RT Journal Article
T1 Critical examination of chemically modified hybrid thermosets: Synthesis, characterization and mechanical behavior in the plateau regime of polyaminosiloxane-nitrile-DGEBA
A1 Loayza Argüelles, Artemia
A1 Cabanelas Valcárcel, Juan Carlos
A1 Gonzalez Gonzalez, Maria
A1 Baselga Llidó, Juan
AB Poly(3-aminopropylmethylsiloxane) has been modified with acrylonitrile via aza Michael addition and a broad range of modified oligomers have been prepared with CN:NH₂ ratio ranging between 0.1 and 1. NMR and FTnIR analysis reveals that acrylonitrile modification proceeds without formation of tertiary amines. Modified oligomers have been characterized by DSC and analysis of Tg reveals that the adducts are self-associated probably due to weak hydrogen bonding and dipole interactions. The modified oligomers with a modification degree higher than 0.4 were miscible with DGEBA. The low and high temperature relaxations of the cured thermosets have been measured by DMTA. In addition to the commonly observed β₂ relaxation, a new β₁ process linked by an isosbestic point to β₂ has been found. β₁ is attributed to an extended segment comprising the pendant propionitrile group as well as the aminopropyl segment that connects tertiary amines to the polysiloxane backbone. Elastic modulus as well as the α relaxation can be tuned from high Tg and high rubbery modulus to low Tg and high damping thermosets changing the nitrile content. The experimental network structure obtained from elastic measurements and the Tg were related through well established structure-property relations.
PB Elsevier
SN 0032-3861
YR 2015
FD 2015-07-09
LK https://hdl.handle.net/10016/26005
UL https://hdl.handle.net/10016/26005
LA spa
NO Authors wish to thank Spanish Ministerio de Economía y Competitividad for funding this work under grant MAT2010-17091.
DS e-Archivo
RD 27 jul. 2024