Ethylene-octene Copolymer Research Articles

Effects of Blending Sequence on Morphology and Mechanical Properties of Polypropylene/Ethylene-octene Copolymer/Clay Nanocomposites

The objective of this study was to investigate the effects of three blending sequences on morphology and properties of the ternary nanocomposite of polypropylene (PP)/ethylene-octene copolymer (EOC)/clay with double compatibilizers of maleated PP (PP-g-MA) and maleated EOC (EOC-g-MA) prepared by twin-screw extrusion. The X-ray diffraction results in conjuction with transmission electron microscopy images indicated the mixture of exfoliated and intercalated structures possessed by the nanocomposite prepared by simultaneous addition of the ingredients. The nanocomposite in which clay was first mixed with PP and EOC-g-MA and then with EOC and PP-g-MA showed the same morphology. However, in the nanocomposite when clay was first mixed with PP and PP-g-MA and then mixed with EOC and EOC-g-MA, an intercalated structure was observed. The results of mechanical testing showed that there was no significant difference in the yield strength, tensile modulus and flexural modulus among the three nanocomposites. However, the Charpy impact strength of the nanocomposite prepared by simultaneous addition of ingredients was higher than that of the nanocomposites prepared in two mixing steps because of the presence of more organoclay inside the EOC phase in the former.

Electron beam crosslinking of ethylene-octene copolymers

Seven ethylene-octene copolymers (EOC) with a wide range of octene content (17–45 wt. %) were crosslinked by e-beam radiation (in range 30–120 kGy). Testing methods included differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), high-temperature creep test, analysis of the gel content and rheology. It has been found that copolymers with higher initial molecular weight (or lower MFI) and higher branching density (or higher octene content) attain a higher level of crosslinking density. Increasing octene content brings about lower melting point (Tm), crystallization temperature (Tc), crystallinity (X), glass transition temperature (Tg) and storage modulus. Crosslinking influenced the properties below Tm only marginally. However, the properties above Tm were extremely influenced (high temperature creep). Above Tm (without the presence of crystals) only the chemical bonds hold the amorphous chains together which was manifested by creep gradually decreasing at 150 °C with an increasing irradiation level. Loss factor (tanδ at 0.1 Hz), which is a very important parameter in evaluation of molecular structure, was measured by rheology at 150 °C, and it revealed a decreasing trend (or increasing crosslinking level) with the increasing octene content, surprisingly regardless of the initial molecular weight (or MFI) at 120 kGy.

Structures and properties of low-crystallinity polyolefins modified with nanodiamonds

To search for new methods of governing the structures and properties of low-crystallinity ethylene–octene copolymers with densities of 0.861 and 0.885 g/cm3, the effect of small additives of diamond-like nanoparticles on the mechanical properties and structuring processes in these elastomers is studied. It is shown that nanodiamonds are distributed sufficiently well in the matrixes of the copolymers and improve the stress–strain characteristics even at a low content of nanoparticles. The influence of the functional composition of the modifier surface, the preparation method and thermal prehistory of the composites, and the degree of crystallinity of the elastomer matrix on the structure and properties of the nanocomposites is investigated. The copolymers contain a hexagonal mesophase and orthorhombic crystallites, with their amount in the composites being higher. The efficiency of nanomodifiers in the matrix with a higher crystallinity is noticeably lower. Aerosils rank much below nanodiamonds in terms of efficiency, especially in the low-concentration range. The pattern of deformation dependences of thermodynamic parameters is similar to that of typical thermoplastic elastomers. The effect of nanoparticles on the thermomechanical behavior of the copolymers depends on both the modifier amount and the degree of crystallinity of the matrix.

Dynamic mechanical properties, crystallization behaviors, and low‐temperature performance of polypropylene random copolymer composites

ABSTRACTIn this study, polypropylene random copolymer (PPR) composites were prepared by the addition of either three kinds of thermoplastic rubber (TPR) modifiers (types 2088A, 2095, and 2096) or an ethylene–octene copolymer (POE)/high‐density polyethylene (HDPE; 2 :1 w/w) blend. Differential scanning calorimetry, wide‐angle X‐ray diffraction, and dynamic mechanical analysis were used to characterize the crystallization behaviors and dynamic mechanical properties of the PPR composites. The results indicated that PPR/POE/HDPE and PPR/TPR2088A had better comprehensive mechanical properties, especially the low‐temperature toughness among all of the samples. The obtained PPR/POE/HDPE blends showed a high toughness and good stiffness in the temperature interval from −10 to 23°C with the addition of only 10 wt % POE/HDPE. When the temperature continued to fall below −10°C, the PPR/TPR2088A composites exhibited a better impact toughness without a loss of too much stiffness. The good low‐temperature toughness of those two composites was attributed to both the decrease in the crystallinity and the uniform dispersion, obvious interfacial adhesion, and cavitation ability of POE/HDPE and TPR2088A in the PPR matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42960.

Thermo-responsive shape memory polymer blends based on alpha olefin and ethylene propylene diene rubber

Thermally stimulated novel shape memory polymer blend of ethylene octene copolymer (EOC) and ethylene propylene diene terpolymer (EPDM) has been developed. This novel polyolefinic blends possess superior shape memory behaviour in presence of heat. Shape memory behaviour study at 60 °C of the blends shows that the blends containing higher fraction of EPDM exhibits superior shape memory behaviour in terms of shape fixity (f) and shape recovery ratio (RR). Structural similarities of the pristine components lead to higher degree of compatibility which also results better physicomechanical behaviour. Lower modulus value followed by low relaxation ratio of the blend containing higher proportion of EPDM also supports the superior shape memory behaviour of the EPDM rich blend. Thus EPDM rich blend shows better shape memory effect among the various blends.

Investigation into the structure–property relationship and technical properties of TPEs and TPVs derived from ethylene octene copolymer (EOC) and polydimethyl siloxane (PDMS) rubber blends

This work focuses on the study of thermoplastic vulcanizates based on ethylene octene copolymer (EOC) and poly dimethyl siloxane (PDMS) rubber prepared by melt mixing technique using dicumyl peroxide (DCP). It is found that the addition of peroxide causes crosslinking in both the phases. However, crosslinking without affecting the crystallinity of the EOC polymer leads to tremendous improvement in the mechanical properties, including the tensile strength which has improved by nearly 60%. For better understanding about the crosslinking characteristics of thermoplastic vulcanizates (TPVs), significant correlation has been made between the vulcanized network and the physico-mechanical properties. Further, the dynamic mechanical properties and creep behavior of these thermoplastic elastomers (TPEs) and TPVs have also been studied. It is inferred that the TPVs show a 19% decrease in the creep compliance, i.e. higher creep resistance compared to uncrosslinked blends. Subsequently, the morphology of the blends before and after vulcanization shows a decrease in the spherical PDMS domains from 0.8 μm to > 0.4 μm. Ageing and reprocessing studies of the prepared TPVs also show better physico-mechanical properties even after reprocessing twice. Thus, the prepared TPVs may have tremendous applications in automobile sectors.

Compatibilization efficiency in post-consumer recycled polyethylene/polypropylene blends: Effect of contamination

This work investigates the effect of ethylene–octene copolymer (EOC) as a compatibilizer for two virgin and two recycled polyethylene/polypropylene blends. In particular, a focus is made on the interfering effects of contamination in recycled materials. Scanning electron microscopy (SEM) shows that (i) recycled compounds have smaller domain sizes than virgin compounds, and (ii) addition of a compatibilizer is much more effective on domain sizes reduction in virgin compounds than in recycled ones. Conversely, transmission electron microscopy, coupled with energy dispersive X-ray spectroscopy, shows the presence of nano-size contaminants in both recycled blends. Such contaminants are considered responsible for the above mentioned observations in SEM. Mechanical characterizations are also in good agreement with morphological observations. Although recycled compounds containing EOC show improved deformability, the ultimate deformation of virgin compounds is much higher. POLYM. ENG. SCI., 55:2368–2376, 2015. © 2015 Society of Plastics Engineers

Theoretical and morphological evaluation of dynamic viscoelasticity and thermo-mechanical characteristics of TPV composites

In this work, the regular usage of conventional dynamic mechanical analyzer (DMA) has been extended through the characterization of rubber elasticity and dynamic viscoelasticity of the TPV composites based on natural rubber, ethylene octene copolymer and carbon black (NR/EOC/CB). Two independent theoretical approaches viz. rubber index and damage parameter, have been adopted in order to evaluate the same. Rubber index, which is the function of temperature and entropy, has been utilized here to estimate the elasticity of the rubber networks. On the other hand, a classical damage parameter, which is a measure of dynamic viscoelasticity, has been obtained from initial tangent modulus through cyclic stress softening i.e. Mullins effect. Moreover, the measurement of thread break-up time obtained from the capillary number expression and morphological observations has directed us to revalidate the new mechanism of morphology evolution through the thermodynamic calculations. The reduced interconnectivity between the rubber domains, which has been obtained as a result of uneven filler dispersion into the rubber phase, has resulted in reduced elasticity in the rubber networks, as evident from the experimental results and atomic force micrographs. This study has thus revealed different novel aspects of dynamic mechanical analyzer and provided innovative methods for the characterization of rubber-like materials.

Synergetic effect of polyolefin elastomer and CaCO3 particle on ternary nano-composite (polypropylene/polyolefin elastomers/calcium carbonate) behavior

The mechanical and toughening properties of ternary nano-composites (polypropylene/polyolefin elastomer/calcium carbonate) are investigated. Blends of polypropylene (PP)/ethylene-alpha olefin copolymer (polyolefin elastomer)/nano calcium carbonate were prepared through a two-step process. Stearic acid-treated CaCO3 (denoted CC322) and non-treated CaCO3 (denoted CC31) were used at content of 1%, 3%, and 5%. Two polyolefin elastomers (POE), ethylene-butene and ethylene-octene copolymers at 5 wt% were also used to adjust the phase structure of the ternary nano-composites. Tension surface measurements were correlated to morphological observations. Two phase structures were found: (1) treated calcium carbonate contributes to form the core-shell structure (2) non-treated calcium carbonate builds filler-network structure for the two POE. The mechanical properties of nano-composites were investigated using Izod impact and tensile tests. The influence of the morphologies on the impact strength and toughness of the nano-composites was studied. The formation of a filler-network structure was found to be a key for the toughness enhancement. A positive and synergic effect was found using ethylene-octene copolymer and non-treated calcium carbonate.

The synergistic effects of β-nucleating agent and ethylene–octene copolymer on toughening isotactic polypropylene

The mechanical properties of isotactic polypropylene (iPP) and ethylene–octene copolymer (POE) blends with or without β-nucleating agent (β-NA) were systematically studied. Results demonstrated that, after β-NA and POE were separately added, the impact strength of injection molded iPP samples increased. β-NA and POE were also found to have a synergistic toughening effect on iPP matrix, and the effect was significant. When the contents were 0.05 wt% β-NA and 10 wt% POE, the impact strength reached the maximum, i.e., almost 15 times that of neat iPP. SEM further revealed that POE in skin and core layers existed as long and narrow strips along the flow direction and throughout crystals. The tensile strength did not deteriorate because of the special phase morphology and tight interfacial interaction between POE phase and matrix. WAXD and DSC revealed that POE addition had negligible influence on crystal form, and a considerable number of β crystals was generated by adding β-NA. SEM results also confirmed a critical β-NA content. When β-NA content was lower than the critical value, perfect β sphaerocrystals were generated. When β-NA was higher, “bundle-like” crystal structures formed. Perfect β sphaerocrystals were more efficient for dissipating energy because of the looser stacking pattern, thus showing better toughness.

Dielectric response of conducting carbon-black-filled ethylene-octene copolymer microcellular foams

Dielectric response of conducting carbon-black-filled ethylene–octene copolymer microcellular foams has been investigated with variation of blowing agent and filler loading in the frequency range of 100 Hz to 5 MHz and temperature range from 30 to 100°C. With increase in blowing agent loading, the dielectric permittivity increases for both unfilled as well as carbon-black-filled microcellular foams. The experimental complex impedance plots were compared with model-fitted plots obtained by taking an equivalent circuit of (CQR) (CR).The values of Rb (bulk resistance), Rgb (grain boundary resistance), bulk capacitance (Cb), and grain boundary capacitance (Cgb) at different temperatures were calculated and compared with experimental values. The relaxation time due to bulk effect (τb) has been calculated from relaxation frequency (fr). The dc conductivity (σdc) decreases with rise in temperature indicating the existence of positive temperature coefficient of resistance in the material. The activation energy (Ea) calculated from the relaxation time due to bulk effect (τb) was found to be 0.446 eV, whereas it was 0.363 eV from the dc conductivity plot in the temperature range of 30–100°C. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

An investigation of thermal and mechanical properties of synthesised polyamide-6/γ-alumina composites

Polyamide based composites were formed by melt blending of polyamide 6 (PA6) with a γ) -alumina powder toughened with ethylene–octene copolymer grafted by maleic anhydride (EOC-g-MAH) and also without EOC in a corotating twin screw extruder. Mechanical properties, morphological structure and thermal stability of toughened PA6 (PA6-g-EOC) and PA6-g-EOC/alumina composites were investigated in this study.To study the effect of powder loading of γ-alumina on the mechanical properties of the composites such as tensile strength, modulus of elasticity, break point and impact strength, varied amounts of 5, 10 and 15 wt-% were deployed. The toughened PA6–γ-alumina composites, i.e. blended by EOC-g-MAH, revealed higher impact strength and more toughness compared to that of the PA6–γ-alumina composites without EOC-g-MAH. Morphology of the composites was investigated by scanning electron microscopy (SEM) from the as moulded specimens. Micrographs showed a fine dispersion of γ-alumina particles in polyamide matrix due to appropriate mixing. Furthermore, thermal stability and degradation characteristics of the toughened PA6–γ-alumina composites were measured by thermogravimetric analysis. The addition of γ-alumina into the polyamide matrix showed an increase in thermal resistance so that thermal stability was increased by a rise in the powder loading.

Mechanical and Morphological Properties of Poly(Methyl Methacrylate)/Ethylene-Octene Copolymer/Clay Composites

The effects of the montmorillonite clay surface modified with 25-30 wt% octadecylamine (clay) on mechanical and morphological properties of poly (methyl methacrylate) (PMMA)/ ethylene-octene copolymer (EOC)/clay composites were investigated. The composites of blends of PMMA/EOC with clay were prepared by melt mixing in an internal mixer. The results showed that the Young’s modulus of the composites increased with increasing clay content. The ratio of PMMA and EOC was 80/20 by weight and the clay content was 3 and 5 phr. The results showed Young’s modulus of the composites increased with increasing clay content. While the impact strength, tensile strength and percent strain at break of the composites decreased with increasing clay content. Scanning electron microscopy analysis showed that the droplet of dispersed EOC phase in PMMA matrix was changed to the elongated structure after adding clay.

Aging of Nanosized ZnO Modified Polyoxymethylene Blends with Ethylene–octene Copolymer

The influence of ethylene–octene copolymer and zinc oxide (ZnO) on structure and tensile stress–strain behavior of polyoxymethylene were investigated before and after ultraviolet weathering. Addition of ZnO considerably improved stress–strain characteristics of the ultraviolet-irradiation impaired composites. Crystallinities of ultraviolet-irradiated composites were affected by numerous competitive processes, including suppression of crystallization in the presence of multiple components in the system, nucleation induced by nanofiller, secondary crystallization and amorphization because of the chain scissions of the macromolecules. Addition of ZnO considerably improved stability of the composites, as testified by corresponding changes in the intensities of hydroxyl and carbonyl absorption peaks.

Preparation of an Ultra-Thin, Highly Filled, Neutron-Shielding Material

We develop an ultra-thin, highly filled, neutron-shielding material. This material exhibits a desirable neutron-shielding performance, and also has certain advantageous mechanical properties and uses. We study the physical properties of shielding materials with different polyolefins as base materials, and investigate the neutron-shielding performance of boron-containing and lithium-containing shielding materials. We furthermore report on the effect of additive amounts of functional additives on shielding properties and physical-chemical properties. We additionally study the effect of radiation crosslinking technology on shielding material properties. We show that, using ethylene-octene copolymer (POE) modified low-density polyethylene (PE-LD), the additive amounts of boron carbide (B4C) and nano-montmorillonite (OMMT) are 60–70% and 4%, respectively. The optimal radiation dose is 160 kGy, and the shielding materials exhibit good neutron-shielding performance and mechanical strength.

Radiation crosslinked blends based on an ethylene octene copolymer (EOC) and polydimethyl siloxane (PDMS) rubber with special reference to the optimization of processing parameters

Transformation of morphology of EOC : PDMS blends with the change in processing parameters.

Failure of compression molded all-polyolefin composites studied by acoustic emission

This paper is aimed at studying the failure behavior of polyolefin-based self-reinforced polymer composites (SRPCs) via acoustic emission (AE). Three matrix materials (ethylene octene copolymer (EOC), polypropylene-based ther- moplastic elastomer (ePP), random polypropylene copolymer (rPP), and three kinds of reinforcing structures of PP homopolymer (unidirectional (UD), cross-ply (CP) and woven fabric (WF)) were used. SRPCs were produced by compres- sion molding using the film-stacking method. The composites were characterized by mechanical tests combined with in situ assessment of the burst-type AE events. The results showed that rPP matrix and UD reinforcement produced the greatest reinforcement, with a tensile strength more than six times as high as that of the matrix and a Young's modulus nearly dou- bled compared to the neat matrix. The number of the detected AE events increased with increasing Young's modulus of the applied matrices being associated with reduced sound damping. The AE amplitude distributions shows that failure of the SRPC structure produces AE signals in a broad amplitude range, but the highest detected amplitude range can be clearly linked to fiber fractures.

Effect of 3D Stereoscopic Embossed Polyolefin Nonwovens on Permeability of Diapers

The PP/PE composite fibers were prepared by melt extrusion, using polypropylene (PP) and polyethylene (PE) as raw materials and ethylene-octene block copolymers (OBC), titanium dioxide, antioxidants as additives. 3D stereoscopic embossed polyolefin nonwovens with "cross" pits and "O" type relief structure applied to topsheet of diapers were produced through air bonding process and 3D stereoscopic pressure rollers, respectively. The effect of structure of 3D stereoscopic embossed polyolefin nonwovens on the topsheet run-off and the rewet of diapers were studied by means of a set of permeability test. Comparing with the diapers using hot air nonwoven fabric as topsheet, the results of the diapers using 3D stereoscopic embossed polyolefin nonwovens as topsheet showed that the topsheet run-off decreased by 72.0%, as well as the first and second rewet reduced by 40.4% and 57.5%, respectively.

Dielectric characteristics of conductive carbon black filled ethylene-octene copolymer vulcanizates

Ethylene-octene copolymer (EOC) composites have been prepared by melt- mixing method using different weight fraction (0–40 %) of ENSACO-250G carbon black. The dielectric relaxation behaviour of carbon black-filled ethylene-octene copolymer (EOC) nano-composites of different filler-loadings has been studied in a frequency range of 100 Hz to 5 MHz at room temperature. The variation in ac conductivity, dielectric permittivity, impedance and dielectric loss tangent (tanδ) has been studied as a function of carbon black loading and frequency. Interfacial polarization of the filler in the polymer matrix plays a key role for the variation of dielectric permittivity with filler loading. The calculated relaxation time for the first and second peaks of tanδ curve are found to be 1 7.6\( \mu s \)and 0.24 μs respectively. The percolation threshold was observed at 30 phr carbon black loading. The Nyquist plot was also studied as a function of filler concentration.

Dielectric relaxation of conductive carbon black reinforced ethylene‐octene copolymer vulcanizates

The dielectric relaxation behavior of different conducting carbon black‐filled ethylene‐octene copolymer (EOC) vulcanizates prepared by melt‐mixing method has been studied as a function of frequency (100 Hz–5 MHz) over a wide range of temperatures (25–100°C). The effect of filler loading and frequency on AC conductivity, dielectric permittivity, impedance, and dielectric loss tangent (tanδ) has been studied. The nature of variation of the dielectric permittivity with the filler loadings was explained on the basis of interfacial polarization of the filler in the polymer matrix. The effect of filler loading on the real and complex part of the impedance was explained by the relaxation dynamics of the polymer chains in the vicinity of the fillers. The effect of filler and temperature on dielectric loss tangent, dielectric permittivity, AC conductivity, and Nyquist plot was also reported. The bound rubber (BR) value increases with increase in filler loading suggesting the formation of strong interphase, which is correlated with dielectric loss. Thermal activation energy (Ea) was found to be decreasing with the temperature, which follows the Arrhenius relation: τb = τ0 exp(−Ea/KBT) where τb is the relaxation time for the bulk material. From the plot of lnτb versus inverse of absolute temperature (1/T), the activation energies (Ea) were found to be 0.37 and 0.44eV, respectively. The percolation threshold was observed with 40 phr carbon black loading. POLYM. COMPOS., 37:342–352, 2016. © 2014 Society of Plastics Engineers