Viljanen Eeva K, Skrifvars Mikael, Vallittu Pekka K
Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku, Turku, Finland.
Dent Mater. 2007 Nov;23(11):1420-7. doi: 10.1016/j.dental.2006.11.028. Epub 2007 Jan 9.
The aim of this study was to determine the degree of double bond conversion and thermal properties of photopolymerized dendritic copolymers and particulate filler composites that may be used as dental restorative materials.
The resins consisted of a multifunctional dendritic monomer, methyl methacrylate and varying proportions of acetoacetoxyethyl methacrylate. In addition, one of the composites contained 1,4-butanediol dimethacrylate. Camphorquinone and 2-(N,N-dimethylamino)ethyl methacrylate were used as the light-activated initiation system. The degree of conversion was determined with Fourier transform infrared spectroscopy and the thermal properties with differential scanning calorimetry.
The degree of conversion of copolymers varied from 52 to 60% and increased with increasing concentration of acetoacetoxyethyl methacrylate. The values for the composites were 32-44%. Reaction exotherms of 0.2-9.6J/g were measured for the photopolymerized experimental materials indicating residual reactivity that increased with increasing concentration of acetoacetoxyethyl methacrylate. The residual reactivity trend seemed counter intuitive to the degree of conversion. The glass transition temperatures for the completely polymerized copolymers containing acetoacetoxyethyl methacrylate were 112-116 degrees C and for the particulate filler composites 84-87 degrees C.
The addition of acetoacetoxyethyl methacrylate increased the degree of conversion. The polymerization characteristics of the experimental materials were comparable to those of control materials.
本研究旨在确定可作为牙科修复材料的光聚合树枝状共聚物和颗粒填料复合材料的双键转化率和热性能。
树脂由多功能树枝状单体、甲基丙烯酸甲酯和不同比例的甲基丙烯酸乙酰乙酰氧基乙酯组成。此外，其中一种复合材料含有二甲基丙烯酸1,4 -丁二醇酯。樟脑醌和甲基丙烯酸2-(N,N -二甲基氨基)乙酯用作光活化引发体系。通过傅里叶变换红外光谱法测定转化率，用差示扫描量热法测定热性能。
共聚物的转化率在52%至60%之间变化，并随着甲基丙烯酸乙酰乙酰氧基乙酯浓度的增加而增加。复合材料的转化率值为32% - 44%。对光聚合实验材料测得的反应放热为0.2 - 9.6J/g，表明存在残余反应活性，且随着甲基丙烯酸乙酰乙酰氧基乙酯浓度的增加而增加。残余反应活性趋势似乎与转化率相悖。含有甲基丙烯酸乙酰乙酰氧基乙酯的完全聚合共聚物的玻璃化转变温度为112 - 116℃，颗粒填料复合材料的玻璃化转变温度为84 - 87℃。
甲基丙烯酸乙酰乙酰氧基乙酯的添加提高了转化率。实验材料的聚合特性与对照材料相当。
