Polyesters glyptal

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... 

Polyesters Right now, you are probably using at least five things that are made from polyesters. Your clothes probably have some Dacron polyester fiber in them, and they are almost certainly sewn with Dacron thread. Ancient computers used floppy disks made of Mylar , and the optical film in your DVD is made of Mylar . Some of the electronics in your cell phone are probably potted (covered and insulated from shock) in Glyptal polyester resin. The soft drink in your hand probably came in a plastic bottle that was blow-molded from polyethylene terephthalate) resin, better known as PET. 

Glyptal polyesters were first prodnced in 1901 by heating glycerol and phthalic anhydride. (See Figure 3.) Because the secondary hydroxyl is less active than the terminal, primary hydroxyl in glycerol, the initial product formed is a linear polyester. A cross-linked product is produced by further heating through reaction the third alcohol. 

In this experiment, the syntheses of two polyesters (Experiment 46A), nylon (Experiment 46B), and polystyrene (Experiment 46C) will be described. These polymers represent important commercial plastics. They also represent the main classes of polymers condensation (linear polyester, nylon), addition (polystyrene), and cross-linked (Glyptal polyester). Infrared spectroscopy is used in Experiment 46D to determine the structure of polymers. 

The performance of glyptal polyester coatings was upgraded by Kienle [1], who in 1927 incorporated unsaturable vegetable oils in these polyesters and coined the acronym alcid from the first and last syllables in the reactants, viz. alcohol and acid, and then changed this name to the more euphonious alkyd. 

Polyesters from polybasic acids and polyhydric alcohols. Alkyd resins. The condensation of polyhydric alcohols and polybasic acids or anhydrides leads to polj esters known as alkyd resins. The most common member of the group is a glycerol - phthahc acid polymer, and this has led to the term glyptal resins being frequently apphed to the whole group. 

Glycolyzed PET waste, polyester polyols from, 559-560 Glyptal resins, 18... 

The bulk of polyester production in the United States has gone to the synthetic coatings field in the manufacture of glyptal resin coatings and varnishes, with production between 200,000,000 and 300,000,000 pounds in the postwar years. A recent development has been the use of polyester-styrene copolymers reinforced by Fiberglas for the manufacture of items such as low-pressure molded boats, corrugated structural sheet, and plastic pipe. The 1947 requirements for glycerol in the production of polyester resins and... 

More usually, phthalic anhydride is reacted with a polyfunctional material such as glycerol to form a network polyester (a glyptal). This class of polymer, modified with monofunctional additives and known as alkyd resins, is very important in the paint and plastics industry. Consequently most of the theoretical studies have been concerned with the formation of infinite networks ( microgel ) and the distinction between this and the so-called gel-point [75]. 

If each monomer molecule contains just two functional groups, growth can occur in only two directions, and a linear polymer is obtained, as in nylon 66 or Dacron. But if reaction can occur at more than two positions in a monomer, there is formed a highly cross-linked space network polymer, as in Glyptal, an alkyd resin. Dacron and Glyptal are both polyesters, but their structures are quite different and, as we shall see, so are their uses. 

Thennoset polyesters, such as Glyptal, alkyds and glass reinforced unsaturated polyesters have been available for several decades but Injection moldable polyaryl esters are relatively new. Whinfield and Dickerson extruded polyethylene terephthalate (PET) fibers (Dacron) in the 194O s. ( )pET was also extruded as film (Mylar) in the 1950 s but this polymer was not blow molded commercially until the 1970 s. 

Glyptal is also a polyester condensation product, but glycerol (HOCH2CHOHCH2OH) produces a cross-linked thermosetting resin. In the first stage a linear polymer is formed with the more reactive primary OH groups. 

A particularly strong and rigid polyester used for electronic parts is marketed under the trade name Glyptal . terephthalic acid and glycerol. Draw a segment of the polymer, and explain why it is so strong. 

While commercial polyesters are relatively new, they were synthesized by Berzelius in 1849 by the condensation of glycerol and tartaric acid.— The first commercial polyesters called Glyptals were produced in the early part of the 20th Century by the controlled condensation of trifunctional glycerol and difunctional phthalic anhydride.— —... 

Alkyd resins are based on polymeric resins developed in the 1920s. The first alkyd resins sold commercially under the name Glyptal were made by the General Electric Company (Fig. 3.20). Alkyd resins are a class of polyesters synthesized by condensation between an alcohol and an acid or anhydride. Actually, the anhydride is modified with a monofunctional acid, most commonly C g fatty acid, which can be obtained from vegetable oil (rubber seed oil (RSO) or palm oil) [61-63]. The major advantage of the alkyd resins is their components (fatty acids and triglyceride... 

The author has found the carbohydrate binders (e g. starch, dextrin) superior to phenol formaldehyde resins, maleic and phthalate type resins, polyester, glyptal resins, shellac, vegetable rosins, urea formaldehyde resin and melamine resin in all experiments to date. Dextrins and starches combine good binding properties and low cost with simple handling requirements. 

Poly(ethylene terephthalate) is a linear polyester obtained from the reaction of difunctional monomers. Branched or network polyesters are obtained if at least one of the reagents is tri- or multifunctional. This can be achieved either by the use of polyols such as glycerol in the case of saturated polyesters (glyptal) or by the use of unsaturated dicarboxyhc acids such as maleic anhydride in the ease of unsaturated polyester. In the preparation of glyptal, glycerol and phthalic anhydride reaet to form a viseous liquid initially, which on further reaction hardens as a result of network formation (Equation 2.31). 

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