86444 str (74)

128 BIBLIOGRAPHY

128 BIBLIOGRAPHY

Lkiguton and Williams. /. Phys. Chem., ig₂₇ 1663 ; 1929. XXXIII., 1480, 1485-

596.

63,

% Berlin.

Lkviton and Lłighton. /. Phys. Chem„ *93(5.    |

M*m>. J. GeoJ., 1925, XXXIII., 685.    - ”

NI&ai. ^,f Płasticity,” 1931. McGraw-Hill Book Co. Porter. Trans. Parad. Soc., 1930, XXVI., 233. Richardson. Koli. Zeits., 1933* LXV., 32.

Scott Blair, Watts and Denham. Cer. Chem., ig₂₇ ^ Sharp and Gortner. J. Phys. Chem., 1923, XXVII,, |k;| Sibrbe. Trans. Farad. Soc., 1930, CIV., 26 ; 1931, cxix Smoluchowski. Koli. Zeits., 1916, XVIII., 194.    ’

Staudinger. “ Die hochmol. organ. $erbind,’>1932.® Taylor. Proc. Roy. Soc. (A), 1932, CXXXVIII., 41. Treyan. Blochem. J., 19x8, XII., 60.

CHAPTER XII

General Conclusfons, and Suggestions for the Rheolo-gical Testing of Commercial Materials.

When a materiał is to be investigated rheologically it is first necessary to decide on what type of method to use. The following suggestions may be of some help in making this decision:—

(i)    If the materiał is a true fluid, or a rigid solid, the matter is rełatively simple. One can measure viscosity, viscosity-temperature coefficient, elastic

- moduh, etc., etc., as suits each case.

(ii)    If the materiał is nearly but not quite a true fluid, the investigator should find out if it has a yield-value, and if its flow curves are straight over a reasonable rangę, and if so, fit a Bingham type of eąuation. If not, the Scott Blair modification of the Bingham-Murray plastometer may prove useful. Log(L² — I²)/log t curves give somq measure of the deviation from Poiseuiłłe’s law, but they do not distinguish between thixotropy and structural-viscosity. For thixotropic materials the bali yiscometer may be used, if the materiał is transparent, and large samples are available. It is as well to try to get a measure of the finał (stirred) viscos ity. If big discrepancies from Poisewlle's la w occur, especially if the Bingham treatment is possible, some type of Bingham plastometer can be used; the ąuickest in operation ofthese is the Scott Blair-Crowther pattern.

(iii) If the materials are of the “ dough ” type,

INDUS. RHSO.    ¹²⁹    5