Fabrication And Performance Of Functional Carbon Nanotube Film By Thiol–ene Click Reaction

Preparation of high stably strength and high elongation carbon nanotube(CNT)films is a key challenge to its wide application.In this paper,CNT films prepared from a chemical vapor deposition(CVD)method were functionalized by thiol-ene click reaction under mild reaction condition,fast reaction,high yield,high selectivity and environmental friendliness.Thiol-functionalized CNT films were prepared and the flexible cross-linked networks were formed between CNTs.So the interaction and load transfer between CNTs increased,the tensile strength and stability of the CNT films improved.The main contents of this paper are follows.(1)Preparation,characterization and performance of prime CNT(PCNT)films.Ethanol,acetone,ferrocene and thiophene were used to prepare the PCNT films by a chemical vapor deposition(CVD)method.Structure and morphology of PCNT films were characterized by Raman spectra and SEM technique.The mechanical properties of the PCNT films were studied,and tensile strength,Young's modulus,elongation at break and specific strength of PCNT films were 55.8 MPa,3.9 GPa,18.83% and 0.22 N/tex,respectively.The wettability of the mercaptans on PCNT films were studied using contact angle measuring instrument.It was found that the mercaptans showed good wettability to the PCNT films,which will help complete impregnation of mercaptans on CNT films and functionalize CNT films uniformly.(2)Preparation,characterization and performance of CNT films functionalized by mercaptans with different functionality.Thiol-functionalized CNT films were prepared via the thiol-ene click reaction and characterized by FT-IR,Raman spectra,XPS and SEM technique.The effects of mercaptans,usage of photoinitiator and UV time on functionalized CNT films mechanical properties were discussed.With the increase of thiol group in mercaptans,tensile strength of the functional CNT films increased.The functional CNT(THCNT)films with the highest tensile strength functionalized by tris(2-hydroxyethyl)isocyanurate tris(3-mercaptopropionate)(THMP).With an increase in usage of THMP,usage of photoinitiator and UV time,tensile strength of the THCNT films first increased and then decreased.The highest tensile strength of the CNT films appears at the weight ratio of PCNT films to mercaptans 1:300,UV time for 40 mins,and photoinitiator content of 1.5 wt% of the mercaptans.The maximum tensile strength of THCNT films was 368.1 MPa,the modulus was 21.3 GPa,the specific strength was 0.93 N/tex,and the elongation was 23.67 %.Compared with PCNT films,the tensile strength,modulus,specific strength and elongation of THCNT films were increased by 560 %,451 %,323 % and 25.7 % respectively.CNT films were functionalized via click reaction,using mercaptans as main materials.Cross-linked networks in CNTs were formed,which increase the contact and interaction,and improve the tensile strength of thiol-functionalized CNT films.(3)Preparation,characterization and performance of thiol-ended hyperbranched polymer(THBP-n)functional CNT films.THBP-n functionalized CNT films were prepared via the thiol-ene click reaction,the functionalized CNT films were characterized by FT-IR,Raman spectra,XPS and SEM technique.The effects of click reaction conditions on THBP-n functionalized CNT films mechanical properties were studied.With the increase of thiol groups in THBP,tensile strength of functionalized CNT films increased first and then decreased.The CNT film functionalized by medium functionality THBP(HPCNT-6)improve the tensile strength amplitude most.With an increase in usage of THBP-6,usage of photoinitiator and UV time,the tensile strength of the HPCNT-6 films first increased and then decreased.The highest tensile strength of HPCNT-6 films appears at the weight ratio of PCNT films to THBP-6 1:150,UV time for 30 mins,and photoinitiator content of 1.0 wt% of the THBP-6.The tensile strength was 440.3 MPa,the modulus was 35.8 GPa,the specific strength was 1.24 N/tex and the elongation was 24.93 %.Compared with PCNT films,the tensile strength,modulus,specific strength and elongation at break were increased by 689 %,818 %,463 % and 32.4 % respectively.THBP-n functionalized CNT films were synthesized and flexible cross-linked networks in CNTs were formed,which increase the contact and interaction,and the flexible THBP-n can deform to increase the sliding distance of CNTs,improve the tensile strength and elongation of THBP-n functionalized CNT films.