The use of functionalized nanoparticles as non‐specific compatibilizers for polymer blends

Abstract

The ability to form blends of polymers offers the opportunity of creating a new class of materials with enhanced properties. In addition to the polymer components, recent advances in nanoengineering have resulted in the development of nanosized inorganic particles that can be used to improve the properties of the blend, such as the flammability and the mechanical properties. While traditional methods using copolymer compatibilizers have been used to strengthen polymer blends, here, we show that the inorganic nanosized filler additive can also serve as a compatibilizer as it can localize to the interface between the polymers. We use experimental and theoretical studies to show the fundamental mechanisms by which inorganic fillers with large aspect ratio and at least one-dimension in the nanometer range, can act as non-specific compatibilizers for polymer blends. We examine a series of nanosized fillers, ranging from nanotubes to nanoclays (with varying aspect ratios) in a model polystyrene (PS)/poly(methylmethacyralate) (PMMA) blend. Using a number of experimental techniques such as transmission electron microscopy (TEM), scanning tunneling X-ray microscopy (STXM), and atomic force microscopy (AFM) we postulate that the mechanism of compatibilization occurs as a result of the fillers forming in situ grafts with the immiscible polymers. We also use theoretical studies to show that the aspect ratio and the bending energy of the fillers play a key role in the compatibilization process. Our results indicate that the compatibilization is a general phenomenon, which should occur with all large aspect ratio nanofiller additives to polymer blends.Studies have also demonstrated how colloidal particles are interfacially active agents. [9] Several groups have demonstrated that when nanoscale fillers are added to phase-segregating (wileyonlinelibrary.com)

EPDM-based heat-shielding materials modified by hybrid elastomers of silicone or polyphosphazene

“…The slight increase in the tensile strength in PDAP/EPDM-20/100 is probably due to the good interfacial interactions between fillers by introducing certain amounts of stronger polar molecules of PDAP and appropriate vulcanizing rate with TAIC/DCP. 24 –26 Similar trends of decreasing effects were found for the elongation at break for silicone/EPDM insulations due to the dispersion of the secondary matrix from the continuous phase to the dispersed phase. 27 –29 Meanwhile, the PDAP/EPDM blends retained higher values of elongations, hinting that PDAP might show better compatibility with EPDM due to its higher polarity and the better interfaces between them.…”

Structuration, selective dispersion and compatibilizing effect of (nano)fillers in polymer blends

“…Zhang et al [158] made films based on 50/50 PS/PMMA (prepared by solution in toluene) with 5 vol% of three different nanoparticles: Cloisite ® 6A (that is an organically modified montmorillonite), tungsten disulfide nanotubes and tungsten disulfide multi-layered "onion" shaped particles. They showed that W 2 S onion shaped nanoparticles do not affect the phase segregation morphology, whereas the other two do.…”

Effects of organoclay on the compatibility and interfacial phenomena of PE/EVA blends with UCST phase behavior

“…In comparison with nanotubes and spherical nanofillers such as nanosilica, layered nanosilicate with much larger aspect ratio has been verified to be more efficient in compatibilizing the LCST blends and reducing the interfacial tension of polymers by providing large amounts of in situ grafts between two components at the interface. Moreover, the authors found that the thermodynamic effect of nanoclay (NC) on an immiscible polymer blend was an equilibrium phenomenon whereupon the biphasic morphology was stabilized after long periods of annealing . Likewise, Bousmina's group reported that nanoclay can alter the phase behavior of LCST blends both thermodynamically and kinetically and the phase transition mechanism changes from spinodal decomposition to nucleation and growth by the incorporation of nanoparticles.…”