Chappelow C C, Byerley T J, Pinzino C S, Millich F, Eick J D
Midwest Research Institute, Kansas City, MO 64110, USA.
J Dent Res. 1996 Feb;75(2):761-7. doi: 10.1177/00220345960750020501.
During the last 12 years, significant progress has been made in the development of dental adhesive systems. Some of the more promising systems are based on multifunctional structures that contain polymerizable vinyl double bonds and reactive isocyanate groups. The utility of compounds with such structures as adhesives arises in part because their isocyanate functionality is available for reaction independently, without compromising the reactivity of the vinyl groups. The hypotheses tested in this investigation were: (1) that the monomer reactivity ratios (r1, r2) for the free-radical-initiated copolymerization of ethyl alpha-isocyanatoacrylate (alpha-EIA) and 2-isocyanatoethyl methacrylate (IEM) with selected vinyl monomers can be determined; (2) that these reactivity ratios can be used to establish Q (reactivity) and e (polarity) values for alpha-EIA and IEM; and (3) that these reactivity parameters can be useful in designing copolymers with controlled compositions for dental adhesive applications. The free-radical copolymerization characteristics of alpha-EIA and IEM were studied. The isocyanate monomers were copolymerized at seven comonomer ratios with n-butyl acrylate (NBA), methyl methacrylate (MMA), and styrene (STY). Reactivity ratios, r1 and r2, were calculated for each of the copolymer systems, giving:IEM (r1) = 0.38 and STY (r2) = 0.44; IEM (r1) = 1.19 and MMA (r2) = 0.84; IEM (r1) = 2.50 and NBA (r2) = 0.40; alpha-EIA (r1) = 2.20 and STY (r2) = 0.06; alpha-EIA (r1) = 7.00 and MMA (r2) = 0.10; and alpha-EIA (r1) = 23.50 and NBA (r2) = 0.04. The Q (reactivity) and e (polarity) values for IEM and alpha-EIA were calculated from r1 and r2 with use of the Alfrey-Price equations, giving, for IEM, Q = 0.89 and e = 0.60, and, for alpha-EIA, Q = 7.64 and e = 0.74. These reactivity parameters are useful for tailoring copolymers with controlled compositions and properties. Based on these calculated reactivity parameters, several copolymers of IEM [for example, IEM/2-hydroxyethyl methacrylate (HEMA)] are currently being prepared and evaluated as adhesives.
在过去的12年里，牙科粘结系统的发展取得了显著进展。一些更有前景的系统基于含有可聚合乙烯基双键和反应性异氰酸酯基团的多功能结构。具有这种结构的化合物作为粘合剂的效用部分源于其异氰酸酯官能团可独立进行反应，而不会影响乙烯基的反应性。本研究中测试的假设为：（1）可以确定α-异氰酸乙酯基丙烯酸酯（α-EIA）和甲基丙烯酸异氰酸乙酯（IEM）与选定乙烯基单体进行自由基引发共聚反应的单体竞聚率（r1，r2）；（2）这些竞聚率可用于确定α-EIA和IEM的Q（反应性）值和e（极性）值；（3）这些反应参数可用于设计具有可控组成的共聚物，以用于牙科粘结应用。研究了α-EIA和IEM的自由基共聚特性。异氰酸酯单体与丙烯酸正丁酯（NBA）、甲基丙烯酸甲酯（MMA）和苯乙烯（STY）以七种共聚单体比例进行共聚。计算了每个共聚物体系的竞聚率r1和r2，结果如下：IEM（r1）=0.38，STY（r2）=0.44；IEM（r1）=1.19，MMA（r2）=0.84；IEM（r1）=2.50，NBA（r2）=0.40；α-EIA（r1）=2.20，STY（r2）=0.06；α-EIA（r1）=7.00，MMA（r2）=0.10；α-EIA（r1）=23.50，NBA（r2）=0.04。使用阿尔弗雷-普赖斯方程根据r1和r2计算IEM和α-EIA的Q（反应性）值和e（极性）值，结果为：IEM的Q=0.89，e=0.60；α-EIA的Q=7.64，e=0.74。这些反应参数对于定制具有可控组成和性能的共聚物很有用。基于这些计算出的反应参数，目前正在制备并评估几种IEM共聚物[例如，IEM/甲基丙烯酸2-羟乙酯（HEMA）]作为粘合剂。
