Multiphase blends of poly(lactic acid) (PLA), ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer, and a series of renewable poly(ether-b-amide) elastomeric copolymer (PEBA) were fabricated through reactive melt blending in an effort to improve the toughness of the PLA. Supertoughened PLA blend showing impact strength of ∼500 J/m with partial break impact behavior was achieved at an optimized blending ratio of 70 wt % PLA, 20 wt % EMA-GMA, and 10 wt % PEBA. Miscibility and thermal behavior of the binary blends PLA/PEBA and PLA/EMA-GMA, and the multiphase blends were also investigated through differential scanning calorimetric (DSC) and dynamic mechanical analysis (DMA). Phase morphology and fracture surface morphology of the blends were studied through scanning electron microscopy (SEM) and atomic force microscopy (AFM) to understand the strong corelation between the morphology and its significant effect on imparting tremendous improvement in toughness. A unique “multiple stacked structure...

Supertoughened Renewable PLA Reactive Multiphase Blends System: Phase Morphology and Performance

The effects of SEBS-g-maleic anhydride reaction on the morphology and properties of polypropylene/PA6/SEBS ternary blends

In this work, the morphologies of PMMA/PP/PS blends of different concentrations were studied and compared to the predictions of spreading coefficient, minimum free energy, and dynamic interfacial energy phenomenological models. Different morphologies than the ones predicted by the phenomenological models were observed in the case of PMMA matrix:  a mixture of core−shell morphology (core of PP and shell of PS), dispersed PS, and subinclusions within the core when the concentration of PP was increased were obtained. The quantitative analysis of the morphologies indicated that when PMMA was the matrix, PS acted as an emulsifier. The study of the evolution of morphology in the case of 10/80/10 PMMA/PP/PS blends showed that when PMMA is added to the binary blend of PP/PS, threads of PMMA are formed and break up into droplets with a size comparable to the ones of PS forming a double dispersion type morphology, and then PMMA penetrates the drops of PS, forming a core−shell morphology with only one drop of PMMA i...

Study of Morphologies of PMMA/PP/PS Ternary Blends

The simple cup and rotor mini-mixer, designed to blend very small polymer batches (0.3 g, MiniMAX), was compared to larger lab scale mixers: an internal batch mixer (50 g, Haake); a conical, recirculating twin screw extruder (5 g, DACA); and a 16 mm co-rotating twin screw (300 g/hr, PRISM). All were compared at the maximum shear rate in the cup and rotor mixer, 110 s –1 . Particle sizes of poly(propylene) (PP) dispersed in poly(styrene) (80 wt% PS) were measured by dissolving the PS, filtering and using scanning electron microscopy. The 16 mm twin screw gave somewhat smaller particle sizes than the lab scale mixers (1.2 � m vs 1.7 and 1.9 � m), but dispersion in the cup and rotor mini-mixer was much poorer. Simply adding three steel balls to the cup as suggested by Marechal et al. (Polym Networks Blends, 1997) greatly improved the dispersion (1.8 � m). Modifying the rotor design to allow recirculation yielded similar improvement. The benefit of adding three balls was confirmed in blends of low viscosity poly(dimethyl siloxane) PDMS in PS. When anhydride terminal PDMS was blended with amino terminal PS, the particle sizes were much smaller (10 vs. 0.3 � m) and the differences between the three versions of the cup and rotor were much less pronounced.

Improving Polymer Blend Dispersions in Mini-Mixers

Thermally conductive composites obtained by flake graphite filling immiscible Polyamide 6/Polycarbonate blends

We studied the morphology development of ternary immiscible blends through an interfacial reaction between components. This phenomenon was observed in two ternary blend systems; one is composed of polyamide(6) (PA6), polycarbonate (PC), and poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS), and the other is composed of PA6, PC, and polystyrene (PS), where PA6 forms the continuous matrix in both blend systems. Maleinated SEBS (SEBS-gMA) or maleinated PS (PS-gMA) is incorporated with its unmodified polymer (un-SEBS and un-PS, respectively) at various ratios into the blends of PA6/PC. The blends of PA6/PC/un-SEBS and PA6/PC/un-PS show a similar phase formation in which the two dispersed polymers are stuck together in a PA6 matrix. The use of the maleinated polymers instead of their unmodified polymers in the blends of PA6/PC changes the phase formation drastically. The maleinated polymers react with amine end groups of PA6 at the interface during the melt mixing. Through this interfacial reaction, the ...

Nuanjan Matchariyakul

Papers

Morphology Development through an Interfacial Reaction in Ternary Immiscible Polymer Blends