Positron lifetime as a nanoprobe for free volume distribution in high density polyethylene carbon black conducting composites

	Positron lifetime as a nanoprobe for free volume distribution in high density polyethylene carbon black conducting composites
	Patnaik, A ; Zhu, Z ; Yang, G ; Sun, Y
刊名	PHYSICA STATUS SOLIDI A-APPLIED RESEARCH
	1998-09-16
卷号	169 页码:115-125
ISSN号	0031-8965
英文摘要	The room-temperature electrical conductivity of High Density Polyethylene-Carbon Black (HDPE-CB) switching composites as a function of the conductive filler (CB) content was studied by Positron Annihilation Lifetime Spectroscopy (PALS). The CB, highly structured and porous, imparted high conductivity to its composite, starting at a low level of loading. Deconvolution of the lifetime spectra into 4 components reflected upon 3 different morphologies of the composite structure. The free volume was probed using o-Ps pick-off annihilation lifetime parameter tau(4) as a measure of electron density and the mean free volume cavity radius. The probability of o-Ps formation and the concentration of free volume cavities were probed by the o-Ps pick-off intensity I-4. In the blended composite of 29 phr (parts per hundred parts of resin), the mean free volume size increased to 3.56 Angstrom from 3.27 Angstrom, in the pristine polymer with the corresponding increase in the free volume to 204.5 Angstrom(3) from 146.8 Angstrom(3). The relative number of free volume cavities (I-4) in the composite remained fewer than the host polymer over the CB concentration studied. The changes in the cavity size and concentration, particularly a decrease in the relative intensity I-4 by 10.5% resulted in the introduction of enhanced crystallinity into the composite structure which was evidenced from a variation in crystallinity from approximate to 75% in the pristine to approximate to 85% in the 29 phr CB-HDPE composite in the X-ray diffraction profiles.
WOS关键词	ANNIHILATION LIFETIME ; PRESSURE-DEPENDENCE ; SURFACE OXIDATION ; EPOXY POLYMER ; SPECTROSCOPY ; POLYCARBONATE ; SIZE
WOS研究方向	Materials Science ; Physics
语种	英语
出版者	WILEY-V C H VERLAG GMBH
WOS记录号	WOS:000076351300019
内容类型	期刊论文
源URL	[http://119.78.100.186/handle/113462/35395]
专题	中国科学院近代物理研究所
通讯作者	Patnaik, A
作者单位	1.Indian Inst Technol, Dept Chem, Madras 600036, Tamil Nadu, India 2.Chinese Acad Sci, Inst Modern Phys, Lanzhou, Peoples R China
推荐引用方式 GB/T 7714	Patnaik, A,Zhu, Z,Yang, G,et al. Positron lifetime as a nanoprobe for free volume distribution in high density polyethylene carbon black conducting composites[J]. PHYSICA STATUS SOLIDI A-APPLIED RESEARCH,1998,169:115-125.
APA	Patnaik, A,Zhu, Z,Yang, G,&Sun, Y.(1998).Positron lifetime as a nanoprobe for free volume distribution in high density polyethylene carbon black conducting composites.PHYSICA STATUS SOLIDI A-APPLIED RESEARCH,169,115-125.
MLA	Patnaik, A,et al."Positron lifetime as a nanoprobe for free volume distribution in high density polyethylene carbon black conducting composites".PHYSICA STATUS SOLIDI A-APPLIED RESEARCH 169(1998):115-125.