Polymers chlorinated

To evaluate the counting times obtained on unknown samples, it is obviously desirable to find a function of t/.t that is simply related to the sulfur content, IIV A similar problem was solved in Section 3.8 in eonneetion with the determination of chlorine in a chlorinated polymer. The present problem is different enough to warrant translating the treatment of Hughes and Wilezewski into our language. 

A major difficulty is that so many applicahons employ polymers as though they were readily disposable, despite the fact that they are, in reality, among the more inert of chemical pollutants. In particular, plashc packaging tends to make a single use of a fabricated polymer which is then thrown away. Even when disposed of responsibly, packaging materials are the source of a serious pollution problem. Municipal authorities dispose of such materials by one of two routes, landfilling and incineration, of which the latter cannot be readily used for chlorinated polymers, such as PVC, because of the additional problems caused by organochlorine species in the atmosphere. 

Mass absorption increases strongly with the atomic number Z. For the 14.4 keV radiation of Fe, the coefficient follows approximately the relation k. 0.003 from oxygen to krypton. Therefore, organic solvents containing sulfur or chlorine are virtually opaque to the Mossbauer radiation. The sulfur component of a 2 mm layer of dimethylsulfoxide (DMSO) absorbs 70% of the Mossbauer radiation (/ = 1.1 g cm ) [35]. Even worse is dichloromethane (CH2CI2), having an absorption coefficient of 16.83 cm g. A layer of 0.1 g cm , which is only 0.75 mm thick (p = 1.33 g cm ), absorbs about 82% of 14.4 keV radiation. For the same reason, chlorinated polymers (PVC) or glass should not be used for... 

Carbon materials were obtained from polymeric precursors produced by chemical dehydrochlorination of polyvinyl chloride-polyvinyUdene chloride and chlorinated polyvinyl chloride in the presence of a strong base, followed by subsequent thermal treatment under relatively mild conditions. The sorbents obtained have three types of pores ultra-micropores, miaopores, and mesopores. hi this respect, they differ substantially from microporous activated carbons such as Saran, conventionally prepared from chlorinated polymers by thermal treatment without chemical dehydrochlorination. 

Replacement of polyvinyl chloride (PVC) and other chlorinated polymers such as polyvinylidine chloride (PVdC) with polypropylene. 

The advantages offered by this process are (1) a one-step synthesis to poly(methylchlorosilanes), (2) low cost dimers and (3) fiber processing that leads to phase pure SiC fibers. The primary drawbacks to the Dow-Corning process are (1) a low polymer yield (15-20%), (2) a multistep process and (3) the high cost of LiAUTj reduction of the chlorinated polymer. 

Table 3 Summary of studies devoted to graft copolymers from ozonized polyolefins or chlorinated polymers...

Ballistreri, A. Foti, S. Montaudo, G. Pappalardo, S. Scamporrino, E. Thermal decomposition of flame retardants Mixtures of chlorinated polymers with Sb203 and (Bi0)2C03, Journal of Polymer Science Polymer Chemistry Edition, 1979, 17(8), 2469-2475. 

For unplasticized chlorinated PVC, unplasticized chlorinated polymer blends of vinyl chloride and mixtures of these copolymers with other polymer blends, the following starting materials can be used PVC (homopolymer) polymer blends of vinyl chloride, vinylidene chloride, trans-dichloroethylene, ethylene, propylene, butylene, maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid as well as chlorine. 

Unplasticized PVC and polymer blends of vinyl chloride can be added to chlorinated polymers manufactured using the above starting materials. 

The average value of the dielectric strength of pure polymers in kV/cm is 200. Chlorinated polymers show values up to 500, polymers containing aromatic rings are on the low side (about 160). 

Because these fire-retardant salts are water-soluble and subject to leaching, several new methods have been developed which provide a water-resistant or permanent treatment for cotton fabrics and cellu-losic materials. Perkin developed a process involving successive treatment with sodium stannate and ammonium sulfate, which precipitates stannic oxide in the cellulose libers. Antimony oxide in combination with vinyl chloride or other chlorinated polymers has also been found effective. A more recent approach to this problem involves application of fire-retardant resin-forming or cross-linking compounds. " These include materials and methods based on the copolymerization of tetrakis(hydroxymethyl)phosphonium chloride and methylol — melamine, the reaction of bromoform and triallyl phosphate to form a cross-linked polymer, and the cross-linking reaction of tris(l-aziridinyl)phosphine oxide with cellulose, or its copolymerization with tetrakis(hydroxymethyl)phosphonium chloride and other materials. ... 

Perrocene may accelerate the embrittlement of chlorinated polymers (64). This mechanism also involves a charge-transfer complex wiTE a C-Cl bond in PPC and ferrooene. The formation cation,chloride ion and a polymer macroradical are formedt... 

The product of the interaction of chlorine gas with poly-DCH was studied by scanning electron microscopy (SEM) our SEM studies of pristine and brominated poly-DCH were previously rep>orted (lb). A sample at magnification 1500 is shown in Figure 1. Compared to pristine p>oly-DCH, Figure 1 reveals that a fibrous morphology is reUuned, but the fibers of the chlorinated polymer appear thicker and rougher than those of the reactant. 

Two mechanisms are suggested in the literature for the crosslinking of chlorinated polymers by 2-mercaptoimidazoline when the compound is used alone, emd when Zno is used with it. Csaszar emd Galinsky proposed the following mechanism of crosslinking CPE by NA-22 ... 

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