Well-dispersed cellulose nanocrystals in hydrophobic polymers by in situ polymerization for synthesizing highly reinforced bio-nanocomposites

Abstract

In nanocomposites, dispersing hydrophilic nanomaterials in a hydrophobic matrix using simple and environmentally friendly methods remains challenging. Herein, we report a method based on in situ polymerization to synthesize nanocomposites of well-dispersed cellulose nanocrystals (CNCs) and poly(vinyl acetate) (PVAc). We have also shown that by blending this PVAc/CNC nanocomposite with poly(lactic acid) (PLA), a good dispersion of the CNCs can be reached in PLA. The outstanding dispersion of CNCs in both PVAc and PLA/PVAc matrices was shown by different microscopy techniques and was further supported by the mechanical and rheological properties of the composites. The in situ PVAc/CNC nanocomposites exhibit enhanced mechanical properties compared to the materials produced by mechanical mixing, and a theoretical model based on the interphase effect and dispersion that reflects this behavior was developed. Comparison of the rheological and thermal behaviors of the mixed and in situ PVAc/CNC also confirmed the great improvement in the dispersion of nanocellulose in the latter. Furthermore, a synergistic effect was observed with only 0.1 wt% CNCs when the in situ PVAc/CNC was blended with PLA, as demonstrated by significant increases in elastic modulus, yield strength, elongation to break and glass transition temperature compared to the PLA/PVAc only material.

Nanocrystalline cellulose/fluorinated polyacrylate latex via RAFT‐mediated surfactant‐free emulsion polymerization and its application as waterborne textile finishing agent

“…The increased tensile strength and decreased elongation at break of film is attributed to the increased cross‐linking densities of hybrid polymer as NCC content increased, which render rigid structure to films and prevent molecular chains from migrating. However, when the NCC content is further increased, it would be likely that the agglomeration of NCC in a gel structure could decrease the interfacial strength, which lead to the declined tensile strength …”

“…However, when the NCC content is further increased, it would be likely that the agglomeration of NCC in a gel structure could decrease the interfacial strength, which lead to the declined tensile strength. [28][29][30] Thermal Properties of Nanocrystalline Cellulose/Fluorinated Polyacrylate Nanocomposites Thermal properties of NCC/fluorinated polyacrylate emulsion latex films are investigated using TGA, and TGA are carried out for the four samples with different contents of NCC-g-(PAA-b-PHFBA) (1, 3, 6, and 9 wt %) to understand the differences in thermal properties, as shown in Figure 10. The temperature corresponding to 5 wt % loss is defined as the initial thermal decomposition temperature.…”

Nanocellulose-based polymer hybrids and their emerging applications in biomedical engineering and water purification

“…59 The in situ polymerization of poly(vinyl acetate) using vinyl acetate monomers in the presence of CNC yields a more homogenous and ductile fracture surface compared to that of physically mixed hybrids. 60 A notable improvement in the coating properties was observed in composites synthesized using TEMPO-functionalized CNF with zirconium alkoxide and an epoxy-functionalized silane. The SEM images indicated a decrease in the roughness from composite coating compared to that of the native materials; the roughness further decreased as the content of CNF in the matrix increased.…”

Preparation and applications of wettability-controlled fluoroalkyl end-capped oligomer/cellulose nanofiber composites

“…1–4 Therefore, the transformation of such hydrophilic materials into hydrophobic, especially superhydrophobic derivatives has been hitherto strongly desirable in order to open a new route to the development of novel cellulose-based materials. 5–8 In various cellulose-based materials, it is well known that cellulose nanofibers (CNFs) can be obtained from plant cell walls, and CNFs are one of the most ubiquitous and abundant polymers on the planet. 1–4,9 Especially, there has been considerable interest in CNFs owing to their great applications, such as high-strength lightweight materials, device substrates, textile, food packaging films, cosmetic, and medical materials.…”