Synthetic plasticizers

The first cellular synthetic plastic was an unwanted cellular phenol—formaldehyde resin produced by early workers in this field. The elimination of cell formation in these resins, as given by Baekeland in his 1909 heat and pressure patent (2), is generally considered the birth of the plastics industry. The first commercial cellular polymer was sponge mbber, introduced between 1910 and 1920 (3). 

Phenolic resins were the first totally synthetic plastics invented. They were commercialized by 1910 [I]. Their history begins before the development of the structural theory of chemistry and even before Kekule had his famous dreams of snakes biting their tails. It commences with Gerhardt s 1853 observations of insoluble resin formation while dehydrating sodium salicylate [2]. These were followed by similar reports on the behavior of salicylic acid derivatives under a variety of reaction conditions by Schroder et al. (1869), Baeyer (1872), Velden (1877), Doebner (1896 and 1898), Speyer (1897) and Baekeland (1909-1912) [3-17]. Many of these early reports appear to involve the formation of phenolic polyesters rather than the phenol-aldehyde resins that we think of today. For... 

The first plastic was celluloid, made of nitrocellulose softened by vegetable oils and camphor. It was used for car windshields and for movie film. The first completely synthetic plastic was bakelite (1910) produced from phenol and formaldehyde for use in the electrical industry. 

The basic filter material is produced from glass fiber or synthetic plastic fibers (polyester, acrylic, polyamide). Separation is mainly of particles 5 pm and larger. 

Harz-alkohol, m. resin alcohol, -austauscher, m. ion-exchange resin, -baum, m. pitch tree (applied to various conifers), -bildung, /. resin (or rosin) formation, (of gasoline) giim-ming. -brei, m. a viscous material trapped in the pores of a synthetic plastic, resin magma, -cerat, n. Pharm.) rosin cerate, -elektrizi-tat, /. resinous (negative) eleetricity. 

Although PHAs obtain interest and are widely studied by many researchers, PHAs production is limited by production cost. A major problem to the commercialization of PHAs is much higher production cost than petrochemical-based synthetic plastic (Luengo, 2003). 

A novel non-petroleum based biodegradable plastic produced from sugar based agricultural raw materials as sweet sorghum, sugarcane and molasses, having potential properties comparable with conventional or synthetic plastics, is under development and could lower the contribution of plastic wastes to municipal landfills at about 20% of the total waste by volume and 10% by weight and can achieve a satisfactory for the environmental imperative. 

Any polymer that has commercial value must be stable under a variety of conditions. This means that it must not degrade when exposed to light, heat, or a variety of chemicals, including acids, bases, and oxidizing agents. Over time, polymers with superior stability have replaced less stable materials. For example, the first synthetic plastic, celluloid, is so highly flammable that it is no longer an important commercial polymer. 

The first fibers used by humans were probably those that occur naturally as tissues or excretions of either vegetables or animals (see Table 87). At much later times, after metals had been discovered, humans also learned to manufacture - from some of the ductile metals, mainly gold, silver, and their alloys - thin filaments (not fibers, however), which have since been used to decorate textile fabrics. It was only during the twentieth century, after synthetic plastics were discovered, that it became possible to make artificial human made fibers. The great majority of the natural fibers, such as cotton and wool, occur as staple fibers, short fibers whose length is measured in centimeters. Silk is different from all other natural fibers in that it occurs as extremely long and continuous filaments several hundred meters long. 

Engineering polymers generally comprise a high performance segment of synthetic plastic materials that exhibit premium properties. In this paper, engineering thermoplastics developed for advanced applications, and particularly for enhanced thermal stability are considered. 

Soon after the Bakelite era came other synthetic plastics. 

Synthetic plastic currency stamped with optical ink... 

Synthetic polymers are man-made high molecular mass macromolecules. TTiese include synthetic plastics, fibres and rubbers. The two specific examples are polythene and dacron. 

As shown in Table I, the plastic component of MSW has increased dramatically. Past development of synthetic plastic formulations has focused on reducing the photo, chemical, and biological degradation of the plastic polymers. However, the persistence of plastics in the environment as litter, potential marine hazard, and with concern for global carbon cycling 1,6) has focused recent attention on the recycling of plastics or development of new biodegradable plastic formulations. 

What was the first synthetic plastic Although some nineteenth-century experiments should be mentioned, such as the 1869 molding process for cellulose nitrate discovered by John and Isaiah Hyatt, probably the first major breakthrough came in 1910 with Leo Baekeland s discovery of phenol formaldehyde resins (Bakelite ). These are still the leading thermoset plastics made today. The pioneering work of Wallace Carothers at Du Pont in 1929 produced the nylons now used primarily as fibers but known as the beginning of thermoplastic resin technology. 

Since many synthetic plastics and elastomers and some fibers are prepared by free radical polymerization, this method is important. Table 6.1 contains a listing of commercially important addition polymers including those that will be emphasized in this chapter because they are prepared using the free radical process. 

The discovery that there is no connection between the source of a polymer and the property of biodegradability led to the development of man-made polymers that combine the property of biodegradability with the outstanding processability and properties of synthetic plastics. 

In various kinds of industrial production, materials need to be treated with charged colloidal particles. In such systems, the value of the zeta-potential analyses are needed to control production. For example, in paper, adhesive, and synthetic plastics, colloidal clay can be used as filler. In oil drilling, clay colloidal suspensions are used. The zeta potential is controlled so as to avoid clogging the pumping process in the oil well. It has been found that, for instance, the viscosity of a clay suspension shows a minimum when the zeta potential is changed (with the help of pH from 1 to 7) from 15 to 35 mV. Similar observations have been reported in coal slurry viscosity. The viscosity was controlled by the zeta potential. 

With half-synthetic plastics the polymer chain has been formed in a living tissne, but it has been chemically modified afterwards. 

The development of plastics accompanied synthetic fibers. The first synthetic plastic with the trade name Celluloid was made in 1870 from a form of nitrocellulose called pyroxylin, the same substance used to produce the first rayon. Celluloid was developed in part to meet the demand for expensive billiard balls, which at the end of the nineteenth century were produced from ivory obtained from elephant tusks. John Wesley Hyatt (1837-1920) combined pyroxylin with ether and alcohol to produce a hard substance called collodion. Hyatt s collodion, like Bernigaut s original rayon, was unstable and potentially explosive. He solved this problem by adding camphor to the collodion to produce a stable hard plastic he called Celluloid. 

These sizable outlets for petroleum products are of relatively recent development. Only a decade ago synthetic rubber production was under 20,000,000 pounds per year. Twenty-five years ago synthetic rubber was virtually unknown in America, and total production of synthetic plastics, chiefly phenolics from coal tar, was only 12,000,000 pounds per year. Chemicals and chemical intermediates were produced from coal, minerals, and vegetable products, but the petroleum industry was devoting its interest almost exclusively to the production of fuels and lubricants. 

AN (alone or contg a small amt of dendritic inotg nitrates), 1.5% mineral oil, 1.0% dia-tomaceous earth 16.0% bagasse (or other low-d fuel such as shredded corn stalks or shredded synthetic plastics). This mixt... 

Although cellulose nitrate, a semisynthetic plastic and not really an engineering material, was introduced in 1868, the first completely synthetic plastic, phenol-formaldehyde, was introduced in 1909. Phenol-formaldehyde is certainly an engineering material and the first of many such products to excite the imagination of engineers. 

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