ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
A method was proposed for a scientific description of processability of raw elastomers involving a master curve representing deformation behavior and a failure envelope representing the ultimate properties. When a specific machine is given, the mechanical and environmental conditions may be defined from the geometry and operating condition of the machine. Matching these conditions, specific information on processability may be extracted from the master curve and failure envelope. In constructing the master curve, we have proposed to use the strain-time correspondence principle including the behavior at both small and large deformation. The necessary measurements may be considerably simplified; for example, the Rheovibron and the Mooney rheometer provide necessary data over the entire range of the rubbery behavior. The latter instrument may be operated at a slow speed, i.e., 0.05 RPM and the torque-rise curve is used. With the rotational viscometer, the stress often reaches a maximum before reaching steady state, particularly with rubbers. We have shown that the curve leading to the peak is the shear stress-strain curve. The maximum was found to correspond to the failure point in the tensile deformation. The stress-time correspondence principle is not applicable to some rubbers. In these cases, the same calculation may still be conducted to evaluate the deviation from the master curve. Then, the extent of deviation may be used to represent the degree of long chain branching.
Zusätzliches Material:
15 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760190309
