High-resolution NMR spectra of chlorinated polyethylenes with various chlorine contents were measured on a-dichlorobenzene solutions at ca. 160°C. The chemical shifts for the resonances associated with the distribution of chlorine atoms along the polymer chain were resolved by the triad or pentad units, and content of the chemical units was quantitatively obtained. Chemical units containing geminal dichloride were observed when chlorine content approached ca. 40 wt %. The structure of chlorinated polyethylenes in the region of chlorine content below 40 wt% is characteristic of the statistically random distribution of chlorine atoms along the polymer chain. Various methylenes and methynes in various proton environments were observed, but chemical units such as vinylidene chloride sequences were not observed in the chain. It was found that a chlorination condition slightly affected the chlorine distribution, namely the solution chlorination increased vicinal-dichloride units rather than geminaldichloride units. However, the molecular weight of the parent polymer did not affect the chlorine distribution of chlorinated polyethylenes. The sequence-length distribution of methylenes was also obtained and the contents of longer methylene sequences (-(CH2)n-, were computed using the results of Frensdorff and Ekiner's theoretical treatment. KEY WORDS Chlorinated Polyethylenes I High-Resolution NMR I Assignment I Chlorine Distribution I Methylene-Sequence Length I a, w-Dichloroparaffins I Vinyl Chloride-Ethylene Copolymer I Hydrogenated Poly(Vinyl Chloride) I

simulation was carried out to specify the most probable model sequence and to reveal the sequence distribution of chlorines in chlorinated polyethylene(CPE). The simulation was also applied to study those of hydrogenated poly-(vinyl chloride)(HPVC) and vinyl chloride-ethylene copolymer(VC-Et) for a comparison with those of CPE. The simulation was executed with the conditional probabilities of the second order defined in terms of the actual existence probabilities of triads which can be obtained by NMR spectroscopy. Monitor quantities relating to long methylene sequence and degree of chlorination were introduced into the simulation as a criterion of a convergence. When the convergence conditions were satisfied after a few trials, a linear model sequence composed of one thousand carbons was considered to be the most probable. From the inspection of the model sequence thus determined, it can be pointed out that the distribution of chlorine atoms along the CPE chain is substantially random, being different from those of HPVC and VC-Et. The sequence distribution of various chemical units in the molecular chain was also determined readily and quantitatively without any contradiction by reckoning each sequential unit along the model sequence.