11.12.2012 Views

Nondestructive testing of defects in adhesive joints

Nondestructive testing of defects in adhesive joints

Nondestructive testing of defects in adhesive joints

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

crystallization temperature <strong>of</strong> PBAT <strong>in</strong> the bio-nanocomposites as compared with the ungrafted bionanocomposites.<br />

The thermal stability <strong>of</strong> virg<strong>in</strong> PBAT, PBAT bio-nanocomposite hybrids and MA-g-PBAT bionanocomposites<br />

are assessed employ<strong>in</strong>g TGA showed that <strong>in</strong>corporation <strong>of</strong> organically modified<br />

nanoclays substantially <strong>in</strong>creases the thermal stability <strong>of</strong> the biopolymer. PBAT/C30B nanocomposite<br />

hybrid exhibits the <strong>in</strong>itial degradation temperature around 322.58°C and f<strong>in</strong>al degradation temperature<br />

around 469.58°C which is comparatively higher than that <strong>of</strong> virg<strong>in</strong> matrix. The grafted bionanocomposite<br />

hybrids exhibited a further <strong>in</strong>crease <strong>in</strong> the degradation temperature. MA-g-PBAT/B109<br />

showed maximum <strong>in</strong>itial and f<strong>in</strong>al degradation temperature <strong>of</strong> 339.59°C and 505.82°C. The bionanocomoposite<br />

hybrid samples prepared us<strong>in</strong>g B109 nanoclay exhibited optimum thermal performance<br />

ow<strong>in</strong>g to its higher surface area and smaller platelets (fig 6).<br />

Conclusion<br />

Nanocomposites based on PBAT and layered silicate (C30B, C20A and B109) was prepared us<strong>in</strong>g melt<br />

<strong>in</strong>tercalation and subsequently blown films were prepared. Morphological observation from TEM and<br />

WAXD revealed that PBAT/C30B and PBAT/B109 exhibits <strong>in</strong>tercalated structure whereas MA-g-<br />

PBAT/B109 showed few layers <strong>of</strong> exfoliated clay galleries as well as <strong>in</strong>tercalated structure. Mechanical<br />

tests showed an <strong>in</strong>crease <strong>in</strong> the tensile modulus <strong>of</strong> PBAT nanocomposites hybrid <strong>in</strong> the grafted samples.<br />

Thermal stability <strong>of</strong> the virg<strong>in</strong> biopolymer also <strong>in</strong>creased with the <strong>in</strong>corporation <strong>of</strong> organically modified<br />

nanoclays. Future research will be primarily focused <strong>in</strong> the development <strong>of</strong> nanocomposite hybrid with<br />

improved mechanical performance.<br />

References<br />

1. Alexander, M; Dubois,P; Mater Sci Eng 200,28,1.<br />

2. Li,X; Kang,T; Cho,W,J; Lee,J,K; Ha,C,S; Macromol Rapid Commun 2001,22,1306.<br />

3. Chang,J,H; An,X,U; Sur,G,S; J polym sci part B: polym Phys 2003,41,94.<br />

4. Ray,S,S; Okamoto,M; Macromol Rapid Commun 2003,24,815.<br />

5. Messermith,P,B; Giannelis; E.P.J.Polym Sci Part A: Polym Chem 1995, 33, 1047.<br />

6. Di, Y.; Iannace, S.; Maio, E. D.; Nicolais, L. j Polym Sci Part B: Polym Phys 2003, 41 670.<br />

7. Chen, G. X.; Hao, G. J.; Guo,T. Y; J Appl Polym Sci 2004, 93, 655.<br />

8. Chen, G. X.; Hao, G. J.; Guo,T. Y.; Song, M. D.; Zhang,B. H. J Mater Sci Lett 2002, 21, 1587.<br />

9. Ray, S. S.; Okamoto, K.; Maiti, P.; Okamoto, M. J Nanosci Nanotechnol 2002,2,1.<br />

10. Ray, S. S.; Okamoto, K.; Okamoto, M. Macroolecules 2003, 36, 2355.<br />

Fig 1: WAXD patterns for bio-nanocomposites;<br />

(a). PBAT/C20A,(b). PBAT/C30B, (c).<br />

PBAT/B109, (d). MA-g-PBAT-C30B, (e). MA-g-<br />

PBAT-B109<br />

a b<br />

c d<br />

Fig 2: TEM Micrographs <strong>of</strong> bio-nanocomposites; (a)<br />

PBAT/C30B (b). PBAT/B109, (c). MA-g-PBAT-C30B,<br />

(d). MA-g-PBAT-B109

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!