SEBS-g-MAH as a Reactive Compatibilizer Precursor for PP/PTT/SEBS Ternary Blends: Morphology and Mechanical Properties

Abstract

This article highlights the effect of using maleic anhydride-assisted SEBS compatibilizer precursor on the morphology and mechanical properties of the polypropylene (PP)/poly (trimethylene terephthalate) (PTT)/poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) 70/15/15 ternary blends. In all ternary blends, the amounts of PP and PTT, respectively as the matrix and the primary minor components were kept constant at 70 and 15 wt%; in turn, the amount of constituent polymers within the secondary minor phase containing reactive maleic anhydride grafted SEBS (SEBS-g-MAH) and nonreactive SEBS was changed. The mentioned compatibilizing system was first melt-blended in a co-rotating twin screw extruder and then added into the blend. Theoretical models were also employed to make a comparison with experimental values obtained from morphology characterization through the ternary systems. Accordingly, it is found that the blend containing only non-reactive SEBS exhibited fine dispersion of core-shell particles; however, by diminishing SEBS to SEBS-g-MAH weight ratio, the morphology changed from the pure core-shell to a multi-phase system consisting of both core-shell and detached particles. Eventually, this transition in the phase morphology caused some consequences and/ or advantages on the mechanical properties, so that the blend consisting of 50/50 weight ratio of SEBS/SEBS-g-MAH exhibited the minimum value of modulus; in contrast, the impact strength of that sample was considerably higher than that of neat PP specimen. These alterations in mechanical properties could be ascribed to the formation of some especial microstructures, in another word, the impact of particle size and particle size distribution, which has been well-established through scanning electron micrographs.

An investigation on the role of GMA grafting degree on the efficiency of PET/PP-g-GMA reactive blending: morphology and mechanical properties

“…This shortcoming roots in large difference in their polarities [13,14]. As a consequence of this, PP/PET blends reveal poor mechanical properties because of insufficient interfacial adhesion between components, and hence need to be strengthened by a compatibilizing agent [15][16][17].…”

Looking back to interfacial tension prediction in the compatibilized polymer blends: Discrepancies between theories and experiments

“…Compatibilizer molecules, in general, are assumed to be inhomogeneously distributed across the interface. The molecular nature of the compatibilizer, that is, chain length and number of functional units per chain, determines the final particle size (or characteristic size of the phases) and, subsequently, the degree of change in morphological and mechanical characteristics . Overall, a desired level of interfacial adhesion is considered to be present when the compatibilizer provides sufficient molecular entanglement and penetration into the interface of each phase .…”

Fracture Behavior of Poly(trimethylene terephthalate) Toughened by Maleic Anhydride Grafted Styrene-Ethylene-Butadiene-Styrene Block Copolymer

“…So far, most of the researches have been focused on the direct use of polar elastomers or functionalized elastomers. These elastomers include maleic anhydride grafted ethylene-propylene-diene copolymer (EPDM-g-MA) [13][14][15] , maleic anhydride grafted acrylonitrile-butadiene-styrene (ABS-g-MA) [16,17] , maleic anhydride grafted styreneethylene=butadiene-styrene (SEBS-g-MA) [18] , maleic anhydride grafted poly(ethylene-octene) (POE-g-MA) [19,20] .…”

“…So far, most of the researches have been focused on the direct use of polar elastomers or functionalized elastomers. These elastomers include maleic anhydride grafted ethylene-propylene-diene copolymer (EPDM-g-MA) [13][14][15] , maleic anhydride grafted acrylonitrile-butadiene-styrene (ABS-g-MA) [16,17] , maleic anhydride grafted styreneethylene=butadiene-styrene (SEBS-g-MA) [18] , maleic anhydride grafted poly(ethylene-octene) (POE-g-MA) [19,20] .In addition, the other toughening methods of PTT are related to the use of the vulcanized thermoplastics and coreshell particles. For example, Savadekar and Mhaske [21] introduced vulcanized thermoplastics based on polypropylene (PP) and EPDM, i.e., PP-g-EPDM, into PTT and found that the impact strength was significantly increased with the increase of PP-g-EPDM content.…”