and unique surface-sensitive analysis methods as applied to flat substrates and particles. The study of polymer brushes has benefited from improved dielectric, optical, spectroscopic, and microscopic characterization methods. Understanding the chemistry of these grafting reactions and how... 

The seminal macromolecular hypothesis proposed in 1922 [3, 4] by H. Staudinger initiated one of the most significant technological revolutions of the twentieth century, namely, the polymer (plastics) revolution [5]. Staudinger was not recognized for this monumental contribution by the Nobel committee until 1953. Coincidentally, in that same year Crick and Watson first reported the characterization and structure of DNA. Perhaps two of the most important chemistry discoveries in the twentieth century were Staudinger s macromolecular hypothesis and elucidation of the linear polymer, double helix structure evolved by Nature, namely, DNA [6, 7]. Macromolecular DNA was found to be an elegant covalent biopolymer that was indeed consistent with and could be accounted for by... 

Carothers also produced a number of aliphatic linear polyesters but these did not fulfil his requirements for a fibre-forming polymer which were eventually met by the polyamide, nylon 66. As a consequence the polyesters were discarded by Carothers. However, in 1941 Whinfield and Dickson working at the Calico Printers Association in England announced the discovery of a fibre from poly(ethylene terephthalate). Prompted by the success of such a polymer, Farbenfabriken Bayer initiated a programme in search of other useful polymers containing aromatic rings in the main chain. Carbonic acid derivatives were reacted with many dihydroxy compounds and one of these, bis-phenol A, produced a polymer of immediate promise. 

McMillan, F.M. (1979) The Chain Straighteners - Fruitful Innovation the Discovery of Linear and Stereoregular Synthetic Polymers (Macmillan, London). 

McMillan, F. M. The Chain Straighteners Fruitful Innovation. The Discovery of Linear and Stereoregular Polymers. 1981, The Macmillan Press Ltd. London, U.K. 

Most important, however, was the discovery by Simha et al. [152, 153], de Gennes [4] and des Cloizeaux [154] that the overlap concentration is a suitable parameter for the formulation of universal laws by which semi-dilute solutions can be described. Semi-dilute solutions have already many similarities to polymers in the melt. Their understanding has to be considered as the first essential step for an interpretation of materials properties in terms of molecular parameters. Here now the necessity of the dilute solution properties becomes evident. These molecular solution parameters are not universal, but they allow a definition of the overlap concentration, and with this a universal picture of behavior can be designed. This approach was very successful in the field of linear macromolecules. The following outline will demonstrate the utility of this approach also for branched polymers in the semi-dilute regime. 

He was a Professor of Industrial Chemistry, School of Engineering, Polytechnic Institute of Milan, Milan, Italy since 1937. He became involved with applied research, which led to the production of synthetic rubber in Italy, at the Institute in 1938. He was also interested in the synthesis of petrochemicals such as butadiene and, later, oxo alcohols. At the same time he made important contributions to the understanding of the kinetics of some catalytic processes in both the heterogeneous (methanol synthesis) and homogeneous (oxosynthesis) phase. In 1950, as a result of his interest in petrochemistry, he initiated the research on the use of simple olefins for the synthesis of high polymers. This work led to the discovery, in 1954, of stereospecific polymerization. In this type of polymerization nonsymmetric monomers (e.g., propylene, 1-butene, etc.) produce linear high polymers with a stereoregular structure. 

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