Pyrolysis of polyisobutene (vistanex), polyisoprene, polybutadiene, GR‐S, and polyethylene in a high vacuum

Abstract

Samples of polyisobutene, polyisoprene, polybutadiene, GR‐S, and polyethylene, weighing about 25 to 50 mg., were pyrolyzed in a vacuum of about 10−6mm. of mercury in a specially designed apparatus at temperatures ranging between 300 to 475°C. The volatile products of pyrolysis were separated into four fractions: (IV) gaseous, volatile at ‐196°; (IIIA) liquid, at ‐75°, (IIIB) liquid, at 25°; and (II) waxlike fraction, volatile at the temperature of pyrolysis. The gaseous fraction was analyzed in the mass spectrometer and was found to consist in all cases of CH4. The liquid fraction, IIIA, was analyzed similarly and was found to give a mass spectrum characteristic for any given polymer. A molecular weight determination of the waxlike fraction by the micro freezing point‐lowering method, showed it to vary from 543 to 739, depending on the polymer from which the fraction was obtained. It is shown that the method of pyrolytic fractionation of high molecular weight polymers, in conjunction with mass spectrometer analysis of the more volatile fractions, can serve as a means of identifying the polymers.

A review of dipentene (dl-limonene) production from waste tire pyrolysis

“…This claim was based on a misinterpretation of the papers by Brazier et al and Madorsky [41,42]. The pyrograms presented by Miguel et al confirm that no dipentene is formed from polybutadiene [43].…”

Synthesis and structure–property comparisons of hydrogenated poly(oxanorbornene‐imide)s and poly(norbornene‐imide)s prepared by ring‐opening metathesis polymerization

“…The lower values of T d of poly(ONDI)s when compared with poly(NDI)s is consistent with the fact that the incorporation of ether linkage decreases the thermal stability of polymers in general. 16 The unexpected decrease in T d upon hydrogenation is probably due to the unstable nature of ether linkages susceptible to change by either metal hydride (polymers 4 and 5) or p-toluenesulfinic acid (polymer 6) during hydrogenation. As shown in Table 1, MW values of poly(ONDI)s were significantly decreased after hydrogenation.…”

Detailed mechanistic modeling of high-density polyethylene pyrolysis: Low molecular weight product evolution

“…Polyethylene pyrolysis has a long history of research [4][5][6], but there are still unresolved questions surrounding the mechanism and kinetics, most likely stemming from the difficulty analyzing the broad product spectrum [7]. The importance of both inter-and intramolecular hydrogen transfer reactions in the mechanism was recognized early in the study of polyethylene pyrolysis [6].…”