Interaction of two phases in PP/EPDM polymer blend probed by positron annihilation: CONTIN analysis
✍ Scribed by C. L. Wang; S. J. Wang; Z. N. Qi
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 578 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0887-6266
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✦ Synopsis
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 4 (=lo-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 uR or the width of the free-volume radius PDF in the blend decreases with 4 in the region of 4 = 10-30%, and it increases when 4 increases from 30% to 40%. The difference in the uR of the blend and the calculated value UR 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 uR, which indicates the interaction of two phases, and the impact strength of PP/EPDM blends was found and discussed.