The aim of this work was to evaluate the potential of 2-dimethylamino-6-propionylnaphthalene (denoted Prodan^®) as a sensitive fluorophore for monitoring the oxidation of polymers at low extent of oxidation within the “induction period” and for characterizing the chemical modification of polymers induced by thermal oxidation. The fluorophore was introduced into polyethylene films (80 microns thick) by soaking in a methanolic solution before and after thermal oxidation carried out for various durations. The emission features of this fluorescent probe are known to be strongly dependent on the polarity of the medium. Changes in polarity due to the formation of oxidized products provoked a notable shift of the wavelength at the maximum of fluorescence, which was correlated to the extent of the oxidation measured by infrared spectroscopy. Moreover, the emission intensity of the probe was observed to dramatically increase with the amount of oxidation products. It was observed that there was a good correlation between the wavelength at the emission maximum, the amount of fluorophore absorbed, and the oxidation extent. Interestingly, the modification of the fluorophore features was detected within the induction period when no oxidation product could be detected by infrared spectroscopy. The probe fluorescence was then used as a sensitive and easy method to monitor the chemical modification of the polymer at the early stages of oxidation.

这项工作的目的是评价2-二甲基氨基-6- propionylnaphthalene（表示普罗丹的电位^®）作为敏感的荧光团，用于在“诱导期”内监测低氧化程度的聚合物的氧化，并表征由热氧化引起的聚合物的化学改性。在进行各种时间的热氧化之前和之后，通过浸入甲醇溶液将荧光团引入聚乙烯膜（80微米厚）中。已知该荧光探针的发射特征强烈依赖于介质的极性。由于形成了氧化产物而导致的极性变化引起了在荧光最大值时波长的显着变化，这与通过红外光谱法测得的氧化程度有关。此外，观察到探针的发射强度随氧化产物的量急剧增加。观察到在最大发射波长处，吸收的荧光团数量和氧化程度之间具有良好的相关性。有趣的是，在红外光谱无法检测到氧化产物的情况下，在诱导期内检测到了荧光团特征的修饰。然后，将探针荧光用作一种敏感而简便的方法，以监测氧化初期聚合物的化学修饰。