Electron spin resonance of polymers

Campbell, Darren

doi:10.1002/pol.1970.230040103

Cited by 53 publications

(17 citation statements)

References 158 publications

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“…With increasing temperature, these shoulders gradually disappeared, and the peak to peak deflection gradually decreased. The hyperfine splitting observed for gamma irradiated PVC at low temperature and its disappearance with increasing temperature is well documented 1,3) . In those experiments, the hyperfine splitting was due to the formation of Cl 2 -ions.…”

Section: Resultsmentioning

confidence: 92%

“…Three peaks were found at 2, 15, and 30 min. Four regions of decay for primary radicals 1) with comparable lifetimes are known from the literature, but due to different experimental conditions, a comparison can only be qualitative.…”

Section: Resultsmentioning

confidence: 99%

“…With proceeding degradation process, a color change of PVC was observable caused by formation of a polyene structure. This polyene structure primarily results from elimination of HCl, and H 2 to some extent 1,3) . In this paper, we would like to present an alternative method to study formation and decay of radicals.…”

Section: Introductionmentioning

confidence: 97%

“…Usually, gamma or electron irradiation was used to generate radicals which were stabilized by low temperatures. Three types of primary radicals originating from C1H and C1Cl bond cleavage have been identified 1,3) . With proceeding degradation process, a color change of PVC was observable caused by formation of a polyene structure.…”

Section: Introductionmentioning

confidence: 99%

“…Radical formation in PVC has been well investigated by many authors 1,2) . Usually, gamma or electron irradiation was used to generate radicals which were stabilized by low temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of radical generation in PVC with dibenzoyl peroxide utilizing high-pressure technique

Búcsi¹,

Sźócs

2000

Macromol. Chem. Phys.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

“…Radical formation in PVC has been well investigated by many authors 1,2) . Usually, gamma or electron irradiation was used to generate radicals which were stabilized by low temperatures.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Kinetics of radical generation in PVC with dibenzoyl peroxide utilizing high-pressure technique

Búcsi¹,

Sźócs

2000

Macromol. Chem. Phys.

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ESR study of MMA polymerization by a peroxide/amine system: Bone cement formation

Oldfield

Yasuda

1999

J. Biomed. Mater. Res.

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Electron spin resonance (ESR) spectroscopy was used to gain insight at the molecular level into the curing of bone cement. Methyl methacrylate was polymerized using a N,N-dimethyl-p-toluidine (TD)/benzoyl peroxide (BPO) redox system in the presence of polymethyl methacrylate (PMMA) powder. The conventional nine-line ESR spectrum for the growing polymer radical was detected at the gel stage of polymerization. While the optimum free radical concentration was observed near the equimolar amine/BPO concentration, excess amine led to a change in the chemical structure of the trapped radical and inhibited the polymerization process. At a high amine/BPO ratio the nine-line signal disappeared and a three-line nitroxide-based radical appeared. The appearance of this nitroxide signal seems to depend on the amine/BPO molar ratio and on the presence of PMMA. An excess amount of amine with respect to BPO was found to inhibit the polymerization process. When BPO was removed, the system still polymerized but with a longer gelation time and a lower radical concentration. These results demonstrate that trapped free radicals in the bulk polymerization of MMA convert to polymeric peroxides that act as initiators in bone cement. When the accelerator 4-dimethylamino phenethyl alcohol (TDOH) was used, a higher radical concentration was observed in the polymerizing system. TDOH shows potential for being a more effective accelerator than TD for bone cement curing.

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EPR studies during radical polymerization in the liquid state. Review

Roth

Wünsche

1981

Acta Polymerica

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This paper deals with the possibilities and limitations of obtaining data on the elementary processes of radical formation and polymerization. As examples were especially discussed measurements carried out during the initial reactions of vinyl polymerization and copolymerization and during t h e photolysis of maleic anhydride solutions. Chemical and steric radical structures, internal and external motion of free radicals, intermolecular interactions in polymerizing solutions, the investigation of reaction mechaikms and of processes in the electron spin system (CIDEP) by stationary and time-resolved EPR as well as the determination of rate constants of chemical reactions are reported. EPR-Untersuchungen der radikalischen Polymerisation im fliissigen Zustand. FortschrittsberichtDie Moglichkeiten und Grenzen, EPR-spektroskopisch tiefergehende Erkenntnisse iiber die Elementarprozesse dcr Radikalbildung und der Polymerisation zu gewinnen, werden vorgestellt. Die Darstellung erfolgt hauptsachlich an IIand von Messungen an kurzlehigen Radikalcn, die in der Startphase der Vinylpolymerisation und -copolymerisation und wahrend der Photolyse VOII Maleinsaureanhydrid-Losungen auftreten. Berichtet wird uber chemische und sterische Radikalstrukturen, iiber innermolekulare und Gesamt-Bewegung freier Radikale, iiber zwischenmolekulare Wechselwirkungen in Polymerisationslosungen, iiber die Erforschung von Reaktionsmechanismen und von Vorgangen im Elektronenspinsystem (CIDEP) mittels stationarer und zeitaufgeloster E P R sowie iiher die Ermittlung von Reaktionsgeschwindiglteits-Konstanten. Mayuenue npoyeccos paaunanbnoli nonwepuaayuu8 wuaicow cocmofinuu. 0630p PaCCMaTpHBaioTCH BO3YOXCHOCTH A IIpeHeJIbI HCCJIeROBaHHR C I I O M O q b K ) anP-CneKTpOCKOItliEI BJIeMeHTapHMX np0-I~eCCOB 06pa30BaHHH PaAIlKaJIOB H IIOJIHMepH3aqEIEI. B KaqeCTBe npHMepOB npHBeAeHb1 pe3yJIbTaTbl EI3peHHH KOpOTOKOXAByqEIX PaHHKaJIOB, BO3HUKaIOUIHX B HaqaJIbHOfi CTaAEIH IIOJIEIMepH3aqHA H COnOJIEIMepEI3aqHEI BHHHJIb-HbIX COenHHeHHfi H BO BpeMH @OTOJIH3a PaCTBOpOB aHrHApHRa MaJIeHHOBOfi KEICJIOTbI. PaCCMaTpHBaioTCH BOnpOCM XHMH'4eCKOrO EI CTepEIqeCHOI'o CTPOeHHH paAHKaJIOB, BHYTPHMOJIeKYJIHpHOfi EI o6qefi UOABllmHOCTH CBO6OAHbIX pa~EIKaJIOB, MeXMOJIeKyJIHpHbIX B3aEIMOAefiCTBHfi B IIOJIHMepH3yK)qEIX CHCTeMaX, HCCJIenOBaHHH MeXaHH3MOB peaKgHfi % I IIpOlJeCCOB B 3JIeKTPOHHOfi CIIkiHOBOfi CHCTeMe (xn3) C IlOMOIlJbIO CTaqHOHapHOfi H pa3peWeHHOfi UO BpeMeIIH 3nP, a TaKXe OnpejJeJIeHHFI KHHeTHqeCKHX KOHCTaHT XAMHqeCKAX peaKI[EIfi.

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Electron spin resonance of polymers

Cited by 53 publications

References 158 publications

Kinetics of radical generation in PVC with dibenzoyl peroxide utilizing high-pressure technique

Kinetics of radical generation in PVC with dibenzoyl peroxide utilizing high-pressure technique

ESR study of MMA polymerization by a peroxide/amine system: Bone cement formation

EPR studies during radical polymerization in the liquid state. Review

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