Grafting from versus Grafting to Approaches for the Functionalization of Graphene Nanoplatelets with Poly(methyl methacrylate)

Abstract

Graphene nanoplatelets (GNP) were exfoliated using a nondestructive chemical reduction method and subsequently decorated with polymers using two different approaches: graf ting f rom and graf ting to. Poly(methyl methacrylate) (PMMA) with varying molecular weights was covalently attached to the GNP layers using both methods. The grafting ratios were higher (44.6% to 126.5%) for the graf ting f rom approach compared to the grafting to approach (12.6% to 20.3%). The products were characterized using thermogravimetric analysis−mass spectrometry (TGA-MS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The graf ting f rom products showed an increase in the grafting ratio and dispersibility in acetone with increasing monomer supply; on the other hand, due to steric effects, the graf ting to products showed lower absolute grafting ratios and a decreasing trend with increasing polymer molecular weight. The excellent dispersibility of the grafting f rom functionalized graphene, 900 μg/mL in acetone, indicates an increased compatibility with the solvent and the potential to increase graphene reinforcement performance in nanocomposite applications.

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

“…Conversely, in a "graft-from" reaction, the monomer is added to the end of the growing polymer chains in situ; grafting density then depends on the number of initiation sites on the carbon nanomaterial, which may be sufficiently high (and thus close) to form "brush" polymers. 339 CCNs can initiate anionic graft-from polymerizations directly from the nanocarbon surface without the need to introduce specific initiating groups first. The choice of monomer however is restricted, as for traditional anionic polymerizations, by the need to avoid side reactions and stabilize the negative charge on the growing chain; vinyl 194,340,377 and epoxide 338,378 monomers have been used effectively.…”

“…The graft-from approach has been shown to produce higher grafting ratios and higher solubilities for graphenides. 339 …”

“…435 The use of a reactive polymer solution as the coagulant allows a covalent interface to form between matrix and nanotube in situ as the fiber forms, offering increased composite toughness. 339 …”

Thermal Decomposition of Ternary Sodium Graphite Intercalation Compounds

“…Alkali metal GICs have been dispersed in a variety of solvents, including, for example, potassium GICs introduced in NMP, THF, and even water . Before these solutions are quenched, the negative charges on the graphenide sheets may be exploited for reaction with suitable electrophiles including diazonium salts, alkyl, aryl and polymer halides, bromine, vinyl or acrylate monomers such as styrene or methyl methacrylate, and proton donors such as ethanol, resulting in covalent modification of the graphene sheets.…”

Polymer brushes grafted from graphene via bioinspired polydopamine chemistry and activators regenerated by electron transfer atom transfer radical polymerization

“…The “grafting to” technique usually refers to using click chemistry . “Grafting from” approach is often used to create well‐controlled, densely grafted polymer brushes in comparison with that of “grafting to”approach . Among these controlled radical polymerization strategies, ATRP has provided efficient and versatile tool for building well‐defined polymer brushes functionalized graphene materials .…”