ISSN:
0887-6266
Keywords:
positronium lifetime distribution
;
PP/EPDM blend
;
free-volume distribution
;
phase interaction
;
impact strength
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Positron annihilation lifetime measurements were performed on pure polypropylene (PP), ethylene-propylene-diene monomer (EPDM) rubber, and their blends PP/EPDM with a series of EPDM volume fraction φ (= 10-40%). A numerical Laplace inversion technique (i.e., CONTIN algorithm), was employed to obtain the probability distribution functions (PDF) of free-volume radius. We observed that, first, the average free-volume radius in PP/EPDM blends is generally same as that in PP and is much smaller than that in EPDM. Second, the standard deviation σR or the width of the free-volume radius PDF in the blend decreases with φ in the region of φ = 10ndash;30%, and it increases when φ increases from 30% to 40%. The difference in the σR of the blend and the calculated value σc R according to the simple-mixing rule of PP and EPDM is interpreted by the existence of the two-phase interaction (i.e., the residual thermal pressure and shear stress between PP and EPDM phases in the PP/EPDM blends). The correlation between σR, which indicates the interaction of two phases, and the impact strength of PP/EPDM blends was found and discussed. © 1996 John Wiley & Sons, Inc.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
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