Aqueous Polymer Modification of Cellulose Nanofibrils by Grafting‐Through a Reactive Methacrylate Group

Abstract

Modifying the surface of cellulose nanofibrils (CNFs) produced by mechanical refinement with a variety of polymer functional groups in an entirely water‐based system is challenging because only surface hydroxyl groups are accessible. To address this limitation, an entirely water‐based, polymer modification scheme is developed. CNFs are functionalized with a reactive methacrylate functional group followed by subsequent grafting‐through polymerization. This modification worked with a variety of water‐soluble and water‐insoluble (meth)acrylates and (meth)acrylamides, grafting up to 45 wt% polymer on to the CNFs. The reaction conditions introducing the methacrylate functional group are adjusted to vary the degree of functionality. Soxhlet extraction of modified samples demonstrates that the reactive methacrylate group is necessary to facilitate polymer grafting. The degree of functionalization of the polymers is studied via quantitative transmission IR spectroscopy and the morphology of the resulting cellulose nanofibrils is studied via a combination of optical, scanning electron, and atomic force microscopy. High levels of polymer modification do not significantly affect the micrometer‐scale fibril morphology.

3D Printable Hybrid Gel Made of Polymer Surface-Modified Cellulose Nanofibrils Prepared by Surface-Initiated Controlled Radical Polymerization (SI-SET-LRP) and Upconversion Luminescent Nanoparticles

“…This paper aims to develop a cellulose nanofibril-based hybrid gel material made of polymer-grafted CNFs, cross-linked with inorganic nanoparticleshere UCNPs, via SET-LRP. − Polymers of stearyl acrylate (PSA) grafted on CNF surfaces gave the modified CNF hydrophobic character and reduced the interfibrillar hydrogen bond effect, resulting in modified CNF species that form a highly stable suspension in toluene, which can also be redispersible in toluene from dried status. To evaluate the influence of the fabrication route on the nanostructure of the hybrid materials, we applied small-angle X-ray scattering (SAXS).…”

Aqueous-Based Polyimine Functionalization of Cellulose Nanofibrils for Effective Drying and Polymer Composite Reinforcement

“…Currently, traditional TEMPO-oxidation [(2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation] is one of the few largely explored and industrially produced modifications that occurs in an aqueous medium . There are numerous promising lab-scale, aqueous phase surface modification strategies for nanocellulose published in the literature. − For example, Fein et al functionalized CNF with a norbornene group, which allowed for subsequent thiol–ene reactions with a range of reactants featuring various end groups . The resulting modified CNF featured varying hydrophobicity that allowed for tailorable surface chemistry.…”

“…The resulting modified CNF featured varying hydrophobicity that allowed for tailorable surface chemistry. Others have utilized an aqueous-phase polymer grafting strategy to modify CNF, which has also produced promising materials for a range of applications. − …”

Functional engineering strategies of 3D printed implants for hard tissue replacement

“…Methacrylation is one of common-used methods to prepare photo-responsive polymers, including gelatin, hyaluronan acid and chitosan. Methacrylate group (MA) including glycidyl methacrylate or methacrylic anhydride can interact with carboxyl, hydroxyl and amine groups of polymers [ 322 ].…”