ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Anisotropy and molecular orientation are well-known phenomena in the field of thermoplastics. In the case of rubber materials only a few studies have described anisotropy. Injection molding has been shown to give rise to higher anisotropy than compression molding. The anisotropy in the rubber material is assumed to be due to molecular orientation and is strengthened by carbon black. In order to understand the mechanism of anisotropy in rubber materials, an extensive study has been performed. In this paper, results from two injection-molded ethylene-propylene-diene (EPDM) rubbers, compounded both with and without carbon black, are presented. The polymers had different molecular weight distributions and the compounds were injected into center-gated 1- and 4-mm-thick disks. The properties measured in different directions were mechanical, dynamic mechanical, and swelling. These measurements show that anisotropy can be a very important factor to take into account. The origin of anisotropy is presumably the molecular orientation which arises during the filling of the mold with the rubber melt.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760341107
Permalink
