Graphical Abstract
![](https://wqketang.oss-cn-beijing.aliyuncs.com/unzip/large-zip/zip-d46fa870-bd16-42a3-b705-003bb4e85cce/6397/files/6397-TOC.jpg?Expires=1725756108&OSSAccessKeyId=STS.NT5eViCkqzTYdbfdqxMkjpyyq&Signature=rRrFD0fM0N63WMaczepJe7GL8vA%3D&security-token=CAISywJ1q6Ft5B2yfSjIr5eALuzdrrRQzZayZkTXgHEtQeRGn7zSkzz2IHtKenhsBOsbtfk1mG5W5%2FgZlqJ9SptIAEfJa9d99MzUP%2FpFltCT1fau5Jko1beHewHKeTOZsebWZ%2BLmNqC%2FHt6md1HDkAJq3LL%2Bbk%2FMdle5MJqP%2B%2FUFB5ZtKWveVzddA8pMLQZPsdITMWCrVcygKRn3mGHdfiEK00he8TouufTinpHMskGA1Aell7Mvyt6vcsT%2BXa5FJ4xiVtq55utye5fa3TRYgxowr%2Fwo0v0YpGya5YzHXwcPskvdKZbo78UqLQlla6w%2BGqFJqvPxr%2Fp8t%2Fx5fWJKAezhVgs8cVM8JOjIqKOscIsiJsO71SmqFV55c8Fdm%2BgUooJVgIMhTnduUfAPJAGOxzJitP%2BUVGGphr60TEnBL4rB5MUctfzRp75SXVPUTzDnGoABjuNLcf76FQN6p3t%2BSlCg%2FxR5C72RIk78k%2BUi44L9ZBmFT6F8GV7aXA52D1Ps56knKF6PAnhRivwyTxgsolycBfvccb3t5jGJ24SgY0aYosAECutxAo7sJhSwlwZvGwGDZJsop1vGiZ8eN1MbtZeRRuMeaZ2I%2BQo%2BnVP6Cf%2F0pDsgAA%3D%3D)
Discover the SciOpen Platform and Achieve Your Research Goals with Ease.
Thermoplastic polyurethane (PU) elastomers have attracted significant attention because of their many important industrial applications. However, the creation of fire-retardant and anti-dripping PU elastomers has remained a grant challenge due to the lack of crosslinking and weak interchain interactions. Herein, we report a mechanically robust, biodegradable, fire-retardant, and anti-dripping biobased PU elastomer with excellent biodegradability using an abietic acid-based compound as hard segments and polycaprolactone diol (PCL) as soft segments, followed by physically crosslinking with cellulose nanocrystals (CNC) through dynamic hydrogen-bonding. The resultant elastomer shows the balanced mechanical and fire-retardant properties, e.g., a tensile strength and break strain of 9.1 MPa and 560%, a self-extinguishing ability (V-0 rating in UL-94 testing), and an anti-dripping behavior. Moreover, the as-developed PU can be completely degraded in 1.0 wt.% lipase solution at 37 °C in 60 days, arising from the catalytic and wicking effect of CNC on PU chains. This work provides an innovative and versatile strategy for constructing robust, fire-retardant, anti-dripping, and biodegradable PU elastomers, which hold great promise for practical applications in electronic and automobile sectors.
Wang, F. F.; Yang, Z. J.; Li, J.; Zhang, C.; Sun, P. C. Bioinspired polyurethane using multifunctional block modules with synergistic dynamic bonds. ACS Macro Lett. 2021, 10, 510–517.
Ying, W. B.; Wang, G. Y.; Kong, Z. Y.; Yao, C. K.; Wang, Y. B.; Hu, H.; Li, F. L.; Chen, C.; Tian, Y.; Zhang, J. W. et al. A biologically muscle-inspired polyurethane with super-tough, thermal reparable and self-healing capabilities for stretchable electronics. Adv. Funct. Mater. 2021, 31, 2009869.
Du, R. C.; Xu, Z. C.; Zhu, C.; Jiang, Y. W.; Yan, H. P.; Wu, H. C.; Vardoulis, O.; Cai, Y. F.; Zhu, X. Y.; Bao, Z. N. et al. A highly stretchable and self-healing supramolecular elastomer based on sliding crosslinks and hydrogen bonds. Adv. Funct. Mater. 2020, 30, 1907139.
Xu, W.; Zhang, R. Y.; Liu, W.; Zhu, J.; Dong, X.; Guo, H. X.; Hu, G. H. A multiscale investigation on the mechanism of shape recovery for IPDI to PPDI hard segment substitution in polyurethane. Macromolecules 2016, 49, 5931–5944.
Hu, J.; Mo, R. B.; Sheng, X. X.; Zhang, X. Y. A self-healing polyurethane elastomer with excellent mechanical properties based on phase-locked dynamic imine bonds. Polym. Chem. 2020, 11, 2585–2594.
Li, Z. Q.; Zhu, Y. L.; Niu, W. W.; Yang, X.; Jiang, Z. Y.; Lu, Z. Y.; Liu, X. K.; Sun, J. Q. Healable and recyclable elastomers with record-high mechanical robustness, unprecedented crack tolerance, and superhigh elastic restorability. Adv. Mater. 2021, 33, 2101498.
Yao, Y.; Liu, B.; Xu, Z. Y.; Yang, J. H.; Liu, W. G. An unparalleled H-bonding and ion-bonding crosslinked waterborne polyurethane with super toughness and unprecedented fracture energy. Mater. Horiz. 2021, 8, 2742–2749.
Wang, X. H.; Zhan, S. N.; Lu, Z. Y.; Li, J.; Yang, X.; Qiao, Y. N.; Men, Y.; Sun, J. Q. Healable, recyclable, and mechanically tough polyurethane elastomers with exceptional damage tolerance. Adv. Mater. 2020, 32, 2005759.
Chen, H.; Deng, C.; Zhao, Z. Y.; Huang, S. C.; Wei, Y. X.; Wang, Y. Z. Novel alkynyl-containing phosphonate ester oligomer with high charring capability as flame retardant additive for thermoplastic polyurethane. Compos. Part B: Eng. 2020, 199, 108315.
Chen, H.; Deng, C.; Zhao, Z. Y.; Wan, L.; Yang, A. H.; Wang, Y. Z. Novel piperazine-containing oligomer as flame retardant and crystallization induction additive for thermoplastics polyurethane. Chem. Eng. J. 2020, 400, 125941.
Xing, W. Y.; Xi, J. C.; Qi, L. Y.; Hai, Z. B.; Cai, W.; Zhang, W. J.; Wang, B. Y.; Chen, L.; Hu, Y. Construction of a flame retardant polyurethane elastomer with degradability, high mechanical strength and shape memory. Compos. Part A: Appl. Sci. Manuf. 2023, 169, 107512.
Wang, H.; Liu, Q.; Zhao, X.; Jin, Z. Synthesis of reactive DOPO-based flame retardant and its application in polyurethane elastomers. Polym. Degrad. Stab. 2021, 183, 109440.
Pan, G. F.; Wang, Z.; Kong, D. Q.; Sun, T. W.; Zhai, H.; Tian, T.; Wang, Y. F.; Xing, R. G.; Zhang, B. W. Transparent, flame-retarded, self-healable, mechanically strong polyurethane elastomers: Enabled by the synthesis of phosphorus/nitrogen-containing oxime chain-extender. J. Appl. Polym. Sci. 2022, 139, 51598.
Kang, K. S.; Phan, A.; Olikagu, C.; Lee, T.; Loy, D. A.; Kwon, M.; Paik, H. J.; Hong, S. J.; Bang, J.; Parker, W. O. Jr. et al. Segmented polyurethanes and thermoplastic elastomers from elemental sulfur with enhanced thermomechanical properties and flame retardancy. Angew. Chem., Int. Ed. 2021, 60, 22900–22907.
Xue, Y. J.; Lin, J. Y.; Wan, T.; Luo, Y. L.; Ma, Z. W.; Zhou, Y. H.; Tuten, B. T.; Zhang, M.; Tao, X. Y.; Song, P. A. Stretchable, ultratough, and intrinsically self-extinguishing elastomers with desirable recyclability. Adv. Sci. 2023, 10, 2207268.
Xue, Y. J.; Ma, Z. W.; Xu, X. D.; Shen, M. X.; Huang, G. B.; Bourbigot, S.; Liu, X. Q.; Song, P. A. Mechanically robust and flame-retardant polylactide composites based on molecularly-engineered polyphosphoramides. Compos. Part A: Appl. Sci. Manuf. 2021, 144, 106317.
Xue, Y. J.; Zhang, T. C.; Tian, L. F.; Feng, J. B.; Song, F.; Pan, Z.; Zhang, M.; Zhou, Y. H.; Song, P. A. A molecularly engineered bioderived polyphosphonate containing Schiff base towards fire-retardant PLA with enhanced crystallinity and mechanical properties. Chem. Eng. J. 2023, 472, 144986.
Xue, Y. J.; Feng, J. B.; Huo, S. Q.; Song, P. A.; Yu, B.; Liu, L.; Wang, H. Polyphosphoramide-intercalated MXene for simultaneously enhancing thermal stability, flame retardancy and mechanical properties of polylactide. Chem. Eng. J. 2020, 397, 125336.
Xue, Y. J.; Feng, J. B.; Ma, Z. W.; Liu, L. N.; Zhang, Y.; Dai, J. F.; Xu, Z. G.; Bourbigot, S.; Wang, H.; Song, P. A. Advances and challenges in eco-benign fire-retardant polylactide. Mater. Today Phys. 2021, 21, 100568.
Wang, H. F.; Wang, J.; Guo, H. M.; Chen, X. G.; Yu, X. Y.; Ma, Y. H.; Ji, P. G.; Naito, K.; Zhang, Z. J.; Zhang, Q. X. A novel high temperature vinylpyridine-based phthalonitrile polymer with a low melting point and good mechanical properties. Polym. Chem. 2018, 9, 976–983.
Gu, J. W.; Dang, J.; Wu, Y. L.; Xie, C.; Han, Y. Flame-retardant, thermal, mechanical and dielectric properties of structural non-halogenated epoxy resin composites. Polym. Plast. Technol. Eng. 2012, 51, 1198–1203.
Jiao, Y. Z.; Rong, Z. H.; Gao, C. H.; Wu, Y. M.; Liu, Y. T. Tannic acid crosslinked self-healing and reprocessable silicone elastomers with improved antibacterial and flame retardant properties. Macromol. Rapid Commun. 2023, 44, 2200681.
Wang, Z. H.; Liu, B. W.; Zeng, F. R.; Lin, X. C.; Zhang, J. Y.; Wang, X. L.; Wang, Y. Z.; Zhao, H. B. Fully recyclable multifunctional adhesive with high durability, transparency, flame retardancy, and harsh-environment resistance. Sci. Adv. 2022, 8, eadd8527.
Grimme, S. Do special noncovalent π–π stacking interactions really exist. Angew. Chem., Int. Ed. 2008, 47, 3430–3434.
Wang, L.; Peng, Y. W.; Xu, Y. L.; Zhang, J. J.; Liu, C. G.; Tang, X. J.; Lu, Y.; Sun, H. W. Earthworms’ degradable bioplastic diet of polylactic acid: Easy to break down and slow to excrete. Environ. Sci. Technol. 2022, 56, 5020–5028.
Martin, R. T.; Camargo, L. P.; Miller, S. A. Marine-degradable polylactic acid. Green Chem. 2014, 16, 1768–1773.
Mi, H. Y.; Jing, X.; Napiwocki, B. N.; Hagerty, B. S.; Chen, G. J.; Turng, L. S. Biocompatible, degradable thermoplastic polyurethane based on polycaprolactone- block-polytetrahydrofuran- block-polycaprolactone copolymers for soft tissue engineering. J. Mater. Chem. B 2017, 5, 4137–4151.
Al Hosni, A. S.; Pittman, J. K.; Robson, G. D. Microbial degradation of four biodegradable polymers in soil and compost demonstrating polycaprolactone as an ideal compostable plastic. Waste Manage. 2019, 97, 105–114.
Wang, H.; Wei, D. F.; Zheng, A. N.; Xiao, H. N. Soil burial biodegradation of antimicrobial biodegradable PBAT films. Polym. Degrad. Stab. 2015, 116, 14–22.
Liu, B.; Guan, T. H.; Wu, G.; Fu, Y.; Weng, Y. X. Biodegradation behavior of degradable mulch with poly (butylene adipate-co-terephthalate) (PBAT) and poly (butylene succinate) (PBS) in simulation marine environment. Polymers 2022, 14, 1515.
Sun, M.; Yang, Y. K.; Huang, M. L.; Fu, S. K.; Hao, Y. Y.; Hu, S. Y.; Lai, D. L.; Zhao, L. Adsorption behaviors and mechanisms of antibiotic norfloxacin on degradable and nondegradable microplastics. Sci. Total Environ. 2022, 807, 151042.
Qi, J. F.; Wu, J.; Chen, J. Y.; Wang, H. P. An investigation of the thermal and (bio)degradability of PBS copolyesters based on isosorbide. Polym. Degrad. Stab. 2019, 160, 229–241.
Xun, X. C.; Zhao, X.; Li, Q.; Zhao, B.; Ouyang, T.; Zhang, Z.; Kang, Z.; Liao, Q. L.; Zhang, Y. Tough and degradable self-healing elastomer from synergistic soft-hard segments design for biomechano-robust artificial skin. ACS Nano 2021, 15, 20656–20665.
Sun, P. H.; Wang, S. H.; Huang, Z.; Zhang, L.; Dong, F. H.; Xu, X.; Liu, H. Water-resistant, strong, degradable and recyclable rosin-grafted cellulose composite paper. Green Chem. 2022, 24, 7519–7530.
Huo, S. Q.; Sai, T.; Ran, S. Y.; Guo, Z. H.; Fang, Z. P.; Song, P. A.; Wang, H. A hyperbranched P/N/B-containing oligomer as multifunctional flame retardant for epoxy resins. Compos. Part B: Eng. 2022, 234, 109701.
Zhang, H. Y.; Van Hertrooij, A.; Schnitzer, T.; Chen, Y. J.; Majumdar, S.; Van Benthem, R. A. T. M.; Sijbesma, R. P.; Heuts, J. P. A. Benzene tetraamide: A covalent supramolecular dual motif in dynamic covalent polymer networks. Macromolecules 2023, 56, 6452–6460.
Xu, X. D.; Li, L. J.; Seraji, S. M.; Liu, L.; Jiang, Z.; Xu, Z. G.; Li, X.; Zhao, S.; Wang, H.; Song, P. A. Bioinspired, strong, and tough nanostructured poly(vinyl alcohol)/inositol composites: How hydrogen-bond cross-linking works. Macromolecules 2021, 54, 9510–9521.
Yao, Z.; Wu, D. F.; Chen, C.; Zhang, M. Creep behavior of polyurethane nanocomposites with carbon nanotubes. Compos. Part A: Appl. Sci. Manuf. 2013, 50, 65–72.
Huo, S. Q.; Wang, J.; Yang, S.; Li, C.; Wang, X. L.; Cai, H. P. Synthesis of a DOPO-containing imidazole curing agent and its application in reactive flame retarded epoxy resin. Polym. Degrad. Stab. 2019, 159, 79–89.
Huang, Z.; Wang, S. B.; Ren, C. Y.; Liu, H.; Xu, X.; Song, Z. Q. Preparation and application of rosin modified siloxane-based flame retardant. Chem. Ind. For. Prod. 2022, 42, 71–79.
Yao, M. H.; Liu, L. H.; Ma, C. C.; Zhang, H.; Zhang, Y.; Song, R. Y.; Fang, Z. P.; Song, P. A. A lysine-derived flame retardant for improved flame retardancy, crystallinity, and aqueous-phase degradation of polylactide. Chem. Eng. J. 2023, 462, 142189
Yanagisawa, Y.; Nan, Y. L.; Okuro, K.; Aida, T. Mechanically robust, readily repairable polymers via tailored noncovalent cross-linking. Science 2018, 359, 72–76.
Liu, Z.; Fan, X. L.; Zhang, J. L.; Chen, L. X.; Tang, Y. S.; Kong, J.; Gu, J. W. PBO fibers/fluorine-containing liquid crystal compound modified cyanate ester wave-transparent laminated composites with excellent mechanical and flame retardance properties. J. Mater. Sci. Technol. 2023, 152, 16–29.
Zhong, X.; Yang, X. T.; Ruan, K. P.; Zhang, J. L.; Zhang, H. T.; Gu, J. W. Discotic liquid crystal epoxy resins integrating intrinsic high thermal conductivity and intrinsic flame retardancy. Macromol. Rapid Commun. 2022, 43, 2100580.
Luo, Y.; Miao, Y. P.; Wang, H. M.; Dong, K.; Hou, L.; Xu, Y. Y.; Chen, W. C.; Zhang, Y.; Zhang, Y. Y.; Fan, W. Laser-induced Janus graphene/poly(p-phenylene benzobisoxazole) fabrics with intrinsic flame retardancy as flexible sensors and breathable electrodes for fire-fighting field. Nano Res. 2023, 16, 7600–7608.
Yao, K. J.; Wang, J. F.; Zhang, W. J.; Lee, J. S.; Wang, C. P.; Chu, F. X.; He, X. M.; Tang, C. B. Degradable rosin-ester-caprolactone graft copolymers. Biomacromolecules 2011, 12, 2171–2177.
Meabe, L.; Sardon, H.; Mecerreyes, D. Hydrolytically degradable poly(ethylene glycol) based polycarbonates by organocatalyzed condensation. Eur. Polym. J. 2017, 95, 737–745.
Liu, Q. Y.; Zhou, L.; Fan, D.; Guan, M. Z.; Ma, Q. Z.; Li, S.; Ouyang, X. P.; Qiu, X. Q.; Fan, W. Adsorption-enhanced glucan oligomer production from cellulose hydrolysis over hyper-cross-linked polymer in molten salt hydrate. ACS Appl. Mater. Interfaces 2021, 13, 52082–52091.
Schusser, S.; Menzel, S.; Bäcker, M.; Leinhos, M.; Poghossian, A.; Wagner, P.; Schöning, M. J. Degradation of thin poly(lactic acid) films: Characterization by capacitance-voltage, atomic force microscopy, scanning electron microscopy and contact-angle measurements. Electrochim. Acta 2013, 113, 779–784.
Wang, L.; Ma, Z. L.; Zhang, Y. L.; Qiu, H.; Ruan, K. P.; Gu, J. W. Mechanically strong and folding-endurance Ti3C2T x MXene/PBO nanofiber films for efficient electromagnetic interference shielding and thermal management. Carbon Energy 2022, 4, 200–210.