1111111111111111111111111111111111111111111111111111111111111111111111 (12) United States Patent (io) Patent No.: US 9,428,647 B2 Li et al. (45) Date of Patent: Aug. 30, 2016 (54) SELF-HEALING COMPOSITE OF 26/26 (2013.01); C04B 28/02 (2013.01); C08G THERMOSET POLYMER AND 18/4238 (2013.01); C08G 18/664 (2013.01); PROGRAMMED SUPER CONTRACTION C08G 18/7671 (2013.01); DOIF 6/70 FIBERS (2013.01); C04B 210310065 (2013.01); C04B 2111100612 (2013.01); C04B 2111172 (71) Applicants:Guogiang Li, Baton Rouge, LA (US); (2013.01); C08G 210110025 (2013.01); C08G Harper Meng, Baton Rouge, LA (US) 2280100 (2013.01); C08G 2350100 (2013.01) (58) Field of Classification Search (72) Inventors: Guoqiang Li, Baton Rouge, LA (US); CPC ....... C08L 75/04; C04B 26/26; C04B 26/16; Harper Meng, Baton Rouge, LA (US) B29C 73/18; C08G 18/664; C08G 18/7671; C08G 18/4238; DO1F 6/70 (73) Assignee: Board of Supervisors of Louisiana See application file for complete search history. State University And Agricultural and Mechanical College, Baton Rouge, LA (56) References Cited (US) PUBLICATIONS (*) Notice: Subject to any disclaimer, the term of this Li et al. Healable thermoset polymer composite embedded with patent is extended or adjusted under 35 stimuli-responsive fibres. J. R. SOc. Interface (2012)9, 3279-3287. U.S.C. 154(b) by 0 days. Aug. 15, 2012.* (Continued) (21) Appl. No.: 14/248,711 Primary Examiner John Uselding (22) Filed: Apr. 9, 2014 (74) Attorney, Agent, or Firm Timothy J. Lithgow; John H. Runnels (65) Prior Publication Data US 2014/0303287 Al Oct. 9, 2014 (57) ABSTRACT A composition comprising thermoset polymer, shape Related U.S. Application Data memory polymer to facilitate macro scale damage closure, (60) Provisional application No. 61/810,015, filed on Apr. and a thermoplastic polymer for molecular scale healing is 9, 2013. disclosed; the composition has the ability to resolve struc- tural defects by a bio-mimetic close-then heal process. In (51) Int. Cl. use, the shape memory polymer serves to bring surfaces of a structural defect into approximation, whereafter use of the C08L 75/04 (2006.01) thermoplastic polymer for molecular scale healing allowed B29C 73/18 (2006.01) for movement of the thermoplastic polymer into the defect C04B 26/16 (2006.01) and thus obtain molecular scale healing. The thermoplastic C08G 18/66 (2006.01) can be fibers, particles or spheres which are used by heating C08G 18/76 (2006.01) to a level at or above the thermoplastic's melting point, then C08G 18/42 (2006.01) cooling ofthe composition below the melting temperature of (Continued) the thermoplastic. Compositions of the invention have the ability to not only close macroscopic defects, but also to do (52) U.S. Cl. so repeatedly even if another wound/damage occurs in a CPC ................ C08L 75/04 (2013.01); B29C 73/18 previously healed/repaired area. (2013.01); C04B 20/1037 (2013.01); C04B 26/04 (2013.01); C04B 26/16 (2013.01); C04B 8 Claims, 64 Drawing Sheets Healed configuration Molecule entanglement at crack interface7V US 9,428,647 B2 Page 2 (51) Int. C1. (56) References Cited DOIF 6/70 (2006.01) C04B 26/04 (2006.01) PUBLICATIONS C04B 26/26 (2006.01) C04B 28/02 (2006.01) Li et al. Effect of strain hardening of shape memory polymer fibers C04B 20/10 (2006.01) on healing efficiency of thermosetting polymer composites. Poly- 008G 101/00 (2006.01) mer 54 (2012) 920-928. Dec. 22, 2012.* C04B 103/00 (2006.01) C04B 111/00 (2006.01) C04B 111/72 (2006.01) * cited by examiner Fig. 16 Thermoset SMP rib polymer bay Crack i-` closure 4f j -!!%4 ritr Heating I 4 process Damaged configuration z-pin Heating , Diffusion of molten TPs process -- .into the crack surfaces Healed configuration Cooling .mil~,.~ ` f'r t •'*„'ti.` A.~ 3 A~. process v Solidificatii of molten T Molecule entanglement ' at crack interface ' Thermoset polymer molecule :"_~ Macroscale crack x ty Thermoplastic molecule Thermoplastic Particles (TPs) Fig. 1C 300 80 SMP bundle fiber #2 (4 single fibers) a SMP bundle fiber #1 (4 single fibers) 70 250 Strain rate: 50.8(minimum) Strain rate: 50.8(minimum) _ _ _ 31d cycle — — — — 3rd cycle 60 M 2nd cycle 200 2nd cycle - i CL 1s' cycle ' 50 1s' cycle ' M 0- 2 F b 150 b 40 y` x , a" 30 100 t 20 50 10 0 50 100 150 200 250 300 350 0 20 40 60 80 100 120 Strain (%) Strain (%) NM XMI 18 18 SMP single fiber #1 SMP single fiber #2 16 Work hardened in 3 cycles up to 350% 16 Work hardened in 3 cycles up to 180% level level of strain in each of the cycles of strain in each of the cycles i 14 14 Pre-stretched strain level: E =10% Pre-stretched strain level: E =101/1( r Heating rate: °C/Sec Heating rate: 0.35 IC/Sec a12 0.35 t—w,V~ 12 Final temperature: 90 °C a Final temperature: 90 °C j'" ;~10 10 Cn 8 6 4 2 0 0e 0 50 100 150 200 250 0 50 100 150 200 230 Time (Sec) Time(Sec) Fig. 3A Fig. 36 0.6 »»»»- SMP fiber #1 after 3rd cyclic load M 0.5 Non-stretched SMP fiber #1 0.4 co '50.3 0.2 0.1 0 -0.1 30 40 50 60 70 80 90 100 110 120 130 140 Temperature (°C) M 1C M 1V- 20 40 60 80 100 120 140 160 Temperature(°C) AM #.04 1.2 i !M QOM ■ \0.6 % $ON § R 222 m 0.86 Soo 1000 1500 2000 2600 3000 3500 4000 Wav um r(<m®) Fig. 5 Fi Am sating ,ocess Heating J Melting rack TPs process Closure Cooling process Solidification of molten TPs IWO:go ffitedwew of, i# Qracklaterfac crack. Fig. 6C U.S. Patent Aug. 30, 2016 Sheet 8 of 64 US 9,428,647 B2 ~ y L V c c 0 ® L. Q U V CL e 1 LL Soft segment Hard segment C wawi 'tnV ZS Lt,9`8Zt,`6 Sfl b9 3O 6 JaNS 910Z `0£ Jualled -S-fl b Melting transition ~ E of the hard segment E n w 0N .Q Mass transition ; -°0 of the soft segment 1 -20E o 20 40 60 80 100120140160180200220 ~ Temperature (oC) `O N 00 Fig. 9 N 1735cm-1: -MDI ,«««««««»SRF Free(C=0) v BDO PBA 0.14 !• 1730cm-1: Free(C=O) A 0.09 3320cm 1: Hydrogen 1700cm-1: Hydrogen bonded (NH) v .-_-----banded (C=0)v 0.04 _ PBA 3:f34 .......... .......... ......................... .....:......................... MDI 1800 1.760 1.720 1.680 16-40 1600 13600 5 34(0 3~ Wave number(cm -1) Wave number(cm -1) IMM ml i 0.2 fk~ 3500 3000 2500 2000 1500 1000 1 Wavenumber (cm- Fig. 11 U.S. Patent Aug. 30, 2016 Sheet 13 of 64 US 9,428,647 B2 a 2400 cn 1600 0.35 0.75 1.15 1.55 1.95 True Strain Fig. 12A 300 ``'` co $k ~a U.S. Patent Aug. 30, 2016 Sheet 14 of 64 US 9,428,647 B2 00 fir! s~ \ s+L/ m Q w f 077i►►w......... VJM 0 ~l i V PC 9 U.S. Patent Aug. 30, 2016 Sheet 15 of 64 US 9,428,647 B2 100 80 40 Am= 4- c 20 U 0 20 50 80 110 140 170 Temperature (°C) cn 1.5 a) L ~ 1 0 0.5 a)U 3IZ 0 40 80 120 160 200 Temperature (°C) IMM 40 80 120 160 200 Temperature (°C) U.S. Patent Aug. 30, 2016 Sheet 16 of 64 US 9,428,647 B2 SRF (Stimuli-responsive Fiber) ® Thermoplastic particles (TPs) Epoxy matrix 0 Macroscopic crack happens in the composite •. oc Sample is cooled down to Troom (room temperature) to recover yiii f ►~iiEy~ ~wlr►.►~ u►ow; strength I.R.I,'I,'►AI~M.MARiRirA►AI.IA►. w,1►.wA►A►A - glass transitionrange of - T2 = The bonding temperature of the TPI Fig. 15 U.S. Patent Aug. 30, 2016 Sheet 17 of 64 US 9,428,647 B2 Original sample First healing cycle 50 ® Second healing cycle Third healing cycle 40 ....... Fourth healing cycle r D z 30 0 ®' 20 II 10 . 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Extension (mm) Fig. 16A m 20 10 0 NP Aw ` c " Fig. 16 U.S. Patent Aug. 30, 2016 Sheet 18 of 64 US 9,428,647 B2 SMP fiber strand l Av l I Fig. 17A A SMPF bundle hooked to a pin before stretch ~1 Pin a Pin - - - - - - - - - - - - l I Stretch at room temperature The SMPF bundle The SMPF bundle before stretch after stretch Pin - ►Stretch direction Pin l l AMM 80 100% Pre- tr r: ~ o C /50% Pre-strained 20 % Pre-strained 0 0 50 100 Strain(% N Fig. 18 00 J N 21.5 167.9°C 21.0 E 20.5 A c 20.0 0 _0 0 19.5 0 -cu 19.0 m im 0 50 100 150 200 gom M 5 0 72 62 52 cu E h 0 42 -1 32 _2 _3 22 0 10 20 30 40 50 Time (min) Fig. 20 Control 30 25 20 cu a. 100% Pre-strain 15 wuwuu, cn 10 -- 50%® Pre-strain 5 .w ^ 0% Pre-strain t 0- 0 0.25 0.5 0.75 1 1.25 1.5 Strain (%) Fig. 21 U.S.