Catalytic degradation of polymers: Part III—Degradation of polystyrene

Audisio, Guido; Bertini, Fabio; Beltrame, Pier Luigi; Carniti, P.

doi:10.1016/0141-3910(90)90030-b

Cited by 100 publications

(74 citation statements)

References 7 publications

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“…Th3 addition of catalysts increased the variety of products obtained. Many of these were present in low concentrations, but there was an overall decrease in molecular weight [22,30,46]. In ail the studies, both higher temperatures and longer reaction times resulted in an increase of the amount of the volatile fraction [22,30,37,40,[44][45][46][47] and a decrease in the molecular weight of the residue [22,37,[44][45].…”

Section: Results Of Previous Studiesmentioning

confidence: 99%

“…Nor are the positions of these weak points in the polymer chain established. Some researchers beleive them to be randomly distributed along the pol ymer chain [8,14,[28][29][30], while others suggest that they are at the chain ends [31][32][33]. The initiation step occurs by carbon-carbon bond scission at weak points, chain ends and/or randomly to produce free radicals [6b].…”

Section: Initiationmentioning

confidence: 99%

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Thermolysis of polystyrene

Simard

Kamal

Cooper

1995

J of Applied Polymer Sci

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Styrene was r EK:overed trom polystyrene (molecular weight of 138 OO~) by thermolysis in a nitrog,en atmosphem .at templ3ratures between 368°C and 407°C. The' results wc~n9 inaepElndent of thE~ initial weight of polystyrene which was varied between ~30 and 480 grar~s. Up to 70% of the polystyrene was converted to styrene. The styrene yield increased with temp€;'rature. At higher temperatures, the residue left il1 thE! reactor Gonsisted mainly of styrene monomer, dimer and trimer (MW of 190). The maximum rate constant of volatile production was found to fit a first order modal. The activation energy obtained was 166.5 kJ/mol, which is in accordanco with literature values .•

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Section: Results Of Previous Studiesmentioning

confidence: 99%

Section: Initiationmentioning

confidence: 99%

Thermolysis of polystyrene

Simard

Kamal

Cooper

1995

J of Applied Polymer Sci

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“…The reacting system was heated at 383-423 K with stirring for 6 h. The cooled reaction product was placed in a separating funnel. The spent catalyst was washed twice with diethyl ether (2 9 50 cm 3 ) and the solution added to the reaction products. The collected products were washed with sodium hydrogen carbonate solution (2 9 60 cm 3 ) in order to neutralize sulfuric acid.…”

Section: Acid Strength Measurementsmentioning

confidence: 99%

“…At high cracking temperature (673-773 K), PS thermally decomposes forming a mixture of oligomers (dimers, trimers, tetramers…), which subsequently undergo catalytic transformation [1,2]. Solid acids have been frequently used as PS cracking catalysts [3,4]. They are able to protonate styrene oligomers with the formation of reactive carbenium ions.…”

Section: Introductionmentioning

confidence: 99%

“…All these transformation have been already demonstrated. In PS cracking products, styrene oligomers as well as benzene, toluene, styrene, ethylbenzene, cumene and indane, indene and naphthalene derivatives were observed [3][4][5]. Haw [6] reported that the cyclic styrene dimer adsorbed in the structure of HZSM-5 at 373 K dealkylates into benzene and methylindyl cation, which forms naphthalene at elevated temperature.…”

Section: Introductionmentioning

confidence: 99%

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Decomposition of styrene dimers: the influence of the acid strength of the catalyst

Marczewski

Kaminska

Marczewska

2012

Reac Kinet Mech Cat

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A relation between the acid strength of the active centers of sulfated alumina catalysts and the results of transformation of styrene dimers was studied. The acid strength measurements were performed according to the test reaction method using a-methylstyrene, styrene, tert-butylbenzene and cumene reactions at 2) allowed to transform them selectively (96 %) into benzene and alkylbenzenes. When the acid strength of the catalyst was higher (H O B -3.5), the selectivity of the reaction changed. The selectivity of benzene and its derivatives diminished (to 65 %) and dicyclic compounds (indane and indene derivatives) appeared (selectivity 21 %) among the reaction products.

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Hydrous pyrolysis of silica-supported polystyrene

Bertini

Audisio

Beltrame

et al. 1998

J. Appl. Polym. Sci.

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Thermal degradation of polystyrene has been studied in the presence of water under subcritical conditions (hydrous pyrolysis). The experiments were performed in closed systems under inert atmosphere, in the temperature range of 300 -320°C, for 1-24 h. The results showed that the presence of water increases the yields of the volatile products, mainly in the first steps of the pyrolitic process, with a higher selectivity of monomer. In order to improve the effective phase contact between water and the polymer during the degradation, hydrous pyrolysis runs have been carried out on silica-supported polystyrene. Some of these experiments were performed using a stirred reactor. Under these conditions, the above effects appeared to be greatly emphasized. Qualitative and quantitative analyses of the degradation products have been reported for the series of runs investigated. The best recovery of styrene has been achieved at 320°C and 8 h, being close to 71%.

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Catalytic degradation of polymers: Part III—Degradation of polystyrene

Cited by 100 publications

References 7 publications

Thermolysis of polystyrene

Thermolysis of polystyrene

Decomposition of styrene dimers: the influence of the acid strength of the catalyst

Hydrous pyrolysis of silica-supported polystyrene

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