Synthetic plastic chemical structure

Biodegradable plastics have been used on an industrial scale since the end of the 1990s when BASF launched Ecoflex . This is a fossil-based, man-made polyester but yet is completely biodegradable due to its chemical structure. This structure is also the reason why Ecoflex combines excellent mechanical properties with the good processability of synthetic thermoplastics. Ecoflex is the preferred blend partner for bio-based and biodegradable polymers, which typically do not exhibit good mechanics and processability for film applications by themselves. Ecoflex therefore is a synthetic polymer that enables the extensive use of renewable raw materials (e.g., starch). 

Polyoxyethylene. Synthetic polymers with a variety of composition-ally similar chemical structures are as follows. Based on polarity, poly(oxymethylene) (1) would be expected to be water soluble. It is a highly crystalline polymer used in engineering plastics but it is not water-soluble. Polyoxypropylcnc (PPO) (2) and poly(mcthyl vinyl ether) (PYlVE) (3) have... 

Polymer A natural or synthetic chemical structure in which two or more like molecules are joined to form a more complex molecular structure (e.g., polyethylene in plastic). 

Although synthetic fibers and synthetic elastomers have the same chemical structure as plastics, they are not included among the latter group. Their identification will therefore be treated in this book only if they also occur as plastics. For example, polycaprolactam (Nylon 6) is used both for fiber production and as a molding material (see Sections 6.2.10 and 6.2.20). 

Chlorinated rubber resins are produced by the chlorination of synthetic and natural rubbers. The chemical structure shown in Fig. 13.3 is synthesized by the addition of chlorine to unsaturated double bonds until the resin contains 65% chlorine. These resins have similar properties to those of vinyl resins. Plasticizers are added to increase elasticity and resin adhesion. These coatings are resistant to water but have poor resistance to sunhght. 

Fiber, rayon The generic term for fibers, staples, and continuous filament yarns composed of regenerated cellulose but also frequently used to describe fibers obtained from cellulose acetate or cellulose triacetate. Rayon fibers are similar in chemical structure to natural cellulose fibers (cotton) except that the synthetic fiber contains short plastic units. Most rayon is made using the viscose process. 

The significance of synthetic polymers, on the other hand, lies more in their mechanical, electrical, or optical properties. Their use as raw materials for plastics, elastomers, or synthetic fibers is especially important. The chemical structure of these substances plays a subordinate role for their application, and it is desirable that such substances are as chemically inert as possible otherwise the useful properties could change unfavorably with time. Since the properties of plastics depend on physical quantities, the chemistry of synthetic macromolecules is bound inseparably to the physics and physical chemistry of such substances. Thus, a clear-cut division into pure preparative chemistry and pure physics of macromolecules is inadvisable. Macromolecular science represents a true interdisciplinary science. ... 

Chlorinated rubber resins include those resins produced by the chlorination of both natural and synthetic rubbers. Chlorine is added to unsaturated double bonds until the final product contains approximately 65% chlorine with the chemical structure shown in Figure 12.2. Since the final product is a hard, brittle material with poor adhesion and elasticity, a plasticizer must be added. The volume of solids of the coating is somewhat higher than that of a vinyl therefore, a suitably protective chlorinated rubber system often consists of only three coats. 

The early history of polymers is really the conversion of natural polymers into useful materials. Examples include the vulcanization of rubber (Goodyear, 1839), celluloid (which is plasticized cellulose nitrate—Hyatt, 1868), and cellulose-derived fibres, e.g. cuprammonia rayon (Despeisses, 1890) and viscose rayon (Cross, Bevan and Beadle, 1892). The first truly synthetic polymer, that is, one made from laboratory chemicals, was Bakelite (Bakeland, 1907). This was made from phenol and formaldehyde. Bakeland probably did not know the chemical structure of the Bakelite, but he did realize that organic chemicals containing multiple functionality yielded insoluble materials. The various phenol-formaldehyde resins (PF), e.g. Bakelite and novolacs, were thus obtained in an empirical manner. 

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