Tailor-Made Thermoplastic Elastomeric Stereoblock Polypropylenes by Modulation of Monomer Pressure

Moshonov, Moshe; Aharonovich, Sinai; Eisen, Moris S.

doi:10.1021/acs.macromol.6b01825

Cited by 9 publications

(12 citation statements)

References 29 publications

(45 reference statements)

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“…In general, the polyethylene displaying the higher branching content and lower crystallinity showed the lowest ultimate tensile strength but higher εb [64,66,67]. On the other hand, the stress/strain data for the polymers obtained at 1 atm C2H4 revealed inferior mechanical properties when compared to those generated at higher pressure [74,75]. For example, by comparing PE-30M/1atm with PE-70M/10atm, both the stress (0.02 MPa) and strain (εb = 86.2%) for PE-30M/1atm are significantly lower (c.f.…”

Section: Mechanical Properties Of the Polyethylenesmentioning

confidence: 94%

Branched polyethylenes attainable using thermally enhanced bis(imino)acenaphthene-nickel catalysts: Exploring the effects of temperature and pressure

Zhang

et al. 2019

Applied Catalysis A: General

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Section: Mechanical Properties Of the Polyethylenesmentioning

confidence: 94%

Branched polyethylenes attainable using thermally enhanced bis(imino)acenaphthene-nickel catalysts: Exploring the effects of temperature and pressure

Zhang

et al. 2019

Applied Catalysis A: General

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“…Based on chemical building blocks, there are several commercially available TPEs: two generic classes are block copolymers (styrenics, polyesters, polyurethanes, and polyamides) and thermoplastic/elastomer blends. Among these, polyolefin TPEs have received considerable attention because of the wide availability of commodity olefins, high chemical resistance, low density, and reversible shape memory that make polyolefin TPEs desirable in several applications ranging from biomedical devices to packaging, adhesives, lightweight engineering plastics for automotive, textile and in additive manufacturing techniques such as 3D printing. − …”

Section: Introductionmentioning

confidence: 99%

Semibatch Terpolymerization of Ethylene, Propylene, and 5-Ethylidene-2-norbornene: Heterogeneous High-Ethylene EPDM Thermoplastic Elastomers

Leone¹,

Zanchin²,

Girolamo

et al. 2020

Macromolecules

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Thermoplastic elastomers (TPEs) are materials combining the processability of thermoplastics and the elasticity of rubbers. The global value and demand of TPEs is expected to grow in coming years, and advancement in synthetic chemistry is the key driving force. This contribution provides a simple synthesis of high−ethylene EPDMs with high molecular weight, narrow molecular weight distribution (1.9 < M w /M n < 2.3), and properties which can be adjusted from soft thermoplastic to elastomer. EPDMs are prepared through the terpolymerization of ethylene with propylene and 5ethylidene-2-norbornene (ENB), where ethylene is continuously supplied to the reaction bath, while 2 propylene and ENB are added only at the beginning. Polymerizations are catalyzed by three known imido vanadium(IV), differing in the imido substituents and coligand, in combination with Et 2 AlCl and Cl 3 CCO 2 Et. The obtained EPDMs are a mixture of macromolecules each of them featuring a non random comonomer distribution, and non uniform composition. Each chain likely contains multiblocks where the comonomers are segmented, i.e., blocks with high ethylene content that may crystallize, and blocks with high propylene and ENB content that may not crystallize. This broad chemical composition distribution is due to time drift that occurs during the polymerization, which in turn depends on the experimental conditions and ligand set. Composition drift causes variation in the instantaneous feed comonomer ratio, and hence in the chemical composition of the terpolymer over the period of conversion. In proper experimental conditions, EPDMs behave as TPEs without the need of vulcanization, polymer blending, and reinforcement through the addition of fillers. They exhibit high elongation at break, strain hardening at large deformation, remarkable shape retention properties (up to 76% recovery after 10 cycles at 300%, and about 90% at 410% strain), and remelting processability with no fall in properties for recycle and reuse.atmosphere for 8 h, distilled, and stored over 5Å molecular sieves away from bright light. Ethyltrichloroacetate (ETA, Aldrich, 97%) was dried by stirring over CaH 2 for about 4 h, and then distilled under reduced pressure. Et 2 AlCl (Aldrich) was used as received. ENB (Aldrich, mixture of endo and exo, 99% pure), 1-hexene (Aldrich, 97% pure), and 1-octene (Aldrich, 98% pure) were dried by stirring over CaH 2 for about 4 h, then distilled under reduced pressure and, finally, stored under dry nitrogen and kept at -30 °C. The synthesis of imido V(IV) complexes, hereinafter referred as 1a, 2a and 2b, is reported in our previous work. 35,36 Polymerization Experiment. Polymerizations were carried out in a 100 mL roundbottomed Schlenk flask containing a stirring bar. Prior to starting polymerization, the reactor was heated to 110 °C under vacuum for 1 h, and backfilled with nitrogen. The typical reaction procedure for ethylene/propylene/ENB terpolymerization is as follows. Toluene, the appropriate amount of propylene (as a toluene solution), ENB, ...

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“…Polymer chemists in academia and industry have invested considerable attention and efforts in finding alternatives to thermoset elastomers from α-olefins. Polyolefin thermoplastic elastomers (TPEs) are an important class of materials with applications ranging from packaging to lightweight engineering plastics for automotive, textiles, rubbers, sporting goods, and electrical and thermal insulation. − The global TPEs demand will grow in the coming years, and part of this growth comes from applications where TPEs have directly displaced more traditional thermoset, vulcanized rubbers. TPEs combine the processing advantages (i.e., they can be processed by injection molding, extrusion, and blow molding) and recycling potential of thermoplastics with the flexibility, low modulus, and soft touch of elastomers. , A two-phase molecular structure usually gives TPEs their combination of strength and flexibility: amorphous domains in the polymer are soft and provide its elastomeric nature, while the hard crystalline segments, usually dispersed throughout the amorphous matrix, form physical cross-links that give tensile strength, resistance to chemicals, and produce recoverable elasticity after strain-induced deformation .…”

Section: Introductionmentioning

confidence: 99%

Chain-Walking Polymerization of α-Olefins by α-Diimine Ni(II) Complexes: Effect of Reducing the Steric Hindrance of Ortho- and Para-Aryl Substituents on the Catalytic Behavior, Monomer Enchainment, and Polymer Properties

et al. 2018

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With Brookhart type α-diimine Ni(II) based catalysts, it is highly challenging to tune polymers branching level and branch-type distribution, which in turn strongly affects thermal and mechanical properties, through the aryl ortho-positions modification, while maintaining high turnover frequencies (TOFs). Herein, we are interested in performing a systematic investigation on the polymerization of 1-octene, 1-decene, and 1-octadecene catalyzed by a series of α-diimine nickel(II) complexes with methyl ligand backbone and different substituents in aryl positions (Ni1−Ni6). In addition to bulky isopropyl and tert-butyl substituents described in the original Brookhart's work, complexes with different aryl ortho-and para-substituted α-diimine ligands, including the less sterically demanding methyl and ethyl substituents, are investigated. The 13 C NMR spectra of the polymers have been assigned in detail, and some unique features have been identified and related to the chain-walking coordination/insertion mechanism. Changes in the ligand structure and monomer size have important effects on the numerous combinations of insertion and chain-walking paths from which different branches are installed. We have also carried out a comprehensive investigation of the mechanical behavior of the polymers by means of uniaxial stretching until failure, step-cycle, and creep tensile tests. Overall, the resulting polymers exhibited a broad spectrum of tensile properties, depending on their microstructure and crystallinity which in turn are strongly affected by monomer length and type of α-diimine ligand. 1-Octene and 1-decene polymers behave as elastomers with excellent mechanical properties, i.e., high elongation at break (up to 2000%) and good strain recovery, while 1-octadecene polymers behave as plastomers.

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Tailor-Made Thermoplastic Elastomeric Stereoblock Polypropylenes by Modulation of Monomer Pressure

Cited by 9 publications

References 29 publications

Branched polyethylenes attainable using thermally enhanced bis(imino)acenaphthene-nickel catalysts: Exploring the effects of temperature and pressure

Branched polyethylenes attainable using thermally enhanced bis(imino)acenaphthene-nickel catalysts: Exploring the effects of temperature and pressure

Semibatch Terpolymerization of Ethylene, Propylene, and 5-Ethylidene-2-norbornene: Heterogeneous High-Ethylene EPDM Thermoplastic Elastomers

Chain-Walking Polymerization of α-Olefins by α-Diimine Ni(II) Complexes: Effect of Reducing the Steric Hindrance of Ortho- and Para-Aryl Substituents on the Catalytic Behavior, Monomer Enchainment, and Polymer Properties

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