Polyoxazoline‐modified graphene oxides with improved water and epoxy resin dispersibility and stability towards composite applications

Abstract

Graphene oxide (GO) is modified with poly(2-ethyl-2-oxazoline) (PEOZ) and poly [(2-ethyl-2-oxazoline-co-(ethylenimine)] (PEOZ-PEI) to enhance its dispersibility in water and epoxy resin. PEOZ with a terminal primary amine and POZ-PEI with multiple backbone secondary amines are synthesized with scalable methods and characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). GO modifications are performed at room temperature and 90 C with/without N,N 0 -dicyclohexylcarbodiimide (DCC) and modified-GOs are analyzed by FTIR, thermogravimetric analysis (TGA), and scanning electron microscopyenergy-dispersive X-ray spectroscopy (SEM-EDX). It is observed that the polymer incorporation varies based on the reaction condition, polymer type, and functional group type and position. The dispersion quality and stability of modified GOs are studied in water by particle size analyzer and visually and in epoxy resin by rheometer. PEOZ-modified GOs show better dispersibility and stability than PEOZ-PEI-modified GOs in both media since PEOZ is monofunctional, preventing the agglomerate formation and improving polymer exposure to the dispersion media by its longer length and higher water-solubility, whereas PEOZ-PEI has lower water solubility, multiple amines for interactions leading to agglomeration and limited polymer exposure to the dispersion media. The tailorable polymer grafting and the increased dispersibility of modified GOs in both media are promising indicators of their possible applications in composites.

Amphiphilic Polyoxazoline Copolymer–Imidazole Complexes as Tailorable Thermal Latent Curing Agents for One-Component Epoxy Resins

“…Owing to their unique properties such as controlled synthesis, tunability of properties, versatility, and stimuli-responsiveness, POZs have attracted attention for applications in different fields with a major focus on biomedical applications. − 2-oxazoline monomers carrying a variety of functionalities such as aryl or alkyl group can be synthesized through developed methods and later polymerized through cationic ring-opening polymerization (CROP). − The versatility of 2-oxazoline monomers paves the way to obtain polymers with desired chemical, physical, and mechanical properties . Moreover, functionalities of the obtained polymers can be tuned by implementing proper initiating and terminating groups .…”

Synthesis and Structure–Property Relationship of Amphiphilic Poly(2-ethyl-co-2-(alkyl/aryl)-2-oxazoline) Copolymers

“…Even though the use of numerous initiators and terminating agents has been reported in the literature to fine-tune the chemical and physical properties of POZs, altering the 2-substituent group of the monomer remains the most prevalent method for adjusting the polymer properties due to the large number of side chains as opposed to two terminal groups brought by initiator and terminating agent. Pendant side groups of the POZs greatly affect various properties of the polymer including solubility in water and organic solvents, crystallinity, stimuli-responsiveness, and amphiphilicity. , In recent years, POZs with various pendant groups including alkyl, aryl, amino, aldehyde, alkene, and alkynes , giving rise to different properties have been investigated for various applications including drug delivery, ,, coatings, , and composites …”

“…9,10 In recent years, POZs with various pendant groups including alkyl, aryl, 11 amino, 12 aldehyde, 13 alkene, 14 and alkynes 15,16 giving rise to different properties have been investigated for various applications including drug delivery, 15,17,18 coatings, 19,20 and composites. 21 Since CROP of 2-oxazolines is a heat-induced polymerization, two main methods of heat transfer, namely, microwave irradiation and conventional heating, have been proposed and investigated to control the polymerization rate. 22 The scale of the synthesis, targeted molecular weight, and the synthesis infrastructure are important parameters for choosing the heating method.…”

“… 9 , 10 In recent years, POZs with various pendant groups including alkyl, aryl, 11 amino, 12 aldehyde, 13 alkene, 14 and alkynes 15 , 16 giving rise to different properties have been investigated for various applications including drug delivery, 15 , 17 , 18 coatings, 19 , 20 and composites. 21 …”

Plasma surface modification of graphene oxide nanosheets for the synthesis of GO/PES nanocomposite ultrafiltration membrane for enhanced oily separation

“…In recent years, carbon-based nanomaterials such as carbon nanotubes (CNTs) and graphene oxide (GO) have been considered as hydrophilic modifier to improve the separation performance of the membranes as well as their mechanical strength and thermal stability. [13][14][15] Various techniques such as chemical modification, 16 oxidation methods, 17 covalent functionalization, 18 and chemical vapor deposition (CVD) 19 can be used to functionalize surfaces of nanomaterials to improve their dispersion rate in solution. Among them, CVD process offers various advantages over solution-based processes such as being an all-dry, single step, environmentally friendly (without involving organic/hazardous solvents) and low-temperature process.…”