Kinetic study of free radicals trapped in dental resins stored in different environments
Kinetic study of free radicals trapped in dental resins stored in different environments
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DOI：
10.1016/j.actbio.2009.04.034
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发表时间：
2009-09-01
影响因子：
9.7
通讯作者：
Leloup, Gaetane
中科院分区：
文献类型：
--
作者：
Leprince, Julian;Lamblin, Guillaume;Leloup, Gaetane
在这项工作中，我们使用电子顺磁共振跟踪在实验树脂（ER）和商业复合材料（Charisma（R）（Ch））中捕获的自由基在不同条件下（在25和37 ℃的空气中，在25 ℃的氩气，氧气和水中）的减少动力学。在第一天，烯丙基自由基的衰变速度较快（0-24 h），为1700-1000 a.u. Ch，1700-1500 a.u.对于ER），并且储存条件对动力学没有影响。这一阶段归因于后聚合现象。从1天到1个月，腐烂率取决于储存环境。在氩气中，自由基是相当稳定的（1天至1个月-烯丙基自由基的衰减速率：1200-1000 a.u. Ch，1400-1200 a.u.对于ER）。对于其他储存环境，在ER中，在水中的衰变速率高于在氧气和空气中的衰变速率（1天至1个月-烯丙基自由基的衰变速率：1400 a.u.至100、500和800 a. u.，分别）。在Ch中，自由基比在ER中褪色更快，因为在1个月之前达到不可检测的水平，这证明了填料对自由基减少动力学的影响。还进行了加热实验，在较高的温度下，自由基浓度下降更快，特别是在玻璃化转变温度以上。总之，环境氧主要参与自由基的终止过程。因此，影响氧扩散的条件对自由基动力学也有影响。(C)2009 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
In this work, we used electron paramagnetic resonance to follow the decrease kinetics of free radicals trapped in an experimental resin (ER) and in a commercial composite (Charisma (R) (Ch)) stored under different conditions (in air at 25 and 37 degrees C in argon, oxygen and water at 25 degrees C). During the first day, the decay was fast (0-24 h-rate of decay of allylic radical: 1700-1000 a.u. for Ch, 1700-1500 a.u. for ER) and the storage conditions had no influence on the kinetics. This phase was ascribed to a post-polymerization phenomenon. From 1 day to 1 month, the rate of decay depended on the storage environment. In argon, free radicals were quite stable (1 day to 1 month-rate of decay of allylic radical: 1200-1000 a.u. for Ch, 1400-1200 a.u. for ER). For the other storage environments, in ER, the rate of decay was higher in water than in oxygen and in air (1 day to 1 month-rate of decay of allyl radical: 1400 a.u. to 100, 500 and 800 a.u., respectively). In Ch, free radicals faded quicker than in ER, as undetectable levels were reached before 1 month, which attests to the influence of fillers on radical decrease kinetics. Heating experiments were also performed, and free radical concentrations decreased faster at higher temperatures, especially above the glass transition temperature. In conclusion, ambient oxygen is mainly involved in the termination process of free radicals. Therefore, conditions influencing oxygen diffusion have an impact on radical kinetics as well. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.