Polymer is derived from the Greek words: 'Poly meaning many, and meros meaning parts.' Polymer therefore implies many parts. The parts are units described monomers; hence polymers are derived from huge number of repeating units termed monomers. The procedure via which this is achieved is termed polymerization. Several are biopolymers since they are naturally occurring, while many are synthetic polymers. Many significant products which make us comfortable are polymers.
A polymer (from Greek means: much, many and part) is a huge molecule (macromolecule) composed of repeating structural units typically attached through covalent chemical bonds. The term 'polymer' refers to huge class of natural and synthetic materials through varieties of properties. We will be concerned in polymer Chemistry by the structures, properties and preparations of important polymers. How to attain them should be paramount in mind.
General Information on Polymers
Polymers are giant organic compounds composed of many repeating units termed monomers, with high relative molecular masses ranging from not less than several hundred, to thousands or even millions. They are as well termed to as macromolecules, but not all macromolecules are polymers! General molecular formula of polymers is generally symbolized as [-monomer(s)-] n where 'n' is a range of huge numbers that aren't fixed. Polymers can be attained from nature (Natural polymers), and they are as well synthesized (Synthetic polymers). The reaction that guides to the formation of polymers is termed polymerization. Natural polymers, as well recognized as biopolymers comprise natural rubber (latex), nucleic acids, proteins, polysaccharides, wool, silk and cotton. For instance, natural rubber has a molecular weight of 12,000; starch, 40,000; and proteins, 1000-1,000,000. Procedures of polymerization involve easy procedures of addition, condensation and cyclization reactions, to more complex and joined reactions.
Polymer compounds are extremely helpful in day-to-day activities of man. Useful polymers are utilized in cosmetics, paints, clothing and wears, agricultural implements, plastics and rubber, vulcanization, wrappers, furniture, compact discs, photographic films, parts of automobiles, soles of shoes, glues, packs, flasks, bottles and toys, electrical insulators and so on. Polymer products as well provide as physiological aids to the crippled, people through heart problems, providing hearing and vision aids, protective wears and goggles, industrial and domestic appliances.
Activity A: Why are all polymers macromolecules, while all macromolecules aren't polymers?
Answer: Macromolecules with no repeating units termed monomers; though by huge molecular weights [102s to 106s] aren't polymers. If macromolecules aren't formed via the procedure of polymerization reaction between monomers, they aren't polymers.
There are numerous conventions for naming polymer materials. Many commonly utilized polymers, such as those found in consumer products, are termed to as via a common or unimportant name. The trivial name is allocated depend on historical precedent or popular practice rather than a standardized naming gathering. Both the American Chemical Society and IUPAC have suggested normalized naming conventions; the ACS and IUPAC conventions are similar but not the same. Instances of the differences between the diverse naming conventions are specified in the table beneath:
Table: Common, ACS and IUPAC Names of Polymers
Poly (ethylene oxide)
In both standardized conventions, the polymers' names are proposed to reflect the monomer(s) from that they are synthesized rather than the accurate nature of the repeating subunit. For instance, the polymer synthesized from the simple alkene ethene is termed polyethylene, keeping the -ene suffix even although the double bond is eliminated during the polymerization procedure
Some distinct Polymer Scientists
Earlier in the year 19th century many scientists like Alexander Parke, John Wesley Hyatt, Louis Chardonnet, and Hermann Staudinger synthesized many helpful polymers. Before this time Jons Jakob Berzelius formed the word polymer meaning in Greek language 'many parts'. They demonstrated that polymers are long chains of monomers bonded mutually. Not until recently is much appreciation following to studies on Polymer Chemistry that is a major, aspect of studies on Material Science.
Who was born on 29th December 1813, and lived till 29th June in the year 1890 a native of Birmingham, England. He was a metallurgist and invented the 1st thermoplastic celluloid depend on nitrocellulose through ethanol as solvent. He termed it 'Parkesine' the 1st man-made plastic. The material anticipated many of the current aesthetic and usefulness utilizes of plastics. It was first exhibited at the 1862 London International Exhibition. A. Parkes has a total of 66 patents on developing processes and products related to electroplating and plastic. Several of his outstanding works are summarized thus:
In the year 1850 he developed and patented the Parkes procedure for economically desilvering lead, as well patenting refinements to the process in the year 1851 and 1852. In 1855 he developed Parkesine - the 1st thermoplastic - celluloid depends on nitrocellulose through the solvent ethanol. This material, exhibited at the year 1862 London International Exhibition, anticipated many of the modern aesthetic and utility utilizes of plastics.
In the year 1866 he set up The Parkesine Company in London for bulk low-cost production. It was not, though, a commercial achievement as Parkesine was expensive to generate, prone to cracking and extremely flammable. The business closed in the year 1868. Parkes' material was developed later in improved form as Xylonite via his associate D. Spill, who brought a patent infringement lawsuit against J.W. Hyatt who developed celluloid in the U.S. It was eventually unsuccessful since in 1870, the judge ruled that it was Parkes who was the true discoverer due to his original experiments. Remembrances of Parkes are made at many locations. Plastics Historical Society put up a blue plastic plague in the year 2002 in his home town Dulwich, London. He was commemorated via The Birmingham Civic Society who erected a blue plague in the year 2004 on the unique Elkington Silver Electroplating Works.
The blue plaque on the old Birmingham Science Museum
John Wesley Hyatt
He lived November 28, 1837 to May 10, 1920 an American inventor, who contributed to the development of celluloid with his brothers, and began producing in 1872. He also invented the Hyatt filter, a means of chemically purifying water while it is in motion; a widely utilized kind of roller bearing; a sugarcane mill superior to any before utilize; a sewing machine for making machine belting; and a substitute for ivory in the manufacture of billiard balls and other articles. Hyatt's eventual effect was a commercially feasible method of producing solid, steady nitrocellulose that he patented in the U.S. in the year 1869 as 'Celluloid' (US patent 50359; now a genericized trademark). In the year 1870 Hyatt formed the Albany Dental Plate Company (later renamed the Celluloid Manufacturing Company) to create billiard balls, false teeth and piano keys, among other products.
In parallel, a 3rd English inventor, Daniel Spill, had independently increased basically the similar product that he patented in the UK as 'Xylonite'. Spill in a while followed Hyatt in a number of costly court cases between 1877 and 1884. The ultimate resolution was that the true discoverer of celluloid was Parkes, but that all manufacturing of celluloid could continue, including Hyatt's. Hyatt's other patented creations comprise roller bearings and a multiple-stitch sewing machine.
L. Chardonnet is a French chemist who lived 1839 to T1924. He invented rayon and generated arti?cial silk from nitrocellulose.
The French chemist L.M.H.B. Chardonnet, who invented rayon. Louis-Marie-Hilaire Bernigaud, Comte de Chardonnet, was born in Besancon, France. He is credited via having developed artificial silk that came to be known as rayon. Around in the year 1860s Chardonnet, initially trained as an engineer, assisted Louis Pasteur in an effort to save the French silk industry from an endemic influencing silkworms. In the year 1878, while working in a photographic darkroom, Chardonnet by mistake reversed a bottle of nitrocellulose. Whenever he started to clean up the spill, he saw that the nitrocellulose had happen to viscous due to evaporation. As he wiped it, he observed long, thin strands of fiber similar to those of silk. Chardonnet began to experiment additional through the nitrocellulose. He worked by the silkworm's food, mulberry leaves, revolving them into a cellulose pulp through nitric and sulfuric acids, and enlarged the consequential fleshy tissue into fibers. This fiber, cellulose nitrate, could be utilized in garments, but it was extremely flammable. Several garments completed of this untimely synthetic silk reportedly burst into flame when a lit cigarette was nearby. Chardonnet solved this difficulty via denitrating such fibers through ammonium sulfide, which decreased the flammability of the material with no sacrificing its strength. Chardonnet received his 1st patent for artificial silk in 1884 and began manufacturing the material in the year 1891. In 1924 artificial silk came to be recognized as rayon.
Hermann Staudinger (23rd March 1881 to 8th September 1965), is a German chemist from Worms who demonstrated the subsistence of macromolecules that he characterized as polymers. For this work he obtained the year 1953 Nobel Prize in Chemistry. He is as well recognized for his innovation of ketenes and of the Staudinger reaction.
After he got his Ph.D. from the University of Halle in the year 1903, Staudinger took a position at University of Strasbourg where he discovered the ketenes. Ketene [R,R' = H or alkyl]
Ketenes are synthetically-important intermediate for the production of yet-to-be-determined antibiotics like penicillin and amoxicillin. In the year 1907, Staudinger starts an assistant professorship at the Technical University of Karlsruhe where he effectively isolated a number of useful organic compounds (including a synthetic coffee flavoring) as more entirely reviewed via Mülhaupt.
In the year 1912, Staudinger commenced studies that led to discovery of the Staudinger reaction at the Swiss Federal Institute of Technology in Zurich, Switzerland. One of his earliest discoveries came in 1919, whenever he and colleague Meyer reported that azides react with triphenylphosphine to form phosphazide and gaseous nitrogen by way of the reaction commonly referred to as the Staudinger reaction with a high yield of phosphazide.
At Zurich, Staudinger while here started research in the chemistry of rubber, determine high molecular weights by the physical methods of Raoult and van't Hoff. Contrary to prevailing ideas as stated below. Staudinger proposed in a landmark paper published in the year 1920 that rubber and other polymeric materials these as proteins, starch and cellulose are long chains of short repeating molecular units bonded via covalent bonds several are in a head-to-tail fashion. In other words, polymers are as chains of paper clips, completed up of tiny constituent parts associated from end to end therefore:
This period, leading organic chemists like Heinrich Wieland and Emil Fischer believed that the computed high molecular weights were only apparent values reasoned through the aggregation of tiny molecules into colloids. At 1st the majority of Staudinger's colleagues as well rejected to accept the possibility that small molecules could bond mutually covalently to form high-molecular weight compounds. Mülhaupt aptly noted that this is due in part to the fact that molecular structure and bonding theory were not entirely understood in the early 20th century.
Evidences that supported Staudinger's hypothesis came-up in the 1930s. High molecular weights polymers were confirmed by membrane osmometry, and as well via Staudinger's measurements of viscosity in solution. X-ray diffraction studies of polymers via Herman Mark provided direct evidence for long chains of replicating molecular units.
As well the synthetic work led by Carothers demonstrated that polymers such as polyesters and nylon could be prepared by well-understood organic reactions. Staudinger's elucidation of the nature of high-molecular weight compounds which he termed Makromoleküle tremendously led to the birth of the studies of polymer chemistry. Staudinger himself saw the potential for this science long before it was entirely realized. 'It isn't improbable,' Staudinger elegantly commented in the year 1936, "that sooner or later a method will be determined to get ready artificial fibers from synthetic high-molecular products, since the strength and elasticity of natural fibers based completely on their macro-molecular structure - for example, on their long thread-shaped molecules." Staudinger originated the 1st polymer chemistry journal in 1940, and in 1953 received the Nobel Prize in chemistry for 'his discoveries in the field of macromolecular chemistry'. His pioneering research has afforded the world myriad plastics, textiles, and other polymeric materials that build consumer products more affordable, attractive, and fun.
Introduction to more classifications and nomenclature of Polymers
Polymers can be classified into kinds depending on their chemical mode of structure or on their physical properties and shapes. Based on their physical nature we have the subsequent polymers: elastomers, fibers, resins, plastics, plasticizers, thermoplastics, thermosetting, nylons, polyesters, acrylonitriles. Polymers can be grouped depending on their chemical nature as: (i) kind of reaction leading to their formation- addition polymers, and condensation polymers; (ii) kind of functional group in monomers, number and their linkages- bifunctional, trifunctional polymers, linear, cross-bonded polymers, homopolymers, copolymers and terpolymers. Each of these groupings will be well explained in the next two units, and in module 5. Activity C: Provide brief description on each of the groupings of polymers listed in above; depend on the physical and chemical natures as stated above.
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