Linear low-density polyethylenes by co-polymerization of ethylene with 1-hexene in the presence of titanium precursors and organoaluminium co-catalysts

Carlini, Carlo; D’Alessio, Aldo; Giaiacopi, Simone; Pò, Riccardo; Pracellà, Mariano; Galletti, Anna Maria Raspolli; Sbrana, Glauco

doi:10.1016/j.polymer.2007.01.009

Cited by 17 publications

(12 citation statements)

References 34 publications

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“…The DSC crystallinities were found in good agreement with those calculated from wide-angle X-ray spectra, which displayed a continuous decrease in the intensity of crystalline peaks at about 2u ¼ 218 and 2u ¼ 248 (corresponding respectively to 110 and 200 reflections of orthorhombic PE crystals) with an increase in the 1-hexene content. [7] The above results are consistent with a decrease in both size and perfection of crystal lamellae as well as tightness of their packing, as the comonomer concentration in the macromolecules increases. These effects, which are strictly related with the reduced length of crystallizable sequences in the copolymer chains, have been reported in literature for several olefin copolymers [15,24] .…”

Section: Thermal Behavioursupporting

confidence: 75%

“…[7] In the present paper, we report on the study of characterisation of the above ethylene-1-hexene (E/H) copolymers by means of spectroscopic, diffractometric and calorimetric methods.…”

Section: Full Papermentioning

confidence: 99%

“…[7] Poly(1-hexene) (PH) was synthesised by means of a conventional Ziegler-Natta catalyst. In a Schlenk vessel 10 mL of anhydrous heptane, 80 mL (0.72 mmol) of TiCl 4 , 2.1 mL (2.1 mmol) of Al-iBu 3 (1 M in hexanes) and 2.6 mL (20.8 mmol) of 1-hexene were introduced, under Ar atmosphere.…”

Section: Experimental Part Materialsmentioning

confidence: 99%

“…The sequence distribution of the co-units in these samples, at the level of diads and triads distributions, was analysed by 13 C NMR spectroscopy with a Bruker AM-270 spectrometer working at 67.89 MHz on 1,1,2,2-d 2 -tetrachloroethane solutions at 103 8C. [7] The co-monomer content of the examined E/H copolymers is listed in Table 1, together with the values of DSC phase transition parameters and crystallinity degree.…”

Section: Experimental Part Materialsmentioning

confidence: 99%

“…The values of 1-hexene concentration obtained by FTIR-M, as reported in Table 1, show a very satisfactory agreement with those determined by 13 C NMR analysis. [7] The regions 1 500-1 400 and 750-690 cm À1 were analysed to evaluate the effect of co-monomer content on the phase transitions of the samples. The former region consists of the absorption bands at 1 473 and 1 463 cm À1 due respectively to the bending of CH 2 sequences in the crystalline and amorphous phases of PE, respectively.…”

Section: Ftir Analysismentioning

confidence: 99%

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FTIR Microanalysis and Phase Behaviour of Ethylene/1‐Hexene Random Copolymers

Pracellà¹,

D’Alessio

Giaiacopi

et al. 2007

Macro Chemistry & Physics

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Ethylene/1‐hexene random copolymers with 1‐hexene content in the range of 1–5 mol‐%, synthesised in the presence of new heterogeneous catalyst systems based on bis‐carboxylato and ‐bis‐chloro‐carboxylato titanium chelate complexes, have been characterised by FTIR microspectroscopy (FTIR‐M), DSC calorimetry and X‐ray scattering. The co‐monomer content and sequence distribution in the various samples were determined by means of both FTIR‐M and 13C NMR spectroscopy. The deformation bands of methyl groups in the region of 1 400–1 330 cm−1 were used for the structural analysis of these copolymers. The effect of composition on the crystallinity and phase transitions of copolymers was analysed both in 1 500–1 300 and 760–690 cm−1 frequency ranges as a function of the annealing temperature. A neat variation of the absorbance ratio of methyl band at 1 378 cm−1 was recorded between 110 and 130 °C corresponding to the melting range of the copolymer crystals. The crystallisation behaviour of the copolymers was examined by DSC in dynamic and isothermal conditions; the isothermal kinetics were analysed according to the Avrami model. A marked decrease in the bulk crystallisation rate, accompanied by changes in the nucleation and growth of crystals, was found with an increase in the co‐monomer content. The melting behaviour of isothermally crystallised samples was also investigated and the melting temperatures of the copolymers at equilibrium conditions were related to the composition; the experimental data were consistent with the Flory exclusion model of side branches from the crystalline phase. The lowering of crystal growth rate in the copolymers has been accounted for by an increase in the free energy of formation of critical size nuclei due to the effect of the side branches.magnified image

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Section: Thermal Behavioursupporting

confidence: 75%

“…[7] In the present paper, we report on the study of characterisation of the above ethylene-1-hexene (E/H) copolymers by means of spectroscopic, diffractometric and calorimetric methods.…”

Section: Full Papermentioning

confidence: 99%

Section: Experimental Part Materialsmentioning

confidence: 99%

Section: Experimental Part Materialsmentioning

confidence: 99%

Section: Ftir Analysismentioning

confidence: 99%

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FTIR Microanalysis and Phase Behaviour of Ethylene/1‐Hexene Random Copolymers

Pracellà¹,

D’Alessio

Giaiacopi

et al. 2007

Macro Chemistry & Physics

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Effect of ZnCl₂‐ and SiCl₄‐doped TiCl₄/MgCl₂/THF catalysts for ethylene polymerization

Phiwkliang

Jongsomjit

Praserthdam

2013

J of Applied Polymer Sci

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In this research, ethylene polymerization was carried out in the presence of different additives (ZnCl2, SiCl4, and the combined ZnCl2‐SiCl4) on TiCl4/MgCl2/THF catalytic system. The presence of ZnCl2‐SiCl4 mixtures showed higher activity in ethylene polymerization when compared with the catalytic activity in the presence of single Lewis acids, ZnCl2, or SiCl4. The modified catalyst with ZnCl2‐SiCl4 demonstrated the highest activity, which was more than three times the activity of the system without Lewis acid modification. The enhanced activity can be attributed to the reduction in the peak intensity of MgCl2/THF complexes with Lewis acid compounds as proven by XRD. This was reasonable because of some THF removal from the structure of MgCl2/THF by Lewis acid compounds. In addition to the effect of modification with additives on the partial elimination of THF, the catalytic activities could be increased due to the titanium atoms that have been locally concentrated on the surface as seen by energy dispersive X‐ray spectroscopy measurement. On the basis of the in situ electron spin resonance measurement, the mixed metal chlorides (ZnCl2‐SiCl4) addition could promote the amount of Ti3+after reduction with triethylaluminum. It revealed that the modification of TiCl4/MgCl2/THF catalytic system with mixed metal chlorides (ZnCl2‐SiCl4) is very useful for ethylene polymerization. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1588–1594, 2013

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A new post-metallocene catalyst for alkene polymerization: copolymerization of ethylene and 1-hexene with titanium complexes bearingN,N-dialkylcarbamato ligands

et al. 2013

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A new type of post-metallocene polymerization catalyst based on titanium complexes with N,N-dialkylcarbamato ligands was used to copolymerize ethylene and 1-hexene. These easy-to-synthesize and stable complexes in combination with different organoaluminium co-catalysts produce random ethylene/1-hexene copolymers characterized by a broad molecular weight distribution and high 1-hexene incorporation, as confirmed by SEC, DSC and 13 C NMR analysis. The influence of the main reaction parameters on the polymerization reactions was studied including the type of catalyst components, solvent, temperature, the ethylene partial pressure and the [Al]/[Ti] ratio in the catalyst. A higher activity and a higher 1-hexene incorporation were achieved with AlMe 3 -depleted methylalumoxane as co-catalyst and chlorobenzene as solvent. EXPERIMENTAL MaterialsAll manipulations of air-and water-sensitive compounds were performed under dry nitrogen using standard Schlenk and vacuum-line techniques. Ethylene (>99%; Rivoira, Torino, Italy) was used as received. Toluene (Baker, Deventer, Holland) and chlorobenzene (Fluka, Steinheim, Germany) were dried by refluxing for 8 h over a K/Na alloy and CaH 2 , respectively, and distilled under dry nitrogen before use. TiCl 4 (Fluka), MAO (toluene solution, 10 wt%), ethylaluminium sesquichloride (Et 3 Al 2 Cl 3 , 97%) and Al i Bu 3 (toluene solution, 25 wt%) were purchased from

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Linear low-density polyethylenes by co-polymerization of ethylene with 1-hexene in the presence of titanium precursors and organoaluminium co-catalysts

Cited by 17 publications

References 34 publications

FTIR Microanalysis and Phase Behaviour of Ethylene/1‐Hexene Random Copolymers

FTIR Microanalysis and Phase Behaviour of Ethylene/1‐Hexene Random Copolymers

Effect of ZnCl₂‐ and SiCl₄‐doped TiCl₄/MgCl₂/THF catalysts for ethylene polymerization

A new post-metallocene catalyst for alkene polymerization: copolymerization of ethylene and 1-hexene with titanium complexes bearingN,N-dialkylcarbamato ligands

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Linear low-density polyethylenes by co-polymerization of ethylene with 1-hexene in the presence of titanium precursors and organoaluminium co-catalysts

Cited by 17 publications

References 34 publications

FTIR Microanalysis and Phase Behaviour of Ethylene/1‐Hexene Random Copolymers

FTIR Microanalysis and Phase Behaviour of Ethylene/1‐Hexene Random Copolymers

Effect of ZnCl2‐ and SiCl4‐doped TiCl4/MgCl2/THF catalysts for ethylene polymerization

A new post-metallocene catalyst for alkene polymerization: copolymerization of ethylene and 1-hexene with titanium complexes bearingN,N-dialkylcarbamato ligands

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Effect of ZnCl₂‐ and SiCl₄‐doped TiCl₄/MgCl₂/THF catalysts for ethylene polymerization