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Noda H.,Yamagata University | Ogata T.,Yamagata University | Manabe N.,Research and Evaluation Center Sumitomo Wiring Systems Co.
Bunseki Kagaku | Year: 2015

An evaluation of the thermal-oxidation degree of poly(butylene terephthalate) [PBT] mold parts at practical temperatures was made by applying a fluorescence imaging method with a UV light excitation. Methyl 4-methoxybutyrate (MMB), based on the reactive pyrolysis-GC/MS method, was used as an index of the thermal-oxidation degree. The fluorescence intensities of the PBT mold parts increased with the increase of the thermal aging times at 120-180 °C. The fluorescence intensities also increased with the increase of the amount of MMB. From the above results, it is suggested that this method can be used as a useful technique for evaluating the thermal-oxidation degree of PBT mold parts. © 2015 The Japan Society for Analytical Chemistry. Source


Manabe N.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Minami H.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Ishikawa M.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Otsuka M.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Nakamura A.,Research and Evaluation Center Sumitomo Wiring Systems Co.
Bunseki Kagaku | Year: 2011

The effects of copper-based metals on thermal oxidative degradation and the evaluation methods to analyze different degrees of thermo oxidative degradation with polypropylene (PP) wrere invesigated. In the state of inserting the terminal into the connector of molded PP, thermal aging took place at 140 oC for 120 hours. Four types of terminal components (cartridge brass, high copper alloy, tinning cartridge brass, and tinning high copper alloy) and PP with different thermal stability were used. From SEM observations of tin-copper alloy in the tinning layer and the ICP quantification of copper in PP, the influence of the PP thermal stability and terminal components on PP thermo oxidative degradation could be quantitatively identified. The convenient high-temperature GPC, ATR-FTIR, Oxidation Onset Temperature (OOT) with DSC, and iodometric hydroperoxide determination were used as methods to analyze oxidative degradation. Due to the master curve for the degree of degradation, OOT was effective for evaluating the degree of PP thermo oxidative degradation, ranging from the initial to increased degradation and correlated with the molecular-weight change behavior. Rapid decreases of the molecular weight could be sensitively predicted by the iodometric method in a simple manner. Source


Manabe N.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Minami H.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Ishikawa M.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Otsuka M.,Research and Evaluation Center Sumitomo Wiring Systems Co. | Nakamura A.,Research and Evaluation Center Sumitomo Wiring Systems Co.
Bunseki Kagaku | Year: 2011

The estimated thermal-oxidation degree and corresponding thermal aging times at practical temperatures with poly(butylene terephthalate) [PBT] mold parts taken from used cars was investigated by applying the time-temperature superposition principle. Methyl 4-methoxybutyrate (MMB), based on the reactive pyrolysis-GC/MS method, was used as an index of the thermal-oxidation degree. This method was applied for pars taken from the engine compartment of the used cars with mileage of 46000 km; the amount of MMB was 0.0071 wt%. The thermal aging times converted at a thermal history temperature of 84 °C by the DSC method and 100 °C were 4200 hours and 3500 hours, respectively. Based on the fact that the thermaloxidation degree can now be represented as a thermal aging time for any assumed temperature, the thermal-oxidation degree can be more accurately evaluated through the relationship between the amount of MMB and t 100 than through mileage. The lifetime of parts can also be estimated by adding the mechanical properties. The dependency of the thermal-oxidation rate on the sample thickness and the diffusion controll over the thermal-oxidation rate were mentioned. © 2011 The Japan Society for Analytical Chemistry. Source

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