Morphology and mechanical properties of polyamide 12 blends with styrene/ethylene–butylene/styrene rubbers with and without maleation

Abstract

Blends of polyamide 12 (PA12) with styrene/ethylene-butylene/styrene (SEBS) and maleic anhydride grafted SEBS (SEBS-g-MA) were prepared by twinscrew extrusion and injection molding. The morphology, mechanical properties, and dynamic mechanical properties of the blends were studied. The morphology of the blends was evaluated from the etched surfaces of cryogenically fractured specimens with scanning electron microscopy. The morphological parameters showed that the PA12/SEBSg-MA blends (PM series) exhibited a finer and more uniform rubber dispersion than the PA12/SEBS blends (PS series) because of the interfacial chemical reactions. SEBS functionalization via maleic anhydride grafting strongly affected the morphological parameters, such as the domain size, interfacial area per unit of volume, and critical interparticle distance, but the distribution of the rubber domains in the blends was less affected. Tensile and impact studies showed that the PS blends had worse mechanical properties than the PM blends. The tensile strength and elongation at break of the PM blends were considerably greater than those of the PS blends. The fracture toughness and energy values determined for notched Charpy specimens in high-speed impact tests were markedly higher for the PM blends than for the PS blends. A similar observation was obtained from instrumented falling weight impact studies. Dynamic mechanical analysis confirmed the incompatibility of the blend components because the glass-transition temperatures of PA12 and the rubber phase (SEBS and SEBS-g-MA) were not affected.

Thermal and crystallisation behaviours of blends of polyamide 12 with styrene–ethylene/butylene–styrene rubbers

“…Thus, the interfacial situation is improved resulting in a better compatibility in PM blends. A detailed discussion is given elsewhere [30]. It has been revealed from this study that this stabilisation of morphology through chemical reaction has a profound effect on the thermal properties of the blends.…”

“…Specific attention has been paid to analyse the effect of functional group present in rubber phase on the thermal and crystallisation behaviours. It has been revealed from our previous studies that functional group present in rubber phase has profound effect on the mechanical properties and morphology of these blends [30]. Therefore, it is very important to correlate thermal and crystallisation behaviours of the blends in the presence and absence of functional group on rubber phase to the morphology and phase structure of the blends derived from scanning electron microscopic studies and dynamic mechanical thermal analysis, respectively.…”

Sliding wear, viscoelasticity, and brittleness of polymers

“…We recall now a detailed study by Karger-Kocsis and coworkers 33 of polyamide 12 containing blends with copolymers containing styrene units. As argued by them, PS has the advantage of easy melt processability.…”

Toughening and brittle‐tough transition in polyamide 12‐organoclay/maleated styrene‐ethylene‐co‐butylene‐styrene nanocomposites

“…This is why it is often necessary to toughen the PNs, as has been done, for instance, with semicrystalline polyamide‐based PNs [4, 13–22]. The compatibilization between PA12 and the toughening polymer is necessary to produce the required fine particle size (below 2 μm) [23]. Besides modifying the mechanical properties of the matrix [1, 11], the incorporation of OMMT gives rise to an important perturbation of the fracture mechanism characteristic of the matrix.…”