Rheological properties of ionically and covalently crosslinked polypropylene‐type thermoplastic elastomers

Abstract

Maleic anhydride was grafted onto a polypropylene-type thermoplastic elastomer PER by reactive processing with a screw extruder, and a maleated PER (MPER) was prepared. Aiming at ionic crosslinking, magnesium 12-hydroxy stearate (MgStOH), zinc oxide (ZnO), and zinc sulfide (ZnS), and aiming at covalent crosslinking, melamine as an amino compound, and Epocizer and GRYCI-ALE as epoxy compounds, were added to the MPER, melt-mixed by use of the screw extruder, and crosslinked compounds were obtained. The rheological properties such as capillary flow properties and dynamic viscoelasticities of the compounds were measured and their melt processabilities were evaluated. The degree of crosslinking was in the order of epoxy compounds Ͼ MgStOH Ͼ melamine Ͼ ZnO, ZnS Ͼ MPER (blank). In the case of the compound with MgStOH of a moderately high degree of crosslinking, the nonNewtonian behavior is remarkable and the die swell ratio is low and suitable for extrusion. However, in the case of compounds with epoxy compounds of an excessive degree of crosslinking, fine extrudate cannot be obtained due to the lack of fusion and the control of degree of crosslinking is necessary.

Ionic cross-linked methacrylic copolymers for carbon fiber reinforced thermoplastic composites

“…Therefore, improvement in the solvent resistance by the introduction of an ionic crosslinked structure into methacrylic copolymer matrices was investigated in this study. Although ionic cross-linked polymers, i.e., ionomers, behave similarly to covalent cross-linked polymers at room temperature, they can deform and flow at high temperature [30]. Many researchers have reported the physical properties and structures of polymeric ionomers [30][31][32][33][34].…”

“…Although ionic cross-linked polymers, i.e., ionomers, behave similarly to covalent cross-linked polymers at room temperature, they can deform and flow at high temperature [30]. Many researchers have reported the physical properties and structures of polymeric ionomers [30][31][32][33][34]. Ionomers with high toughness and abrasion resistance have been utilized for packaging materials, the outer skin of golf balls, ski boots, and automotive parts.…”

“…The interaction of ionomers at the cross-link points decreased with an increase in temperature, which indicated that the ionomers would flow at high temperature. However, ionomers generally have a higher melt viscosity than the corresponding precursors without ionic cross-linking [30,34]. Hirasawa et al [34] showed that the melt viscosity of the polymer increased with ionomerization, i.e., the degree of neutralization of the acrylic acid unit in the ethyleneacrylic acid copolymers.…”

Thermal oxidation‐induced long chain branching and its effect on phase separation kinetics of a polyethylene blend

“…Polyolefins as the most widely used thermoplastics have gained a rapid progress during the past decades with the development of new catalysts and modified methods. The properties of polyolefins such as impact strength, thermal performance, chemical resistance, aging characteristics, and rheological behaviors can be largely improved through cross‐linking or introducing long chain branching (LCB) 1, 2. For semicrystalline polyolefins, LCB affects not only on the bulk properties, but also on the crystallization behaviors including crystallization rate, crystallinity, lamellar thickness, and even unit cell parameters of the crystals under both static conditions3 and flow fields,4 which shows obvious effects on the final properties of their industrial products.…”

Rheological properties of ionically crosslinked poly(propylene)‐type thermoplastic elastomers

“…Because PER contains so much EPR, many carboxyl groups, such as maleic anhydride, can be easily grafted. 4 In our previous paper, 5 maleic anhydride was grafted onto PER by reactive processing with a screw extruder, and a maleated PER (MPER) was prepared. With the intent of ionic crosslinking, magnesium 12-hydroxy stearate (MgStOH), zinc oxide (ZnO), and zinc sulfide (ZnS), and with the intent of covalent crosslinking, melamine as an amino compound and Epocizer and GRYCI-ALE as epoxy compounds, were added to the MPER in 5 weight parts (phr) and meltmixed with a screw extruder and crosslinked compounds were obtained.…”