Selective Localization of Nanofillers: Effect on Morphology and Crystallization of PLA/PCL Blends

Abstract

Adding nanofillers to PLA/PCL blends to change their surface and interface properties can improve their phase morphology. Here the selective localization of CNTs and organoclays as the third component in the blend is studied. It is found that clay is selectively localized in the PLA phase and at the phase interface whereas CNTs are mainly found in the PCL phase and at the phase interface. With a reduced viscosity ratio of the blend matrices, the CNTs change their preferred localization from PCL to PLA. The effects of the different selective localization of clay and CNTs on the morphologies are studied. In addition, the crystallization behavior of ternary systems also shows a strong dependence on the selective localization of nanofillers. magnified image

Epoxy/PCL nanocomposites: Effect of layered silicate on structure and behavior

“…In the case the 95/5 epoxy/PCL matrix, Figure 6 clearly shows that best values of the strength and toughness occurred in the sample without added clay, in contrast to the systems with higher PCL contents and the analogous systems with different Figure 6. Effect of clay content on strength and toughness of epoxy containing (a) 5 wt% and (b) 10 wt% polycaprolactone thermoplastic modifiers, which show the synergy of the clay/thermoplastic combination [14][15][16][17]19]. The reduced properties in the presence of clay appear to be a consequence of the lower PCL content (and the resulting lower number of particles), as well as the related increase of the interparticle distance (Figure 1), especially when the low crystallinity of PCL the inclusions (< 5 %) and the resulting significant rubbery character are considered.…”

“…The NF influences the structure by affecting the dynamic phase behavior in the case of immiscible thermoplastics [7][8][9] and the phase separation (including RIPS) that occurs in thermosets. In both cases, the change of morphology type and dimension, including the formation of complex structures, is accompanied by an influence on the interface and crystallinity parameters [19]. The effect of inorganic particles on the structure of multiphase polymers has been demonstrated in both experimental and theoretical studies [21][22][23][24].…”

“…This effect was observed in both immiscible thermoplastic systems [7][8][9] and epoxies with two phase structures formed by the reaction-induced phase separation (RIPS) [10] of a modifier dissolved in an uncured resin. The enhanced mechanical performance of epoxy systems was mostly observed in liquid rubbers and clays [11][12][13] and in combinations of thermoplastics (PEEK, PEI, PES, ABS) and clays [14][15][16][17][18][19][20]. The synergistic effect of the nanofiller consists in its complex effect on the multiphase system by reinforcement, leading also to a change in the component parameter profile combined with a significant influence on the structure and parameters of the interface.…”

Effect of halloysite on structure and properties of melt-drawn PCL/PLA microfibrillar composites

“…The mostly applied PLLA containing 2-4% D-isomer has low compatibility with PCL [5]; therefore, various compatibilizing techniques [6,7] must be applied. In this area, application of various nanofillers (NF) leading to simultaneous reinforcement, compatibilization, and improvement of other material parameters may also be beneficial [8][9][10][11][12]. Recently, halloysite nanotubes have been successfully applied to modification of PLA [13,14] and PCL [15,16]; their advantage is dispersion even without organophilization in these polar polymers.…”

Phase behavior of UCST blends: Effects of pristine nanoclay as an effective or ineffective compatibilizer

“…It has been found that the addition of solid nanoparticles with at least one dimension in the nanometer scale can affect the compatibility of components and improve the physical, mechanical and thermal properties of the blends [2][3][4][5]. The improved miscibility of polymer mixtures in the presence of nanofillers has been reported by different groups with reduced dispersed phase domains, narrower droplet size distribution in matrix-dispersed morphology, enhanced ductility and mechanical properties, lower interfacial tension between two phases and more morphological stability in the subsequent melt blending processes [5][6][7][8][9][10]. As shown theoretically by Nesterov and Lipatov [11][12], the compatibilization effect of solid filler (F) on an immiscible polymer pair (A and B) can be described by the mixing free energy of system (!G mix ) which consists of the absorption free energy of each polymer on the solid surface of F (!G AF and !G BF ) and the interaction …”