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Effects of high nano‐SiO 2 contents on properties of epoxy‐modified polybenzoxazine
Author(s) -
Okhawilai Manunya,
Dueramae Isala,
Jubsilp Chanchira,
Rimdusit Sarawut
Publication year - 2017
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.23807
Subject(s) - epoxy , materials science , composite material , glass transition , copolymer , nano , fourier transform infrared spectroscopy , scanning electron microscope , dynamic mechanical analysis , composite number , polymer , chemical engineering , engineering
High‐performance nanosilica composites based on epoxy‐modified polybenzoxazine matrices are developed. Chemorheological study of benzoxazine–epoxy resin mixtures reveals that processing window of the benzoxazine resin (BA‐a) is substantially broadened with an addition of the liquid epoxy. Glass transition temperature ( T g ) of the BA‐a copolymerized with epoxy resin shows a synergistic behavior with a maximum T g value (174°C) at the benzoxazine–epoxy mass ratio of 80:20. The copolymer at this composition is also used as a matrix for nano‐SiO 2 composites. A very low melt viscosity of the benzoxazine–epoxy mixtures promotes good processability with the maximum attainable nano‐SiO 2 loading up to 35 wt%. From scanning electron microscopy investigation, fracture surface of the 35 wt% nano‐SiO 2 ‐filled benzoxazine–epoxy composite reveals relatively homogeneous distribution of the nano‐SiO 2 in the copolymer with good particle wet‐out. In addition, very high reinforcing effect was also observed in such high content of the nano‐SiO 2 , i.e., about 2.5 times in modulus improvement. This improvement is attributed to the strong bonding between the copolymer matrix and the nano‐SiO 2 through ether linkage as confirmed by Fourier‐transform infrared investigation. POLYM. COMPOS., 38:2261–2271, 2017. © 2015 Society of Plastics Engineers