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Development and characterization of graphite nanoplatelets filled copolymer of benzoxazine and epoxy
Author(s) -
Barjasteh Ehsan,
Narongdej Poom,
Shipley Wade,
Denk Jack
Publication year - 2020
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.25639
Subject(s) - materials science , composite material , ultimate tensile strength , epoxy , calendering , glass transition , dynamic mechanical analysis , nanocomposite , copolymer , sonication , conductivity , percolation threshold , electrical resistivity and conductivity , polymer , chemical engineering , chemistry , electrical engineering , engineering
In this study, graphite nanoplatelets (GNPs) were dispersed in a copolymer matrix consisting of bisphenol‐A based benzoxazine (BZ) and bi‐functional cycloaliphatic epoxy (CER), using two solvent‐free techniques: ultrasonication and three‐roll mill (3RM). The effects of GNP addition on the tensile performance, storage modulus, glass‐transition temperature ( T g ) , and electrical conductivity were evaluated. A maximum increase of nearly 46% and 20% in tensile modulus and strength, respectively, was found at 1.8 wt% of GNP content dispersed using the ultrasonication technique. In comparison, a superior enhancement with 55% and 37% increase in the tensile modulus and strength could be obtained at a lower GNP content, 0.9 wt%, dispersed via 3RM calendering, respectively. In the electrical conductivity measurement, a percolation threshold was achieved in the range between 0.6 wt% and 0.9 wt% of GNP content using the 3RM technique, which was in agreement with the predicted values. The theoretical stiffness obtained from the simplified Halpin‐Tsai model corresponded with the experimental data at low fractions. The incorporation of GNPs into the BZ/CER copolymer resulted in the full recovery of all the performance losses from the addition of CER to BZ. Choosing a proper dispersing technique, the 3RM calendering in this case, could lead to a minimum required GNP content for achieving superior nanocomposite performances.