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The subject of this research is a relatively detailed investigation of the rheological, morphological and electrical properties of nanocomposites based on polyolefin elastomer (POE), cyclic olefin copolymer (COC) and multi‐walled carbon nanotubes (MWCNTs). To formulate a mixture of two polymers (COC and POE), the melt mixing method was used and their morphology was studied by SEM technique and it was found that the morphology is of co‐continuous type. When the weight percentage ratio of COC was between 40 and 60, the desired morphology (co‐continuous) appeared. Interfacial tension calculations and TEM images proved that the nanotube particles were stabilized both within the phase of POE as well as at the interface of the two polymer phases. The rheological behavior was analyzed for composite samples containing 0–3 wt % MWCNT. The electrical and rheological percolation thresholds appeared at 1 and a 0.5 percent by weight of nanotube particles, respectively, which may be better to consider as related to the phenomenon of dual percolation. The highest conductivity was obtained for the nanocomposite containing 3% MWCNT. The results of mechanical tests also showed a strong upward trend of properties due to the addition of nanotube. Highlights: The effect of COC content on the morphology of POE/COC blend was investigated.The Morphology for the POE/COC blend at low COC content was droplet‐matrix type.MWCNT has a greater tendency to be in the POE phase than COC.Rheological behavior strongly depended on the amount of nanotube particles.The highest conductivity was obtained for the sample containing 3% MWCNT. [ABSTRACT FROM AUTHOR]

Bicenter (BCn) cobalt-bis(imine) catalysts were synthesized to be used for the polymerization of methyl methacrylate (MMA) and 1-hexene. The effect of catalyst structure, bridging ligand and polymerization reaction conditions was investigated. Synthesis of primary ligand (2,6-dibenzhydryl-4-ethoxyphenyl)-N=(CH3 )- C(CH3 )=O was also done. Following to that, the final ligands of the BC1 and BC2 bicenter catalysts were prepared via reacting the primary ligand with 2,3,5,6-tetramethylbenzene-1,4-diamine and 4,4-methylenedianiline bridges, respectively. The BC1 catalyst demonstrated higher activity than the BC2 catalyst. The highest activity for the BC1 catalyst was obtained when the co-catalyst to catalyst molar ratio was [Al]/[Co]=1500:1, and the polymerization temperature was 40°C. In comparison, the BC2 catalyst demonstrated the highest activity and higher thermal stability in the conditions of: [Al]/[Co]=500:1 ratio and 70°C polymerization temperature. The ¹H NMR analysis results revealed that the highest branching density for the poly(methyl methacrylate) (PMMA) produced by the BC1 and BC2 catalysts was 222 and 249 branches per 1000 carbon atoms, respectively. The PMMA synthesized with the BC2 catalysts had the highest syndiotacticity (59%). The polymer produced with the bicenter catalyst (BC1) showed a relatively broad molecular weight distribution (2.9), according to the GPC analysis results. The synthesized catalysts demonstrated appropriate activity for the polymerization of MMA, but only moderate activity for 1-hexene monomer. [ABSTRACT FROM AUTHOR]

Here, an attempt is made to study one of the less noticed aspects of the polymerization of 5‐ethylidene‐2‐norbornene (ENB) by nickel α‐diimine catalysts. Therefore, several (co)polymerization runs using MMAO‐activated binuclear catalyst (BNC) and mononuclear catalyst (MNC) were undertaken. Catalyst activities as high as 561.1 and 925.0 (kgpol mol−1Ni h−1) were observed for ENB polymerization by MNC and BNC, respectively. However, the utilization of comonomer (norbornene [NB]) led to a dramatic decline in the catalyst activities, reaching low levels of 69.4 and 144.4 (kgpol mol−1Ni h−1), respectively. Structural characterization (NMR and FTIR) corroborated the occurrence of ring opening via β‐C elimination and the subsequent β‐H elimination. Additionally, tandem transannular polymerization and ring‐opening metathesis polymerization of ENB were evidenced. The findings demonstrated that the transannular polymerization prevailed during the polymerization, albeit the MNC catalyst showed a higher contribution of ring opening via β‐C elimination. Importantly, comonomer (NB) was displayed to alter the governing polymerization mechanism. According to DMTA analysis, the structures of the monomer and catalyst were found to significantly influence the polymer damping behavior and microstructure heterogeneity. That is, the NB‐ENB copolymer obtained by MNC exhibited the lowest Tg value and highest tan δ along with the diminished microstructure heterogeneity. [ABSTRACT FROM AUTHOR]

The functionalization of poly (1‐hexene) with maleic anhydride (MA) in the presence of benzoyl peroxide as initiator was investigated and the effect of reaction parameters such as initiator content, maleic anhydride concentrations, reaction temperature and reaction time were studied. Furthermore, changing the catalyst system from a commercial Ziegler‐Natta (TiCl4/MgCl2/Internal donor) to α‐diimine Nickel catalyst led to a higher degree of functionalization (DOF) thanks to higher unsaturation content of polymer chains made by the Nickel catalyst system. The obtained polymer moreover was contacted with polyethylene glycol methyl ether to ensure the attachment of the functionalizing agent on the poly (1‐hexene) chains. Different analyses were used to support the observations. For instance, thermogravimetric analysis (TGA) exhibited no weight loss at 210 °C for the sample confirming, the complete reaction of maleic anhydride, or FTIR analysis, where the presence of ester group bands was evidence for the reaction. [ABSTRACT FROM AUTHOR]

A mono-nuclear catalyst of bis-imine cobalt (MC) was synthesized with using 2,6-dibenzhydryl-4-ethoxy phenyl as a ligand. The so huge ligand was prepared via the reaction of 2,6-dibenzhydryl-4-ethoxy phenyl)-N=(CH3)-C(CH3)=O with diacetyl with equal mole stoichiometry in presence of formic acid catalysis. The catalyst was synthesized via a reaction between the ligands and cobalt salt (CoCl2). The catalyst was used for polymerization of methyl methacrylate (MMA), (a polar monomer) in the presence of modified methylaluminoxane (MMAO). The highest polymerization activity (8.6 g PMMA/mmol cat. h) was obtained at [cocatalyst]/[catalyst]=1000:1 molar ratio and at room temperature reaction. For the prepared PMMA, Polymer with branching density of 263/1000C was obtained using ¹H NMR technique calculation. The microstructure of one of the produced PMMA was as follow: 48% syndiotactic, 29% isotactic and 23% atactic. GPC analysis of the polymer showed a number average molecular weight of about 5.7 × 105 g/mol and a narrow molecular weight distribution of 1.57. [ABSTRACT FROM AUTHOR]

An ethoxylated polyethylene wax (E‐OPEW) was synthesized by PEGylation reaction between methoxy polyethylene glycol and oxidized PE wax. Clay nanoparticles were modified with different ratios of E‐OPEW and then compounded with PP by the melt mixing process. E‐OPEW and PP showed excellent compatibility, but at high percentages of wax (15%), incompatibility occurred between the two phases. In addition, the presence of modified clays in the PP matrix decreased the crystallinity percentage, though it did not change the melting temperature significantly. The results showed that functionalized wax is able to penetrate between clay platelets and increase the distance between them and improve their dispersion in the polymer matrix. Furthermore, it was observed that the distance between clay platelets increased by increasing E‐OPEW content. In addition, this result led to a significant improvement in the barrier properties of clay platelets and the thermal stability of the modified nanocomposite compared to other cases. Despite the improved dispersion of nanoparticles, the mechanical strength of nanocomposites decreased at a high percentage of E‐OPEW. [ABSTRACT FROM AUTHOR]

The reactive co‐polymer approach is one of the most promising techniques for the synthesis of functional polyolefins. Following this concept, 1‐hexene and p‐methylstyrene are co‐polymerized in the presence of a generic Brookhart‐type catalyst. The microstructures of the co‐polymers imply the tendency of p‐methylstyrene co‐monomers to place at the end of the structural branches formed by the chain walking reaction. The molar masses of the co‐polymers decrease, not only at higher levels of co‐monomer but surprisingly by decreasing reaction temperature. A mechanism consisting of a highly stable η3 metal–benzyl intermediate, which is quantitatively approved by density functional theory calculations, can delicately justify all the aforementioned observations. A series of the produced co‐polymers is selectively functionalized by maleic anhydride at the benzylic position of p‐methylstyrene, under very mild reaction conditions. Such a reactive intermediate opens the path for the introduction of different types of functionalities in polyolefins. Namely, the grafted co‐polymers were further functionalized by a triazole ring, which provides a transient supramolecular network through intermolecular hydrogen bonding. [ABSTRACT FROM AUTHOR]