Ethylene-octene Copolymer Research Articles

Compression molding of ethylene–octene copolymer‐toughened polypropylene/graphene surfaces with actively controlled shape‐morphing microarchitectures induced by friction and wear

AbstractSuperhydrophobic microarchitectured polyolefin surfaces are currently used intensively in various industrial applications. However, the deployment of products made of these materials into practical application is typically constrained by their inferior dry sliding behaviors, which stem from their limited strength and toughness. To obtain reinforced and toughened superhydrophobic microstructured surfaces that can be easy to demold and overcome friction in the workplace, elastomeric ethylene–octene copolymer (POE) and rigid graphene (GP) were introduced into the polypropylene (PP) matrix to prepare microstructured PP/POE/GP surfaces by compression molding. The elongation at break is significantly improved by 2000% and reached up to 520.33%. The contact angle (CA) of the microstructured PP/POE/GP surface increases to 154.4°. They exhibit superhydrophobic and low adhesion characteristic, that is, lotus effect. The enhanced toughness of PP/POE/GP composites reduces wear debris and damage to microarchitecture during the abrasion process. Even after the microstructured PP/POE/GP surfaces were worn after a distance length of 3000 mm, they still exhibited superhydrophobic, but high adhesion characteristic, that is, petal effect. The controlled shape‐morphing microarchitectures formed on the microstructured PP/POE/GP surface abraded after 1000 mm, possessing wetting stability during droplet impacting.Highlights The elongation at break of composites was improved by 2000% through adding POE. The composite microstructure deforms to consume energy during abrasion and POE reinforces this energy dissipation process. POE improves fracture toughness and wetting stability of composites.

Self-healing, adaptive and shape memory polymer-based thermal interface phase change materials via boron ester cross-linking

Addressing the thermal resistance between rough interfaces without applying pressure to the interfacial sandwich has been a challenge. Herein, a thermal interface phase change material (TIPCM) is designed to realize a 3D support skeleton with a dynamic crosslinking network by introducing a boron ester crosslinking backbone into paraffin wax (PW) and ethylene-octene copolymer (EOC), thus enabling the TIPCM to ensure mechanical integrity without leakage even above the melting temperature of EOC. The chemical cross-linking between the organic solid–liquid phase change material (PCM) and the polymer realizes thermally triggered self-healing and adaptive shape memory properties. The phase transition of PW leads to a decrease in the modulus of TIPCM and activates the ester exchange of the dynamic covalent bonding of boron esters, which allows TIPCM to self-heal and self-adapt to a variety of object surfaces. These enabled the TIPCM to fill the interface gaps through small stress deformations, forming an interlocking structure that reduces contact thermal resistance and promotes heat transfer. The obtained TIPCM achieves excellent chip thermal management performance, cooling the analog CPU temperature by 67 °C at 5 V. In conclusion, this study provides a potential strategy for redesigning TIPCMs with high latent heat and special physical properties for thermal management.

Physicochemical Properties of Dispersedly Filled Ethylene-Octene Copolymer

Physicochemical Properties of Dispersedly Filled Ethylene-Octene Copolymer

The all‐polymer composites and blends made of ethylene–octene copolymer and partially disentangled polypropylene using a new processing approach

AbstractAll‐polymer composites and blends of ethylene–octene copolymer (EOC) and polypropylene (PP) were produced in the extrusion process. They had the same composition (96:4 wt.%), but five different entanglement densities of PP macromolecules. Depending on the processing temperature, below or above the melting point of PP, fibers or spherical inclusions were formed inside the EOC matrix. The production of PP fibers directly during mixing was possible by reducing the entanglement of macromolecules in this polymer. During fiber formation by solid‐state plastic deformation, the crystallinity of PP decreased, especially for the less entangled polymers. The presence of fibers influenced the mechanical properties of the composites, which were different from those of the blends. Both in blends and composites, the matrix was reinforced, but in the composites the effect was stronger and the measured stresses increased with the lower degree of PP entanglement. SAXS and microscopic observations showed that cavitation occurred in the deformed composites. All‐polymer composites, in which the reinforcement was created as a result of polymer deformation with limited entanglements, have properties that are advantageously different from traditional ones, which opens the prospect of their application.

Exploring the Effects of Nano-CaCO3 on the Core-Shell Structure and Properties of HDPE/POE/Nano-CaCO3 Ternary Nanocomposites.

To address the dilemma of the stiffness and toughness properties of high-density polyethylene (HDPE) composites, titanate coupling agent-treated CaCO3 nanoparticles (nano-CaCO3) and ethylene-octene copolymer (POE) were utilized to blend with HDPE to prepare ternary nanocomposites via a two-sequence-step process. Meanwhile, a one-step process was also studied as a control. The obtained ternary nanocomposites were characterized by scanning electron microscopy (SEM), Advanced Rheometrics Expansion System (ARES), Dynamic Mechanical Analysis (DMA), wide-angle X-ray diffraction analysis (WXRD), and mechanical test. The SEM results showed one or two CaCO3 nanoparticles were well-encapsulated by POE and were uniformly dispersed into the HDPE matrix to form a core-shell structure of 100-200 nm in size by the two-step process, while CaCO3 nanoparticles were aggregated in the HDPE matrix by the one-step method. The result of the XRD showed that the nano-CaCO3 particle played a role in promoting crystallization in HDPE nanocomposites. Mechanical tests showed that the synergistic effect of both the POE elastomer and CaCO3 nanoparticles should account for the balanced performance of the ternary composites. In comparison with neat HDPE, the notched impact toughness of the ternary nanocomposites of HDPE/POE/nano-CaCO3 was significantly increased. In addition, the core-shell structure absorbed the fracture impact energy and prevent further propagation of micro-cracks, thus obtaining a higher notched Izod impact strength.

Titanium(+4) and vanadium(+5) 8-oxyquinolinates as catalysts for the synthesis of high-molecular-weight polyethylene and ethylene-octene copolymers

Titanium(+4) and vanadium(+5) 8-oxyquinolinates as catalysts for the synthesis of high-molecular-weight polyethylene and ethylene-octene copolymers

Improving the material extrusion processing of thermoplastic olefin/graphene nanoplatelet composites through control of the morphology.

The aim of this research is to develop thermoplastic olefin (TPO) composites containing polypropylene (PP), an elastomeric ethylene-octene copolymer (EOC) and graphene nanoplatelets (GNPs), suitable for material extrusion (MEX). A PP functionalized with amino-pyridine (PP-g-Py) was used as a compatibilizer. The composite blends had droplet-matrix morphology at compositions as high as 40wt% EOC. Imaging by Transmission Electron Microscopy showed that the GNPs resided at the interface between the blend components. This microstructure promoted higher thermal conductivity of the TPO/GNP composite blends, as compared to the PP/GNP composite (1.54W/m K, vs 1.3W/m K respectively). PP/GNP composites processed by MEX exhibited inadequate interfacial fusion between the deposited strands, which resulted in severe delamination during tensile and flexural testing, and consequently poor mechanical properties. In the TPO/GNP composites containing 40wt% EOC, the slower crystallization of the elongated EOC domains promoted interfacial adhesion between the strands, resulting in better part consolidation, more consistent mechanical properties and improved ductility compared to the PP/GNP composites.

A pragmatic approach to analyze the ability of ethylene‐octene copolymer in the long chain branching of polypropylene in molten and solid state

AbstractThe investigation of chain branching in polypropylene (PP) holds significant importance for comprehending the impact of structural modifications on the properties of PP. The utilization of ethylene‐octene copolymer (EOC) presents a valuable opportunity to examine the influence of branching density on the ability of electron beam irradiation or a chemical agent in a PP blend. The introducing long chain branches (LCB) into PP can enhance its mechanical properties, particularly impact strength. This characteristic is of particular significance in applications where the material is subjected to mechanical stress, such as automotive components or packaging materials. Blends of PP/EOC were produced using 20 and 30 wt% of EOC and 0.5 phr trimethylolpropane trimethacrylate (TMPTMA) monomer. To evaluate the efficiency of branching in both solid and molten states, irradiated samples and samples mixed with dicumyl peroxide (DCP) were selected. The rheological properties of the molten blends in shear and extensional modes were assessed, and their morphology was examined using scanning electron microscopy. The existence of LCB in all samples was confirmed through dynamic viscoelastic measurements. It was concluded that although the irradiation promoted chain scission within the backbone, which resulted in long chain branching, DCP created LCB on the backbone chains of PP through chemical reaction in the melt state. Additionally, the strain hardening constant (n) was calculated, and its value for the irradiated sample PP/EOC 80/20 was 0.19, whereas its value for this blend when employing DCP was 0.14. While the complex viscosity of irradiated blend (8764 Pa.s) was greater than that of melt state branched blend (8377 Pa.s) at 0.1 rad/s, in the higher frequencies it became smaller due to the more effective creation of long chain branches through peroxide grafting in the molten state. The results of the study verified the presence of LCB in the materials by observing longer relaxation time and strain hardening behavior.Highlights The chain branching of PP/EOC blends was investigated in both the melt state and solid state through the presence of TMPTMA monomer. The effectiveness of TMPTMA monomer in grafting was mostly notable in the molten state. The steady state viscosity of LCB‐(PP/EOC) was higher in the presence of dicumyl peroxide compared to irradiated PP/EOC. The samples containing 80 wt% of PP exhibited longer side branches compared to the sample with 70 wt% of PP according to shear and extensional rheometry. The induced side chain branches resulting from irradiation and the use of dicumyl peroxide help increase the miscibility of the polymers to a similar extent.

Two‐dimensional Ti3C2Tx (MXene)‐multiwalled carbon nanotubes reinforced ethyl methyl acrylate/ethylene octene copolymer binary blend hybrid nanocomposites with enhanced thermal and dielectric properties

AbstractPolymer composites with high dielectric constant and minimal dielectric losses have wide ranging prospects for advanced applications in the flexible electronics and electrical industry. In this study, we used the advantages of carbonaceous hybrid nanofillers to develop a flexible dielectric material. Herein, a set of hybrid nanocomposites were successfully fabricated by incorporating the Ti3C2Tx (MXene) and MWCNTs (multi‐walled carbon nanotubes) hybrid mixture as the conductive moiety into the poly(ethylene‐co‐methyl acrylate) (EMA)/ethylene‐octene co‐polymer (EOC) binary blend as the matrices using solution mixing technique followed by compression molding. As prepared, EMA/EOC/Ti3C2Tx/MWCNTs hybrid composites have been characterized by FTIR (Fourier transform infrared) spectroscopy, XRD (X‐ray diffraction), TGA (thermogravimetric analysis), FESEM (field emission scanning electron microscopy), and DSC (differential scanning calorimetry). We studied the effects of Ti3C2Tx and MWCNTs contents in the hybrid composites on the thermal, dielectric, and electrical properties. Among all the 15 wt% hybrid mixture containing 2 wt% MWCNTs loaded composite has the highest dielectric constant (ℇr = 122.21) and the lowest dissipation loss (tan δ = 0.030) at 100 Hz. The present studies recommend the EMA/EOC/Ti3C2Tx/MWCNTs hybrid composites can be used in smart and flexible electronic storage material.Highlights EMA‐EOC blend composites with hybrid Ti3C2Tx/MWCNTs were processed. 2.5 wt% MWCNTs loaded hybrid composite shows excellent thermal stability. Composite with 2 wt% MWCNTs has ℇ' = 122.21 and tanδ = 0.03 at 100 Hz. 2.5 wt% MWCNTs composite has electrical conductivity of 3.26 × 10−8 Ω−1 m−1. This composite can be used in smart and flexible electronic storage material.

Thermo-Responsive Shape Memory Thermoplastic Elastomer Based on Natural Rubber and Ethylene Octene Copolymer Blends

The shape memory (SM) polymers with superior SM properties were successfully fabricated based on melt blending of natural rubber (NR) and ethylene octene copolymer (EOC) at various crystallinity of EOC phase. The differential scanning calorimetry analysis, mechanical properties, temperature scanning stress relaxation, and shape memory properties were studied. Results revealed that the mechanical and thermal properties of the prepared NR/EOC blends improved as a function of amount of ethylene fraction in the EOC phase. The ethylene segment of EOC in the NR/EOC blend is triggered as a stimulus-sensitive domain. The shape memory properties in terms of shape fixity and shape recovery efficiencies of the blends tended to increase with the increasing of crystalline segments in the blends. The shape memory properties of the prepared blends substantially exceed the best performance (close to 100%) by blending the NR/EOC at 50/50 parts by weight, having 62%–80% of ethylene content in the EOC phase, which corresponds to approximately 3°–16° of crystallinity of EOC phase in the blends.

Correlation of morphology, rheology, thermal, and mechanical properties in PP/EOC blends in presence of nanoclay and compatibilizer

ABSTRACT To expand the range of applications and overcome mechanical limitations of Polypropylene (PP), a commonly used industrial polymer, toughness modification is required. In this study, PP was toughened with ethylene octene copolymer (EOC) and nanoclay platelets and the blends and nanocomposites of PP/EOC were prepared by means of a melt mixing process, and the effect of different grades of EOC, the addition of nanoclay platelets, and the effect of compatibilizer on properties of the final system were investigated. Scanning and transition electron microscopy, X-ray diffraction, rheology, differential scanning calorimetry, and dynamic-mechanical analysis were conducted to correlate the structure to the resulting properties. The results indicate that different grades of EOC with different molecular weights and viscosity can have a tremendous impact on droplet size and final properties of the blend sample. From a morphological point of view, the addition of EOC grade with higher viscosity (ƞi) in PP/EOC blends results in droplet matrix structure with larger EOC droplets. To decrease the droplet size, and hence improvement in final properties, nanoclay and compatibilizer were introduced to the blend. According to the results, selective localization of nanoclay and proper dispersion degree of nanoclay in the PP/EOC blend with higher viscosity grade of EOC containing nanoclay up to 3 wt.% lead to amelioration of the final properties of the system including complex viscosity, storage modulus, damping, and crystallinity. Moreover, the addition of the compatibilizer to the nanocomposite samples with 5 wt.% nanoclay can compensate for the deteriorated properties which occurred as a result of nanoclay aggregation in this system. This indicates that the addition of the nanoclay and compatibilizer plays an important role in toughening, morphology, and determining the final properties of the system as well.

Thermal Cycling Induced Aging on Polypropylene/Elastomer Blends for DC Cable Insulation

This paper reports on the ageing phenomenon of the polypropylene (PP) /elastomer blends that are used as DC cable insulation. The elastomers employed are propylene-based elastomer (PBE) and ethylene-octene copolymer elastomer (EOC), which are blended into the PP to form the test samples. The samples go through thermal cycling treatment with temperatures from -30 to 150 °C, after which the trap distribution and the DC breakdown strength are measured. Structural changes in the samples are estimated through Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and differential scanning calorimetry (DSC) measurements. The test results indicate that, with the growth of the thermal cycling number, the trap center decreases whereas the trap density increases, and the DC breakdown strength tends to be reduced. The appearance of oxidation product, loose structure and decreased crystallinity with the thermal cycling ageing should be responsible for the encouragement in charge transport and the reduction in the breakdown strength. The degradation of PP/EOC is more obvious than that of PP/PBE due to its worse compatibility, the PP/PBE exhibits better resistance to the thermal cycling ageing.

Toward understanding the crystallization behavior of polypropylene‐based nanocomposites: Effect of ethylene–octene copolymer and nanoclay localization

AbstractThe crystallization properties of polypropylene (PP), a widely used polymer in industry, can be modified to overcome its mechanical limitations. In the current work, we investigated the effect of ethylene octene copolymer (EOC), blend morphology, nanoclay loading, nano‐localization, and component ratios on PP/EOC crystallization behavior in various aspects, including crystallization rate, degree of crystallinity, nucleation state, and crystalline phases. The results revealed that adding EOC with varying ratios can decrease PP crystallinity both in degree and rate due to the partial miscibility of components through grafting. Furthermore, it was found that the effect of the nanoclay on the crystallization behavior of PP is dependent on the nanoclay loading and its localization in the blend. The nanoclay, therefore, served as a nucleation agent at low nanoparticle contents, accelerating the crystallization rate regardless of the blend's microstructure. However, the crystallization rate of the blend samples at high nanoclay contents (above the rheological percolation threshold) was strongly influenced by the type of morphology. Accordingly, high nanoclay concentrations in blends with matrix‐dispersed morphologies reduced crystallization rates (increasing half‐time from 164 to 216 and 186 s), primarily because PP chains slowed down due to their interactions with nanoparticles and nanoclay hindrance. In contrast, in a blend with a co‐continues‐type morphology, the crystallization rates increased (decreasing half‐time from 624 to 270 and 236 s) due to nano‐localization at the interface and morphology transformation to the matrix‐dispersed one. The blends and nanocomposites based on PP/EOC were also investigated to determine the relationship between the crystallization behavior and mechanical properties.

Molecular Layer Deposition of Polyurea on Silica Nanoparticles and Its Application in Dielectric Nanocomposites.

Polymer nanocomposites (NCs) offer outstanding potential for dielectric applications including insulation materials. The large interfacial area introduced by the nanoscale fillers plays a major role in improving the dielectric properties of NCs. Therefore, an effort to tailor the properties of these interfaces can lead to substantial improvement of the material's macroscopic dielectric response. Grafting electrically active functional groups to the surface of nanoparticles (NPs) in a controlled manner can yield reproducible alterations in charge trapping and transport as well as space charge phenomena in nanodielectrics. In the present study, fumed silica NPs are surface modified with polyurea from phenyl diisocyanate (PDIC) and ethylenediamine (ED) via molecular layer deposition (MLD) in a fluidized bed. The modified NPs are then incorporated into a polymer blend based on polypropylene (PP)/ethylene-octene-copolymer (EOC), and their morphological and dielectric properties are investigated. We demonstrate the alterations in the electronic structure of silica upon depositing urea units using density functional theory (DFT) calculations. Subsequently, the effect of urea functionalization on the dielectric properties of NCs is studied using thermally stimulated depolarization current (TSDC) and broadband dielectric spectroscopy (BDS) methods. The DFT calculations reveal the contribution of both shallow and deep traps upon deposition of urea units onto the NPs. It could be concluded that the deposition of polyurea on NPs results in a bi-modal distribution of trap depths that are related to each monomer in the urea units and can lead to a reduction of space charge formation at filler-polymer interfaces. MLD offers a promising tool for tailoring the interfacial interactions in dielectric NCs.

Elastic Electrically Conductive Composites Based on Vapor-Grown Carbon Fibers for Use in Sensors.

Elastic electrically conductive composites with an ethylene octene copolymer matrix (EOC) and vapor-grown carbon fibers (VGCF) were prepared by ultrasonication in a toluene solution, and their morphology, mechanical and electrical properties were also evaluated. EOC/CF composites were estimated for their mechanical and viscoelastic properties. The morphology of the composites was analyzed using scanning electron microscopy (SEM), and stress-strain curves were generated to measure the stress and tensile modulus of the composites. The experimental results were compared with various theoretical models, including the Burgers model, which separates viscoelastic behavior into several components. A dynamic mechanical analysis was also used to measure the composites' storage modulus, loss modulus, and damping factor at different frequencies. The composites' complex viscosity and storage modulus were increased with higher wt.% of CF, which enhances the elastic response. Electrical resistivity measurements were conducted on the composites and it was found that the resistivity decreased as the sample was loaded and increased as it was unloaded. Overall, the study provides insights into the mechanical and viscoelastic properties of EOC/CF composites, which could be helpful in developing sensors such as pressure/strain sensors.

Effect of Processing Temperature on Crystallization, Phase Morphology and Mechanical Property of a Linear Low Density Polyethylene/Ethylene-Octene Copolymer Blend

Temperature is one of the key parameters to determine the structures and properties of polymers during processing, but the effect of processing temperature on similar-structured polymer blends has rarely been reported. In this work, a linear low-density polyethylene (LLDPE)/ethylene-octene copolymer (EOC) blend with similar-structured components was chosen as a model system to study the effect of processing temperature (including compounding temperature and molding temperature) on its crystallization, phase morphology, and tensile behavior. It was found that the blends presented evenly distributed rubbery domains at lower processing temperatures, whereas a special, EOC-rich phase domain consisting of a less stable crystalline phase and a rubbery phase was observed at higher processing temperatures. The phase morphology was mainly determined by the final processing temperature, which had a major effect on the yield stress of the material. This work not only reports novel results on processing-structure-performance relations of similar-structured blends but can also guide the design and production of LLDPE-based products with tailored properties.

Self-healing and wear resistance stable superhydrophobic composite coating with electrothermal and photothermal effects for anti-icing

Superhydrophobic material has great potential applications in the field of anti-icing due to its special wettability. However, the poor wear resistance of the material has restricted its practical applications. Based on this, a simple two-step spray method was used to prepare a self-healing and robust superhydrophobic coating with excellent photothermal/electrothermal effect for anti-icing using epoxy modified ethylene octene copolymer (POEG) resin as the substrate layer and the fluorinated carbon black as the top coating. Results showed that the obtained composite coating showed multi-level rough structure and possessed excellent superhydrophobicity toward water droplets with different pH. Meanwhile, the composite coating could resist abrasion and kept superhydropbobicity even 250 cycles abrasion test with a water contact angle higher than 150o. When the surface was subjected to the intense abrasion, the rough structure and the superhydrophobic property of the surface were destroyed. However, it could be restored by the abrasion of the rougher surface. In addition, the scratches on the surface could be completely repaired by the heat treatment, indicating the good self-healing performance of the composite coating. Due to the existence of the carbon black particles, the superhydrophobic coating had good photothermal/electrothermal effects, which endowed the surface with excellent anti-icing performance of removing the icing under the conditions of electrothermal and light. This paper provides a simple and convenient way to prepare functional self-healing superhydrophobic coating, and a new idea for the preparation of anti-icing coating.

Crystallization, Phase and Mechanical Behaviors of Linear Low Density Polyethylene/Thermoplastic Polyolefin Elastomer Blends

Blending polyethylene with thermoplastic polyolefin elastomers (TPOs) is a promising way to manipulate its structures and tailor its properties. Herein, three TPOs, i.e., two ethylene–octene copolymers (EOCs) and an olefin block copolymer (OBC) with different structures, were used to comparatively investigate the miscibility, crystallization, and phase behavior of their blends with a linear low-density polyethylene (LLDPE). It was found that large differences occurred in the crystallization and phase behaviors of the blends due to the different extent of similarity in the molecular structure between the TPO and the LLDPE matrix. In particular, a unique segregated phase morphology comprised a less stable crystalline phase and a rubbery phase was found in an LLDPE/EOC blend. The tensile performance and elasticity of the blends were also studied and correlated with the structures of the blends. This work not only provides novel results on the miscibility and phase behavior of the similar-structured LLDPE/TPO blends, but can also guide the design of LLDPE-based products with tailored performances.

Novel covalent adaptable networks (CANs) of ethylene/1-octene copolymers (EOCs) made by free-radical processing: comparison of structure–property relationships of EOC CANs with EOC thermosets

Various ethylene/1-octene copolymers were upcycled into reprocessable covalent adaptable networks to study structure–property relationships relative to their thermoset counterparts.

Spatial Distribution of the Amorphous Region Constrained by Polymer Crystallites

Many studies have supported the existence of the amorphous region with reduced mobility induced by crystallization in semicrystalline polymers. However, the spatial distribution of the amorphous region with reduced mobility (rigid amorphous region) has not been fully clarified. Therefore, we applied contrast variation small-angle X-ray scattering (CV-SAXS) to the swollen ethylene-octene copolymer with granular crystallites to clarify the spatial distribution of the rigid amorphous region. The analysis with CV-SAXS revealed that the rigid amorphous region existed around the crystallites and bridged among the crystallites. Furthermore, the weight fraction of the rigid amorphous region estimated by CV-SAXS was in good agreement with that obtained by pulsed proton nuclear magnetic resonance measurements.