Chain scission efficiency of some polymers in γ‐radiation

Ouano, A. C.; Johnson, Dale E.; Dawson, B.; Pederson, Lester A.

doi:10.1002/pol.1976.170140319

Cited by 27 publications

(7 citation statements)

References 9 publications

(2 reference statements)

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“…The lower molecular weight PMMAs (G 1.04), however, agree more closely with the 1.1 reported by Kircher et at [21]. These results imply that the G-value is independent of the molecular weight (M n > 55000) [26] and the tacticity of the polymer.…”

Section: Molecular Weight Stereochemistry Effectssupporting

confidence: 91%

Parameters Affecting the Electron Beam Sensitivity of Poly(methyl methacrylate)

et al. 1977

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Poly(methyl methacrylate), PMMA, is used as a model polymer to determine quantitatively the effect of molecular weight, molecular weight distribution, and tacticity on electron beam sensitivity. The heterotactic, syndiotactic, and isotactic stereoforms of PMMA were synthesized with molecular weights ranging from 10 4 to 10 7 and dispersivities from 1.2 to about 10. The G-values as determined by gamma radiation are about 1.3 and are independent of the three parameters. However, the solubility rate of PMMA is very dependent on the tacticity, and the relative solubility rates are in the order syndiotactic < heterotactic-s isotactic. The weightaverage molecular weight ratio was found to give a better correlation with solubility rate ratio than the number-average molecular weight ratio. The molecular size of the developer solvent was shown to have a much greater effect on the solubility rate than the molecular weight of the resist. An optimal developer solvent for PMMA can be systematically selected from a homologous series of nalkyl acetates which enhance the resist sensitivity.

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Section: Molecular Weight Stereochemistry Effectssupporting

confidence: 91%

Parameters Affecting the Electron Beam Sensitivity of Poly(methyl methacrylate)

et al. 1977

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“…10,11 Wall and Brown 12 monitored intrinsic viscosity and calculated the number of scissions events in PMMA per unit dose of radiation. Ouano et al 13 analyzed the molecular weight distribution in PMMA arising from gamma irradiation by the gel-permeation chromatography technique. Knappe and Yamamoto 14 studied the effect of dose on color center formation.…”

Section: Introductionmentioning

confidence: 99%

Hardness of irradiated poly(methyl methacrylate) at elevated temperatures

Lee

Cheng

2001

Journal of Applied Physics

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The decrease in hardness induced by gamma irradiation in poly͑methyl methacrylate͒ ͑PMMA͒ has been investigated. The hardness is assumed to decrease linearly with the concentration of radiation-induced defects. Annealing at high temperatures induces defect annihilation as tracked by an increase in hardness. The annihilation follows first-order kinetics during isothermal annealing. The dependence of hardness on the reciprocal of the time constant satisfies the Arrhenius equation, and the corresponding activation energy of the kinetic process decreases with increasing dose. The hardness of postannealed PMMA decreases linearly with increasing dose.

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“…The molecular weight of I11 is significantly lower than that of I or 11, but scission s u 5 ceptibility is not a function of molecular weight. 26 Therefore, I11 with higher molecular weight can not be expected to be more sensitive than I or 11. All three samples in Table I showed some crosslinking propensity according to the G, value (the number of crosslinking events per 100 eV of absorbed dose).…”

Section: Resultsmentioning

confidence: 99%

Chain scission efficiency and reactive‐ion etch resistance of alternating copolymers of styrene and olefins trisubstituted or tetrasubstituted with electron‐withdrawing groups

Itô

Hrusa

Hall

et al. 1986

J. Polym. Sci. A Polym. Chem.

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Alternating copolymers of styrene (St) with electron‐deficient olefins trisubstituted or tetrasubstituted with cyano and carboalkoxy groups have been subjected to 60Co γ‐radiolysis together with a series of copolymers of methyl methacrylate (MMA) and St. The chain scission susceptibility Gs—Gx determined by membrane osmometry drastically decreases as St is incorporated in poly(methyl methacrylate) (PMMA). Whereas the alternating St‐MMA copolymer is slightly crosslinked upon irradiation, an alternating copolymer of St with diethyl 2‐cyano‐1,1‐ethylenedicarboxylate maintains a fairly high degradation sensitivity (Gs—Gx = 1.2). The reactive‐ion etch rates were determined for the series of polymers in CF4/O2 (92/8). The etch resistance is significantly increased by introduction of St units in PMMA, and the highly substituted alternating copolymer etches as slowly as the MMA(50)—St(50) copolymers. Thus the alternating copolymer of NCCH=C(CO2Et)2 with St behaves like PMMA when exposed to high‐energy radiation but is comparable to PSt in plasma environments.

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Chain scission efficiency of some polymers in γ‐radiation

Cited by 27 publications

References 9 publications

Parameters Affecting the Electron Beam Sensitivity of Poly(methyl methacrylate)

Parameters Affecting the Electron Beam Sensitivity of Poly(methyl methacrylate)

Hardness of irradiated poly(methyl methacrylate) at elevated temperatures

Chain scission efficiency and reactive‐ion etch resistance of alternating copolymers of styrene and olefins trisubstituted or tetrasubstituted with electron‐withdrawing groups

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