Studies on thermal,mechanical and morphological properties of organoclay filled azomethine modified epoxy nanocomposites

Abstract

Inter cross-linked networks of organoclay-filled, azomethine-modified epoxy nanocomposites have been developed. Two types of azomethine epoxies (AE1 and AE2) incorporated into diglycidyl ether of bisphenol A (DGEBA) epoxy resin with varying percentages (5, 10 and 15%) were cured with diamine diphenyl methane (DDM). The azomethine epoxies were synthesized and characterized by Fourier transform infrared and ¹H-NMR spectroscopy. The incorporation of azomethine epoxies into DGEBA epoxy resin improved both thermal and mechanical properties to an appreciable extent. The introduction of organoclay into DGEBA epoxy resin exhibited almost similar characteristics to that of the azomethine-modified DGEBA epoxy resin. Both azomethine epoxy and organoclay have been incorporated into DGEBA epoxy resin in order to improve the thermal and mechanical properties in comparing other modified epoxies. The glass transition temperature and thermal degradation temperature of azomethine-modified epoxies, organoclay-filled epoxy and organoclay-filled azomethine-modified DGEBA epoxies were determined by using differential scanning calorimeter and thermogravimetric analysis. The mechanical properties, namely the tensile strength, flexural strength and impact strength of the resultant nanocomposites were studied as per ASTM standards. X-ray diffraction studies of the cured nanocomposites indicate that the organophillic montmorillonite clay was exfoliated into the cured product. The homogeneous morphology of azomethine-modified DGEBA epoxy and organoclay-filled azomethine-modified epoxy were ascertained by scanning electron microscopy.

Keywords

Schiff base azomethine epoxy epoxy resin thermal stability morphology

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References

Deng BL , Hu YS , Chen LW , Chiu WY , Wu TK The curing reaction and physical properties of DGEBA/DETA epoxy resin blended with propyl ester phosphazene. J. Appl. Polym. Sci . 1999; 74: 229-237.

Lin MS , Liuc C. , Lee CT Toughened interpenetrating polymer network materials based on unsaturated polyester and epoxy. J. Appl. Polym. Sci. 1999; 72: 585-592.

Li Y. , Shen S. , Liu Y. , Gao J. Kinetics of 4, 4’-diaminodiphenylmethane curing of bisphenol-S epoxy resin. J. Appl. Polym. Sci. 1999; 73: 1799-1803.

Akatsu U. , Inoki M. , Daicho N. , Kasahima Y. , Shiraishi N. , Marushima I. Curing behavior and properties of epoxy resins cured with the diamine having the quinoxaline or triazine structure. J. Appl. Polym. Sci. 1998; 69: 1737-1741.

Bucknall CB Toughened plastics. London : Applied Science Publishers, 1990 .

Yee AF , Pearson RA Toughening mechanism in elastomer modified epoxies part I: mechanical studies . J. Mater. Sci. 1986; 21: 2462-2474.

Mormann W. , Bröcher M. , Schwarz P. Mesogenic azomethine based diepoxides - monomers for the synthesis of ‘liquid crystal’ thermoset networks, Macromol. Chem. Phys. 1997; 198: 3615-3626.

Castell P. , Serra A. , Galia M. , Giamberini M. , Carfagna C. Anisotropic thermosets from liquid-crystalline azomethine epoxy resins and primary aromatic diamines. J. Polym. Sci., Part-A: Polym. Chem. 2003; 41: 1-12.

Mormann W. , Bröcher M. Liquid crystalline thermosets from triaromatic azomethine group containing diepoxides and 4, 4’-methylenedianiline. Macromol. Chem. Phys. 1998; 199: 1935-1938.

10.

Zhang XH , Huang LH , Chen S. , Qi GR Improvement of thermal properties and flame retardancy of epoxy-amine thermosets by introducing bisphenol containing azomethine moiety, express . Poly. Lett. 2007; 1: 326-332.

11.

Lee A. , Lichtenhan JD Thermal and viscoelastic property of epoxy-clay and hybrid inorganic-organic epoxy nanocomposites. J. Appl. Poly Sci. 1999 ; 73: 1993-2001.

12.

Okamoto M. , Morita S. , Kotak T. Dispersed structure and ionic conductivity of smectic clay/polymer nanocomposites . Polymer 2001; 42: 2685-2688.

13.

Vaia RA , Ishii H. , Giannelis EP Synthesis and properties of two-dimensional nanostructures by direct intercalation of polymer melts in layered silicates. Chem. Mater. 1999; 5: 1694-1696.

14.

Tseng CR , Wu JY , Lee HY , Chang FC Preparation and crystallization behavior of syndiotactic polystyrene-clay nanocomposites. Polymer 2001; 42: 10063-10070.

15.

Chin I. , Thurn-Albrecht T. , Kim H. , Russell T. , Wang J. On exfoliation of montmorillonite in epoxy. Polymer 2001; 42: 5947-5952.

16.

Kornmann X. , Lindberg H. , Berglund LA Synthesis of epoxy- clay nanocomposites. Influence of the nature of the curing agent on structure . Polymer 2001; 42: 4493-4499.

17.

Pinnavaia GB Polymer-clay nano composites. New York: John Wiley & Sons, 2000.

18.

Wang MS , Pinnavaia TJ Clay-polymer nanocomposites formed from acidic derivatives of montmorillonite and an epoxy resin. Chem. Mater. 1994; 6: 468-474.

19.

Kelly P. , Akelah A. , Qutubuddin S. , Moet A. Reduction of residual stress in Montmorillonite/epoxy compounds. Mater. Sci. 1994; 29: 2274-2280.

20.

Lan T. , Pinnavaia TJ Clay-reinforced epoxy nanocomposites. Chem. Mater . 1994; 6: 2216-2219.

21.

Lindberg H. , Berglund LA Synthesis of epoxy-clay nanocomposites: influence of the nature of the clay on structure. Polymer 2000; 42: 1303-1310.

22.

Mangeng L. , Sangwook K. , Mija S. Novel liquid crystalline epoxides containing azomethine mesogens. Korea Polym. J. 1999; 7: 304-309.

23.

Dinakaran K. , Alagar M. Preparation and characterization of epoxy-cyanate ester interpenetrating network matrices/organoclay nanocomposites . Polym. Adv. Tech. 2003; 14: 574.

24.

Zongyong G. , Yu Y. , Xu Y. , Li S. Synthesis and characterization of a liquid crystalline epoxy containing azomethine mesogen for modification of epoxy resin. J. Appl. Polym. Sci. 2007; 105: 1861-1868.

25.

Park J. , Jana SC Effect of plasticization of epoxy networks by organic modifier on exfoliation of nanoclay. Macromolecules 2003 ; 36: 8391-8397.

26.

Hussain M. , Varley RJ , Mathys Z. , Cheng B. , Simon GP Effect of organo-phosphorus and nano-clay materials on the thermal and fire performance of epoxy resins. J. Appl. Polym. Sci. 2004; 91: 1233-1253.

27.

Cascaval CN Thermal degradation of p-nonylphenol formaldehyde epoxy resins. Eur. Polym. J. 1994; 30: 969-973.

28.

Su WFA , Chen KC , Tseng SY Effects of chemical structure changes on thermal, mechanical, and crystalline properties of rigid rod epoxy resins . J. Appl. Polym. Sci . 2000; 78: 446-451.

29.

Mourchid A. , Lecolier E. , VanDamme H. , Levitz P. On viscoelastic, birefringent, and swelling properties of laponite clay suspensions: revisited phase diagram. Langmuir 1998; 14: 4718-4723.

30.

Krishnamoorthy R. , Giannelis EP Rheology of end-tethered polymer layered silicate nanocomposites. Macromolecules 1997; 30: 4097-4102.

31.

Kailiang Z. , Wang L. , Wang F. , Wang G. Preparation and characterization of modified-clay-reinforced and toughened epoxy-resin nanocomposites . J. Appl. Polym. Sci. 2004; 91: 2649-2652.

32.

Zulfiqar S. , Ahmad Z. , Sarwar MI Soluble aromatic polyamide bearing ether linkages: synthesis and characterization. Colloid. Polym. Sci. 2007; 285: 1749-1754.