PMMA-grafted graphene nanoplatelets to reinforce the mechanical and thermal properties of PMMA composites

Abstract

In order to realise the potential of graphene nanocomposites it is vital to control the degree of dispersion and achieve a strong graphene/polymer interface. Herein, we developed a facile 'grafting to' functionalisation approach for graphene nanoplatelets. NH2-terminated graphene nanoplatelets (NH2-GNPs) prepared by a diazonium coupling were used as a 'platform' to covalently graft PMMA chains to the surface of graphene through an amidation between the -NH2 groups and PMMA chains (PMMA-NH-GNPs). A degree of PMMA grafting of ~3.8 wt.% (one chain per ~40 carbon atoms) was found to both improve the dispersion of the GNPs in a PMMA matrix and give strong graphene/polymer interfaces compared to asprovided GNPs. Thus, 2 wt.% of PMMA-NH-GNPs in PMMA was found to increase the elastic modulus, strength and strain at break of PMMA, whereas the incorporation of unmodified GNPs showed poor levels of reinforcement at all loadings. Furthermore, Tg and Td of PMMA were increased by 15 °C and 29 °C, respectively, by adding 5 wt.% of PMMA-NH-GNPs, whereas incorporating unmodified GNPs led to smaller increases. This work offers the possibility of controlling the properties of graphene/polymer composites through * Corresponding authors. cristina.valles@manchester.ac.uk; Tel: +44(0)161 306 1454 ian.kinloch@manchester.ac.uk; Tel: +44(0)161 306 3615 2 chemically tuning the graphene/polymer interface, which will have broad implications in the field of nanocomposites.

Electrical and optical properties of novel brilliant cresyl blue dye‐doped poly(methyl methacrylate) as selective cut‐off laser filters

“…These findings indicate that BCB doped PMMA films did not incur any degradation or defragmentation upon exposure to high power incident laser irradiation. 64,65 Mechanical properties Tensile testing is one of the most widely used mechanical tests in polymers. 3,65,66 It serves to find some efficient mechanical parameters such as Young's modulus, tensile strength and elongation at break.…”

“…64,65 Mechanical properties Tensile testing is one of the most widely used mechanical tests in polymers. 3,65,66 It serves to find some efficient mechanical parameters such as Young's modulus, tensile strength and elongation at break. Figure 14 depicts a set of stress-strain curves for pure PMMA and BCB dye doped PMMA films.…”

“…However, the decrease in Young's modulus and tensile strength with higher doping levels may be due to the aggregation of BCB molecules. [65][66][67] The elongation at break of the studied films is improved by BCB dye incorporation up to 1 wt% and then decreased at higher ratios. This behavior is in good agreement with that reported for other dye doped polymers.…”

Diazonium Modification of Inorganic and Organic Fillers for the Design of Robust Composites: A Review

“…The drug loading and release experiment indicated that this hydrogel could be used to control drug release efficiently. Modification with 4-amino benzene diazonium salt was performed to improve the compatibility of graphene nanoplatelets with polymer matrix by strong covalent filler-polymer interactions [73]. Thus, diazonium modification allows the incorporation of amino groups, which take part in the polymerization of PMMA through amidation between the amino groups and PMMA chains (Fig.…”

“…Fullerene Sulfonated polyether ether ketone Non-covalent [65] Graphene Bismaleimide Covalent [66] Epoxy resin Covalent [67] Poly (acrylic acid) Covalent [68] Polyaniline Non-covalent [69] Polybenzimidazolium Non-covalent [70] Poly(ether ether ketone) Non-covalent [71] Polyimide Non-covalent [72] Polymethyl methacrylate Covalent [73] Polypyrrole Covalent [74] effect of the modified filler on improving properties of composites has also been extensively described.…”