Depolymerization as a chain reaction

Simha, Robert; Wall, Leo A.; Blatz, P. J.

doi:10.1002/pol.1950.120050509

Cited by 135 publications

(46 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One criticism of the earlier treatment [1,2] that is not totally valid since some monodisperse polymers can now be prepared by appropriate polymerization techniques, has been that existing polymeric materials are polydisperse. Since the assumption that a "most probable" distribution exists in many polymers and is maintained throughout the degradation process simplifies the theoretical treatment, several efforts in this area were made [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…Some time ago a theory [1,2] 1 was developed for the thermal degradation of those polymers that undergo pure chain bond ruptures and hence in an open system are completely volatilized. The mechanism assumed was comprised of four elementary free radical processes: initiation, propagation, intermolecular transfer, and termination.…”

Section: Introductionmentioning

confidence: 99%

“…At the time, long kinetic chain lengths were anticipated in many polymer decompositions [5,6] and for such situations the method of bimolec ular termination is of small consequence. Also, termination can be actually effectively first order if the degree of polymerization is shorter than the zip [1,2] or kinetic chain length. A recent study of the decomposition of polytetrafluoroethylene [7] has, however, demonstrated that the mechanism for this polymer has a short zip length with termination mainly by combination.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Pyrolysis of anionic and thermally prepared polystyrenes

Wall¹,

Straus²,

Florin³

et al. 1973

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

View full text Add to dashboard Cite

The changes in molecular weights, their distributions, and initial rates have been measured, for a series of polystyrenes prepared by thermal and anionic procedures. The information obtained and previous results can be explained to a very large extent by a kinetic chain decomposition comprised of competing end and random initiation, depropagation, intra-and intermolecular transfer and termination by combination.Key words: Anioni c polysl yre ne; molec ular weight distributions; molecular weights; thermal poly· s t yre :1 e; polymer ; pc ! ys t y !"e~e de g!"2da t!op. ; pyrolys is; thermolys is.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pyrolysis of anionic and thermally prepared polystyrenes

Wall¹,

Straus²,

Florin³

et al. 1973

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

View full text Add to dashboard Cite

show abstract

“…The weight of this fraction wa calculated from i ts volume, pressure, and composition. 3 . Pyrolysis of Styrene Polymers 3.1.…”

mentioning

confidence: 99%

“…It was prepared by the Dow Chemical Co. by low-temperature polymerization and had , an average molecular weight of 450,000, as determined by the light-scattering method . 3 • Too small to be accurately d etcrmined.…”

mentioning

confidence: 99%

Pyrolysis of styrene, acrylate, and isoprene polymers in a vacuum

Straus¹,

Madorsky²

1953

J. RES. NATL. BUR. STAN.

View full text Add to dashboard Cite

Pyrolysis was carried out in a vacuum in the temperature range 250 0 to 400 0 C. The volatile products were collected and fractionated. The more volatile products were analyzed in t he mass spectrometer , whereas t he less volatile products were tested fo r their average molecular weights.In t he styrene group of polymers, poly-alpha-methylstyrene yielded practically 100 percent of monomer, and poly-meta-methylstyrene and poly-alpha-deuterostyrene yielded about 52 and 70 percent, respective ly, of monomer or similar products, the other volatiles consisting of dimer, trimer, and some tetramer. Hydrogenated polystyrene y ielded volat il es consisting of 6 percent of small molecules and a m ixture of products of average molecular ,""eight of 602.In t he acrylate group of polymers, benzoyl peroxide polymerized polymethyl methacrylate, molecular weight 150,000, and the rm all y prepared polymethyl methacrylate, molecular weight 5,1 00,000, yielded almost 100 percent of monomer. Polymethy l acrylate yielded carbon dioxide, methanol, and a m ixtu re of various fragments, of average molecular weight of 686.In the isoprene group of polymers, synthetic polyisoprene, natural rubber (cis-p oly isoprene), and gutta hydrocarbon (trans-polyisoprene) , y ielded isop rene, dipentene, and mixtu res of large molecules of average molecular weight of about 600.

show abstract

Depolymerization

Sawada¹

2007

Encyclopedia of Polymer Science and Technology

View full text Add to dashboard Cite

This article provides an overview of depolymerization from a thermodynamic and kinetic perspective. Depolymerization is characterized by the scission of the main chain backbone. Three types of reactions such as random degradation, depolymerization and weak‐link degradation may occur separately or in conjunction with each other. The kinetic treatment of depolymerization processes has been described in the case of random degradation and chain depolymerization. Depolymerization is characterized as their thermodynamic and energetic features such as heat, entropy, free energy for polymerization, bond‐dissociation energy, and activation energy. Current applications of depolymerization are found in various fields such as biological recycling (biorecycling), chemical recycling, agricultural uses in natural environment, and medical uses.

show abstract

Depolymerization as a chain reaction

Cited by 135 publications

References 12 publications

Pyrolysis of anionic and thermally prepared polystyrenes

Pyrolysis of anionic and thermally prepared polystyrenes

Pyrolysis of styrene, acrylate, and isoprene polymers in a vacuum

Depolymerization

Contact Info

Product

Resources

About