Zhou Yanqiu, Chen Junjie, Zhang Limin, Huang Hui, Peng Rufang, Jin Bo
State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, China.
China Academy of Engineering Physics, Mianyang 621900, China.
Polymers (Basel). 2023 Jan 6;15(2):288. doi: 10.3390/polym15020288.
Polype ntafluoropropane glycidyl ether (PPFEE), a new random block hydroxyl-terminated polyfluoroether, was synthesized successfully by cationic ring-opening polymerization of 2-(2,2,3,3,3-pentafluoropropoxymethyl) oxirane, and its molecular structure was confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectrometry, and gel permeation chromatography. The PPFEE-based polyurethane elastomers featuring fluorine in their side chains were prepared using PPFEE as soft segments, polyisocyanate polyaryl polymethylene isocyanate as hard segments, and dibutyltin dilaurate as catalysts under different curing conditions. The microphase separation, mechanical performance, and thermal behavior of the elastomers were investigated by differential scanning calorimetry, uniaxial tensile test, and thermal gravimetric analysis, respectively. Based on the results, the percentage of hard segments dissolved into the soft segments of elastomers was opposite to the change in breaking strength. The PPFEE-based polyurethane elastomer cured with 20 wt% PAPI at the curing temperature of 50 °C displayed the maximum tensile elongation of 2.26 MPa with an elongation at break of nearly 150%. The increased contents of PAPI can effectively strengthen the tensile strength, and the maximum tensile elongation was 3.04 MPa with an elongation at break of nearly 90% when the content of PAPI was 26 wt%. In addition, the PPFEE-based polyurethane elastomers exhibited excellent resistance to thermal decomposition and a sharp weight loss temperature at around 371 °C. All the results demonstrated that the PPFEE may be a potential polymeric binder as one of the ingredients applied to future propellant formulations.
聚五氟丙烷缩水甘油醚（PPFEE）是一种新型无规嵌段端羟基聚氟醚，通过2-(2,2,3,3,3-五氟丙氧基甲基)环氧乙烷的阳离子开环聚合成功合成，其分子结构通过傅里叶变换红外光谱、核磁共振光谱和凝胶渗透色谱法得到确认。以PPFEE为软段、多亚苯基多亚甲基多异氰酸酯为硬段、二月桂酸二丁基锡为催化剂，在不同固化条件下制备了侧链含氟的基于PPFEE的聚氨酯弹性体。分别通过差示扫描量热法、单轴拉伸试验和热重分析研究了弹性体的微相分离、力学性能和热行为。基于这些结果，弹性体硬段溶解到软段中的百分比与断裂强度的变化相反。在50℃固化温度下用20 wt%多亚苯基多亚甲基多异氰酸酯（PAPI）固化的基于PPFEE的聚氨酯弹性体表现出最大拉伸强度为2.26 MPa，断裂伸长率接近150%。PAPI含量增加可有效提高拉伸强度，当PAPI含量为26 wt%时，最大拉伸强度为3.04 MPa，断裂伸长率接近90%。此外，基于PPFEE的聚氨酯弹性体表现出优异的热分解抗性，在约371℃有急剧的失重温度。所有结果表明，PPFEE作为未来推进剂配方中的一种成分，可能是一种潜在的聚合物粘合剂。
