Supporting Information SELF-DECONTAMINATING FIBROUS MATERIALS REACTIVE TOWARD CHEMICAL THREATS Lev Bromberg, a Xiao Su, a Vladimir Martis, b Yunfei Zhang, a and T. Alan Hatton a* a Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA b Surface Measurement Systems, Ltd., Unit 5, Wharfside, Rosemont Road, Alperton, London, HA0 4PE, UK. *Corresponding author: tahatton@mit.edu S-1
S-1. Synthesis of DAAP and terpolymer 4-Aminopyridine (10 g, 0.106 mol) was dissolved in 60 ml of anhydrous tetrahydrofuran (THF), sodium hydride (5.1 g, 0.213 mol) was added under stirring and the mixture was deaerated by nitrogen flow for 0.5 h. Allyl chloride (15.4 g, 0.201 mol) was dissolved in 20 ml of anhydrous THF and the solution was chilled to 0 o C. Then the allyl chloride solution was added to the solution of 4-aminopyridine dropwise and the reaction mixture was kept stirring under reflux overnight under nitrogen atmosphere. The mixture was cooled to ambient temperature and gently filtered using glass filter and washed with methylene chloride. The excess solvents was evaporated from the filtrate under vacuum. The resulted dark-red to brown, oily product was distilled at reduced pressure (0.5 mm Hg) to obtain 12.4 g (66%) of brown-red product at 88-93 C. 1 H NMR (DMSOd6, 400 MHz): δ 3.75 (d, 4H); 5.31 (q, 4H); 5.98 (m,2h); 8.22 (m, 2H); 8.31 (m, 2H). 13 C (DMSOd6): 110 (4-pyridine CH), 117 (CH2=), 129 (CH=), 149, 150 (4-pyridine CH). Elemental analysis, Calcd.(%): C, 75.8; H, 8.10; N, 16.1; found (%): 75.9;H, 8.13; N, 16.1. Synthesis of DAAP. Copolymerization with N-vinylformamide with DAAP was conducted as follows. Copolymerization of DAAP with N-vinylformamide (NVF) followed by acidic hydrolysis resulting in poly(daap-co-vam-co-nvf) terpolymer. S-2
Batch 1. NVF (11.5 g, 162 mmol) and DAAP (5.6 g, 32.1 mmol) were dissolved in 100 ml of 20% aqueous hydrochloric acid and the solution was deaerated by nitrogen flow for 1 h. To this solution, 1 ml of aqueous solution of 2,2 -azobis(2-methylpropionamidine) dihydrochloride (30 mg, 0.11 mmol) were injected and the resulting solution was kept stirring under nitrogen blanket at 75 o C for 72 h. Strong viscosification of the brown-red solution was observed. The polymer product was precipitated by saturated NaHCO3 (0.5 L). The polymer precipitate was separated and redissolved in 30% HCl at 80 o C to hydrolyze NVF, which converted a fraction of NVF into VAm. The resulting polymer was precipitated and washed by hexane and then dried under vacuum. In separate series of experiments, an identical synthetic procedure was repeated without the addition of DAAP, resulting in a PVAm product. Typical 1 H NMR spectra of the poly(daap-co-vam-co- NVF) copolymer, a commercially available poly(vam-co-nvf) (Lupamin 9095), and PVAm synthesized here are shown in Fig.S1. Using proton resonance integrations, we were able to estimate DAAP, VAm and NVF content in the terpolymer to be 20, 60 and 20 mol%, respectively. Batch 2. NVF (11.5 g, 162 mmol) and DAAP (13.5 g, 77.5 mmol) were dissolved in 100 ml of 20% aqueous hydrochloric acid and the solution was deaerated by nitrogen flow for 1 h. To this solution, 1 ml of aqueous solution of 2,2 -azobis(2-methylpropionamidine) dihydrochloride (50 mg) were injected and the resulting solution was kept stirring under nitrogen blanket at 75 o C for 72 h. Viscosification of the brown-black solution was observed. The polymer product was precipitated by saturated NaHCO3 (0.5 L). The polymer precipitate was separated and redissolved in 30% HCl at 80 o C to hydrolyze NVF. The polymer solution was kept at 60 o C for 72 h. The resulting polymer was precipitated by adding the solution dropwise into 1 M NaOH. The precipitated polymer was washed by deionized water, acetone and ether then dried under vacuum until constant weight. Using proton resonance integrations in 1 H NMR, we were able to estimate DAAP, VAm and NVF contents in the terpolymer (Batch 2) to be 40, 55 and 5 mol%, respectively. Hence, we succeeded in generating two batches of the water-soluble copolymer that contained 20 and 40 mol% of DAAP, a highly nucleophilic component. Using THF as an eluent and PMMA molecular weight standards in organic SEC, we estimated the weight-average molecular weights of Batch 1 and Batch 2 to be 52 and 40 kda, respectively. The poly(daap-co-nvf-co-vam) polymers were utilized for the nucleophilic polymer attachment to the fibers. S-3
a g b d 3 2 1 9 6 ppm 3 0 Figure S1. 1H NMR spectra of synthesized PVAm (1), commercial PVAm (2) and synthesized poly(daap-co-vam-co-nvf) (3). Polymer species were dissolved in D2O (1), 1:3 DMSOd6/D2O (2) and 1:1 DMSO-d6/D2O (3). Synthesized PVAm (1) was dialyzed against deionized water (MWCO 12-14 kda) for a week and lyophilized prior to the NMR measurement, in order to remove detached formamide as completely as possible. Proton resonances used in polymer composition estimates were assigned as shown. Another DAAP-containing polymer was synthesized for comparative studies. Poly(butadiene-copyrrolidinopyridine) (polybpp). Poly(butadiene-co-maleic anhydride) (polybma, nominal molecular weight, 10-15 kda, butadiene/anhydride mol ratio, 1:1) (8 g, dry powder) was dissolved in anhydrous DMF (20 ml), and a solution of 4-aminopyridine (5.1 g, 54 mmol) in DMF was added dropwise to the above solution under nitrogen blanket. Diisopropylethylamine, DIEA (4.5 ml, 26 mmol) was then added with stirring. The resulting reaction mixture was heated to reflux for 48 h, cooled, and concentrated. The product was precipitated by dropwise addition of the mixture to ether. The resulting polymer (2) was reprecipitated three times and dried under vacuum at 70 C for 24 h. Lithium aluminum hydride (2.0 g, 52.6 mmol) was carefully dissolved into 40 ml anhydrous pyridine, which resulted into a yellow-green slurry. The polymer 2 (2.0 g) was dissolved in 20 ml pyridine, and the solution was slowly (within 1-2 h) added into the LiAlH4 slurry via a dropping funnel at 0 C. The reaction mixture was vigorously stirred under argon and slowly warmed up to room temperature where it was kept for 16 h and then stirred at 80 C for 1 h. The excess LiAlH4 was carefully quenched at 0 C by a successive dropwise addition of 2.0 ml of water, 2.0 ml of 15% NaOH solution, and 6.0 ml of water. Anhydrous MgSO4 was added and the mixture was stirred at r. t. for 15 min. Formed granular precipitates were filtered and the solvent was evaporated under vacuum. The final product (polybpp) was precipitated by adding its pyridine solution into ether, then filtered and dried under vacuum at 70 C for 24 h. 1H NMR S-4
(400 MHz, (CD3)2NCOD), d (ppm): 1.39, 1.59 (m, CH2), 1.75, 2.0 (m, CH2 a to -C=C), 3.30 (m, pyrrolidine), 5.64 (m, 1-ethylene), 7.1 (m, 4-pyridine), 8.4 (m, 4-pyridine). Elemental Analysis, Calc: C, 78.4; H, 8.67; N, 12.9; Found: C, 79.2; H, 9.26; N, 12.8. Mol content of pyrrolidinopyridine groups per total content of monomeric units was estimated using 1 H NMR integrations to be approximately 50%. S-2. Kinetics of DMMP sorption 40 M (%), P/P o (%) 30 20 10 P/P o M 0 0 200 400 600 800 time (min) Figure S2. Typical kinetics of mass change ( M) of rayon fibers humidified at 100% water vapor pressure upon a stepwise entry and cessation of the DMMP vapor delivery. P/Po refers to the partial pressure of DMMP vapors at 25 o C and atmospheric pressure. S-3. FTIR spectrum of Desmodur DN. S-5
Absorbance (a.u.) 3600 2400 1200 Wavenumber (cm -1 ) Figure S3. FTIR spectrum of Demodur DN in KBr. Assignments: 2935 (CH3 of polyether), 2273 (asymmetric stretching vibration of the N=C=O group), 16 85 (C=) in isocyanurate ring), 1463 (OC-NR-CO in isocyanurate ring), 1220 (ester C-O stretch), 1085 (antisym and sym COC stretch in polyether. 1,2 S-4. SEM images of rayon and NYCO fibers, as received and coated with DDN and poly(daap-co-nvf-co-vam). S-6
rayon coated rayon 200 mm 200 200 mm mm NYCO coated NYCO 200 mm 200 mm Figure S4. SEM images of cellulosic fibers, coated and uncoated. S-5. SEM images of Kevlar 119 fibers, original and coated with DDN and poly(daap-co- NVF-co-VAm). S-7
original 500 mm coated 50 mm Figure S5. SEM images of Kevlar 119 fibers, original and coated by Desmodur DDN and poly(daap-co-vam-co-nvf), followed by curing. S-6. FTIR spectra of Kevlar fibers: original, treated with H3PO4 and coated with Desmodur DN and poly(daap-co-vam-co-nvf). S-8
Absorbance (a.u.) 3 2 1 3200 2400 1600 Wavenumber (cm -1 ) 800 Figure S6. FTIR spectra of Kevlar fibers: original (1), treated with H3PO4 (2) and coated with Desmodur DN and poly(daap-co-vam-co-nvf) (3). The fibers coated with polymers were cured at 60 o C for 2 days. Spectra are taken in KBr pellets, 64 scans, and resolution of 1 cm -1. Dashed vertical lines show the following assignments: OH stretching, 3400 cm -1 ; N-H hydrogenbonded, 3300 cm -1 ; C=O stretch, 1650 cm -1. Note the absence of the NCO stretching bands at 2270 cm -1 in cured fibers coated with polymers. References 1. Bromberg, L. Temperature-Sensitive Star-Branched Poly(ethylene oxide)-b- Poly(propylene oxide)-b-poly(ethylene oxide) Networks, Polymer, 1998, 39, 5663-5669. 2. Bello, D.; Smith, T. J.; Woskie, S. R.; Streicher, R. P.; Boeniger, M. F.; Redlich, C. A.; Liu, Y. An FTIR Investigation of Isocyanate Skin Absorption Using in Vitro Guinea Pig Skin, J. Environ. Monit., 2006, 8, 523 529. S-9