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A polycaprolactone‐based compatibilization treatment to improve dispersion and interphase structure of silica polyurethane composites
Author(s) -
Chiacchiarelli Leonel Matias,
Monsalve Leandro,
Vázquez Analía,
Kenny José M.,
Torre Luigi
Publication year - 2014
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.23723
Subject(s) - materials science , thermogravimetric analysis , nanocomposite , dynamic mechanical analysis , thermal stability , compatibilization , differential scanning calorimetry , composite material , polyurethane , crystallinity , thermoplastic polyurethane , polycaprolactone , chemical engineering , polymer , copolymer , polymer blend , elastomer , physics , engineering , thermodynamics
Silica nanoparticles (SNs) were grafted with ε ‐caprolactone using an environmentally friendly approach. By using tartaric acid as a catalyst and the silanol groups as initiators, grafted nanoparticles (GNs) with organic weight fractions ( w of ) within the range 0–46 wt% were synthesized. Thermogravimetric (TGA) and infrared analysis were used to measure the w of and to corroborate the covalent bond between the SN and the caprolactone monomer. Transmission electron micrographs of the polyurethane (PU) nanocomposites based on the SN and the GN revealed that the interfacial area of the GN‐based PU increased by the reduction of agglomerate dimensions from 10 µm to around 0.1 µm. Dynamic mechanical analysis showed that the GN nanocomposites improved the storage shear modulus from 616±11 to 849±8 MPa for a GN with w of = 16.7% and 3 wt% filler concentration. In addition, the GN particles prevented a relevant decrease of the transition temperature ( T g ). Differential scanning calorimetry corroborated that GN increased the enthalpic energy associated to the physical crosslinking of the hard segments (HS). Wide‐angle X‐ray diffraction proved that the GN formed a HS structure with improved crystallinity. The thermal stability of the GN‐based PU a nanocomposite was improved by an increase of the thermal stability of the castor oil soft segments. POLYM. ENG. SCI., 54:1817–1826, 2014. © 2013 Society of Plastics Engineers