Polyimide Composites
Composites Science and Technology 61 (2001) 1253–1264 www.elsevier.com/locate/compscitech
Preparation, structure, properties and thermal behavior of rigid-rod polyimide/montmorillonite nanocomposites
Rathanawan Magaraphan a,*, Wittaya Lilayuthalert a, Anuvat Sirivat a, Johannes W. Schwank b a The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330, Thailand b University of Michigan, Ann Arbor, Michigan, USA
Received 10 August 1999; received in revised form 20 November 2000; accepted 13 February 2001
Abstract Polyimide/montmorillonite nanocomposites were prepared from solution of poly(amic acid) precursors and the dodecyl-montmorillonite (DMONT) using N-methyl-2-pyrrolidone as a solvent. The cured films of the rigid-rod polyimide/DMONT hybrids as characterized by FTIR, TEM and WAXD were exfoliated nanocomposites at low DMONT content ( 6 wt.%). It can be explained that when temperature is raised upon curing some dodecylamine molecules in DMONT can loosen out (aggregates are formed and their amine groups can react with acid groups in poly(amic acid). As a result, the imidisation extent is lowered allowing more mobility of polymeric chains so that glass transition temperatures of the nanocomposites decrease and do not seem to depend on DMONT content. These results agree with the results from FTIR, WAXD, and TEM showing the formation of silicate layer aggregates and the weak interaction between the clay layers and dodecylamine. The reduction in the degree of imidisation can result to optimize the physical properties shown previously. However, this side reaction is less significant to lower the glass transition temperature for the flexible polyimide (BTDA/ODAMDA) nanocomposites. This can be explained that although the side reaction occurred while curing leads to enhance the flow or to lower glass transition temperature of these nanocomposites, the rigidity of the clay silicate layer causes a strong suppression to flow for the flexible
Preparation, structure, properties and thermal behavior of rigid-rod polyimide/montmorillonite nanocomposites
Rathanawan Magaraphan a,*, Wittaya Lilayuthalert a, Anuvat Sirivat a, Johannes W. Schwank b a The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330, Thailand b University of Michigan, Ann Arbor, Michigan, USA
Received 10 August 1999; received in revised form 20 November 2000; accepted 13 February 2001
Abstract Polyimide/montmorillonite nanocomposites were prepared from solution of poly(amic acid) precursors and the dodecyl-montmorillonite (DMONT) using N-methyl-2-pyrrolidone as a solvent. The cured films of the rigid-rod polyimide/DMONT hybrids as characterized by FTIR, TEM and WAXD were exfoliated nanocomposites at low DMONT content ( 6 wt.%). It can be explained that when temperature is raised upon curing some dodecylamine molecules in DMONT can loosen out (aggregates are formed and their amine groups can react with acid groups in poly(amic acid). As a result, the imidisation extent is lowered allowing more mobility of polymeric chains so that glass transition temperatures of the nanocomposites decrease and do not seem to depend on DMONT content. These results agree with the results from FTIR, WAXD, and TEM showing the formation of silicate layer aggregates and the weak interaction between the clay layers and dodecylamine. The reduction in the degree of imidisation can result to optimize the physical properties shown previously. However, this side reaction is less significant to lower the glass transition temperature for the flexible polyimide (BTDA/ODAMDA) nanocomposites. This can be explained that although the side reaction occurred while curing leads to enhance the flow or to lower glass transition temperature of these nanocomposites, the rigidity of the clay silicate layer causes a strong suppression to flow for the flexible
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