Unexpected Improvement of Both Mechanical Strength and Elasticity of EPDM/PP Thermoplastic Vulcanizates by Introducing β-Nucleating Agents

Abstract

Thermoplastic vulcanizates (TPVs) are among the most concerned polymer materials because they exhibit a combination of good elasticity and easy processibility and recyclability. Herein, a β-nucleating agent (β-NA) was introduced into ethylene propylene diene monomer (EPDM)/polypropylene (PP) TPVs through a simple and effective postprocessing method to induce the formation of β-PP crystals for preparing high-performance TPV products. High content of β-PP crystals is achieved in TPV, but the total crystallinity of the PP matrix remains constant. Unexpectedly, both mechanical strength and elasticity of TPV with β-PP crystals (β-TPV) are significantly higher than those of TPV with α-PP crystals (α-TPV). The change in the structure of both α-TPV and β-TPV during real-time deformation and the deformation mechanism was carefully studied by combining Synchrotron two-dimensional wide-angle X-ray diffraction (2D-WAXD) and atomic force microscopy nanomechanical mapping (AFM-NM) techniques. The mechanism for the simultaneous improvement of mechanical strength and elasticity of TPV is revealed.

Effects of Ethylene-Propylene-Diene Monomers (EPDMs) with Different Moony Viscosity on Crystallization Behavior, Structure, and Mechanical Properties of Thermoplastic Vulcanizates (TPVs)

“…Both the EPDM NORDEL™ 4770P and 4725P used in this study have an ethylene content of 70 wt%. β-PP crystals in TPV can have an effect on both mechanical strength and elasticity [ 3 , 23 ]. Synchrotron WAXD was used to study the crystal structure of EPDMs and different EPDM-based TPVs at 25 °C (see Figure 2 ).…”

“…Ethylene-propylene-diene monomer (EPDM)/polypropylene (PP) thermoplastic vulcanizates (TPVs), with a high proportion (50–80 wt%) of EPDM dispersed in a low content of continuous thermoplastic PP phase [ 1 ], are usually prepared by pre-blending elastomer and semicrystalline thermoplastics, followed by dynamic vulcanization. Dynamic vulcanization involves crosslinking high-content elastomer components via an in-situ process and dispersing these in the low-content section of the continuous thermoplastic PP by means of a shearing action [ 2 , 3 , 4 , 5 , 6 ]. The dispersed crosslinked elastomer phase improves the toughness and elasticity of the TPV, whereas the thermoplastic PP phase provides good melt processing properties, and the crystalline structure of the plastic phase also gives the TPV its physical and mechanical properties [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

Stretchable, Ultratough, and Intrinsically Self‐Extinguishing Elastomers with Desirable Recyclability

“…Meanwhile, the two diffraction spots observed in the 2D WAXD patterns correspond to the deconvoluted Peak 1 and Peak 2 in the 1D WAXD profiles, centered at the scattering vector q of 13.6 and 16.5 nm −1 (Figure 3d), respectively, assigned to the (020) and (110) planes of the crystalline methylene groups in the PTMEG segments. [37][38][39] The newly-formed PTMEG crystalline regions can also serve as physical crosslinking sites to form a selfreinforcing phase, thus leading to a sharp increase in mechanical properties of PU(P-Van-N), as evidenced by a strain-hardening zone (Figure 2a).…”

New low‐temperature resistant shape memory elastomer: Ethylene‐octene copolymer/methyl vinyl silicone rubber composites

“…In the 1970s, the American company ExxonMobil took the lead in achieving the industrial production of ethylene‐propylene‐diene rubber (EPDM)/polypropylene (PP) TPV materials. Currently, this variety of TPVs remains to be the most widely applied and most productive TPV type in the industry 15–18 . Moreover, researchers have sought to meet the functional requirements of TPV materials in various fields by designing new TPV composites using a diverse range of thermoplastics, rubber materials, and fillers as raw materials.…”

“…Currently, this variety of TPVs remains to be the most widely applied and most productive TPV type in the industry. [15][16][17][18] Moreover, researchers have sought to meet the functional requirements of TPV materials in various fields by designing new TPV composites using a diverse range of thermoplastics, rubber materials, and fillers as raw materials. The most studied TPVs comprise epoxy natural rubber/propylene (PP) TPV, 19 natural rubber/high-density polyethylene (HDPE) TPV, 20,21 and so forth.…”