A novel process for the chlorination of polymers in solution

Abstract

A new uniform process for the solution chlorination of PVC, PE, and natural rubber has been developed with initiation by y-irradiation or radical initiators (azocompounds). The solvent used is dichloromethane instead of the industrially used tetrachloroethane or tetrachloromethane. The reaction is carried out in an autoclave with stirrer at temperatures between 70 and 100 "C and pressures from 4 to 7 bar. As a result of the simultaneous chlorination of the solvent, trichloromethane is formed and only less than 1 wt.-Yo tetrachloromethane. Characterization of the chlorinated polymers by DSC and NMR measurements showed no differences to conventionally chlorinated products. ZUSAMMENFASSUNG:Es wird ein neuer und einheitlicher ProzeD fur die Liisungschlorierung von PVC, PE und Naturkautschuk mit Initiierung durch y-Strahlung oder radikalische Initiatoren (Azo-Verbindungen) beschrieben. Dichlormethan wird an Stelle der industriellen Liisungsmittel Tetrachlormethan oder -ethan verwendet. Die Reaktion wird in einem Riihrautoklaven bei 70-100°C und 4-7 bar durchgefuhrt. Bei der gleichzeitig stattfindenden Chlorierung des Liisungsmittels entsteht als Hauptprodukt Trichlormethan und weniger als 1 Gew.-Yo Tetrachlormethan. Die Charakterisierung der chlorierten Polymeren durch DSC-und NMR-Messungen ergab keine Unterschiede zu konventiell hergestellten Proben.

Toughening modification of poly(vinyl chloride)/ α-methylstyrene-acrylonitrile-butadiene-styrene copolymer blends via adding chlorinated polyethylene

“…With regard to the chlorinated polyethylene, the glass transition behaviors are not exhibited due to the lack of low‐temperature condition in DSC tests. However, it is expected to be −21.2°C for CPE with 36% of chlorine following the below equation : where x is the content of chlorine. With the incorporation of CPE into PVC/AMS‐ABS (70/30) binary blends, one can see that no obvious changes occur in the glass transition behaviors, and the ternary blends still exhibit a single T g .…”

“…With regard to the chlorinated polyethylene, the glass transition behaviors are not exhibited due to the lack of low-temperature condition in DSC tests. However, it is expected to be 221.28C for CPE with 36% of chlorine following the below equation [31]:…”

An analysis of the reaction-diffusion mechanism governing the chlorination process of poly(vinyl chloride)

“…5 Previous studies have shown that the chlorine radical substitutes preferentially for the hydrogen atom of the -CH 2 -groups in the PVC repeat unit. 8,10,13,[15][16][17][18] Thus, the chain reaction proceeds as…”

In situ chlorination of poly(vinyl chloride) in aqueous hydrochloric acid

“…The chlorination of PVC is a widely used technology for improvement of mechanical and thermal properties of PVC. The usual way of chlorination is the reaction of chlorine gas in chlorinated hydrocarbon solvents, in fluidized bed or in aqueous suspensions in the presence of a radical-forming catalyst, or UV/ionizing irradiation [1][2][3] . The product is separated by adding methanol or other solvents, because its solubility becomes higher because of the elevated chlorine content of the chlorinated solvent.…”