Structure-property relations of heterophasic ethylene-propylene copolymers based on a single-site catalyst

Aarnio-Winterhof, M.; Doshev, Petar; Seppälä, Jukka; Gahleitner, Markus

doi:10.3144/expresspolymlett.2017.16

Cited by 13 publications

(15 citation statements)

References 32 publications

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“…Using a block or graft copolymer as matrix giving constituent fairly wide processing window can be ensured for SRPC preparation, wide enough even for injection moulding technology . In the case of polypropylene, the increasing ethylene copolymer content is also positively correlated to the increase of the impact strength . Sterzynski et al used co‐extruded composite pellets and bicomponent fibres as input materials for injection moulding of SRPCs, but to achieve homogeneous distribution of reinforcing fibres in the injection moulded products proved to be rather challenging, and due to undesired fibre aggregations the reinforcing efficacy remained moderate in both cases.…”

Section: Introductionmentioning

confidence: 99%

“…5 In the case of polypropylene, the increasing ethylene copolymer content is also positively correlated to the increase of the impact strength. 6 Sterzynski et al used co-extruded composite pellets 7 and bicomponent fibres 8 as input materials for injection moulding of SRPCs, but to achieve homogeneous distribution of reinforcing fibres in the injection moulded products proved to be rather challenging, and due to undesired fibre aggregations the reinforcing efficacy remained moderate in both cases. Kmetty et al proposed to use pre-impregnated pellets, prepared by film-stacking of high tenacity polymer fibres and copolymer matrix, serving as adequate starting material for injection moulding of SRPCs with homogeneous fibre distribution and improved mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

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Flame retarded self‐reinforced polypropylene composites prepared by injection moulding

Vadas

Kmetty

Bárány

et al. 2017

Polymers for Advanced Techs

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A method was elaborated to prepare flame retarded self-reinforced polypropylene composites by injection moulding. The effect of intumescent flame retardant (FR) loading was comprehensively investigated on the morphology, flammability, and mechanical properties of the self-reinforced polypropylene composites and compared with non-reinforced counterparts of identical additive contents. Homogeneous distribution of both the reinforcing polypropylene fibres and the FR additive was achieved endowing significantly improved strength and stiffness accompanied with increased fire resistance. At 10% FR content, 37% reduction of peak of heat release rate, UL94 V-2 rating, and LOI of 24.5 vol% were achieved without compromising the improved mechanical performance of the injection moulded self-reinforced composites, ie, a 4-fold increase of tensile strength and a 7-fold increase of tensile modulus were reached compared with the non-reinforced counterpart. At higher loading (15% FR), the FR properties improved further (LOI of 29.5 vol% was reached); however, due to the abrasive effect of the FR particles in the matrix, the structure of the reinforcing fibres tends to get damaged during the thermo-mechanical processing, and thus their reinforcing efficacy deteriorated. It is demonstrated that the combination of polymer fibre reinforcement with other fillers (such as FRs) is advantageous and feasible even by injection moulding, but the balance between the individual attributed properties needs to be found. This concept provides advantages in terms of interfacial properties, mechanical performance to weight ratio, recyclability, and environmental impact; 1 therefore, SRPCs gain increasing interest in both academia and industries.Nowadays, SRPCs are mainly produced by 3 processing methods:hot compaction, consolidation of coextruded tapes, and film stacking. 2 All of these methods yield in sheet-like (pre) products; these ways 3-dimensional parts with complex geometry cannot be directly produced. Therefore, increasing attempts are being made to produceSRPCs by the more versatile injection moulding method. Polymer fibres with highly aligned molecular or supramolecular structure, 3 generally created during spinning or drawing, can serve as suitable reinforcements in the structurally similar polymer matrix. One of the greatest challenges in using thermoplastic fibres to reinforce thermoplastic matrices is in their combination into a well-consolidated composite, which, normally achieved by thermal means, is complicated by the narrow window between the melting temperature of the matrix and that of the reinforcing fibres. 4 One possible way to disturb the regularity of the macromolecular chain and thus lower the crystalline melting temperature is copolymerization. Using a block or graft copolymer as matrix giving constituent fairly wide processing window can be ensured for SRPC preparation, wide enough even for injection moulding technology. 5 In the case of polypropylene, the increasing ethylene copolymer content is also positively corr...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flame retarded self‐reinforced polypropylene composites prepared by injection moulding

Vadas

Kmetty

Bárány

et al. 2017

Polymers for Advanced Techs

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“…Assignment of the peaks, quantification of the comonomer fraction, analyses temperature, and spectrometer specifications can be found in ref. .…”

Section: Methodsmentioning

confidence: 99%

The Effect of Reactor Conditions on High‐Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

Cancelas

Yang

Girod

et al. 2018

Macro Reaction Engineering

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High impact polypropylene (hiPP) powders are made in a 2.5 L semi‐batch gas‐phase reactor using a Ziegler–Natta catalyst and two sequential polymerization steps. The amount of copolymer, reactor temperature and pressure, the relative amounts of ethylene and propylene, and the presence of hydrogen are varied systematically to understand their impact on the copolymerization kinetics, hiPP properties, and on rubber distribution. Examples of discoveries are that the presence of hydrogen can reduce copolymerization activity, depending on the catalyst system, and that the fraction of crystalline copolymer decreases with 1) copolymer content in hiPP; and 2) copolymerization activity. The last implies a resistance to mass transfer of ethylene during copolymerization. To understand this phenomenon, atomic force microscopy analyses of hiPP samples with distinct morphology of the polypropylene matrix (isotactic polypropylene, iPP) and copolymer ethylene/propylene ratios are performed after microtoming. It is found that mesoparticles are the determining structure for the copolymer distribution, and that powders with more ethylene in the copolymer or an iPP matrix better suited for mass transfer had more rubber in the center of the mesoparticles. This indicates that the length scales of the mesoparticles that control transfer limitations for ethylene also impact the properties of the final impact copolymer.

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“…One major drawback of PP is that it presents some serious limitations in impact toughness, especially when operating at room temperature and below. 3,4 When it comes to improving the toughness of plastics, there are two general approaches: copolymerization with a suitable monomer, 5 and the preparation of multi-component polymeric materials through blending. [6][7][8] The latter method is the more common, since it can be easily adapted to those processing techniques that are generally present in the plastic industry, like extrusion or injection molding.…”

Section: Introductionmentioning

confidence: 99%

A novel preparation method of polypropylene/natural rubber blends with improved toughness

Lendvai

2020

Polymer International

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A novel melt compounding methodoriginally introduced for the preparation of nanocompositeswas adapted to produce polypropylene (PP) based blends toughened with up to 20 wt% natural rubber (NR). This water-assisted technique is based on batchwise melt mixing, where the additives are introduced as an aqueous dispersion into the matrix, drop by drop. The efficiency of this preparation technique was analyzed by comparing the resulting blends with reference samples produced by traditional melt mixing. Mechanical, thermomechanical and morphological properties were determined in order to investigate the structure-property relationships. According to SEM analyses, the average domain size of NR within the PP matrix became significantly smaller when the water-assisted method was applied. Charpy impact tests showed that the toughening efficiency of NR particles within the PP was enhanced as a result of their decreased size. This improvement was more prominent when the difference between the viscosity of PP and NR was higher. In addition, applying the water-assisted technique led to an enhanced deformability with similar strength and stiffness compared to common melt mixing.

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Structure-property relations of heterophasic ethylene-propylene copolymers based on a single-site catalyst

Cited by 13 publications

References 32 publications

Flame retarded self‐reinforced polypropylene composites prepared by injection moulding

Flame retarded self‐reinforced polypropylene composites prepared by injection moulding

The Effect of Reactor Conditions on High‐Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

A novel preparation method of polypropylene/natural rubber blends with improved toughness

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