This study was conducted to investigate the effects of organoclay type and concentration on the nanocomposites synthesized by &ldquo / In-Situ Polymerization&rdquo / and &ldquo / Prepolymerization&rdquo / methods. In-Situ Polymerization Method was in fact a new route which consisted of dispersing the monomers / propylene glycol, maleic anhydride and o-phthalic anhydride into the galleries of montmorillonite followed by subsequent polymerization. The Prepolymerization Method involved the addition of montmorillonite to the previously synthesized unsaturated polyester. As the first step, all the compositions were prepared by Cloisite 30B, and then for comparison of clay type, nanocomposites containing 3 wt.% of Cloisite 15A and Cloisite 25A were also synthesized.
The efficiency of the two methods were compared with regards to their structural, thermal and mechanical properties. According to the results of XRD analysis, in both methods, maximum intercalation was observed when Cloisite 30B was used. An exfoliated structure was obtained in the Prepolymerization Method at 3 wt. % Cloisite 30B content. In all clay types, the increase in the d-spacings of the organoclays was higher when the Prepolymerization Method was applied.
With Cloisite 30B, maximum improvement in the impact strength was obtained at 3 wt. % organoclay loading and the In-Situ Method yielded better results leading to a 77% increase in the impact strength at this organoclay loading. Among the organoclay types, Cloisite 15A was found to give rise to maximum increase in the impact strength.
With the Prepolymerization Method higher improvement in flexural strength and flexural modulus was obtained owing to the lower styrene content in the crosslinking medium. The elongation at break values followed a decreasing trend with increasing clay content but did not show any significant difference when the clay types were compared.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12605430/index.pdf |
| Date | 01 September 2004 |
| Creators | Toprak, Pelin |
| Contributors | Yilmazer, Ulku |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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