Natural and Synthetic Rubber. I. Products of the Destructive Distillation of Natural Rubber

Midgley, Thomas; Henne, Albert L.

doi:10.1021/ja01379a034

Cited by 33 publications

(10 citation statements)

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“…As shown in Scheme 3, the first one is the pyrolysis accompanied by the formation of isoprene and dipentene at high temperatures; the second one is that adventitious agents stopped or terminated the allylic radicals at mild conditions. Obviously, the reaction at the first step is consistent with that proposed by Midgely et al [9].…”

Section: Thermal Decomposition Of Nrsupporting

confidence: 91%

“…Colin et al [8] studied the long-term thermal oxidation decomposition of the un-stabilized and un-vulcanized polyisoprene rubber in the temperature range from 40 to 140 • C, and the result showed that the macromolecular chains broke rapidly because hydrogen atoms were replaced by the initially produced free radicals, and then a large amount of oxygen molecules attacked main chains of NR, accelerating the thermal decomposition of NR. Midgely et al [9] further studied the thermal decomposition of NR and considered that the produced dominant matter was dipentene during heating, accompanied by the appearance of isoprene monomer. For the formation of dipentene, two possible reasons are as follows: one is due to the Diels-Alder addition reaction between two isoprene molecules; the other one is from the back-biting reaction of the pyrolysis product of polyisoprene [10].…”

Section: Thermal Decomposition Of Nrmentioning

confidence: 99%

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Flame Retardation of Natural Rubber: Strategy and Recent Progress

et al. 2020

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Natural rubber (NR) as a kind of commercial polymer or engineering elastomer is widely used in tires, dampers, suspension elements, etc., because of its unique overall performance. For some NR products, their work environment is extremely harsh, facing a serious fire safety challenge. Accordingly, it is important and necessary to endow NR with flame retardancy via different strategies. Until now, different methods have been used to improve the flame retardancy of NR, mainly including intrinsic flame retardation through the incorporation of some flame-retarding units into polymer chains and additive-type flame retardation via adding some halogen or halogen-free flame retardants into NR matrix. For them, the synergistic flame-retarding action is usually applied to simultaneously enhance flame retardancy and mechanical properties, in which some synergistic flame retardants such as organo-montmorillonite (OMMT), carbon materials, halloysite nanotube (HNT), etc., are utilized to achieve the above-mentioned aim. The used flame-retarding units in polymer chains for intrinsic flame retardation mainly include phosphorus-containing small molecules, an unsaturated chemical bonds-containing structure, a cross-linking structure, etc.; flame retardants in additive-type flame retardation contain organic and inorganic flame retardants, such as magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, and so on. Concerning the flame retardation of NR, great progress has been made in the past work. To achieve the comprehensive understanding for the strategy and recent progress in the flame retardation of NR, we thoroughly analyze and discuss the past and current flame-retardant strategies and the obtained progress in the flame-retarding NR field in this review, and a brief prospect for the flame retardation of NR is also presented.

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Section: Thermal Decomposition Of Nrsupporting

confidence: 91%

Section: Thermal Decomposition Of Nrmentioning

confidence: 99%

Flame Retardation of Natural Rubber: Strategy and Recent Progress

et al. 2020

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“…Our results on the behavior of polystyrene when pyrolyzed at high temperature and pressure are in general agreement with those found in the literature for the same and other polymers. Midgley and Henne [13] pryolyzed natural crepe rubber in air at atmospheric pressure by heating it rapidly in an iron retort to 700° C and obtained a monomer yield of 10 percent of the pyrolyzed part, as compared with 5 percent [2] obtained in a vacuum in the temperature range 300° to 400° C. Bassett and Williams [14] heated smoked crepe rubber in air at a very fast rate to 600° C and obtained an isoprene yield of 19 percent. Boonstra and van Amerongen [15] pyrolyzed polyisoprene and other polymers in nitrogen at various pressures up to atmospheric, and at various temperatures up to 775° C. They obtained a maximum of 60 percent monomer from polyisoprene heated at 775° C and at 5 to 13 mm pressure.…”

Section: Pyrolysismentioning

confidence: 99%

Thermal degradation of polymers at high temperatures

Madorsky¹,

Straus²

1959

J. RES. NATL. BUR. STAN. SECT. A.

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Work o n thermal ~egradation of poly mers h as prev io usly been carried o ut aL lempC'mt ures up to a bout 500 G. In the present work the range has been extend cd to 850 0 C. Polystyrene was pyrolyzed in a vacuum and also in helium at at mos pheric press ure at 3620 and at 850 0 C. Analysis of t he volatile products indicates that higher temperatures a nd hi~h er. pressures cause a greater fragm en tation of the volatile prod ucts. Samples of poly (vmyh dene fl uoride), polyae ry IOl1ltnle, a nd polytn vlllylbenz ene, were pyrolyzed in a vaeu um at temperatures from 350 0 to 800 0 C. Thc more vo lat il e products were analyzed qu a li tat ively and qLl[),ntita,t ively in a mass s pectrometer. T he less volatile products were tested fo r t heir ave rage molec ular we ig ht by a microcryoscopic method . R ates of thermal degradat i:> n were als') determin ed fo r t he last t hree poly mers. Th e activation energ ies in th e temperature range 218 0 to 440 0 C lVere found to be 48 31 an d 73 kcal/ mole, r espect ively, for poly(v inyl idenc fluor id e), polyac ry lo ni t rile, a nd polytr ivin y lbcnllene.

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“…Studies were recen tly made by the present authors on the pyrolysis or polymers in a vacuum and, in 1 Figures in brackets indicate t ile literature references at tbe end of this paper. some cases, in a helium atmosphere in the t,emperature range of 500 to 1,200 °C.…”

Section: Introductionmentioning

confidence: 96%

Pyrolysis of some polyvinyl polymers at temperatures up to 1,200 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€šÃ‚Â°C

Straus¹,

Madorsky²

1962

J. RES. NATL. BUR. STAN. SECT. A.

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A study was made of t he thermal behavior in a vac uum of polystyrcne, polytetra fluoroethvlcne, poly (a-m et h y 1 s tyrcne), polypropylene, polyisobutylen(', and poly (meth yl methacrylate), when pyrolized at 500, 800, and 1,200 .0C. The v olatile products of degradation were collected and fractionated, and the fractlOns analyzed by mass-spectrometn c and microcryoscopic methods. Generally, the results from 500 °0 pyrolysis resemble those obtained prev ious ly from t he same polymer at lower temperatures. The r es uILs at 800° and 1 :200° indicate a much greater fragmentation of the pyrolys is products than at lower temp~ratures. Thus, for example, at 1,200° polystyrene yields less monomer but co nsidcrable greater amounts of 0 2H2, 0 21 -14, 0 3H" and OsI-Is than at lower te mperatures. Similarly, poly(a-methylstyrcnc) yields 100 percent monomer below 500 °0 , but at 800 and 1,200 °0 t he yields are 88 p ercen t an d 34 percent, res pec t ively. A lso at the higher temperatures, pronounced amounLs of Hz, 0I-I4, OzH 2, 0 21-14, 0 3H" 0 3HS, O,H" 0 6I-I6, O,Hs, and OsT -l s are formed.

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Natural and Synthetic Rubber. I. Products of the Destructive Distillation of Natural Rubber

Abstract: A method has been described for the quantitative estimation of total tin in a variety of organotin compounds. The method consists of a preliminary decomposition by bromine in carbon tetrachloride followed by a nitric-sulfuric acid oxidation to stannic oxide.

Cited by 33 publications

References 0 publications

Flame Retardation of Natural Rubber: Strategy and Recent Progress

Flame Retardation of Natural Rubber: Strategy and Recent Progress

Thermal degradation of polymers at high temperatures

Pyrolysis of some polyvinyl polymers at temperatures up to 1,200 ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€šÃ‚Â°C

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