Different behaviors of metallocene and Ziegler–Natta catalysts in ethylene/1,5‐hexadiene copolymerization

Rahmatiyan, Sanaz; Bahri‐Laleh, Naeimeh; Hanifpour, Ahad; Nekoomanesh‐Haghighi, Mehdi

doi:10.1002/pi.5700

Cited by 16 publications

(9 citation statements)

References 40 publications

(57 reference statements)

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“…Many studies have been focused on the catalyst structure, activity, polymerization, and properties of the polymer [15,16], but only a few investigations have been carried out on the reactions and interactions of cocatalyst [17,18]. The process of cocatalyst interaction with Ziegler-Natta catalysts is well understood, but the performance of different types of cocatalyst in these interactions is still unclear [19,20].…”

Section: Introductionmentioning

confidence: 99%

Exploring cocatalyst type effect on the Ziegler–Natta catalyzed ethylene polymerizations: experimental and DFT studies

et al. 2022

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Due to the important role of cocatalyst in the polymerization process employing industrially favored Ziegler–Natta catalysts, its effect on kinetic behavior, catalyst activity, and polymer properties is discussed. In this paper, triethyl aluminum (TEA) and triisobutyl aluminum (TIBA) have been used as the main cocatalyst ingredient with 10–20 mol percent of diethyl aluminum chloride (DEAC) and ethyl aluminum dichloride (EADC) cocatalysts, being neat TEA the cocatalysts with the highest activity. Moreover, TEA-DEAC and TEA-EADC cocatalysts revealed a built-up kinetic profile, while TIBA-DEAC and TIBA-EADC show a decay-type kinetic curve. According to melt flow index results, no considerable change in flowability was detected in the synthesized polyethylenes (PE). On the other hand, the ethylene insertion and chain termination mechanisms were investigated by means of density functional calculations using Ti active center located in (110) and (104) facets of the MgCl2 surface. To shed light on the bulkiness level of employed cocatalysts, buried volume (VBur) together with the two-dimensional map of cocatalyst systems were considered. Higher VBur of TIBA complex can explain its lower activity and decay type kinetic profile obtained by experimental studies.

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Section: Introductionmentioning

confidence: 99%

Exploring cocatalyst type effect on the Ziegler–Natta catalyzed ethylene polymerizations: experimental and DFT studies

et al. 2022

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“…To achieve information about comonomer distribution and crystallinity behavior of produced polyolefins, SSA technique is usually employed. 30,40 This method relies on the principle that the lamellae thickness (l c ) is corresponded to the length of successive ethylene sequence and provides useful information on lamellar thickness from melting points values which is representative of produced polymer microstructure. The SSA curves of polymer powders with small and big particle size values (BM-1, BM-6, Film-1, and Film-6) were depicted in Figure 9 and the derived data were gathered in Table 5.…”

Section: Resultsmentioning

confidence: 99%

Structure–property relationship in film and blow molding type high‐density polyethylene polymers from a slurry‐process industrial plant

Mansouri

Emami

Yousefi

et al. 2022

J of Applied Polymer Sci

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In this study, the microstructural, flow, and mechanical properties of two commercially available high‐density polyethylene (HDPE) samples with different particle sizes were quantified. Specifically, two different blow molding and film grade HDPEs produced by the same catalyst under different conditions were acquired in powder form after dryer section of an industrial plant. They were fractioned according to their particle sizes into six samples: ≤125, 125–200, 200–315, 315–400, 400–500, and ≥ 500 μm. According to sieve analysis, the film grade (D50 = 304 μm) had larger particle sizes related to the counterpart injection sample (D50 = 289 μm). A peak value in density, bulk density, viscosity molecular weight (Mv), melt flow index (MFI), and comonomer content characteristics was found in the particles with the diameter of 125–200 μm in both samples, indicating extremely non‐homogeneity of these HDPE samples. Chemical composition distribution (CCD) of the as received polymers as well as sieved fractions was surveyed via SSA or TREF analyses. The film sample represented lower MFI and density and higher Mv and comonomer content in all fractions, originated from different reactor conditions during the samples synthesis, which translate into improved mechanical properties comparing with the blow molding sample.

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“…This achievement indicated that cyclization reactions suppressed branching mechanism in the case of 1,5‐hexadiene. We assumed that this observation is due to more stability of five‐member rings in oligo‐hexa than seven‐member rings in oligo‐octa sample …”

Section: Resultsmentioning

confidence: 99%

Preparation of novel, liquid, solvent‐free, polyolefin‐based adhesives

Hanifpour

Bahri‐Laleh

Nekoomanesh‐Haghighi

2019

Polymers for Advanced Techs

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An innovative procedure for functionalization of polyolefins was developed. It was found that synthesized polyolefins end-capped with trimethoxysilane (silylated polyolefins) are new polyolefin-based adhesives. To prepare the mentioned materials,1-octene as a higher α-olefin was cooligomerized with two linear, nonconjugated dienes (ie, 1,5-hexadiene and 1,7-octadiene) by using metallocene catalyst system, Cp 2 HfCl 2 /MAO, at room temperature. Then, amine-terminated trimethoxysilane (3-aminopropyltrimethoxysilane) was reacted with unsaturated bonds of synthesized cooligomers in the presence of palladium(II) acetate. Embedding of the dienes on 1-octene oligomeric chains was explored by Fourier transform infrared (FTIR), 1 H, and 13 C-NMR spectroscopy. On the basis of the results, 1,5-hexadiene showed both 1-butene branch and five-member ring. On the other hand, 1,7-octadiene was incorporated by 1,2-addition, forming both 1-hexene branch and seven-member ring in the cooligomer backbone. Mole percentage of C C and cyclic moieties reached to a value of 28.54, 18.59% mol in 1-octene/1,5-hexadiene, and 38.04, 6.71% mol in 1-octene/1,7-octadiene cooligomers, respectively. Reaction of synthesized cooligomers with 3-aminopropyltrimethoxysilane was confirmed by FTIR spectroscopy, which yielded targeted adhesives. To study the adhesion properties, resulting adhesives were applied to different substrates. Obtained results demonstrated that tensile shear strength of synthesized adhesives to polar substrates was 2.21% to 2.84% more than nonpolar substrates. Among studied systems, the best performance was achieved by1-octene/1,7-octadiene-based adhesive and Al substrate with tensile shear strength of 1.45 N/mm 2 .

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Different behaviors of metallocene and Ziegler–Natta catalysts in ethylene/1,5‐hexadiene copolymerization

Cited by 16 publications

References 40 publications

Exploring cocatalyst type effect on the Ziegler–Natta catalyzed ethylene polymerizations: experimental and DFT studies

Exploring cocatalyst type effect on the Ziegler–Natta catalyzed ethylene polymerizations: experimental and DFT studies

Structure–property relationship in film and blow molding type high‐density polyethylene polymers from a slurry‐process industrial plant

Preparation of novel, liquid, solvent‐free, polyolefin‐based adhesives

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