Bakelite polymers

Bakelite Polymer produced by condensation of phenol and formaldehyde first by Leo Baekeland, bifnnctional Molecule with two active functional groups, bisphenol A 2,2 -bis(4-hydroxphenol)propane. 

The first aromatic sulfone polymer produced commercially was introduced as Bakelite polysulfone but now is sold by Union Carbide under the trade name Udel. It is made by reaction of the disodium salt of bisphenol A (BPA) with 4,4 -dichIorodiphenyl sulfone in a mixed solvent of chlorobenzene and dimethyl sulfoxide (eq. 12). 

The generic thermosets are the epoxies and the polyesters (both widely used as matrix materials for fibre-reinforced polymers) and the formaldehyde-based plastics (widely used for moulding and hard surfacing). Other formaldehyde plastics, which now replace bakelite, are ureaformaldehyde (used for electrical fittings) and melamine-formaldehyde (used for tableware). 

Whereas celluloid was the first plastics material obtained by chemical modification of a polymer to be exploited, the phenolics were the first commercially successful fully synthetic resins. It is interesting to note that in 1963, by a merger of two subsidiary companies of the Union Carbide and the Distillers organisations, there was formed the Bakelite Xylonite Company, an intriguing marriage of two of the earliest names in the plastics industry. 

The first commercial polymer Table 21.3, II) was offered in 1965 by Union Carbide as Bakelite Polysulfone, now renamed Udel. In 1967 Minnesota Mining and Manufacturing introduced Astrel 360 Table 21.3, V), which they referred to as a polyarylsulfone. In 1972 ICI brought a third material onto the market which they called a polyethersulphone (III) and which they then marketed as Victrex. They also introduced a material intermediate between III and V known as Polyethersulphone 720P (IV) but which has now been withdrawn. In the late 1970s Union Carbide introduced Radel (VI), which has a higher level of toughness. Around 1986 Union Carbide sold their interest in polysulphones to Amoco. In addition the Astrel materials were produced by Carborundum under licence from ICI. 

Polymers have come a long way from parkesine, celluloid and bakelite they have become functional as well as structural materials. Indeed, they have become both at the same time one novel use for polymers depends upon precision micro-embossing of polymers, with precise pressure and temperature control, for replicating electronic chips containing microchannels for capillary electrophoresis and for microfluidics devices or micro-optical components. 

Thermosetting resins are polymers that become highly cross-linked and solidify into a hard, insoluble mass when heated. Bakelite, a thermosetting resin first produced in 1907, has been in commercial use longer than any other... 

Chcmically, Bakelite is a phenolic resin, produced by reaction of phenol and formaldehyde. On heating, water is eliminated, many cross-links form, and the polymer sets into a rocklike mass. The cross-linking in Bakelite and other thermosetting resins is three-dimensional and is so extensive that we can t really speak of polymer "chains." A piece of Bakelite is essentially one large molecule. 

The smoking salons of the Hindenburg and other hydrogen-filled dirigibles of Ihe 1930s were insulated with urea-formaldehyde polymer foams. The structure of this polymer is highly cross-linked, like that of Bakelite (Section 31.5). Propose a structure. 

One of the earliest, and still one of the most important, polymers is the material known as Bakelite, which is a condensation polymer of phenol, C6H5OH, and formaldehyde, H2C=0. Formaldehyde will react with phenol to produce the following compounds when the ratio is 1 1 ... 

Baekeland in America obtained his first patent for materials prepared from these two compounds. In 1910 he founded the General Bakelite Company to exploit this development, in the process making phenol-formaldehydes, the first synthetic polymers to achieve commercial importance. 

However, such polymers, which are of the Bakelite type (phenol-formaldehyde... 

Thermosets differ molecularly from thermoplastics in that their individual chains are anchored to one another through crosslinks. The resulting network creates cohesive materials that demonstrate better thermal stability, rigidity, and dimensional stability than thermoplastics. Some examples of traditional thermosets are melamine-formaldehyde resins, which are used to treat fabrics to make them wrinkle-free, and Bakelite (a phenol-formaldehyde resin), a historically important polymer used in many applications, such as costume jewelry, electrical switches, and radio casings. 

The first widely used synthetic polymer was phenol formaldehyde (Bakelite). It is made by heating phenol (C6H5OH—hydroxybenzene) together with formalde-hyde (H2CO).These react to yield a three-dimensionally cross-linked polymer. To reduce the brittleness of Bakelite, it is usually filled with fibers or platelets of an inert solid. It is a good electrical insulator, relatively hard, and thermally stable to a few hundred degrees Centigrade. Its hardness is 50-60 kg/ mm2 (Mott, 1956). 

Baekeland A process for making organic polymers by reacting phenols with formaldehyde. Based on an observation by A. von Bayer in 1872 and developed into an industrial process by L. H. Baekeland from 1905 to 1909. It was used to make Bakelite, one of the first commercial plastics. The first industrial manufacture began in Germany in 1910. 

He found out in 1909 that a resinous plastic substance is formed in this reaction. This substance could be heated and moulded into a shape. Further heating of a substance in the mould sets it in the fine shape. Further heating does not resoften this substance. Baekeland patented this substance and called it Bakelite. Bakelite was the first Synthetic polymer. The industry of Bakelite led to a study and establishment success of polymer science. 

Some other example of condensation polymers are Dacron (a polymer of ethylene glycol), polyester (a polymer of p-terephthalic acid), Bakelite (a polymer of phenol and formaldehyde). 

True synthetic polymers came into use when Bakeland came from Belgium and applied his knowledge of the formation of a moldable plastic from phenol and formaldehyde to give the product named Bakelite. This was about 1914. This product, under heat and pressure, set up to a thermo-setting resin and had useful properties especially as an insulating material for electrical items. 

The first synthetic polymer utilized on a large commercial scale was Bakelite produced by Leo Baekeland, one of many foreign-born scientists who helped create American technology. By 1909 he had demonstrated a number of Bakelite articles to members of the recently formed Chemists Club of New York. 

Classify the following as addition and condensation polymers Teiylene, Bakelite, Poljwinyl chloride, Polythene. 

While condensation polymers account for only a modest fraction of all synthetic polymers, most natural polymers are of the condensation type. The first all-synthetic polymer, Bakelite, was produced by the stepwise polycondensation of phenol and formaldehyde. 

Frederick Frey and Walter Shultze were instrumental early researchers. Frey was among the first to dehydrogenate paraffins catalytically to olefins and then the olefins to diolefins that serve as feedstocks to the production of many of today s polymers. In competition with Bakelite, he discovered the preparation of polysulfone polymers made from the reaction of sulfur dioxide and olefins creating a hard Bakelite-like material. Frey and Schultz also developed a process that allowed the production of 1,3-butadiene from butane that allowed the synthesis of SR. 

Little rhyme or reason is associated with many of the common names of polymers. Some names are derived from the place of origin of the material, such as Hevea brasilliensis literally rubber from Brazil —for natural rubber. Other polymers are named after their discoverer, as is Bakelite, the three-dimensional polymer produced by condensation of phenol and formaldehyde, which was commercialized by Leo Baekeland in 1905. 

Till this time, polymer science was largely empirical, instinctive, and intuitive. Several polymers were commercially available prior to World War I celluloid, shellac, Galalith (casein), Bakelite, and cellulose acetate plastics hevea rubber, cotton, wool, and silk rayon fibers Glyptal polyester coatings bitumen or asphalt, and coumarone-indene and petroleum resins. However, as evidenced by the chronological data shown in Table 1.1, there was little... 

Furthermore, we often know how a polymer was made, but do not know the structure of the resulting product - a famous example of this is Bakelite (phe-nol/formaldehyde resin). Conversely, as is often the case for industrial polymers, we may have some property data, but do not know how the polymer was made or any structural details. Polymeric materials in general have a history and, more often than not, it is that history which influences or completely determines its property characteristics and not the structural characteristics. The implication of this is, that a description/encoding of a polymer s history is often more relevant than an encoding of its structure. 

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