Search Results (8)

In this work, we report a new facile method for the preparation of myrcene-limonene copolymers and nanocomposites using a Lewis acid as a catalyst (AlCl₃) and organo-modified clay as a nano-reinforcing filler. The copolymer (myr-co-lim) was prepared by cationic copolymerization using AlCl₃ as a catalyst. The structure of the obtained copolymer is studied and confirmed by Fourier Transform Infrared spectroscopy, Nuclear Magnetic Resonance spectroscopy, and Differential Scanning Calorimetry. By improving the dispersion of the matrix polymer in sheets of the organoclay, Maghnite-CTA⁺ (Mag-CTA⁺), an Algerian natural organophilic clay, was used to preparenanocomposites of linear copolymer (myr-co-lim). In order to identify and assess their structural, morphological, and thermal properties, the effect of the organoclay, used in varyingamounts (1, 4, 7, and 10% by weight), and the preparation process were investigated. The Mag-CTA⁺ is an organophylic montmorillonite silicate clay prepared through a direct exchange process in which they were used as green nano-reinforcing filler. The X-ray diffraction of the resulting nanocomposites revealed a considerable alteration in the interlayer spacing of Mag-CTA⁺. As a result, interlayer expansion and myr-co-lim exfoliation between layers of Mag-CTA⁺ were observed. Thermogravimetric analysis provided information on the synthesized nanocomposites’ thermal properties. Fourier transform infrared spectroscopy and scanning electronic microscopy, respectively, were used to determine the structure and morphology of the produced nanocomposites (myr-co-lim/Mag). The intercalation of myr-co-lim in the Mag-CTA⁺ sheets has been supported by the results, and the optimum amount of organoclay needed to create a nanocomposite with high thermal stability is 10% by weight. Finally, a new method for the preparation of copolymer and nanocomposites from myrcene and limonene in a short reaction time was developed. Full article

In the present work, we report a simple synthesis method for preparation of copolymers and nanocomposites from limonene and styrene using clay as a catalyst. The copolymerization reaction is carried out by using a proton exchanged clay as a catalyst called Mag-H⁺. The effect of temperature, reaction time and amount of catalyst were studied, and the obtained copolymer structure (lim-co-sty) is characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹H-NMR) and differential scanning calorimetry (DSC). The molecular weight of the obtained copolymer is determined by gel permeation chromatography (GPC) and is about 4500 g·mol⁻¹. The (lim-co-sty/Mag 1%, 3%, 7% and 10% by weight of clay) nanocomposites were prepared through polymer/clay mixture in solution method using ultrasonic irradiation, in the presence of Mag-CTA⁺ as green nano-reinforcing filler. The Mag-CTA⁺ is organophilic silicate clay prepared through a direct exchange process, using cetyltrimethylammonuim bromide (CTAB). The prepared lim-co-sty/Mag nanocomposites have been extensively characterized by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). TEM analysis confirms the results obtained by XRD and clearly show that the obtained nanocomposites are partially exfoliated for the lower amount of clay (1% and 3% wt) and intercalated for higher amounts of clay (7% and 10% wt). Moreover, thermogravimetric analysis (TGA) indicated an enhancement of thermal stability of nanocomposites compared with the pure copolymer. Full article

Green nanocomposites from rosin-limonene (Ros-Lim) copolymers based on Algerian organophilic-clay named Maghnite-CTA⁺ (Mag-CTA⁺) were prepared by in-situ polymerization using different amounts (1, 5 and 10% by weight) of Mag-CTA⁺ and azobisisobutyronitrile as a catalyst. The Mag-CTA⁺ is an organophilic montmorillonite silicate clay prepared through a direct exchange process; the clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide in which it used as green nano-filler.The preparation method of nanocomposites was studied in order to determine and improve structural, morphological, mechanical and thermal properties ofsin.The structure and morphology of the obtained nanocomposites(Ros-Lim/Mag-CTA⁺) were determined using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electronic microscopy and transmission electronic microscopy. The analyses confirmed the chemical modification of clay layers and the intercalation of rosin-limonene copolymer within the organophilic-clay sheets. An exfoliated structure was obtained for the lower amount of clay (1% wt of Mag-CTA⁺), while intercalated structures were detected for high amounts of clay (5 and 10% wt of Mag-CTA⁺). The thermal properties of the nanocomposites were studied by thermogravimetric analysis (TGA) and show a significant improvement inthe thermal stability of the obtained nanocomposites compared to the purerosin-limonene copolymer (a degradation temperature up to 280 °C). Full article

The polycondensation of tetrahydrofuran with maleic anhydride catalyzed byMaghnite-H⁺ (Mag-H) was investigated. Maghnite is a montmorillonite sheet silicateclay that is exchanged with protons to produce Maghnite-H [1]. It was found that thepolymerization in bulk is initiated by Mag-H in the presence of acetic anhydride at 40°C.The effects of the amounts of Mag-H and acetic anhydride were studied. Thepolymerization yield increased as the proportions of catalyst and acetic anhydride wereincreased. Full article

The polymerization of propylene oxide (PO) catalysed by maghnite-H⁺ (mag-H⁺) in the presence of ethylene glycol was investigated. Mag-H⁺ is a montmorillonite silicate sheet clay was prepared through a straight forward proton exchange process. It was found that the cationic polymerization of PO was initiated by mag-H⁺ at 20 °C both in bulk and in solution. The effect of the amount of mag-H⁺ and solvent was studied. These results indicated the cationic nature of the polymerization A possible initiation pathway, via the transfer of protons from mag-H⁺ to the monomer, is proposed. Full article

“Maghnite”, a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for cationic polymerisation of many heterocyclic and vinylic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structural compositions of both “Maghnite” and “H-Maghnite” have already been determined. Epichlorhydrin monomer, which is polymerizable by a cationic process (Odian,G. La Polymerisation: Principes et Applications; Ed.Technica: New York, 1994; pp 222-226), was used to elucidate the polymerization cationic character. The polymerization was performed under optimum conditions at 20°C. Experiments revealed that the polymerisation induced by “H-Maghnite” proceeds in bulk. In bulk polymerization, Epichlorhydrin conversion increases with increasing “H-Maghnite” concentration and temperature. Full article

“Maghnite” a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for polymerization of many vinylic and heterocyclic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structure compositions of both “Maghnite” and “H-Maghnite” have been developed. This catalyst was used for the polycondensation of the tetrahydrofuran with phthalic anhydride. The polymerization was performed under suitable conditions at temperature (40°C), in presence of acetic anhydride. Experiments revealed that polymerization induced by “H-Maghnite”, proceed in bulk and the conversion increases with increasing “H-Maghnite” proportion. Full article

“Maghnite” a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for cationic polymerization of many vinylic and heterocyclic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structure compositions of both “Maghnite” and “H-Maghnite” have been developed. Isobutylene monomer, wich is polymerizable only by cationic process (Odian,G. La Polymerisation :principes et Applications; Ed.Technica: New York, 1994; pp 222-226), was used to elucidate the cationic character of polymerization. The polymerization was performed under suitable conditions at isobutylene vaporization temperature (–7°C). Experiments revealed that polymerization induced by “H-Maghnite” proceed in bulk and in solution. In contrast to findings with methylene chloride CH₂Cl₂ as a polar solvent, polymerization yields with hexane C₆H₁₄ non-polar solvent is very significant. In bulk polymerization, Isobutylene conversion increases with increasing “H-Maghnite” proportion. Full article