Starch Nanocrystal Stabilized Pickering Emulsion Polymerization for Nanocomposites with Improved Performance

Abstract

Latex/starch nanocrystal (SNC) nanocomposite dispersions were successfully synthesized via a one-step surfactant-free Pickering emulsion polymerization route using SNC as the sole stabilizer. The effect of the SNC content, initiator type and comonomer on the particle size, colloidal stability, and film properties were investigated. Both HCl and H2SO4-hydrolysed starch nanocrystals, each bearing different surface charges, were used as Pickering emulsion stabilizing nanoparticles. SNCs from HCl hydrolysis were found to provide a better stabilization effect, giving rise to a polymer dispersion with a lower average particle size. The mechanistic aspects of the Pickering emulsion polymerization were also discussed. Nanocomposites formed by film-casting the polymer Pickering emulsions showed better mechanical properties and optical transparency than those obtained by blending the polymer emulsion with a nanocrystal dispersion, showing the one-pot route to nanocomposite precursors to be doubly advantageous. Therefore, this in situ polymerization technique not only facilitates the use of SNC nanoparticles, it also provides a valuable nanocomposite with enhanced mechanical properties and high transparency level.

Self‐Assembled Colloidal Particle Clusters from In Situ Pickering‐Like Emulsion Polymerization via Single Electron Transfer Mechanism

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seeded emulsion polymerization, [ 8 ] controlled phase separation, [ 9 ] and Pickering emulsion polymerization. [ 10 ] Among these, seeded emulsion polymerization is effi cient and potentially scalable for the preparation of anisotropic particles. A variety of nonspherical particles have been acquired using this method, such as snowman-like (or Janus), [ 11 ] dumbbell-like, [ 12 ] raspberry-like, [ 13 ] and acornshaped particles.

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The use of amylose‐rich starch nanoparticles in emulsion polymerization

“…Starch is among the most common industrially used, solely bio‐based, materials due to its abundance, sustainability, and low cost . It can also impart beneficial properties such as increases in tensile strength, Young's modulus, oxygen barrier properties, biodegradability, water swelling capacity, and compatibility with certain substrates for film formation. Starch contains two hydrophilic naturally occurring polysaccharides with the repeat unit (C 6 H 10 O 5 ) n (Figure ), linear amylose and branched amylopectin .…”

Tuning Amphiphilicity of Particles for Controllable Pickering Emulsion

“…The control of Pickering emulsions plays a pivotal part in many significant processes, for example, oil extraction and recovery [29,30], emulsion polymerization [31,32,33,34], and heterogeneous catalysis [35,36,37]. In this regard, many endeavors have been made in developing controllable Pickering emulsions.…”