Effect of Surface Energy on Dispersion and Mechanical Properties of Polymer/Nanocrystalline Cellulose Nanocomposites

Khoshkava, Vahid; Kamal, Musa R.

doi:10.1021/bm400784j

Cited by 196 publications

(139 citation statements)

References 55 publications

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“…Both surfaces are uniform and smooth as the root mean square (R q ) and arithmetic average (R a ) roughness values for silicon wafers are 0.3 and 0.2 nm and those of silicon modified with APTES are 9.6 and 7.5, respectively. As shown previously, 61,62 contact angle measurements are independent of surface roughness for values less than 150 nm. Figure 8 shows the contact angle of PLA on silica-APTES surfaces as a function of the pressure of surrounding CO 2 at 153º C (426 K).…”

Section: Figure 4 Interfacial Tension Values Of Pla-silica Aptes Comsupporting

confidence: 80%

Adsorption of Surface-Modified Silica Nanoparticles to the Interface of Melt Poly(lactic acid) and Supercritical Carbon Dioxide

Sarikhani¹,

Jeddi²,

Thompson³

et al. 2015

Langmuir

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With the purpose of fabricating polymer nanocomposite foams and preventing coalescence in foaming processes, the interfacial tension of poly (lactic acid) (PLA) -silica composites is investigated in this work. Synthesized silica nanoparticles (SNs) with a CO 2 -philic surface modification are used as the dispersed nanoparticles. Interfacial tension is a key parameter in processing of polymer foams since it directly affects the final foam properties, such as cell size and cell density. Interfacial tension of silica-containing PLA and supercritical carbon dioxide (CO 2 ) is measured using Axisymmetric Drop Shape Analysis Profile (ADSA-P) pendant drop method at high pressures and high temperatures. The interfacial tension between PLA and supercritical CO 2 is observed to decrease as a result of nanoparticles' adsorption to the interface. These results indicate that the reduction in interfacial tension with increasing silica content significantly deviates from a linear trend; there is a minimum at 2 wt. % loading of the SNs and then the interfacial tension curve reaches a plateau. Contact angle measurements show an affinity of the SNs for the polymer-supercritical CO 2 interface, and these obtained results are used to calculate the binding energy of the nanoparticles to the PLA / CO 2 interface. In addition to interfacial properties, the adsorption of silica nanoparticles at the interface is also studied in detail with Scanning Electron Microscopy.

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Section: Figure 4 Interfacial Tension Values Of Pla-silica Aptes Comsupporting

confidence: 80%

Adsorption of Surface-Modified Silica Nanoparticles to the Interface of Melt Poly(lactic acid) and Supercritical Carbon Dioxide

Sarikhani¹,

Jeddi²,

Thompson³

et al. 2015

Langmuir

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“…(Herein we define cohesion as the interaction between nanoparticles of the same material in contrast to the traditional definition of cohesion being within a material; this is also used in the powder and composites materials community. 3 ) Advancing the field of reinforced nanocomposites requires methods to extract and predict these interactions in a variety of systems.…”

Section: Introductionmentioning

confidence: 99%

Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

2016

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The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particlepolymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water).Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R 2 =0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites.

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“…The interfacial and surface tension of polymers is a key thermodynamic parameter in various applications such as polymer blending [1], wetting [2], dispersion of particles or fibres in polymers [3], and polymer foaming [4].…”

Section: Introductionmentioning

confidence: 99%

Effect of pressure and temperature on interfacial tension of poly lactic acid melt in supercritical carbon dioxide

et al. 2015

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Effect of Surface Energy on Dispersion and Mechanical Properties of Polymer/Nanocrystalline Cellulose Nanocomposites

Cited by 196 publications

References 55 publications

Adsorption of Surface-Modified Silica Nanoparticles to the Interface of Melt Poly(lactic acid) and Supercritical Carbon Dioxide

Adsorption of Surface-Modified Silica Nanoparticles to the Interface of Melt Poly(lactic acid) and Supercritical Carbon Dioxide

Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

Effect of pressure and temperature on interfacial tension of poly lactic acid melt in supercritical carbon dioxide

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