Synthesis and Characterization of Cellulose Derivatives for Water Repellent Properties SeChin Chang and Brian Condon Cotton Chemistry and Utilization Research Unit USDA-ARS-Southern Regional Research Center, New Orleans, LA Cotton Chemistry & Utilization Research Southern Regional Research Center Beltwide Cotton Conference, January 11, 2007, New Orleans

Mission of CRIS D CRIS ( Current Research Information Service ) Our CRIS is on Value Added Products and Processes from Cotton involves increasing cotton’s consumption by inventing products and processes that demonstrate preferred use of cotton over competing fibers in needed and emerging applications

Talk Outline Design Criteria Synthesis –Nitro-benzylated (NB) cotton and cellulose –Amino-benzylated (AB) cotton and cellulose Characterization –Nitro-benzylated cotton and cellulose FT-IR spectroscopy TGA CP-MAS carbon-13 NMR –Amino-benzylated cotton and cellulose FT-IR spectroscopy TGA CP-MAS carbon-13 NMR Curing properties with Bis-phenol-A-di-glycidyl-ether (BADGE) Conclusions

Design criteria Water repellency, reactivity with epoxide and isocyanates, and the ability to complex main group and transition metals; Potential uses: adhesives, powder coatings, and composites Method of cellulose modification: –Synthesis nitro-benzylcellulose (cotton or microcrystalline); –Reduced nitro-group to amine [heterogeneous reduction in ethanol]; or –Substitute nitro-group on aryl ring to H, S-, C-, P- and other groups

Synthesis of nitro-benzyl (NB) cotton & cellulose Cellulose was subjected to a solvent exchange. Prepared solution of 2.5g Cellulose, 7g LiCl, and ~100ml DMAc Added 1.88g DMAP and 10.6g of 4-nitrobenzyl chloride Heated to 80ºC for 6h under Nitrogen Work up included: cooling, washing with water Obtained a brown powder in 70-78% yield Modified Lit. Method of: N. Joly, R. Granet and P. Krausz, Journal of Carbohydrate Chemistry, Vol. 22, No.1, 47, 2003

FT-IR of cellulose and NB cellulose

Synthesis of amino-benzyl (AB) cotton & cellulose Suspended 1.0g of Nitro-benzyl cotton or cellulose treated with –50ml EtOH, 2g Indium metal and saturated ammonium chloride solution 5.0 ml Heated to 90ºC, overnight, under nitrogen Work up included: cooling, dilution with water, decanting, washing with water and ether, and drying in vacuo at 40ºC Obtained a light brown powder in 90-95% yields. Modified Lit. Method of: Pitts, M.R., Harrison, J.R., and Moody, C.J. J. Chem. Soc., Perkin Trans, 1, 2001,

FT-IR data of NB & AB cellulose

IR Spectral Interpretation In the IR spectrum of nitro-benzylcellulose, some peaks for acetone addition oligomers may be present. However, upon reduction of aryl-nitro to amine-group, the other side products were removed. CelluloseNB CelluloseNB CottonAB CelluloseAB Cotton OH stretch3320 cm -1 (broad) 3357 cm -1 (broad) 3345 cm -1 (broad) Overlap (broad) C-H stretch2895 cm cm cm -1 Overlap~2900 cm -1 C-O stretch~1180 cm cm -1 and 1019cm cm -1 and 1016 cm cm cm -1 and 1017 cm -1 C-O-C Bend & OH Bend 1103 cm -1 and 1026 cm cm -1 and 1020 cm -1 Overlap~1060 cm -1 Overlap (broad) N=(O) 2 asymmetric 1593 cm -1 and 1504 cm cm -1 and 1509 cm -1 N=(O) 2 symmetric 1335 cm cm -1 C-N stretch for aromatic 851 cm cm cm cm -1 N-H bend stretch 1609 cm -1 and 1516 cm cm -1 and 1514 cm -1 N-H stretch3221 cm -1 and 3121 cm cm -1

C6 C3, C2, C5 C4C1 NB-cotton NB-cellulose 13 C CP/MAS NMR of NB cotton & NB cellulose ~106 ~89 80~70 ~64, 62ppm ~ ~120 ~114 ~105 ~89,84 80~70 ~62ppm ~54ppm Overlap ~147 ~130 ~124 ~105 ~89,84 80~70 ~62, 54ppm cotton

13 C CP/MAS NMR of NB & AB cotton NB-cotton AB-cotton ~ ~120 ~114 ~105 ~89,84 80~70 ~62ppm ~ ~125 ~116 ~105 ~89,84 80~70 ~62ppm

13 C CP/MAS NMR of NB & AB cellulose NB-cellulose AB-cellulose ~147 ~130 ~124 ~105 ~89,84 80~70 ~62, 54ppm ~ ~ ~105 ~89,84 80~70 ~62ppm

DSC data for AB cotton & cellulose Endotherms in first runs: Polymer relaxation and loss of water NB cotton and cellulose: broad endotherm peak at 30~80  C AB cellulose AB cotton Heating Cooling

TGA data for NB & AB cotton CottonNB- cotton AB- cotton Decomposition (ºC) ~350~260 ~445 ~170 ~340 Char content % at 500ºC Char content % at 600ºC cotton NB-cotton AB-cotton

TGA data for NB &AB cellulose celluloseNB- cellulose AB- cellulose Decomposition (ºC) ~300~250 ~290 ~190 ~330 Char content % at 500ºC Char content % at 600ºC cellulose NB-cellulose AB-cellulose

Thermal Degradation Mechanism

Curing reaction of the NB & AB cotton with Bisphenol-A diglycidyl ether (BADGE) + DSC cure The second NH does not react see: Sachinvala et al. J. Polym. Sci. 1998, 36,

DSC data for NB & AB cotton with BADGE AB cotton w/BADGE NB cotton w/BADGE -30 ºC ~ 300 ºC, 20 ºC/min, 3 cycles Water and/or methanol are known to accelerate decomposition and cure near ºC. Hence, the exothermic spike in the first run. So why no changes in the second and third heating and cooling runs?

DSC data for NB & AB cellulose with BADGE AB cellulose w/ BADGE NB cellulose w/ BADGE -30 ºC ~ 300 ºC, 20 ºC/min, 3 cycles Same spike and no changes in the heating and cooling runs in DSC

Proposed Explanation for Curing without Observable Enthalpy Changes Aryl Amino groups react with epoxies beyond 280 deg. C; Hydroxyl group mediated curing does not show heat changes because the enthalpies of bonds made and bonds broken are about the same. That is, delta-H of bonds broken minus bonds formed ~ zero; DSC is not sensitive to show enthalpy changes in ring strain energy as the epoxy ring opens; Therefore, changes in enthalpies in DSC heating and cooling runs are not readily seen. Mechanism and curing of epoxy groups by aryl double bonds is not known, and is under investigation.

TGA of the AB cotton & cellulose with Bis-phenol-A diglycidyl ether (BADGE) AB-cotton + BADGE Char at 500deg.C: AB-cellulose-BADGE > AB-cotton-BADGE because of greater substitution of AB groups in cellulose AB-cellulose + BADGE Plane cellulose AB-celluloseAB-cottonAB-cellulose w/BADGE AB-cotton w/BADGE Decomposition (ºC) ~300~190 ~330 ~170 ~340 ~305 ~350 ~300 ~365 Char content % at 500ºC

Synthesis of Pentafluoro-benzyl cellulose Cellulose was subjected to a solvent exchange Prepared solution of 3.0g Cellulose, 6.7g LiCl, and ~100ml DMAc Added 0.23g DMAP and 1.93g of pentafluorobenzyl bromide Heated to 80ºC for overnight under nitrogen Work up and obtained a brown gel solution in high yield Obtained film, fiber and powder

Conclusions and Future Work New nitro benzyl (NB) and amino benzyl (AB) cotton and cellulose derivatives were prepared and characterized by FT-IR, 13 C CP/MAS NMR, DSC and TGA Benzylation occurred better in cellulose than in cotton because of ease of swelling the lower MW cellulose DP over cotton > 10,000 DP Nitro- and amino-benzylated cellulose and cotton cured Bis-phenol A diglycidyl ether (BADGE). No examples of these composites exist in the literature. TGA studies show high thermal stability cured AB-cellulose-BADGE composites 1 H, 13 C NMR, swelling studies, contact angle, and mass characterizations in addition to applications development are on going Pentafluorobenzyl cellulose will be continue study about physical properties Acknowledgements Funding from USDA-ARS, CRIS: D Funding from USDA-ARS, CRIS: D