Synthesis and Characterization of Hydroxyl-terminated Block Fluorinated Copolyether(FPO-PTHF-FPO)

Abstract

We introduced fluorine into hydroxyl-terminated block copolyether so as to prepare polyurethane adhesive with better performance. Fluorine-containing epoxy compounds (FO) was synthesized by one-step method from 2,2,3,3-tetrafluoro-1-propanol (TFP) and epichlorohydrin (ECH). Then, a novel hydroxyl-terminated block fluorinated copolyether (FPO-PTHF-FPO) was prepared by cationic ring-opening polymerization of fluorinated epoxy compound (FO) with polytetrahydrofuran (PTHF) as the macromolecular initiator and boron trifluoride diethyl ether (BF₃·OEt₂) as the catalyst. The structure and properties of hydroxyl-terminated block fluorinated copolyether were characterized by FTIR, ¹HNMR, GPC, DSC, TGA, and viscosity-temperature curve analysis. In comparison with polytetrahydrofuran (PTHF), hydroxyl-terminated block fluorinated copolyether (FPO-PTHF-FPO) has lower viscosity and only one lower glass transition temperature (−66.6 °C) on DSC curve. In addition, hydroxyl-terminated block fluorinated copolyether (FPO-PTHF-FPO) begins to decompose at 187.2 °C and is completely decomposed until 431.6 °C, which indicates that it has a good thermal stability.

Keywords

polytetrahydrofuran / fluoride-containing / hydroxyl-terminated block copolyether / cationic ring-opening polymerization

References

[1] Ye Q, Yu YG, Li WF. Study on Cook-off Behavior of HTPE Propellant in Solid Rocket Motor[J]. Appl. Therm. Eng., 2020, 167: 114798.

[2] Doisneau F, Laurent F, Murrone A, Dupays J, Massot M. Eulerian Multi-fluid Models for the Simulation of Dynamics and Coalescence of Particles in Solid Propellant Combustion[J]. J. Comput. Phys., 2013, 234: 230-262.

[3] Li G, Jin B, Chai ZH, Liao L, Chu SJ, Peng RF. Synthesis and Stabilization Mechanism of Novel Stabilizers for Fullerenemalonamide Derivatives in Nitrocellulose-based Propellants[J]. Polym. Test., 2020, 86: 106493.

[4] Zhang PG, Pang AM, Tang G, Deng GR. Molecular Dynamics Simulation study on the Mechanism of NPBA Enhancing Interface Strength of NEPE Propellant[J]. Appl. Surf. Sci., 2019, 493: 131-138.

[5] Xie WX, Zhao Y, Zhang W, Liu YF, Fan XZ, Wang BZ, He W, Yan QL. Sensitivity and Stability Improvements of NEPE Propellants by Inclusion of FOX-7[J]. Propellants Explos. Pyrotech., 2018, 43: 1-8.

[6] Zhao Y, Zhang XH, Zhang W, Xu HG, Xie WX, Du JJ, Liu YZ. Simulation and Experimental on the Solvation Interaction between the GAP Matrix and Insensitive Energetic Plasticizers in Solid Propellants[J]. J. Phys. Chem. A, 2016, 120(5): 765-70.

[7] Wen XM, Chen KK, Sang C, Yuan S, Luo YJ. Applying Modified Hyperbranched Polyester in Hydroxyl-terminated Polyether/Ammonium Perchlorate/Aluminium/Cyclotrimethylenetrinitramine (HTPE/AP/Al/RDX) Composite Solid Propellant[J]. Polym. Int., 2021, 70: 123-134.

[8] Zhang QH, Shreeve JM. Energetic Ionic Liquids as Explosives and Propellant Fuels: A New Journey of Ionic Liquid Chemistry[J]. Chem. Rev., 2014, 114(20): 10527-10574.

[9] Kim CK, Bae SB, Ahn JR, Chung IJ. Structure-property Relationships of Hydroxy-terminated Polyether based Polyurethane Network[J]. Polym. Bull., 2008, 61: 225-233.

[10] Akhavan J. Investigation into the Network Structure of Plasticized Rocket Propellant[J]. Polymer., 1998, 39: 215-221.

[11] Lee DH, Kim KT, Jung H, Kim SH, Park S, Jeon HB, Paik HJ, Min BS, Kim W. Characterization of 1,2,3-triazole Crosslinked Polymers Based on Azide Chainends Prepolymers and a Dipolarophile Curing Agent as Propellant Binders: The Effect of a Plasticizer[J]. J. Taiwan Inst. of Chem. E., 2014, 45: 3110-3116.

[12] Desai S, Thakore IM, Sarawade BD, Devi S. Effect of Polyols and Dissocyanates on Thermo-mechanical and Morphological Properties of Polyurethanes[J]. Eur. Polym. J., 2000, 36: 711-725.

[13] Mao KZ, Xia M, Luo YJ. Thermal and Mechanical Properties of Two Kinds of Hydroxyl-terminated Polyether Prepolymers and the Corresponding Polyurethane Elastomers[J]. J. Elastom. Plast., 2016, 48: 546-560.

[14] Zhang Q, Liu N, Xu MH, Ma L, Lu XM, Shu YJ, Wang XC. PolyNIMMO-HTPE-polyNIMMO Triblock Copolymer as a Potential Energetic Binder: Synthesis and Characterization[J]. J. Eur. Polym. J., 2019, 119: 514-522.

[15] Chen KK, Wen XM, Li GP, Pang SP, Luo YJ. Improvement of Mechanical Properties of in Situ-prepared HTPE Binder in Propellants[J]. RSC. Adv., 2020, 10: 30150-30161.

[16] Li Y, Zhu ZQ, Wang X. Synthesis and Thermal Properties of Organically Modified Palygorskite/Fluorinated Polyurethane Nanocomposites[J]. J. Appl. Polym. Sci., 2017, 134: 45460.

[17] Li LL, Wang X, Li Z, Bi W, Li Y, Qi YC, Dong QZ. The Synthesis and Curing Kinetics Study of a New Fluorinated Polyurethane with Fluorinated Side Chains Attached to Soft blocks[J]. New J. Chem., 2016, 40: 596-605.

[18] Wang X, Hu JJ, Li Y, Zhang JR, Ding YY. The Surface Properties and Corrosion Resistance of Fluorinated Polyurethane Coatings[J]. J. Fluorine. Chem., 2015, 176: 14-19.

[19] Wang X, Xu JC, Li LL, Liu Y, Li Y, Dong QZ. Influences of Fluorine on Microphase Separation in Fluorinated Polyurethanes[J]. Polymer, 2016, 98: 311-319.

[20] Li LL, Li Y, Wang X, Dong QZ. Synthesis and Application of Fluorinated Epoxy Compounds[J]. Emerg. Mater. Res., 2015, 4: 102-107.

[21] Zhang WB, Fan XD, Tian W, Chen H, Zhu XZ, Zhang HT. Preparation of a P(THF-co-PO)-b-PB-b-P(THF-coPO) Triblock Copolymer via Cationic Ring-opening Polymerization and Its Use as a Thermoset Polyme[J]. RSC. Adv., 2015, 5: 66073-66081.

[22] Yagci Y, Serhatli IE, Kubisa P, Biedron T. Synthesis of Block Copolymers by Combination of an Activated Monomer and Free Radical Polymerization Mechanism[J]. Macromolecules., 1993, 26: 2397-2399.

[23] Kohga M, Okamoto K. Thermal Decomposition Behaviors and Burning Characteristics of Ammonium Nitrate/Polytetrahydrofuran/Glycerin Composite Propellant[J]. Combust. Flame., 2011, 15: 573-582.

[24] Kohga M. Mechanical Characteristics and Thermal Decomposition Behaviors of Polytetrahydrofuran Binder with Glycerol Propoxylate (M _n=1 500) as a Crosslinking Agent[J]. Propell. Explos. Pyrot., 2017, 42: 1283.