Thermoplastic Vulcanizates Based on Highly Compatible Blends of Isotactic Poly(propylene) and Copolymers of Atactic Poly(propylene) and 5‐Ethylidene‐2‐norbornene

Abstract

Highly compatible thermoplastic/elastomer blends were used to prepare thermoplastic vulcanizates (TPVs) with refined morphologies and improved mechanical properties. Copolymers of atactic poly(propylene) (aPP) and 5‐ethylidene‐2‐norbornene (ENB) (aPP‐co‐ENB) were prepared via metallocene catalysis. Blends of isotactic poly(propylene) (iPP) and the aPP‐co‐ENB rubbers are immiscible in the melt, but the very high compatibility leads to a refinement of the morphology in comparison to blends based on iPP and ethylene‐propylene‐ diene (EPDM) rubber. The aPP‐co‐ENB‐based blends show improved tensile properties, while the relatively high Tg of the rubber phase retards the elastic recovery at room temperature. Dilution of the TPVs with oil broadens the temperature window for applications by a signification reduction of the Tg and improves the elasticity of the TPVs. This study demonstrates that the lower limit of the rubber particle size of TPVs that is attainable via dynamic vulcanization of immiscible blends is in the order of 300–500 nm.magnified image

On the injection molding of thick‐walled thermoplastic vulcanizates: linking static and dynamic mechanical properties with morphology

“…Moreover, the PP crystalline lamellae penetrate into the vulcanized EPDM. Similar phenomena have been reported in several studies where the effect of shearing stresses on the PP crystal orientation has been investigated 30,31 …”

“…Similar phenomena have been reported in several studies where the effect of shearing stresses on the PP crystal orientation has been investigated. 30,31 wileyonlinelibrary.com/journal/pi AFM was used for further analysis of the morphology of samples shA60-M and shD41-M. Figure 7 shows the peak-force results for the three areas studied per sample (see the Experimental section).…”

Semi‐interpenetrating Networks in Blends of Epoxidized Natural Rubbers

“…Figure 5A,B give an image of the (62.5/37.5) and (85/15) blends, respectively, at the same magnification. In the former case, the image shows a continuous morphology, which is coarse in accordance to the incompatibility of both polymers 23. Even though the crosslinkable rubber is the minor phase in this case, the ENR50 domains can connect during the crosslinking process.…”

A Polyolefin Elastomer Encapsulant Modified by an Ethylene–Propylene–Diene Terpolymer for Photovoltaic Applications

“…These phenomena might be attributed to the increased content of shorter crystallizable chain blocks and the crystal regions surrounded by the crosslinked amorphous region in the POE matrix, respectively. 46,47 The glass transition temperature (T g ) of the neat POE was detected at approximately −53.3 °C, and the T g values of its compounds were detected at a similar temperature because m-EPDM and POEs have similar T g values. 48 Meanwhile, the T g values of all samples cross-linked using peroxide were detected at a higher temperature than that used to detect the uncrosslinked counterparts.…”