High Performance Thermoplastic Elastomers Research Articles

Novel Design of Eco-Friendly High-Performance Thermoplastic Elastomer Based on Polyurethane and Ground Tire Rubber toward Upcycling of Waste Tires.

Waste rubber tires are an area of global concern in relation to reducing the consumption of petrochemical products and environmental pollution. Herein, eco-friendly high-performance thermoplastic polyurethane (PU) elastomers were successfully in-situ synthesized through the incorporation of ground tire rubber (GTR). The excellent wet-skid resistance of PU/GTR elastomer was achieved by using mixed polycaprolactone polyols with Mn = 1000 g/mol (PCL-1K) and PCL-2K as soft segments. More importantly, an efficient solution to balance the contradiction between dynamic heat build-up and wet-skid resistance in PU/GTR elastomers was that low heat build-up was realized through the limited friction between PU molecular chains, which was achieved with the help of the network structure formed from GTR particles uniformly distributed in the PU matrix. Impressively, the tanδ at 60 °C and the DIN abrasion volume (Δrel) of the optimal PU/GTR elastomer with 59.5% of PCL-1K and 5.0% of GTR were 0.03 and 38.5 mm3, respectively, which are significantly lower than the 0.12 and 158.32 mm3 for pure PU elastomer, indicating that the PU/GTR elastomer possesses extremely low rolling resistance and excellent wear resistance. Meanwhile, the tanδ at 0 °C of the above-mentioned PU/GTR elastomer was 0.92, which is higher than the 0.80 of pure PU elastomer, evidencing the high wet-skid resistance. To some extent, the as-prepared PU/GTR elastomer has effectively solved the "magic triangle" problem in the tire industry. Moreover, this novel research will be expected to make contributions in the upcycling of waste tires.

Synthesis and Characterization of Graft Copolymers with Poly(ε-caprolactone) Side Chain Using Hydroxylated Poly(β-myrcene-co-α-methyl styrene).

Graft copolymers have unique application scenarios in the field of high-performance thermoplastic elastomers, resins and rubbers. β-myrcene (My) is a biomass monomer derived from renewable plant resources, and its homopolymer has a low glass transition temperature and high elasticity. In this work, a series of tapered copolymers P(My-co-AMS)k (k = 1, 2, 3) were first synthesized in cyclohexane by one-pot anionic polymerization of My and α-methyl styrene (AMS) using sec-BuLi as the initiator. PAMS chain would fracture when heated at high temperature and could endow the copolymer with thermal degradation property. The effect of the incorporation of AMS unit on the thermal stability and glass transition temperature of polymyrcene main chain was studied. Subsequently, the double bonds in the linear copolymers were partially epoxidized and hydroxylated into hydroxyl groups to obtain hydroxylated copolymer, which was finally used to initiate the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) to synthesize the graft copolymer with PCL as the side chain. All these copolymers before and after modifications were characterized by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), thermogravimetry analysis (TGA), and differential scanning calorimeter (DSC).

Nanostructures, Linear Rheological Responses, and Tunable Mechanical Properties of Microphase-Separated Cellulose-graft-Diblock Bottlebrush Copolymer Elastomers.

A series of cellulose-graft-diblock bottlebrush copolymer elastomers (cellulose-graft-poly(n-butyl acrylate)-block-poly(methyl methacrylate) (Cell-g-PBA-b-PMMA)) with short side chains were synthesized via successive atom transfer radical polymerization (ATRP) to study the influence of varying compositions and lengths of the graft diblock side chains on microphase morphologies and properties. The microphase-separated morphologies from misaligned spheres to cylinders were observed by atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS) measurements. These bottlebrush copolymer elastomers possessed thermal stability and enhanced mechanical properties because the PMMA outer block could self-assemble into hard microdomains, which served as physical cross-links. The viscoelastic responses of these bottlebrush copolymers within the linear viscoelastic (LVE) regime were carried out by the oscillatory shear rheology. The time-temperature superposition (tTs) principle was applied to construct the master curves of the dynamic moduli, and the sequential relaxation of dense bottlebrush copolymers with different PMMA hard outer block lengths was analyzed. The rheological behaviors in this work could be utilized to build up the connection of microstructures and properties for the application of these bottlebrush copolymers as high-performance thermoplastic elastomers.

Construction of sacrificial network in styrene-ethylene/butadiene-styrene triblock copolymer composites and their mechanical behaviors

Herein, benefiting from effective energy-dissipation mechanism, the high-performance thermoplastic elastomers (ZASM/SEBS composites) with excellent mechanical strength-toughness combination were prepared by blending 3-Amino-1,2,4-triazole (ATA), maleic anhydride grafted styrene-ethylene/butadiene-styrene triblock copolymer (SEBS-g-MA), zinc acetate and styrene-ethylene/butadiene-styrene triblock copolymer (SEBS) successively. The Zn2+-carboxyl coordination and hydrogen bonding dual-dynamic network of composites was proved by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The mechanical performance of ZASM/SEBS composites was investigated by tensile test. With the decreasing mass ratio of ZASM in ZASM/SEBS composites, the tensile strength and elongation at break increased firstly and then decreased. When the mass ratio of ZASM in composites was 30%, the tensile strength reached 32.1 MPa along with the elongation at break of 1383%, attaining the best mechanical strength-toughness combination. It is demonstrated that the ZASM/SEBS composites could be a promising substitute for traditional vulcanized rubber.

One-Pot Synthesis of Supertough, Sustainable Polyester Thermoplastic Elastomers Using Block-Like, Gradient Copolymer as Soft Midblock

It remains challenging to synthesize supertough thermoplastic elastomers (TPEs) since the stretchability and tensile strength are mutually exclusive. Here, we report a one-pot strategy for the prep...

Tailoring the properties of PA6 into high-performance thermoplastic elastomer: Simultaneous reinforcement and impact property modification

The effectiveness of the simultaneous addition of carbon nanotubes (CNTs) and maleic-anhydride-grafted-ethylene propylene diene (EPDM-g-MA) with a maleation content of 0.4 wt% was evaluated on the toughness of two grades of polyamide6 (PA6) with different molecular weight. The samples were fabricated in the presence or absence of 1.5 wt. % of CNTs by melt-mixing using an internal mixer where the PA6/EPDM-g-MA content weight ratio was 100/0, 90/10, and 80/20. Scanning electron microscopy (SEM) revealed a rougher fracture surface by EPDM-g-MA with high-molecular-weight PA6 (HPA6) than low-molecular-weight PA6 (LPA6) as noted from the finer EPDM-g-MA particles owing to higher PA6/EPDM-g-MA interfacial adhesion. A remarkable decrease in EPDM-g-MA droplet size accompanied by shape transformation was also observed by the introduction of CNTs. Transmission electron microscopy (TEM) exhibited more homogeneous and fine CNT dispersion in the HPA6-based nanocomposites as compared to LPA6-based ones. Tensile results revealed that CNTs can counteract the plasticizing effect of EPDM-g-MA on Young’s modulus of the PA6. Though the presence of CNTs was expected to sacrifice the ductility, HPA6-based nanocomposite maintained reasonable levels of ductility owing to the absence of CNTs agglomerations. The crystallization study showed the nucleating and reinforcing effect of CNTs in the formulated system. The rheological test confirmed the effective CNT/polymer interaction with substantially higher G' and η* for HPA6-based nanocomposites. Dynamic mechanical studies suggested higher toughening effectiveness of EPDM-g-MA on HPA6 over LPA6 by the lower tanδmax peak height and Tg for the PA6 phase.

Styrene Moiety-Carrying Diorganozinc Compound Preparation for Polystyrene-Poly(ethylene-co-1-hexene)-Polystyrene Triblock Copolymer Production

Polystyrene (PS)-block-poly(ethylene-co-1-butene)-block-PS (SEBS), produced by PS-block-polybutadiene-block-PS hydrogenation, is a high-performance thermoplastic elastomer. Hydrogenation is costly ...

Modification of poly(ethylene 2,5-furandicarboxylate) with aliphatic polycarbonate diols: 1. Randomnized copolymers with significantly improved ductility and high CO2 barrier performance

Poly(ethylene 2,5-furandicarboxylate) (PEF) is a very promising biobased polymer possessing very high mechanical strength, rigidity and gas barrier performance. But its poor ductility and toughness may limit its applications. In this study, PEF-based copolymers with high intrinsic viscosity were successfully synthesized via melt polycondensation of dimethyl 2,5-furandicarboxylate (DMFD) and ethylene glycol in the presence of a copolycarbonate diol (PPeHC diol) as produced from 1,5-pentylene diol (PeDO), 1,6-hexylene diol (HDO) and dimethyl carbonate, and characterized with 1H NMR, 13C NMR, DSC, TGA, tensile, impact and gas barrier testing. The products were “randomnized” as a result of ester-carbonate exchange reaction occurring along melt polycondensation, and therefore became amorphous copolymers possessing composition-dependent physico-mechanical properties which can be tunable from rigid-to-ductile thermoplastics to thermoplastic elastomers. Particularily, the copolymers with φPPeHC of 25 wt% and 30 wt% are thermoplastics possessing greatly improved ductility (elongation at break up to 194%) and CO2 barrier performance higher than poly(ethylene terephthalate) (PET; BIFCO2 3.6–2.8), and retaining high tensile modulus (2.2–1.9 GPa) and yielding strength (69–58 MPa) comparable to the bottle-grade PET. In comparison, the copolymer with φPPeHC of 40 wt% behaves as a high performance thermoplastic elastomer with excellent gas barrier performance as well as high tensile strength (23 MPa).

High Performance Thermoplastic Elastomers with Biomass Lignin as Plastic Phase

For the first time, the coordination-based energy sacrificial bonds have been constructed in the interface between lignin and polyolefin elastomer for preparing a new class of high performance ther...

Effect of cross-linking degree of EPDM phase on the electrical properties and formation of dual networks of thermoplastic vulcanizate composites based on isotactic polypropylene (iPP)/ethylene–propylene–diene rubber (EPDM) blends

Thermoplastic vulcanizates (TPVs), as a special class of high-performance thermoplastic elastomers, have been widely used in the automotive industry, building, and electronics due to their good processability and recyclability.

High performance thermoplastic elastomer (TPE) nanocomposite based on graphene nanoplates (GNPs)

This paper examines the enhancement in the properties of thermoplastic elastomer (TPE) reinforced by graphene nanoplates (GNPs). TPE is a blend of polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR), which is used as a compatibiliser at a percentage of volume ratio 70:10:20, respectively. Using TPE as the host matrix, TPE/GNPs nanocomposites are processed, and the mechanical, electrical and structural properties are characterised. The results extracted from the tensile and the impact tests showed that the tensile strength, Young’s modulus and the impact strength of the nanocomposites also increased as the filler loading increased until an optimum value of filler loading was reached. Based on the experimental results, GNPs strongly affected the electrical conductivity due to disruption of the GNPs percolated network. It is believed that the high aspect ratio of GNPs is a critical issue concerning the constitution of a special interface region between the GNPs and TPE matrix and the high performance of the composites.

Reactive Compatibilization of Recycled Polyethylenes and Scrap Rubber in Thermoplastic Elastomers: Chemical and Radiation-Chemical Approach

Abstract Reactive compatibilization of recycled low- or high-density polyethylenes (LDPE and HDPE, respectively) and ground tire rubber (GTR) via chemical interactions of pre-functionalized components in their blend interface has been carried out. Polyethylene component was functionalized with maleic anhydride (MAH); as well, the rubber component was modified via functionalization with MAH or acrylamide (AAm) using chemically or irradiation (γ-rays) induced grafting techniques. The grafting degree and molecular mass distribution of the functionalized polymers have been measured via FTIR and Size Exclusion Chromatography (SEC) analyses, respectively. Additional coupling agents such as p-phenylene diamine (PDA) and polyamide fiber were used for producing some thermoplastic elastomer (TPE). Thermoplastic elastomer materials based on synthesized reactive polyethylenes and GTR as well as ethylene-propylenediene monomer rubber (EPDM) were prepared by dynamic vulcanization of the rubber phase inside thermoplastic (polyethylene) matrix and their phase structure, and main properties have been studied using DSC, DMTA and mechanical testing. As a result, high performance thermoplastic elastomers based on functionalized polyethylene and ground rubber with improved mechanical properties have been developed.

Reactive Compatibilization of Polyethylene/Ground Tire Rubber Inhomogeneous Blends via Interactions of Pre‐Functionalized Polymers in Interface

AbstractSummary: Reactive compatibilization of recycled low‐ or high‐density polyethylenes (LDPE and HDPE, respectively) and ground tire rubber (GTR) via chemical interactions of pre‐functionalized components in their blend interface has been carried out. Polyethylene component was functionalized with maleic anhydride (MAH) as well as the rubber component was modified via functionalization with MAH or acrylamide (AAm) using chemically or irradiation (γ‐rays) induced grafting techniques. The grafting degree and molecular mass distribution of the functionalized polymers have been measured via FTIR and Size Exclusion Chromatography (SEC) analyses, respectively. Thermoplastic elastomer (TPE) materials based on synthesized reactive polyethylenes and GTR as well as ethylene‐propylene‐diene rubber, EPDM were prepared by dynamic vulcanization of the rubber phase inside thermoplastic (polyethylene) matrix and their phase structure, and main properties have been studied using DSC and mechanical testing. As a final result, the high performance TPE with improved mechanical properties have been developed.

Segmented polyether ester copolymers—A new generation of high performance thermoplastic elastomers

AbstractThis paper reviews a series of high‐melting thermoplastic polyether esters prepared by transesterification from dimethyl terephthalate, polytetramethylene ether glycol (MW 600–2000), and 1,4‐butanediol. The resulting copolyesters exhibit a two‐phase domain structure consisting of amorphous polyether ester soft segments and crystalline tetramethylene terephthalate hard segments. By proper selection of the relative amounts of soft and hard segments, polymers ranging from relatively soft elastomers to impact resistant elastoplastics may be obtained. The preparation, polymer structure as well as the physical and environmental properties of polyether esters are discussed. The combination of good melt flow properties, excellent melt stability, and rapid hardening rates permits the processing of these polymers by a wide variety of methods. The excellent processing characteristics in conjunction with the unusual physical and mechanical properties of segmented polyether esters has led to their wide acceptance.