Chloration d'un polyethylene ramifie influence de la temperature et du solvant

Quenum, Bienvenu-Magloire; Berticat, Philippe; Pham, Quang Tho

doi:10.1016/0014-3057(73)90010-4

Cited by 6 publications

(5 citation statements)

References 8 publications

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“…6 This phenomenon is enhanced when the TCB is photochlorinated between the 50-70°C range. 6 Other authors 14 have stated only that PCB absorbs the UV beams under 290 nm.…”

Section: Influence Of the Chlorination Temperature Andmentioning

confidence: 99%

“…One of these by-products is 1,1 ,2,2-tetrachloroethylene or perchloroethylene (PCB) (CCl2=CCl2). 6 Comparative UV spectroscopic studies of a pure TCB sample and of a photochlorinated one showed that the latter absorbs the UV wavelengths under 400 nm with a maximum of absorption at about· 290 nm. 6 This phenomenon is enhanced when the TCB is photochlorinated between the 50-70°C range.…”

Section: Influence Of the Chlorination Temperature Andmentioning

confidence: 99%

“…6 Comparative UV spectroscopic studies of a pure TCB sample and of a photochlorinated one showed that the latter absorbs the UV wavelengths under 400 nm with a maximum of absorption at about· 290 nm. 6 This phenomenon is enhanced when the TCB is photochlorinated between the 50-70°C range. 6 Other authors 14 have stated only that PCB absorbs the UV beams under 290 nm.…”

Section: Influence Of the Chlorination Temperature Andmentioning

confidence: 99%

“…7 The chlorination temperature. 6 The solvents used, 6 etc. Following these various CPE studies it is possible to investigate the photochlorination and thermal-chlorination mechanisms of polyethylene.…”

Section: I Imentioning

confidence: 99%

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Chlorinated Polyethylene. II. Mechanisms of Chlorination

Quenum

Berticat

Vallet

1975

Polym J

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ABSTRACT:The present paper deals with the mechanisms of photochlorination and thermal chlorination of polyethylene as influenced by the microtacticity evolution of the polymer under chlorination. The investigations have been carried out on a branched low-density polyethylene and a linear high-density polyethylene, both chlorinated under various conditions which enabled us to study the influences of the chlorination time, the chlorination temperature, the chlorination method, the solvents used, etc., on the mechanisms of chlorination. The high-resolution nuclear magnetic resonance analyses published elsewhere,5•6,12 the infrared spectroscopy,8 the ratios (Cl/C), and (number of CHCl units/number of CH2 units) and the degree of polymerization are the main results discussed.

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“…6 This phenomenon is enhanced when the TCB is photochlorinated between the 50-70°C range. 6 Other authors 14 have stated only that PCB absorbs the UV beams under 290 nm.…”

Section: Influence Of the Chlorination Temperature Andmentioning

confidence: 99%

Section: Influence Of the Chlorination Temperature Andmentioning

confidence: 99%

Section: Influence Of the Chlorination Temperature Andmentioning

confidence: 99%

Section: I Imentioning

confidence: 99%

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Chlorinated Polyethylene. II. Mechanisms of Chlorination

Quenum

Berticat

Vallet

1975

Polym J

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“…5 Those chlorinated at saturation level (73-% Cl2): i.e., branched polyethylene samples (type Ila) and linear polyethylene samples (type Ila') photochlorinated at 20°C in carbon tetrachloride (CCl4) during 4-6-8 hr; 7 branched polyethylene samples (type lib) and linear polyethylene samples (type Ilb')photochlorinated during 4 hr at 20°C; 40°C; 60°C 8 …”

Section: Methodsmentioning

confidence: 99%

Chlorinated Polyethylene. III. Relationships of Microstructure and Thermal Properties

Quenum

Berticat

Vallet

1975

Polym J

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ABSTRACT:The thermal properties (viz., second-order transitions, melting points, dynamic and isothermal heat behaviour) of chlorinated polyethylene (CPE) samples are studied here. Thermomechanical analysis (TMA), differential thermal analysis (DTA), and thermogravimetric analysis (TGA) results are listed together to correlate the thermal properties and the microstructure of CPE samples, of various chlorine contents by weight, produced from thermal chlorinated or photochlorinated linear and branched polyethylene samples. The dehydrochlorination rate of a CPE sample is shown to be strongly dependent on its microtacticity up to a 56-61-% chlorine content by weight value· Beyond this 56-61-%Cb interval the microtacticity influence is screened by the steric hindrance introduced by the err (-CHz-C!:!Cl-CCb-or -CHCl-C!:!Cl-CCb-), an -CHCl-C!:!Cl-CHCl-or -CHz-C!:!Cl-CHCl-), and [3n (-CHCl-C!:!z-CCb-) structures. At the saturation level (73-% Clz), the higher a CPE ratio, nb CHCllnb CHz, is, the lower is its maximum dehydrochlorination rate. When its ratio, nb 2 CHCllnb CHz, is less than 4, a saturated (73%) CPE sample has a unique global dehydrochlorination activation energy (Ea); when this ratio stands between 4 and 6, there are two global dehydrochlorination E.. The structures which could be regarded as responsible for these different global Ea and the second-order transitions are specified.KEY WORDS Chlorinated Polyethylene I Thermomechanical Analysis I Differential Thermal Analysis I Thermogravimetric Analysis I Second-Order Transitions I Maximum Dehydrochlorination Rate I Very few studies have been published about the thermal properties of CPE. The first one, made by Oswald and Kubu 1 dealt with glass-transition temperatures (Tg)· Era and Lindberg 2 showed the effect of heat treatment on crystallinity. Abu I sa 3 studied the dechlorination mechanism and the effect of added antimony oxide on the rate of dehydrochlorination. Saglio, et at., 4 studied the degradation of saturated (73 %) CPE and showed that fibers of saturated CPE can be used as a carbon fiber precursor.relate their microstructure and thermal properties in this paper.In carbon backbone high polymers secondary transitions can be detected besides the main second-order transition, i.e., the glass-transition temperature (T g), and the main first-order transition, i.e. the solid-liquid-transition or the melting temperature. They are:(1) The secondary second-order transitions occuring, generally, at temperatures less than Tg. They are related to the motion of short segments of the polymer's backbone (viz., branchings, substituants, "crankshaft" or "kink" mechanisms11'12) related to motions in the amorphous or crystalline phase.The CPE samples used for the above studies were, generally, commercial ones supplied without the specific conditions of their preparation which are required 5 to correlate microstructure and properties. In addition, their microstructural characterizations have been made only with infrared analysis, which is not sufficient.Since we have...

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