Thermal decomposition of poly(vinyl chloride)

Abstract

Poly(vinyl chloride), polymerized with the use of γ‐radiation, benzoyl peroxide, and 2,2′‐azobis(isobutyroitrile) as initiators, was thermally decomposed in vacuo. The gaseous decomposition products as analyzed by mass spectrometry consist primarily of hydrogen chloride for decomposition temperatures below approximately 300°C. At temperatures approximating 400°C., various hYdrocarbons are evolved along with the hydrogen chloride. Energetic considerations are discussed and the activition energy is determined. A free radical mechanism for the dehydrochlorination reaction that appears consistent with the reaction rate data for a three‐halves‐order reaction is postulated.

Characteristics and mechanism of low temperature dehydrochlorination of poly(vinyl chloride) in the presence of zinc(II) oxide

“…This result suggests that the activation energy of cross-linking dehydrochlorination is lowered in the presence of ZnO. Hendrikse et al [25,26] There have been many kinetic studies [1,4,11,22,24] for the dehydrochlorination of pure PVC, and the activation energy of the dehydrochlorination 1 is 109-134 kJ mol -1 .…”

“…It is widely accepted that the first step of thermal decomposition of PVC is polyene formation accompanying evolution of a large quantity of HCl gas [1][2][3][4][5][6]. The polyene once formed easily turns to aromatic compounds such as benzene and toluene via C-C bond cleavage.…”

Thermal degradation of polyacrylonitrile, polybutadiene, and copolymers of butadiene with acrylonitrile and styrene

“…This is charac terisLic of polym ers in which th e loss of side groups from a.d jacent carbons of th e ch ain r esults in conjugated double bonds in the ch ain, sin ce th ese double bonds tend to enhance th e th ermal sLability of Lhe chain. Polyvinyl chlorid e [12] and polyviJ1~TlideJ1e fluoride [13] may b e cited a.s examples of a behavior similar to t hat of polyacrylon itrile.…”

“…The hydrogen cyanide most likely forms by spli tting-off the chain in the same manner as CH3COOH in the pyrolysis of polyvin yl acetate [11], H Cl in tbe pyrolysis of polyvinyl chloride [12], and HF in the pyrolysis of hydroAuoroethylene polymeTs [13]. Formation of monomer can b e visualized as follows.…”

Ranking PVC Roofing Membranes Using Thermal Analysis

“…It has been reported that practically all HCI (60 wt%) is released by the time the sample has reached 220~ (Turi 1981). Thermogravimetricmass spectrometric (TG-MS) studies have shown that the degradation products of PVC were composed of HC1, aromatics, and other hydrocarbons such as ethylene, ethane, propylene, xylene, and methane (Stromberg et al 1959;Mardosky 1964). The first weight loss observed in Fig.…”