Vinyl chloride other technology

Although poly(vinyl chloride) (PVC) is one of the most important commercial polymers, its outdoor use has been restricted by its photochemical instability. The reasons for this instability are incompletely understood, but some progress has been made recently on this problem, and the present paper attempts to summarize the current status of fundamental knowledge in this field. This survey is not intended to be comprehensive it is concerned primarily with work published since the early 1970 s and with basic chemical principles rather than technological developments. The photodegradation of PVC has been discussed in other recent reviews (1,2, 3 4) ... 

The ARS Technologies, Inc., Ferox process is an in situ remediation technology for the treatment of chlorinated hydrocarbons, leachable heavy metals, and other contaminants. The process involves the subsurface injection and dispersion of reactive zero-valence iron powder into the saturated or unsaturated zones of a contaminated area. ARS Technologies claims that Ferox is applicable for treating the following chemicals trichloroethene (TCE), 1,1,1-trichloroethane (TCA), carbon tetrachloride, 1,1,2,2-tetrachloroethane, lindane, aromatic azo compounds, 1,2,3-trichloropropane, tetrachloroethene (PCE), nitro aromatic compounds, 1,2-dichloroethene (DCE), vinyl chloride, 4-chlorophenol, hexachloroethane, tribromomethane, ethylene dibromide (EDB), polychlorinated biphenyls (PCBs), Freon-113, unexploded ordinances (UXO), and soluble metals (copper, nickel, lead, cadmium, arsenic, and chromium). 

The Perox-Pure system is most effective in treating water with contaminant concentrations less than about 500 mg/liter. Removal efficiencies are high for organic compounds with double bonds (e.g., trichloroethylene, perchloroethylene, and vinyl chloride) and for aromatic compounds (e.g., phenol, benzene, and toluene). These compounds are easily oxidized. The Perox-Pure system can be used alone or in combination with other remedial technologies, such as air stripping. 

Reclaim is commercially available and suitable for the recovery of VOCs, vinyl chloride, trichloroethylene, carbon tetrachloride, dense non-aqueous-phase liquid (DNAPL) compounds, and, in particular, petroleum hydrocarbons. The vendor states this technology has been used in a wide variety of industrial applications, such as the remediation of groundwater at service stations, dry cleaners, herbicide production facilities, and municipal and industrial landfills, among others. 

Processes for manufacturing vinyl chloride from acetylene, which, for many years, were the only ones employed, offer the advantage of simplicity. Hence they benefit from lower capital expenditures, but, on the other hand, require the use of a much more expensive hydrocarbon raw material. This explains why they have been supplanted by technologies employing ethylene, and why they enjoyed a revival as the price of crude oil increased, although ethylene produced from gas-field ethane is ultimately the most advantageous economic alternative. 

This chapter will cover the chemistry and technology of poly(vinyl chloride) (PVC) homopolymers having a repeating unit of -CH2-CHCI-as well as copolymers of vinyl chloride with smaller amounts of other unsaturated monomers such as vinyl acetate, ethylene, propylene, acrylates, and vinylidene chloride. 

Typical bond performance of adhesives of the first generation type is shown in Table 2. The adhesives have good adhesion to thermoplastics such as polystyrene, ABS, and poly(vinyl chloride), to wood and rubber, and to steel and aluminum provided the metals are clean. It can also be seen from this table that adhesion to galvanized steel is lower than to other metals. Bonding to galvanized steel was a problem with first generation acrylic adhesives but it has been overcome with more recent embodiments of this technology covered later in this chapter. 

General Description Polyvinylidene chloride (PVDC) resin is a copolymer of vinylidene chloride (VDC) with vinyl chloride or other monomers and is used as a coating over DuPont Teijin Films Mylar films. Enhance Packaging Technologies Sclairfihn BL LLDPE Film, Dartek B-601 and B-602, nylon 66, and PVDC coated nylon. The PVDC coating provides the film with excellent oxygen-and moisture-barrier properties. 

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