Reported is a study evaluating the potential of esterified tannins as plastic additives in poly(lactic acid) (PLA). Tannin esterification using anhydrides was investigated as a route to synthesize tannin esters possessing varying ester chain length and degree of substitution (DS). Esterification decreased the tannin UV absorbance, predominately in the UVB region. However, tannin materials with longer ester chain lengths exhibited melt behaviors suitable for processing in plastics. On compounding into PLA, tannin hexanoate esters lowered the PLA glass transition by 5–6 °C. Shorter chain length tannin esters had a reduced effect on PLA polymer properties. The PLA flexural properties were significantly altered with stiffness decreases of up to 15% depending on ester chain length and loading. Artificial weathering of modified the PLA samples suggests the presence of tannin esters may confer a protection role to PLA on extended exposure. Overall, results suggest scope for the use of tannin esters possessing longer ester chain length as plastic additives.
References
[1]
Auras, R.; Harte, B.; Selke, S. An overview of polylactides as packaging materials. Macromol. Biosci. 2004, 4, 835–864, doi:10.1002/mabi.200400043.
[2]
Vieira, M.G.A.; Silva, M.A.; Santos1, L.O.; Beppu, M.M. Natural-based plasticizers and biopolymer films: A review. Eur. Polym. J. 2011, 47, 254–263, doi:10.1016/j.eurpolymj.2010.12.011.
[3]
Zweifel, H. Plastics Additives Handbook; Hanser Gardner Publications: Cincinnati, OH, USA, 2001.
[4]
Verlinden, R.A.J.; Hill, D.J.; Kenward, M.A.; Williams, C.D.; Radecka, I. Bacterial synthesis of biodegradable polyhydroxyalkanoates. J. Appl. Microbiol. 2007, 102, 1437–1449, doi:10.1111/j.1365-2672.2007.03335.x.
[5]
Fenollar, O.; Sanchez-Nacher, L.; Garcia-Sanoguera, D.; López, J.; Balart, R. The effect of the curing time and temperature on final properties of flexible PVC with an epoxidized fatty acid ester as natural-based plasticizer. J. Mater. Sci. 2009, 44, 3702–3711, doi:10.1007/s10853-009-3495-7.
[6]
Banu, D.; El-Aghoury, A.; Feldman, D. Contributions to characterization of poly(vinyl chloride)–lignin blends. J. Appl. Polym. Sci. 2006, 101, 2732–2748, doi:10.1002/app.23026.
[7]
Ko？íková, B.; Sláviková, E. Use of lignin products derived from wood pulping as environmentally desirable additives of polypropylene films. Wood Res. 2010, 55, 87–92.
[8]
Gaugler, M.; Grigsby, W.; Harper, D.; Rials, T. Chemical imaging of the spatial distribution and interactions of tannin dispersal in bioplastic systems. Adv. Mater. Proc. IV 2007, 29–30, 173–176.
[9]
Ge, J.; Shi, X.; Cai, M.; Wu, R.; Wang, M. A novel biodegradable antimicrobial PU foam from wattle tannin. J. Appl. Polym. Sci. 2003, 90, 2756–2763.
[10]
Siddiqui, I.A.; Adhami, V.M.; Ahmad, N.; Mukhtar, H. Nanochemoprevention: Sustained release of bioactive food components for cancer prevention. Nutr. Cancer 2010, 62, 883–890, doi:10.1080/01635581.2010.509537.
[11]
Harborne, J.B. The Flavonoids: Advances in Research Since 1986, 1st ed.; Chapman & Hall: Great Britain, UK, 1994.
[12]
Hemingway, R.W.; Karchesy, J.J.; Branham, S.J. The Chemistry and Significance of Condensed Tannins; Plenum Press: New York, NY, USA, 1989.
[13]
Ajila, C.M.; Brar, S.K.; Verma, M.; Tyagi, R.D.; Godbout, S.; Valéro, J.R. Extraction and analysis of polyphenols: Recent trends. Crit.Rev. Biotechnol. 2011, 31, 227–249, doi:10.3109/07388551.2010.513677.
[14]
Cottman, K.S. Polymer compositions containing esters of polyphenolic compounds as built-in antioxidants. U.S. Patent 3,984,372, 25 July 1975.
Perrier, E.M.; Boumendjel, A.; Bresson-Rival, D. Flavonoid esters and their use notably in cosmetics. U.S. Patent 6,235,294, 10 July 1998.
[17]
Barbosa, A.P.; Mano, E.B.; Andrade, C.T. Tannin-based resins modified to reduce wood adhesive brittleness. For. Prod. J. 2000, 50, 89–92.
[18]
Gaugler, M.; Grigsby, W.J. Thermal degradation of condensed tannins from radiata pine bark. J. Wood Chem. Technol. 2009, 29, 305–321, doi:10.1080/02773810903165671.
[19]
Luo, C.; Grigsby, W.; Edmonds, N.; Easteal, A.; Al-Hakkak, J. Synthesis, characterization, and thermal behaviors of tannin stearates prepared from quebracho and pine bark extracts. J. Appl. Polym. Sci. 2010, 117, 352–360.
[20]
Bridson, J.H.; Grigsby, W.J.; Main, L. Synthesis and characterization of flavonoid laurate esters by transesterification. J. Appl. Polym. Sci. 2013, doi:10.1002/app.38731.
[21]
Grigsby, W.J.; Hill, S.J.; McIntosh, C.D. NMR estimation of extractables from bark: Analysis method for quantifying tannin extraction from bark. J. Wood Chem. Technol. 2003, 23, 179–195, doi:10.1081/WCT-120021924.
[22]
George, B.; Suttie, Ed.; Merlin, A.; Deglise, X. Photodegradation and photostabilisation of wood-The state of the art. Polym. Degrad. Stab. 2005, 88, 268–274, doi:10.1016/j.polymdegradstab.2004.10.018.
[23]
Agrawal, P.K. Carbon-13 NMR of Flavonoids; Elsevier Science Publishers: Amsterdam, The Netherlands, 1989.
[24]
Pizzi, A.; Stephanou, A. A comparative C13 NMR study of polyflavonoid tannin extracts for phenolic polycondensates. J. Appl. Polym. Sci. 1993, 50, 2105–2113, doi:10.1002/app.1993.070501209.
[25]
Bocalandro, C.; Sanhueza, V.; Gómez-Caravaca, A.M.; González-álvarez, J.; Fernández, K.; Roeckel, M.; Rodríguez-Estrada, M.T. Comparison of the composition of Pinus radiata bark extracts obtained at bench- and pilot-scales. Ind. Crops Prod. 2012, 38, 21–26, doi:10.1016/j.indcrop.2012.01.001.
[26]
Lemmouchi, Y.; Murariu, M.; Dos Santos, A.M.; Amass, A.J.; Schacht, E.; Dubois, P. Plasticization of poly(lactide) with blends of tributyl citrate and low molecular weight poly(d,l-lactide)-b-poly(ethylene glycol) copolymers. Eur. Polym. J. 2009, 45, 2839–2848, doi:10.1016/j.eurpolymj.2009.07.006.
[27]
Hu, Y.; Rogunova, M.; Topolkaraev, V.; Hiltner, A.; Baer, E. Aging of poly(lactide)/poly(ethylene glycol) blends. Part 1. Poly(lactide) with low stereoregularity. Polymer 2003, 44, 5701–5710, doi:10.1016/S0032-3861(03)00614-1.
[28]
Baiardo, M.; Frisoni, G.; Scandola, M.; Rimelen, M.; Lips, D.; Ruffieux, K.; Wintermantel, E. Thermal and mechanical properties of plasticized poly(L-lactic acid). J. Appl. Polym. Sci. 2003, 90, 1731–1738, doi:10.1002/app.12549.
[29]
Zaidi, L.; Kaci, M.; Bruzaud, S.; Bourmaud, A.; Grohens, Y. Effect of natural weather on the structure and properties of polylactide/Cloisite 30B nanocomposites. Polym. Degrad. Stab. 2010, 95, 1751–1758, doi:10.1016/j.polymdegradstab.2010.05.014.
