Positron lifetime study of the free-volume properties in the polymer polyacrylonitrile

Ravindrachary, V.; Chandrashekara, A.; Sreepad, H. R.; Sreeramalu, V.; Ranganathaiah, C.; Gopal, S.

doi:10.1016/0375-9601(93)90203-c

Cited by 8 publications

(2 citation statements)

References 11 publications

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“…The o‐Ps quenching and inhibition effects were considered to have an insignificant effect on the positron parameters in this study because scavengers have influence within a limited concentration 21, 28. Previous reports17, 18, 26, 29 on positron parameters focused mainly on commercial polymers, but here a systematic copolymer series was synthesized and characterized in conjunction with the positron parameters.…”

Section: Introductionmentioning

confidence: 99%

Poly(acrylonitrile‐co‐methyl acrylate) copolymers: Correlation between copolymer composition, morphology and positron annihilation lifetime parameters

Zengeni

Hartmann

Sanderson

et al. 2010

J of Applied Polymer Sci

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A series of poly(acrylonitrile-co-methyl acrylate) copolymers of differing copolymer compositions are synthesized through free radical emulsion copolymerisation of methyl acrylate (MA) and acrylonitrile (AN) and by variation of the monomer feed ratios. The copolymers are characterized by NMR, SEC, WAXD, DMA, and positron annihilation lifetime spectroscopy. Results show that, there is a linear decrease in the glass transition temperature (T g ) of the copolymers and the MA content. There is also a progressive decrease in the crystallinity of the copolymers with increasing MA content. Positron results show a sigmoidal variation in the ortho positronium lifetime with an increasing MA content. The low MA content, semi-crystalline copolymers show a positive deviation from the linear additive relationship between the o-Ps lifetime and MA content, whereas the higher MA content amorphous copolymers show a negative deviation from the linear additive behavior. The o-PS intensity shows a linear behavior with MA content with a slight deviation from the additive linear behavior for the very high-content MA copolymer. These variations in the measured positron lifetime parameters are interpreted in terms of the copolymer morphology.

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Section: Introductionmentioning

confidence: 99%

Poly(acrylonitrile‐co‐methyl acrylate) copolymers: Correlation between copolymer composition, morphology and positron annihilation lifetime parameters

Zengeni

Hartmann

Sanderson

et al. 2010

J of Applied Polymer Sci

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show abstract

“…The results for polyacrylonitrile (PAN) were taken rom Ref. [2]. Furthermore, we studied a random copolymer of 76% (by weight) styrene and 24% acrylonitrile (SAN), an acrylonitrile-butadiene-styrene block copolymer (ABS), a styrene-butadiene-styrene block copolymer containing 25% styrene (SBS) and a blend consisting of 40% PP and 60% EPDM (PP/EPDM, compare Table 1).…”

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confidence: 99%