Property evolution during vitrification of dimethacrylate photopolymer networks.
Property evolution during vitrification of dimethacrylate photopolymer networks.
复制标题
DOI：
10.1016/j.dental.2013.09.002
复制
发表时间：
2013-11
期刊：
影响因子：
5
通讯作者：
Stansbury, Jeffrey W.
中科院分区：
文献类型：
--
作者：
Abu-elenain, Dalia A.;Lewis, Steven H.;Stansbury, Jeffrey W.
本研究旨在关联的转化率，收缩率，模量和应力的二甲基丙烯酸酯网络从橡胶态过渡到玻璃态光聚合过程中的相互关联的属性。一个未填充的BisGMA/TEGDMA树脂进行光固化的各种照射间隔（7-600秒），以提供控制水平的即时转换，这是连续监测10分钟。光纤近红外光谱允许耦合的实时转换测量与动态聚合收缩率（线性计），模量（动态力学分析仪）和应力（张力计）的发展概况。不同的辐照条件产生的最终转化率范围从6%到大于60%。当光聚合在非常低或非常高的转化水平下中断时，照射后转化（暗固化）是相当有限的，而对于悬浮在后凝胶、橡胶状区域内的光固化反应，可能有显著的暗固化贡献。在光固化期间和之后的基于转化率的性质演变的分析表明，收缩率在约40%转化率下显著增加，随后在约45- 50%转化率下开始的转化率依赖性收缩率的后期抑制。基于模量对转化率数据的广泛但明确定义的拐点，在该转化率范围内的逐渐玻璃化过程是明显的。当接近极限转化率时，由于玻璃化，模量和应力（在较小程度上）急剧上升，应力曲线显示出几乎没有（如果有的话）后期抑制，如收缩所见。在接近该模型树脂的极限转化率时，体积聚合收缩率减慢，而模量的指数级上升促进了玻璃化过程，这似乎在很大程度上决定了应力的发展。
This study seeks to correlate the interrelated properties of conversion, shrinkage, modulus and stress as dimethacrylate networks transition from rubbery to glassy states during photopolymerization. An unfilled BisGMA/TEGDMA resin was photocured for various irradiation intervals (7–600 s) to provide controlled levels of immediate conversion, which was monitored continuously for 10 min. Fiber optic near-infrared spectroscopy permitted coupling of real-time conversion measurement with dynamic polymerization shrinkage (linometer), modulus (dynamic mechanical analyzer) and stress (tensometer) development profiles. The varied irradiation conditions produced final conversion ranging from 6 % to more than 60 %. Post-irradiation conversion (dark cure) was quite limited when photopolymerization was interrupted either at very low or very high levels of conversion while significant dark cure contributions were possible for photocuring reactions suspended within the post-gel, rubbery regime. Analysis of conversion-based property evolution during and subsequent to photocuring demonstrated that the shrinkage rate increased significantly at about 40 % conversion followed by late-stage suppression in the conversion-dependent shrinkage rate that begins at about 45–50 % conversion. The gradual vitrification process over this conversion range is evident based on the broad but well-defined inflection in the modulus versus conversion data. As limiting conversion is approached, modulus and, to a somewhat lesser extent, stress rise precipitously as a result of vitrification with the stress profile showing little if any late-stage suppression as seen with shrinkage. Near the limiting conversion for this model resin, the volumetric polymerization shrinkage rate slows while an exponential rise in modulus promotes the vitrification process that appears to largely dictate stress development.
登录
查看更多内容
影响因子：
5
作者：
Stansbury, JW;Trujillo-Lemon, M;Ge, JH
通讯作者：
Ge, JH
影响因子：
3.2
作者：
Stolov, AA;Xie, T;Stidham, HD
通讯作者：
Stidham, HD
影响因子：
9.7
作者：
Leprince, Julian;Lamblin, Guillaume;Leloup, Gaetane
通讯作者：
Leloup, Gaetane
影响因子：
5
作者：
Lovell, LG;Lu, H;Bowman, CN
通讯作者：
Bowman, CN
影响因子：
5
作者：
Lu, H;Stansbury, JW;Bowman, CN
通讯作者：
Bowman, CN