Other Addition Polymers

Various experimental techniques have been used to analyse the volatile decomposition products from vinylic addition polymers selective absorption of products 

BalKstreri. S. Foti, G. Montaudo, S. Pappalardo, E. Scamporrino, A. Arnesano, and S. Calgari. Makromol. Chem., 1979, 180, 2835. 

Okamoto, T. Suzuki, and O. Ishizuka, Nippon Kagaku Kaishi, 1979, 2, 259 (Chem. Abstr, 1979, 90, 152 811). 

The thermal degradation of poly(vinyl bromide), of blends of this polymer with polyfmethyl methacrylate) and of the copolymer of vinyl bromide and methyl methacrylate have been investigated by sub-ambient thermal volatilization analysis and thermogravimetry. The results are discussed in relation to the use of the vinyl bromide unit as a Are retardant. 

Alajbeg, P. Arpino, D. Deur-Siftar, and G. Guiochon.y. Anal. Appl. PyroL, 1980,1,203. 

The pyrolysis of poly(ethyleneterephthalate) was reported to occur in three stages in both air and vacuum. The kinetics of gas evolution were studied by infrared spectroscopy. As an aid to elucidation of the mechanism of decomposition of poly(ethyleneterephthalate) the degradation of RQH4CO2CH2CH2-COaCjHiR (where R = H, Cl, Me, or NOj) has also been investigated.  

A series of papers has been published on the direct degradation of a variety of polyesters in the ion source of a mass spectrometer. Polymers examined were poly(/3-propiolactone), poly(/S-pivalolactone), poly(y-valerolactone) poly-lactide, polyglycolide, and a glycolic acid-lactic acid copolymer poly(oxysuc-cinyloxy-1,4-phenylene) and poly(oxyterephthaloyloxy-l,4-phenylene).  

Luederwald, F. Merz, and M. Rothe, Angew. Makromol. Chem., 1978, 67, 193. 

The thermo-oxidative and thermo-hydrolytic breakdown of polyesters (I) have been studied.  

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Other addition polymers are created by using different monomers. The only requirement is that the monomer must contain a double bond. The monomer propylene, for example, yields polypropylene, as shown in Figure 12.28. Polypropylene is a tough plastic material useful for pipes, hard-shell suitcases, and appliance parts. Fibers of polypropylene are used for upholstery, indoor-outdoor carpets, and even thermal underwear. 

Other addition polymers Thermosoftening and thermosetting plastics Disposal of plastics... 

Many other addition polymers have been produced. Often the plastics are produced with particular properties in mind, for example PVC (polyvinyl chloride or poly(chloroethene)) and PTFE (poly(tetrafluoroethene)). Both of these plastics have monomer units similar to ethene. 

In addition to the above-mentioned polymers, other addition polymers such as polyolefin, polystyrene, polyvinylethers, polychloral, polyisocyanides, polyacetylene, and polyethers were synthesized and evaluated as the precursors for the preparation of CSPs. Some of them were coated or chemically bonded to silica gel and tested for the chiral resolution of different racemic compounds. 

First, a common method of forming polymers by a radical reaction is discussed. After the structures of the addition polymers made by this method are examined, several other procedures that can be used to prepare these or similar polymers are presented. Next, the effect of the structure of a polymer on its physical properties is discussed. This provides a basis for understanding the properties and uses of a number of other addition polymers. Rubbers (elastomers) are then discussed followed by condensation polymers and thermosetting polymers. The chapter concludes with a brief examination of the chemical properties of polymers. 

Many other addition polymers are manufactured commercially, although in much smaller amounts than those just described. For example, poly(methyl methacrylate) is prepared by radical polymerization of the methyl ester of methacrylic acid ... 

Table 17.5 shows other addition polymers that can be made using monomers with different groups attached to the carbons in the monomer s double bond. 

Thermal processes are mainly used for the feedstock recycling of addition polymers whereas, as stated in Chapter 2, condensation polymers are preferably depolymerized by reaction with certain chemical agents. The present chapter will deal with the thermal decomposition of polyethylene, polypropylene, polystyrene and polyvinyl chloride, which are the main components of the plastic waste stream (see Chapter 1). Nevertheless, the thermal degradation of some condensation polymers will also be mentioned, because they can appear mixed with polyolefins and other addition polymers in the plastic waste stream. Both the thermal decomposition of individual plastics and of plastic mixtures will be discussed. Likewise, the thermal coprocessing of plastic wastes with other materials (e.g. coal and biomass) will be considered in this chapter. Finally, the thermal degradation of rubber wastes will also be reviewed because in recent years much research effort has been devoted to the recovery of valuable products by the pyrolysis of used tyres. 

Similarly, the formation of many other addition polymers can be represented by Fig. 3.13. 

Addition polymers are produced in largest tonnages among industrial polymers. The most important monomers are ethylene, propylene, and butadiene. They are based on low-cost petrochemicals or natural gas and are produced by cracking or refining of crude oil. Polyethylene, polypropylene, poly(vinyl chloride), and polystyrene are the four major addition polymers and are by far the least-expensive industrial polymers on the market. In addition to these four products, a wide variety of other addition polymers are commercially available. 

The molecular weight of uncrosslinked rubbers is measured by the same techniques applied to other addition polymers. The concept of a molecular weight for individual chains is not applicable to bulk rubber crosslinked to a degree exceeding the gel point rather, the concept of chain length between tie points is substituted. The use of swelling liquids to elucidate this quantity is described in Chapter 7, Section 8. 

You can find some other addition polymers in Table 16-1. 

Other Addition Polymers. There are few studies on other reported polymer and plastic components of landfills. Poly(vinyl chloride) seems to be inert in landfill showing no degradation in real-world tests (23,24) and laboratory simulations (25). In the latter study, plasticizer migration occinred with its subsequent biodegradation. 

Unlike the other addition polymers described here, PVOH is not prepared from its corresponding monomer, since vinyl alcohol does not exist as a monomer due to tautomerisa-tion to acetaldehyde. However, the polymer can be produced by polymerisation of vinyl acetate followed by partial (85-90%) to complete (>97%) hydrolysis of the acetate groups. In both these cases the product is completely water soluble, although the use of PVOH as a primary thickener is rather limited due to the relatively low molecular weight which is obtained in the preparation of the corresponding polyvinyl acetate. Hydrophilic gels can be obtained when solutions of PVOH are mixed with sodium tetraborate. 

Following the discovery of poly(ethene) and its usefulness, considerable research was carried out to produce other addition polymers with modified properties to suit many diverse practical uses. Propene polymerizes to form poly(propene), often called polypropylene. This polymer is used in the manufacture of clothing, especially thermal wear for outdoor activities. 

There can be many variations on this general description because the substituents bonded to the four carbons in the double bonds can be quite variable. For example, all four bonds may be to hydrogens (CH2 = CHj, ethene, or ethylene), there may be one methyl group attached (CH2 = CHCH3, propene, or propylene), there may be a chlorine attached (CH2 = CHCl, vinyl chloride), and so on. Polyethylene, polypropylene, polyvinyl chloride (PVC), and many other addition polymers have been manufactured in mass quantities by this approach and used for many consumer products. Figure 14.33 lists some of the addition polymers that have been manufactured. Also listed are the individual alkene units (monomers) that are in these polymers and some of the uses of each. 

Similar stereochemical effects can be obtained for other addition polymers made from monomers which contain double bonds. Monomers of the type CH2=CXY and XCH=CHX can both lead to polymers with isotactic, syndiotactic or atactic forms. However, addition polymers from the monomer CH2=CX2 are always stereoregular since the polymer contains no assy metric carbon atoms. The situation is rather more complicated with polymers prepared from XCH=CHY, where X and Y are different groups. In this case it is possible to have two isotactic forms and one syndiotactic form depending upon the configuration of the planar monomer X... 

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