title: Elastic behavior of methyltrimethoxysilane based aerogels reinforced with tri-isocyanate.
abstract: The elastic properties and/or flexibility of polymer reinforced silica aerogels having methyltrimethoxysilane (MTMS) and bis(trimethoxysilylpropyl)amine (BTMSPA) making up the silica structure are examined. The dipropylamine spacer from BTMSPA is used both to provide a flexible linking group in the silica structure, and as a reactive site via its secondary amine for reaction with a tri-isocyanate, Desmodur N3300A. The tri-isocyanate provides an extended degree of branching or reinforcement, resulting in increased compressive strength of the aerogel monoliths while the overall flexibility arising from the underlying silica structure is maintained. The compressive moduli of the reinforced aerogel monoliths in this study range from 0.001 to 158 MPa. Interestingly, formulations across this entire range of modulus recover nearly all of their length after two compressions to 25% strain. Differences in pore structure of the aerogels due to processing conditions and solvent are also discussed.
authors.affiliation: Ohio Aerospace Institute, Brookpark, Ohio 44142, USA. Baochau.n.nguyen@nasa.gov
authors.forename: Bao Chau N
authors.initials: BC
authors.lastname: Nguyen
authors.forename: Mary Ann B
authors.initials: MA
authors.lastname: Meador
authors.forename: Alexandra
authors.initials: A
authors.lastname: Medoro
authors.forename: Victoria
authors.initials: V
authors.lastname: Arendt
authors.forename: Jason
authors.initials: J
authors.lastname: Randall
authors.forename: Linda
authors.initials: L
authors.lastname: McCorkle
authors.forename: Brian
authors.initials: B
authors.lastname: Shonkwiler
mesh_terms: D000388:Air; D055119:Elastic Modulus; D005782:Gels / Q000737:chemistry*; D017953:Isocyanates / Q000737:chemistry*; D008422:Materials Testing; D012821:Silanes / Q000737:chemistry*
chemical_list: D005782:Gels; D017953:Isocyanates; D012821:Silanes; C071718:methyltrimethoxysilane