Characterization of dimethacrylate polymeric networks: a study of the crosslinked structure formed by monomers used in dental composites.
Characterization of dimethacrylate polymeric networks: a study of the crosslinked structure formed by monomers used in dental composites.
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DOI：
10.1016/j.eurpolymj.2010.11.007
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发表时间：
2011-02-01
影响因子：
6
通讯作者：
Stansbury, Jeffrey W.
中科院分区：
文献类型：
--
作者：
Pfeifer, Carmem S.;Shelton, Zachary R.;Braga, Roberto R.;Windmoller, Dario;Machado, Jose C.;Stansbury, Jeffrey W.
牙科复合材料的树脂相主要由二甲基丙烯酸酯共聚单体的组合组成，最终的聚合物网络结构由单体类型/反应性和转化度定义。本基础研究评估了如何增加浓度的灵活的三甘醇二甲基丙烯酸酯（TEGDMA）的影响，在双酚A二缩水甘油基二甲基丙烯酸酯（BisGMA）共聚空隙的形成，并与这方面的网络结构与反应动力学参数和宏观体积收缩。通过近红外（NIR）光谱技术实时跟踪光聚合动力学，用粘度计评估粘度，用线性计跟踪体积收缩，通过正电子湮没寿命光谱（帕尔斯）确定自由体积形成，并且通过用二氯甲烷萃取然后通过1H-NMR分析确定溶胶-凝胶组合物。结果表明，正如预期的那样，体积收缩率随着TEGDMA浓度和单体转化率而增加。提取/1H-NMR研究表明，更灵活的TEGDMA越来越多地参与转化/交联发展的限制阶段。随着转化的进行，基于更长的照射时间或更大的TEGDMA浓度，网络变得更致密，这通过在这些情况下提取后自由体积和重量损失的减少来证明。对于相同的组合物（BisGMA/TEGDMA 60-40摩尔%），光固化增加的时间段（从10秒到600秒），自由体积降低，体积收缩增加，与转化率呈线性关系。然而，自由体积和宏观体积收缩之间的相关性被证明是相当复杂的可变组合物暴露相同的时间（600秒）。TEGDMA的添加将自由体积降低至高达40摩尔%（由于转化率增加），但在该浓度以上，尽管转化率/交联增加，但自由体积孔径由于更柔性的单体的高浓度而增加。在这些情况下，体积收缩率的增加是由于较高的官能团浓度，尽管自由体积较大。因此，通过应用帕尔斯模型，本研究阐明了牙科材料中常用的二甲基丙烯酸酯的网络形成。
The resin phase of dental composites is mainly composed of combinations of dimethacrylate comonomers, with final polymeric network structure defined by monomer type/reactivity and degree of conversion. This fundamental study evaluates how increasing concentrations of the flexible triethylene glycol dimethacrylate (TEGDMA) influences void formation in bisphenol A diglycidyl dimethacrylate (BisGMA) co-polymerizations and correlates this aspect of network structure with reaction kinetic parameters and macroscopic volumetric shrinkage. Photopolymerization kinetics was followed in real-time by a near-infrared (NIR) spectroscopic technique, viscosity was assessed with a viscometer, volumetric shrinkage was followed with a linometer, free volume formation was determined by positron annihilation lifetime spectroscopy (PALS) and the sol-gel composition was determined by extraction with dichloromethane followed by 1H-NMR analysis. Results show that, as expected, volumetric shrinkage increases with TEGDMA concentration and monomer conversion. Extraction/1H-NMR studies show increasing participation of the more flexible TEGDMA towards the limiting stages of conversion/crosslinking development. As the conversion progresses, either based on longer irradiation times or greater TEGDMA concentrations, the network becomes more dense, which is evidenced by the decrease in free volume and weight loss after extraction in these situations. For the same composition (BisGMA/TEGDMA 60–40 mol%) light-cured for increasing periods of time (from 10 to 600 s), free volume decreased and volumetric shrinkage increased, in a linear relationship with conversion. However, the correlation between free volume and macroscopic volumetric shrinkage was shown to be rather complex for variable compositions exposed for the same time (600 s). The addition of TEGDMA decreases free-volume up to 40 mol% (due to increased conversion), but above that concentration, in spite of the increase in conversion/crosslinking, free volume pore size increases due to the high concentration of the more flexible monomer. In those cases, the increase in volumetric shrinkage was due to higher functional group concentration, in spite of the greater free volume. Therefore, through the application of the PALS model, this study elucidates the network formation in dimethacrylates commonly used in dental materials.
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DOI：
10.14219/jada.archive.2000.0207
发表时间：
2000-04-01
影响因子：
3.9
作者：
Condon, JR;Ferracane, JL
通讯作者：
Ferracane, JL
影响因子：
14
作者：
PATEL, MP;BRADEN, M;DAVY, KWM
通讯作者：
DAVY, KWM
影响因子：
--
作者：
Machado, Jose C.;Silva, Glaura G.;Windmoller, Dario
通讯作者：
Windmoller, Dario
影响因子：
5
作者：
Floyd, Cynthia J. E.;Dickens, Sabine H.
通讯作者：
Dickens, Sabine H.
影响因子：
14
作者：
Sideridou, I;Tserki, V;Papanastasiou, G
通讯作者：
Papanastasiou, G