Study On EO-THF Copolymer Reference Materials Used In Solid Propellant

As the binder used in solid propellant, the polyether with narrow molecular weight distribution (MWD) is favourable to obtain the uniform structure of crosslinking network, so as to improve the mechanical properties and increase the propelling power; And if both of mechanical properties and rheology of powder syrupy are taken into account, the polyether with M_n≈5000 should be better. In this thesis, PTHF and P(E-CO-T) with narrow MWD were synthesized and their microstructure were studied. Furthermore, two kinds of P(E-CO-T) standard reference materials containing different M_n and MWD were prepared and their uniformity, uncertainty and storage stability were also evaluated.Cationic polymerization of tetrahydrofuran with H₂SO₄·SO₃ and HClO₄ system as the catalyst was studied firstly. The results show that M_n and MWD of PTHF can be affected via polymerization condition, i.e., M_n decreases with the increase amount of H₂SO₄·SO₃ used; However, the more amount of HClO₄ added, the higher M_n can be obtained. The experiment data indicates that PTHF with the highest M_n can be synthesized at 2℃, and polymerization time exerts less effect after 3 hours. Also, it was found that PTHF prepared in nitrogen atmosphere has the narrower MWD compared with that in air atmosphere; Moreover, under the low conversion ratio, a low dispersity index of 1.12 for PTHF can be obtained.Then the co-polymer of EO and THF with BF₃·OEt₂ and EG system as the catalyst using solution polymerization was synthesized by changing reaction temperature, solvent, feeding process and different nucleophilic agent. And based on it, the synthesis of P(E-CO-T) with narrow MWD was investigated. The results of studying the relationship between M_n and conversion show that by reaching the conversion of 58%, this relationship maintains a similarly linear relationship. At last, the microstructures of polyether synthesized under different polymerization condition were characterized.Two kinds of P(E-CO-T) reference materials were finally synthesized by solution polymerization, and their uniformity, uncertainty and storage stability were also evaluated. The results indicate that certified values of standard reference materials are (4109, 1.230) and (5976, 1.251), and their extended uncertainty are (175, 0.0076) and (175, 0.0066). Furthermore, study on storage stability shows that certified values of...