ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Ultrasound measurements (at four different frequencies) in the range 15 MHz-75 MHz corresponding to a low frequency pulse technique were made on polypropylene (PP) films of different draw ratios, λa = 1,0, 2,8, 4,9 and 5,8. Process-dependent properties such as draw ratio (and/or thickness), quenching and annealing are functions on which attenuation depends. The logarithm of attenuation for all the samples increases almost linearly with frequency (an instrumental parameter). Such linearity is not observed when looking into the dependence of attenuation on draw ratio or thickness. This is explained in terms of the structural and morphological nature of the samples. The variation of attenuation with draw ratio indicates an exponential increase at frequencies greater than 17 MHz. The increase is very sharp at frequencies of 60,11 and 71,00 MHz. At a frequency of 16,58 MHz, a gradual linear increase in attenuation is observed with draw ratio. On the other hand, as expected, the converse situation of these observations is noted in the dependence of attenuation on film thickness.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1990.021910415
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