Guar gum has seen extensive use in blends, however, its application as a filler in thermoset composites has as yet not been investigated. The effect of the addition of guar gum and its acetyl derivatives on the kinetics of water diffusion in unsaturated polyester composites was studied. The effect of water on the mechanical properties of the composites was studied with respect to the nature of filler, filler concentration and time of immersion. All the mechanical properties were observed to decrease on exposure to water. Further, it was observed that acetylated guar gum, with a degree of substitution of 0.21, showed the best mechanical properties, surpassing the other filled composites and that of the pure unsaturated polyester. Thus, acetylated guar gum showed promise as eco-friendly filler in composite formulation.

D’Melo, D., Sabnis, A., Shenoy, M & Kathalewar, M. (2012). Preparation of Acetylated Guar Gum – Unsaturated Polyester Composites & Effect of Water on Their Properties.Current Chemistry Letters, 1(4), 147-156.

Wientjes R. H. W., Duits M. H. G., Jongschaap R. J. J. and Mellema J. (2000) Linear rheology of guar gum solutions. Macromol, 33, 9594-9605.

Painter T. J., Gonzalez J. J. and Hemmer P. C. (1979) The distribution of D-galactose residues in guaran and locust-bean gum. Carbohyd. Res., 69, 217-226.

Grasdalen H. and Painter T. J. (1980) NMR Studies of composition and sequence in legume-seed Galactomannans. Carbohyd. Res., 81, 59-66.

Gassan J. and Cutows V. S. (2000) Effects of corona discharge and UV treatment on the properties of jute-fibre epoxy composites. Compos. Sci. Tech., 60, 2857-2863.

Domka L. (1994) Modification estimate of kaolin, chalk and precipitated calcium carbonate as plastomer and elastomer fillers. Coll. Poly. Sci., 272, 1190-1202.

Liauw C. M., Hurst S. J., Lees G. C., Rothon R. N. and Dobson D. C. (1995) Filler surface treatments for particulate mineral/thermoplastic composites. Prog. Rub. Plast. Tech., 11, 137-153.

Karmaker A. C. (1997) Effect of water absorption on dimensional stability and impact energy of jute fibre reinforced polypropylene, J. Mater. Sci. Lett., 16, 462-464.

Espert A, Vilaplana F. and Karlsson S. (2002) Comparison of water absorption in natural cellulosic fibres from wood and one-year crops in polypropylene composites and its influence on their mechanical properties. Comp. Part-A, 35, 1267-1276.

Yang G. C. (1996) Relation of modification and tensile properties of sisal fiber. Acta Sci. Nat. Uni. Sunyatseni, 35, 53-57.

Thwe M. M. and Liao K. (2002) Effects of environmental aging on the mechanical properties of bamboo-glass fiber reinforced polymer matrix hybrid composites. Comp. Part-A, 33, 43-52.

Joseph K. and Thomas S. (1996) Effect of chemical treatment on the tensile properties of short sisal fibre-reinforced polyethylene composites. Polymer, 37, 5139-5149.

Mwaikamboa L. Y. and Ansell M. P. (2002) Chemical modification of hemp, sisal, jute, and kapok fibers by alkalization. J. Appl. Poly. Sci., 84, 2222-2234.

Shen C. H. and Springer G. (1976) Moisture absorption and desorption of composite materials. J. Comp. Mater., 10, 2-20.

Thomasan J. L. (1995) The interface region in glass fibre-reinforced epoxy resin composites. Compos., 26, 477-485.

Bledzki A. K. and Gassan J. (1999) Composites reinforced with cellulose based fibres. Prog. Poly. Sci., 24, 221-274.

Bolton J. (1995) The potential of plant fibres as crops. Out. Agricul., 24, 85.

D’Melo D. J. and Shenoy M. A. (2009) Effect of water on mechanical properties of unsaturated polyester-acetylated hydroxypropyl guar gum composites. J. Reinfo. Plast. Comp., 28, 2561-2576.

D’Melo D. J. and Shenoy M. A. (2010) Evaluation of properties of unsaturated polyester/ acetylated hydroxypropyl guar gum composites. J. Appl. Poly. Sci., 117, 3204-3210.

D’Melo D. J. and Shenoy M. A. (2007) Evaluation of mechanical properties of unsaturated polyester-guar gum / hydroxypropyl guar gum composites. eXPR. Poly. Lett., 1(9), 622-628.

D’Melo D. J. and Shenoy M. A. (2010) Synthesis and characterization of acryloyloxy guar gum. J. Appl. Poly. Sci., 117, 148-154.

D’Melo D. J. and Shenoy M. A. (2008) Evaluation of mechanical properties of epoxy-guar gum composites. Poly. Eng. Sci., 48(1), 124-132.

D’Melo D. J. and Shenoy M. A. (2008) Evaluation of mechanical properties of acrylated guar gum – unsaturated polyester composites. Poly. Bull., 61, 235-246.

Patil S. (1993) Testing of Paints: Technical Analysis of Paint and Paint Raw Materials; 1st Ed, Current Awareness Service Publishing, Bombay.

Genung L. B. and Mallatt R. C. (1941) Analysis of cellulose derivatives: Determination of total combined acyl in cellulose organic esters. Ind. Eng. Chem. Anal. Ed., 13(6), 369-374.

Trivedi J. H., Kalia K., Patel N. K. and Trivedi H. C. (2005). Graft Copolymerization of Sodium salt of Partially Carboxymethylated Guar Gum with Methyl Methacrylate: An Examination of Reaction Variables. J. Appl. Poly. Sci., 96, 1855-1864.

Bledzki A. K., Reihmane S. and Gassan J. (1996) Properties and modification methods for vegetable fibers for natural fiber composites. J. Appl. Poly. Sci., 59, 1329-1336.

Bledzki A. K., Zhang W. and Chate A. (2001) Natural-fibre-reinforced polyurethane microfoams. Comp. Sci. Tech., 61, 2405-2411.

George J., Carter H. G. and Kibler K. G. (1978) Langmuir-Type Model for Anomalous Moisture Diffusion in Composite Resins. J. Comp. Mater., 2, 118-131.

Camino G., Luda M. P., Polishchuk A., Revellino Y., Blancon M. and Merle R. G. (1997) Kinetic aspects of water sorption in polyester-resin/glass-fibre composites. J. Comp. Sci. Tech., 57, 1469-1482.

Dhakal H. N., Zhang Z. Y. and Richardson M. O. W. (2007) Effect of water absorption on the mechanical properties of hemp fibre reinforced unsaturated polyester composites. Comp. Sci. Tech., 67, 1674-1683.

Mostafa H. M., Nada A. M. A., Elmasry A. M. M. and Mahdi M. E. (2007) Grafting copolymerisation of vinyl monomers onto cellulose Egyptian cotton linters. Pig. Res. Tech., 36(4), 241-248.