Study on curing systems of PBT polyether polyurethane with different active hydrogen components
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摘要: 以3, 3-双叠氮甲基氧杂环丁烷-四氢呋喃共聚醚(PBT)为聚醚聚氨酯的软段,以甲苯二异氰酸酯(TDI)为固化剂、一缩二乙二醇(DEG)为扩链剂、三羟甲基丙烷(TMP)为交联剂,利用二步法制备了不同活泼氢组分的PBT聚醚聚氨酯。采用傅里叶变换红外光谱测试(FT-IR)、差示扫描量热仪(DSC)、电子万能试验机及溶胀比测试,对PBT/TDI、PBT/TDI/DEG、PBT/TDI/TMP/和PBT/TDI/DEG/TMP体系进行了固化反应动力学及力学性能的研究。结果表明:PBT/TDI、PBT/TDI/DEG、PBT/TDI/TMP/和PBT/TDI/DEG/TMP体系的固化反应都为二级反应,活化能分别为135.98、165.57、164.93、164.29 kJ/mol。加入DEG可显著提高黏合剂基体的断裂伸长率,但拉伸强度下降;加入TMP能提高黏合剂基体的拉伸强度,而断裂伸长率下降;同时加入DEG和TMP的黏合剂基体拉伸强度提高,断裂伸长率有所下降。DEG和TMP能不同程度的提高固化体系的交联密度。Abstract: PBT polyether polyurethanes with different active hydrogen components were prepared by a two-step method using 3, 3-diazymoxy-tetrahydrofuran copolymer (PBT) as the soft segment of polyether polyurethanes, toluene diisocyanate (TDI) as the curing agent, diethylene glycol (DEG) as the chain extender and trimethylol propane (TMP) as the crosslinking agent. The curing reaction kinetics and mechanical properties of PBT/TDI, PBT/TDI/DEG, PBT/TDI/TMP and PBT/TDI/DEG/TMP systems were studied by Fourier Transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC), electronic universal testing machine and swelling ratio test. The results show that the curing reactions of PBT / TDI, PBT / TDI / DEG, PBT / TDI / TMP / and PBT / TDI / DEG / TMP systems are second-order reactions, and the activation energies of these systems are 135.98, 165.57, 164.93 and 164.29 kJ / mol respectively. The addition of DEG can significantly increase the elongation at break of the adhesive matrix, but the tensile strength decreases; The addition of TMP can improve the tensile strength of the adhesive matrix and reduce the elongation at break; when DEG and TMP exist simultaneously, the tensile strength of the adhesive matrix increased and the elongation at break decreased. DEG and TMP can both improve the crosslinking density of the curing systems.
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Key words:
- PBT propellant /
- Curing reaction /
- Reaction kinetics /
- mechanical property
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表 1 四组不同活泼氢组分的PBT固化体系
Table 1. PBT propellant curing system with four different active hydrogen components
固化体系 组分 固化参数R 1 PBT+TDI 1.2 2 PBT+TDI+DEG 1.2 3 PBT+TDI+TMP 1.2 4 PBT+TDI+DEG+TMP 1.2 表 2 不同固化体系和不同升温速率下的Tp
Table 2. Tp under different curing systems and different heating rates
β/(K·min−1) Tp/℃ 体系1 体系2 体系3 体系4 5 247 250 249 251 10 258 259 258 259 15 262 264 263 265 20 267 269 268 269 表 3 不同固化体系固化反应动力学参数
Table 3. Curing reaction kinetic parameters of different curing systems
固化体系 Ea/(kJ·mol−1) A/(s−1) n k(60℃)/[kg/(mol·s)] 1 135.984 1.385×1013 0.939 6.47×10−10 2 165.573 1.27×1016 0.949 1.36×10−10 3 164.933 1.18×1016 0.949 1.59×10−10 4 164.292 8.93×1015 0.949 1.51×10−10 表 4 不同固化体系拉伸力学性能
Table 4. Tensile mechanical properties of different curing systems
固化体系 抗拉强度/MPa 断裂伸长率/% 初始拉伸模量/MPa 1 1.0950 10.3930 0.3210 2 0.9280 15.2740 0.2863 3 2.0940 5.7560 0.3412 4 1.9080 7.0710 0.5452 表 5 不同固化体系溶胀系数
Table 5. Swelling coefficient of different curing systems
固化体系 溶胀系数 1 5.20 2 4.93 3 4.36 4 3.76 -
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