Atai Mohammad, Ahmadi Mehdi, Babanzadeh Samal, Watts David C
Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.
Dent Mater. 2007 Aug;23(8):1030-41. doi: 10.1016/j.dental.2007.03.004. Epub 2007 May 9.
The aim of the study was to synthesize and characterize an isophorone-based urethane dimethacrylate (IP-UDMA) resin-monomer and to investigate its shrinkage and curing kinetics.
The IP-UDMA monomer was synthesized through the reaction of polyethylene glycol 400 and isophorone diisocyanate followed by reacting with HEMA to terminate it with methacrylate end groups. The reaction was followed using a standard back titration method and FTIR spectroscopy. The final product was purified and characterized using FTIR, (1)H NMR, elemental analysis and refractive index measurement. The shrinkage-strain of the specimens photopolymerized at circa 700mW/cm(2) was measured using the bonded-disk technique at 23, 35, and 45 degrees C. Initial shrinkage-strain-rates were obtained by numerical differentiation of shrinkage-strain data with respect to time. Degree-of-conversion of the specimens was measured using FTIR spectroscopy. The thermal curing kinetics of the monomer were also studied by differential scanning calorimetry (DSC).
The characterization methods confirmed the suggested reaction route and the synthesized monomer. A low shrinkage-strain of about 4% was obtained for the new monomer. The results showed that the shrinkage-strain-rate of the monomer followed the autocatalytic model of Kamal and Sourour [Kamal MR, Sourour S. Kinetic and thermal characterization of thermoset cure. Polym Eng Sci 1973;13(1):59-64], which is used to describe the reaction kinetics of thermoset resins. The model parameters were calculated by linearization of the equation.
The model prediction was in a good agreement with the experimental data. The properties of the new monomer compare favorably with properties of the commercially available resins.
本研究旨在合成并表征一种异佛尔酮基聚氨酯二甲基丙烯酸酯（IP - UDMA）树脂单体，并研究其收缩率和固化动力学。
通过聚乙二醇400与异佛尔酮二异氰酸酯反应，然后与甲基丙烯酸羟乙酯反应以用甲基丙烯酸酯端基终止反应，合成IP - UDMA单体。采用标准的返滴定法和傅里叶变换红外光谱（FTIR）对反应进行跟踪。使用FTIR、核磁共振氢谱（¹H NMR）、元素分析和折射率测量对最终产物进行纯化和表征。在23、35和45摄氏度下，使用粘结圆盘技术测量在约700mW/cm²光照下光聚合的试样的收缩应变。通过对收缩应变数据进行时间的数值微分获得初始收缩应变率。使用FTIR光谱测量试样的转化率。还通过差示扫描量热法（DSC）研究单体的热固化动力学。
表征方法证实了所提出的反应路线和合成的单体。新单体获得了约4%的低收缩应变。结果表明，单体的收缩应变率遵循Kamal和Sourour的自催化模型[Kamal MR, Sourour S. Kinetic and thermal characterization of thermoset cure. Polym Eng Sci 1973;13(1):59 - 64]，该模型用于描述热固性树脂的反应动力学。通过对方程进行线性化计算模型参数。
模型预测与实验数据吻合良好。新单体的性能优于市售树脂的性能。
