有机硅——聚氨酯嵌段共聚物反应动力学研究

STUDY ON REACTION KINETICS OF POLYDIMETHYLSILOXANE-POLYURENTHANE BLOCK COPOLYMERS

对端异氰酸酯基聚氨酯予聚体(PEU)分别与1,3—二(3—羟丙基)四甲基二硅氧烷(Ⅰ)和α,ω—二羟基聚二甲基硅氧烷齐聚物(Ⅱ)在THF/DOX中的反应动力学进行了研究。结果表明,反应程度直至6O％,这两种反应均为二级反应。PEU与Ⅰ对应于65、56和47℃三个温度的反应速度常数分别为6.3×10^(-2)、3.8×10^(-2)和1.68×10^(-2)1/mol·min, PEU与Ⅰ的反应活化能及频率因子分别为66,14kJ/mol和1.l×10~9;PEU与Ⅱ对应于65、56和47℃三个温度的反应速度常数分别为9.9×10^(-3)、2.4×10^(-3)和1.76×10^(-3)1/mol·min,PEU与Ⅱ的反应活化能及频率因子分别为85.81kJ/mol和1.43×10^(11)。

The kinetics of the reaction between isocyanate groups terminated polyurethane prepoymers(PEU) and 1,3--bis(3-hydroxypropyl)tetramethyldisiloxane (Ⅰ), and that be- tween PEU and α,ω-dihydroxy siloxane oligomers(Ⅱ) are respectively studied in a mixed sol- vent system of 1: 1(W/W) THF/DOX. Analysis of the data showed the reactions were sec- nd order up to 60 percent conversion. For reaction between PEU and Ⅰ, the specific rate con- stants are 6.3×10^(-2), 3.8×10^(-2) and 1.68×10^(-2)/mol·min at 65, 56 and 47℃ respectively. The activation energy of the reaction is 66.14KJ/mol. The frequency factor is 1.1×10~9. For the reaction between PEU and Ⅱ, the specific rate constants are 9.9×10^(-3), 2.4×10^(-3)and 1.76 ×10^(-3)l/mol·min at 65,56 and 47℃ respectively. The activation engergy of the reaction is 85.81KJ/mol. The frequency factor is 1.43×10^(11).