Die Makromolekulare Chemie 151 (1972) 285-288
Department of Synthetic Chemistry, Faculty of Engineering, Nagoya University,Nagoya,JapanKurzmittelung

On the Distribution of Chlorine-Atoms in ChlorinatedPolyvinylchloride Prepared by Various Methods
TADAOKI OKUMOTO, HAJIME ITO, SHIN TSUGE*), and TSUGIO TAKEUCHI(Eingegangen an 6. September 1971)
Polyvinylchloride (PVC) is often chlorinated to develop the heat stability, resistance to chemical agents and so on. The properties of the chlorinated polyvinylchloride (CPVC) may vary not only with the degree ofchlorination hut also with the distribution of chlorine atoms in the polymer chains. Recently we have presented the study of structure of chlorinated PVC by pyrolysis-gas chromatography with a furnace type pyrolyzer1). In this work, the distributions of substituting chlorine atoms were
8tudicd with CPVC synthesized by Yariou,3 methods and their differences
resulting from the method were also discussed by pyrolysis-gas chromatography with a new induction heating pyrolyzer.
Three series of CPVC were prepared by the following methods of chlorination; the first one is a gas phase method, where PVC was chlorinateduder the illumination of a chemical lamp in the atmosphere composed ofone part of nitrogen and one part of chlorine gas, the second one is asuspension method, where the chlorination was carried out in the suspension method composed of one part of 33 % hydrochloric acid and one
third of PVC, and the last one is a solution method1), where the chlorination was performed in chloroform solution of PVC. The resulting polymers by the gas phas-, the suspension- arid the solution method win heabbreviated as CPVC-Gas, CPVC-Susp, and CPVC-Soln, respectively.
The degree of chlorination (A) of the polymer is defined as percentage
nunher of monomer units containing two chlorine atoms as follows :ple wapped by a peace of foil, whose CURIE temperature lay in 423℃, was mounted in
the induction coil and decomposed instaneously by applying current to the coil. The
resulting pyrolysis products were separated by a PEG-20M-column to record pyrograms.
As shown in our previous work1), raw PVC yields benzene almost quantitatively, whereas with the rise of chlorination (A), various chlorinesuhstituted aromatics are observed. A typical pyrogram of CPVC-Susp(A = 56.1) is shown in Fig. 2.

Relative yields of the benzene derivatives from the various CPVC areSummarized in Table 1. Three series of CPVC differ greatly from one
another especially in the yields of mono-, di-, and trichlorobenzenes, which
is illustrated in Fig. 3. Although the yield of benzene decreases with therise of chlorination, any appreciable differences are not observed between

the three series of CPVC. On the other hand, the yields of mono-, di-, andtrichlorobenzenes increase as a function of the degree of chlorination.
Among them, the yield of mono chlorobenzene increases in order ofCPVC-Soln, -Susp, and (or) -Gas, whereas the yields of di- and trichlorobenzenes show the contrary tendency. However, the difference between
CPVC-Susp and -Gas is not so great. These results suggest that the distribution of the introduced chlorine atoms in CPVC-Soln is more homogeneous than those in CPVC-Susp and -Cas.
The distributions are reasonably considered to he dependent upon boththe mobility of the polymer chains and that of chlorine atoms to heintroduced. The polymer chains in solution move more freely than thatin suspension or solid state. On the other hand, the mean free path ofchlorine atom in gas phase is much longer than that in suspension andsolution. More homogeneous distributions of chlorine atoms in CPVC-Sob

than that in CPVC-Gas inform us that the degree of freedom of polymer
chains matters more than that of chlorine atoms. In suspension, the mobility of both chlorine and the chaims is small and, therefore, the distribution is most localized.