Chlorination of irradiated polyethylene single crystals: 2: XES and e.s.c.a. analysis of irradiated-chlorinated PE

Kinetics of the Solid-State Chlorination of High-Density Polyethylene

“…On one hand, as a result from the surface chlorination of the polymer crystals, the CH 2 groups underwent conversion to the bulkier CHCl ones. A number of authors [9,31,32] have claimed that this is accompanied by some distortion of the crystal lattice. According to our previous studies by using wide-angle X-ray analysis, the chlorination of powdery PE was accompanied by increase of the internal microtensions, caused by the lattice distortions.…”

“…Simultaneously, radical addition of chlorine to the double bonds, 90% of which are localized within the amorphous polymer regions, may take place. [9] With chlorine content between 64 and 73 wt.-%, dehydrochlorination is also possible. [11] The chlorination of PE in the suspension and solid state represents a non-steady-state topochemical process, the kinetics of which have already been studied by a number of authors.…”

“…The activation energy values were determined during the initial stage of chlorination of powdery PE with [8,13] and without [15] applying irradiation, and with the chlorination of irradiated PE monocrystals. [9] The rate of chlorination of solid PE was found to be proportional to both the chlorine pressure and concentration of methylene groups. [15] The rate of chlorination of PE films, however, depended mainly on the chlorine concentration at low pressures.…”

“…[16] On the other hand, the chlorination rate for PE granules as well as other parameters such as the residual crystallinity and chlorine distribution along the macromolecular chain depended strongly on temperature. [17] The analysis of literature data obtained so far resulted in some generalizations concerning the solid-state chlorination of PE powder [14] or PE monocrystals [9] under the conditions of c-irradiation. The authors subdivided the whole process into two principal stages.…”

“…The second stage included a slower chemical interaction taking place within 5 (10) to 120 min from the reaction onset. The fast absorption of chlorine was found to result from the interaction of the chlorine atom (Cl 8) or Cl 2 with their derived CH 2 groups or radicals and localized in the surface layers [9] and the amorphous regions. [14] The slow stage was attributed to the diffusion of chlorine through the chlorinated surface layer of PE and its interaction with the inner layers.…”