NIR-spectroscopic investigation of water sorption characteristics of dental resins and composites.
NIR-spectroscopic investigation of water sorption characteristics of dental resins and composites.
复制标题
牙科树脂和复合材料吸水特性的近红外光谱研究。
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
B. Dickens
中科院分区：
文献类型：
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作者：
S. Venz;B. Dickens
采用近红外（NIR）方法，利用5200 cm（-1）的水吸收，以0.01-cm-至0.15-cm-厚的试样形式检测光聚合牙科树脂和复合材料中吸收的水。厚度为t [cm]的试样中吸收水的浓度c [mol L（-1）]通过比尔定律A = ect计算。A是NIR吸光度，e是吸收水的吸收率。e取决于水分子的环境，并且有必要估计每种材料中水的e。通过重量分析法测定吸水性，并与NIR光谱中的吸光度相关。一旦知道了材料的e和水含量之间的关系，就可以在非常薄的样品上快速测定吸水性，以便更快地平衡。当样品发生溶解时，从NIR和重量测量的比较中评价样品的溶解度行为。发现吸收在聚合物介质中的水的NIR吸收率e与聚合物的亲水性程度和氢键能力成反比。在聚环氧乙烷甲基丙烯酸酯聚合物中的水簇的存在是从e与水含量的图中的凸上曲率推断的。
A near infrared (NIR) method using the 5200 cm(-1) absorption of water has been employed to examine water absorbed in photopolymerized dental resins and composites in the form of 0.01-cm- to 0.15-cm-thick specimens. The concentration, c [mol L(-1)], of absorbed water in specimens of thickness t [cm] was calculated by means of Beer's law, A = e ct. A is the NIR absorbance and e is the absorptivity of absorbed water. e depends on the environment of the water molecule and it is necessary to estimate e for water in each material. Water sorption was determined gravimetrically and correlated to the absorbance in the NIR spectrum. Once the relationship between e and water content was known for a material, water sorption was determined rapidly on very thin specimens for faster equilibration. Where dissolution of the specimen occurred, the solubility behavior of the specimen was evaluated from a comparison of NIR and gravimetric measurements. The NIR absorptivity, e, of water absorbed in a polymeric medium was found to be inversely related to the degree of hydrophilicity and hydrogen bonding capability of the polymer. The presence of water clusters in a polyethylene oxide methacrylate polymer was inferred from convex-up curvature in the plot of e vs. water content.