Freeze dried cellulose nanocrystal reinforced unsaturated polyester composites: challenges and potential

Hydrophobic cellulose nanocrystals (CNCs) are encapsulated inside poly(butyl acrylate/vinyl acetate/acrylic acid) latex particles via mini‐emulsion polymerization (MEP). To achieve a genuine MEP, the effects of the concentration of surfactants (sodium dodecyl sulfate/Disponil A3065) and a hydrophobic agent (octadecyl acrylate (ODA)) are optimized in the presence of 0.5 wt% CNC. Using a combination of surfactant and ODA concentrations leading to a particle nucleation method restricted to the monomer droplets, the effects of CNC loading up to 1.5 wt% on the polymerization process and final nanocomposite properties are studied. Despite an increase in particle size and a lower rate of polymerization at higher CNC loadings, the droplet nucleation mechanism remains dominant up to 1.25 wt% CNC loading. Pressure‐sensitive adhesive (PSA) performance for nanocomposites produced using hydrophobic CNCs in MEP decreases whereas performance improves considerably when using hydrophilic and partially hydrophobic CNCs in conventional emulsion polymerization. These results shed light on emulsion polymerization technique selection and CNC surface properties for greener industrial production of water‐based PSAs.

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“…A similar reduction in mechanical strength has been reported when CNCs and the polymer matrix were not sufficiently compatible. [ 61,62 ]…”

Section: Resultsmentioning

confidence: 99%

Incorporating Hydrophobic Cellulose Nanocrystals inside Latex Particles via Mini‐Emulsion Polymerization

Pakdel

Cranston

Dubé

2021

Macro Reaction Engineering

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“…The authors proved that composites were characterized by better mechanical strength compared with pure polymer. DiLoreto et al [14] developed a preliminary process for incorporating freeze-dried cellulose nanocrystals powder into polyester resin, where functionalized cellulose particles were used as a potential reinforcement for an unsaturated polyester resin system, a common material for automotive applications. Kargarzadeh et al [15] prepared new nanocomposites with unsaturated polyester resin (UPR) and silane surface-treated cellulose nanocrystals.…”

Section: Introductionmentioning

confidence: 99%

Composites of Unsaturated Polyester Resins with Microcrystalline Cellulose and Its Derivatives

et al. 2019

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The paper investigates the properties of unsaturated polyester resins and microcrystalline cellulose (MCC) composites. The influence of MCC modification on mechanical, thermomechanical, and thermal properties of obtained materials was discussed. In order to reduce the hydrophilic character of the MCC surface, it was subjected to esterification with the methacrylic anhydride. This resulted in hydroxyl groups blocking and, additionally, the introduction of unsaturated bonds into its structure, which could participate in copolymerization with the curing resin. Composites of varying amounts of cellulose as a filler were obtained from modified MCC and unmodified (comparative) MCC. The modification of MCC resulted in obtaining composites characterized by greater flexural strength and strain at break compared with the analogous composites based on the unmodified MCC.

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“…The reason for this decline in tensile strength is the non‐uniform dispersion of CNC in the hydrogel matrix and the agglomeration of CNC (as shown in Figure 6) which played as stress concentration points that accelerated failure and resulted in lower strength for CNC‐hydrogel composites. [ 46,47 ] For strain at break (%) is concerned, no significant changes have been observed for the hydrogels with and without CNC. The fine dispersion of CNC within hydrogel is required to improve the mechanical properties of CNC‐hydrogel composites.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Superabsorbent Cellulose‐Based Hydrogel for Agriculture Application

et al. 2020

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Hydrogels are 3D network formed by linear (or branched) hydrophilic polymer molecules that are chemically or physically crosslinked. Hydrogels can absorb a prominent amount of water and biological fluids and release them at a controlled rate. This study deals with the synthesis and characterization of carboxymethylcellulose sodium salt (CMCNa) and hydroxyethyl cellulose (HEC)‐based biodegradable hydrogels using citric acid (CA) as a crosslinker. The chemical analysis of synthesized hydrogels is performed using Fourier transform infrared spectroscopy. The cellulose nanocrystals (CNCs) are synthesized by an acid hydrolysis process and are incorporated into the hydrogel matrix and the effects of CNCs on hydrogel properties are assessed. The effects of the CA on hydrogels swelling properties are also studied and about 600% swelling is observed for the hydrogel synthesized using 2% of the CA crosslinker. Using CNCs as reinforcing agents for hydrogel composites decreases the tensile strength of hydrogels because of poor CNC dispersion within the hydrogel matrix is observed that can be seen in the scanning electron microscope images. The optimum use of crosslinkers and proper distribution of CNCs in the hydrogel matrix can provide a promising hydrogel material that can absorb and release water in a controlled manner to improve utilization of available water resources for agricultural applications.

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Freeze dried cellulose nanocrystal reinforced unsaturated polyester composites: challenges and potential

Cited by 20 publications

References 44 publications

Incorporating Hydrophobic Cellulose Nanocrystals inside Latex Particles via Mini‐Emulsion Polymerization

Incorporating Hydrophobic Cellulose Nanocrystals inside Latex Particles via Mini‐Emulsion Polymerization

Composites of Unsaturated Polyester Resins with Microcrystalline Cellulose and Its Derivatives

Synthesis and Characterization of Superabsorbent Cellulose‐Based Hydrogel for Agriculture Application

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