English Abstract
Accuracy and Degradation Detection by the Dynamic Method and the Isothermal Method Using Differential Scanning Calorimetry
Kazumi NAKAYAMA*1, 2,
Tomoko WATANABE*1, 2,
Yoshito OHTAKE*1
Mutsuhisa FURUKAWA*2
*1; Chemicals Evaluation and Research Institute, Japan, Kitakatusika-gun, Saitama, Japan
*2; Graduate School of Science and Technology, Nagasaki University, Nagasaki, Japan
Nippon Gomu Kyokaishi,(2008),81(11),447-453 Original Paper in Japanese

The initial oxidation temperature, which can be measured by DSC using dynamic temperature ramp method, is an index which can be obtained rapidly and with high sensitivity, for quantification of degradation of polymeric materials. On the other hand, there are isothermal DSC methods specified in regulatory methods, such as ASTM D3895 and JWWA K144, mainly for evaluation of thermal stability of polyolefins.
However, one of the disadvantages of these isothermal methods is that their measurement times are long.

Here, we have studied the features of both dynamic and isothermal methods, to investigate the usefulness of the methods for determining degradation of polymers. We compared the accuracy of the results using both methods, with four different polymer samples: polypropylene, high-density polyethylene, poly-4-methyl-1-pentene, and chloroprene rubber.

By using dynamic method, more accurate results compared with that by isothermal one were obtained.
In addition to this, smaller amount of sample was needed for the former method to evaluate the degradation.
Furthermore, the dynamic method was more sensitive than other conventional methods used for degradation studies, such as tensile strength test and FT-IR analysis.

(Received on April 21, 2008)
(Accepted on August 25, 2008)

Differential Scanning Calorimetry (DSC), Initial Oxidation Temperature(IOT), Dynamic Method, Isothermal Method, Degradation Detection