WATER SORPTION OF GLASSY DENTAL POLYMERS

玻璃状牙科聚合物的吸水性

• 批准号: 3219929
• 负责人: DEREK TURNER
• 金额: $ 9.69万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-04-01 至 1988-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3219929
• 关键词: amorphous solid; biomaterial evaluation; chemical structure; composite resins; crosslink; dental materials; dental prosthesis; diffusion; photochemistry; polymerization; polymers; water

The aim is to characterize the water sorption of the glassy, load-bearing, polymers used in dentistry. Plan sheet specimens will be prepared by polymerization of methacrylates and dimethacrylates. Polymerization will be effected by most of the initiating systems used for dental materials, including photochemical techniques. In selected cases, residual monomer will be removed by gamma-irradiation and annealing. Dry specimens will be immersed in water and then periodically removed, mopped dry, and weighed until constant weight is approached. Subsequently, similar measurements will be made during drying. Data will be analyzed to provide equilibrium sorption values and diffusion coefficients, the latter by application of Fick's laws for the case of plane sheet geometry. In another test, measurements of linear changes in dimensions, on equilibrium water sorption, will be made microscopically and used to calculate volumetric changes in cases of isotropic expansion. Volumetric changes will also be determined more directly be periodically weighing specimens suspended in water, as in Archimedes' method. Volumetric data will be analyzed to deduce what fraction of the water uptake is not accompanied by swelling. The working hypothesis is that this is the fraction of water accommodated in microvoids. The general scientific discipline involved in the proposed work is diffusion in glassy polymers. This is a field which, recently, has been designated as requiring further work. The particular problem of water sorption of glassy polymers is an unavoidable responsibility for the field of dental materials. The health-relatedness of such work is that excessive water sorption is an important factor in restricting to temporary use chairside hard denture base reliners and crown and bridge resins. It is also a factor in the wear of composite tooth restorative materials and in the choice of polymers for denture bases. The long term objective is to relate water sorption of glassy polymers to chemical (crosslinks) and physical (microvoids) structure and thereby to design useful dental prostheses.

目的是表征玻璃状的、承重的、 牙科用聚合物。 图则样本将由 甲基丙烯酸酯和二甲基丙烯酸酯的聚合。 聚合将 受到用于牙科材料的大多数引发体系的影响， 包括光化学技术。 在选定的情况下，残留单体 将通过伽马辐照和退火去除。 干燥标本将 浸入水中，然后定期取出，擦干，称重 直到接近恒定重量。 随后，类似的测量 将在干燥过程中进行。 将对数据进行分析，以提供平衡 吸附值和扩散系数，后者通过应用 平面薄板几何情况下的菲克定律。 在另一个测试中， 在平衡水上测量尺寸的线性变化 吸附，将在显微镜下进行，并用于计算体积 各向同性膨胀情况下的变化。 体积变化也将是 更直接地确定定期称重样品悬浮在 水，就像阿基米德的方法一样。 将分析体积数据， 推导出哪部分吸水不伴随着膨胀。 工作假设是，这是水的比例容纳 在微空隙中。 拟议工作涉及的一般科学学科是 玻璃状聚合物中的扩散。 这是一个领域，最近， 被指定为需要进一步的工作。 水的特殊问题 玻璃状聚合物的吸附是该领域不可避免的责任 牙科材料。 这种工作与健康的关系是过分的， 吸水性是限制临时使用的重要因素 椅旁硬义齿基托树脂和冠桥树脂。 是 这也是复合牙齿修复材料磨损和 义齿基托聚合物的选择。 长期目标是 将玻璃状聚合物的吸水性与化学（交联）联系起来， 物理（微孔）结构，从而设计有用的牙科 假体.