Experimental study and modeling of UV‐enhanced PVC chlorination to CPVC using a gas–solid process

Abstract

Experiments were carried out in a vibrated fluidized bed to investigate the dynamic process of UV-enhanced synthesis of chlorinated polyvinyl chloride (PVC) using a gas-solid method, where a UV-Vis online analysis system was used to record the kinetics of chlorination. Meanwhile, a comprehensive mathematical model incorporating the distributed activation energy model was established to describe the hindrance effect of Cl atoms already inserted on the PVC polymer chain on the later insertion during the chlorination process. Each of the hypotheses in the model was validated by the well-designed experiments, and the model predictions matched well with the experimental data under various operating conditions. Sensitivity analyses of three primary operating parameters, that is, temperature, chlorine concentration, and UV intensity, were made for better understanding of the mechanism of PVC chlorination. It is anticipated that the modeling methodology in this work would be also suitable for similar gas-solid reaction systems.

UV‐Enhanced Gas‐Solid Chlorination of Polyvinyl Chloride for Cleaner Production of Chlorinated Polyvinyl Chloride

“…The whole equipment has been introduced in details in our former papers [20,21,23]. The vibrated-bed reactor is composed of a vibration platform and a cylindrical quartz reactor.…”

“…The reaction rate is 2-4 times higher than that of intermittent radiation, and the temperature would also promote the chlorination. Besides, the peak reaction rate is obtained in the beginning because the number of reactive sites in the PVC polymer decreases along with the reaction progress [21,23].…”

Effect of segment structure on the thermal stability ofCPVCin theGas–Solid PVCchlorination process

“…[1][2][3] Moreover, CPVC can help decrease the chlorine, which is an excessive, toxic product in the chlor-alkali industry, by immobilizing the chlorine in the solid-state resins. Therefore, the CPVC is receiving more and more attention and has been widely applied in industrial and civil fields due to its superior physico-chemical properties, [4] such as thermal stability, [5] corrosion resistance, [6,7] and flame resistance. [8,9] There are three methods for chlorination: suspension, gas-solid, and solution.…”

Structure and solubility of chlorinated poly(vinyl chloride) prepared by a gas–solid phase method

“…Their excellent corrosion resistance, high effect resistance, tensile strength, and excellent performance as coatings and adhesives have attracted wide attention locally and globally . Moreover, the continuous development of preparation methods for CPVC, from the solution method to the suspension and gas–solid method, since the 1930s have led to the development of CPVCs and their applications …”

“…7 Moreover, the continuous development of preparation methods for CPVC, from the solution method to the suspension and gas-solid method, 8 since the 1930s have led to the development of CPVCs and their applications. 9 In contrast to other methods, the gas-solid method is an ecofriendly and economical method. 10,11 The initiation method during reaction includes thermal, ultraviolet (UV), 12 and lowtemperature plasma initiations.…”