Vinyl chloride history

The 2-propanol-soluble substances (which were not examined in detail in this study), constituted in aggregate about 5% of the weight of the original sample, varying somewhat with the choice of additives and heat history. Infrared spectra of some of these soluble substances give evidence of the presence of ester groups. These substances con-taind substantially less chlorine than does poly (vinyl chloride). 

The development of plastics also reflects economic history. Restrictions on imported latex, wool, silk and other natural materials to Europe during the Second World War resulted in the rapid development of alternative synthetic plastics. Table 1 shows that between 1935 and 1945, many new polymers were introduced including polyethylene, polyamides, poly(methyl methacrylate), polyurethanes, poly(vinyl chloride) (PVC), silicones, epoxies, polytetrafluoro-ethylene and polystyrene. Polyethylene was incorporated into radar systems while PVC replaced the limited stocks of natural rubber as cable insulation. 

History of Production Manufacture of Vinyl Chloride Monomer Polymerization of Vinyl Chloride Copolymerization of Vinyl Chloride Characterization of Poly(vinyl chloride)... 

Isothermal aging experiments have been used to determine phase behavior in several systems. Blends of poly(vinyl chloride), PVC, (Tg = 80 °C) and poly (isopropyl methaciylate), PiPMA, (Tg = 82.5 °C), are believed to be immiscible, but because of the closeness of the Tg values, this is difficult to confirm. A 50/50 blend was annealed first at 195 °C, to erase previous thermal history, then quenched to 60 °C, i.e., (Tg - T ) 20 °C, and aged for various times (Bosma et al. 1988). 

Thermomechanical history is known to affect the molecular arrangement (morphology) of many polymers, such as poly(vinyl chloride) and branched polyethylene, thus inducing specific properties [21]. 

General discussions on the preparation and properties of PVC will be found in such references as 1, 4, 5, and 22-24. The manufacture, processing, stabilization, and applications of PVC are also discussed in references 4 and 25-32. A review of the history of ionic and Ziegler catalysis polymerization of vinyl chloride is found in Feldman [33] and Yamazaki [34]... 

In regard to the solubility of the monomer in its polymer, the diffusion of vinyl chloride into PVC varies with the physical state of the resin. Earlier work frequently dealt with studies involving PVC films more recently, powdered resins were studied. In the latter case, variations in diffusion rates were found to depend on the method of polymerization (emulsion vs, suspension method) as well as on the physicochemical parameters [53]. The equilibrium solubility of vinyl chloride monomer in poly(vinyl chloride) was found to be a function of polymer type, polymer history, time, temperature, and the VCM partial pressure [7]. Above atmospheric pressure, with the ratio of the partial pressure of VCM to the initial partial pressure of the monomer greater than approximately 0.5, the solubility of vinyl chloride is 0.300 gm per gram of poly(vinyl chloride). At lower pressures, the solubility shows a distinct decrease with temperature. Kuchanov and Bort [36] state that the solubility of VCM in PVC varies between 22.1% and 23.7% between 30° and 60°C. 

---