Azobis 4-cyanopentanoyl Chloride Research Articles

Preparation of hydrophobic macroinimer-based novel hybrid sorbents for efficient removal of organic liquids from wastewater.

Herein, the synthesis of hydrophobic macroinimer-based hybrid sorbents and their use in the removal of organic solvents from wastewater is explored. Polydimethylsiloxane (PDMS), 4,-4'-azobis-4-cyanopentanoyl chloride (ACPC), and methacryloyl chloride were reacted via bulk condensation polymerization to synthesize the macroinimer. The organogel systems were then prepared with macroinimer using different acrylic monomers of methyl acrylate, ethyl acrylate, and butyl acrylate without any additional crosslinker and initiator. The structural properties of the obtained final products were characterized by FT-IR, 1H-NMR, and TGA. The effect of alkyl chain length and macroinimer moieties in the organogel networks, as well as the swelling capacities of the prepared gels, was evaluated for different organic solvents and oils. The maximum solvent absorbencies of macroinimer-based organogels were determined as 85.3%, 100.9%, 1422.1%, 1660.0%, 3809.3%, and 5032.2% for diesel oil, gasoline, acetone, benzene, tetrahydrofuran (THF), and dichloromethane (DCM), respectively. Furthermore, adsorption-desorption kinetics, selective absorption from oil/water mixtures, temperature effect on the absorption capacity, and reusability tests were investigated. Obtained results showed that the prepared organogels possessed high swelling, efficient absorption capacity, and good oil separation performance in the removal of organic solvents from wastewater. The temperature-dependent absorption study shows no significant change in absorption capacity. Thus, the prepared macroinimer-based organogels in the present study demonstrate potential as prospective sorbents for organic pollutant cleanup from wastewater.

Styrenation of triglyceride oil by nitroxide mediated radical polymerization

Styrenated oil was obtained by nitroxide mediated radical polymerization (NMRP) method in the presence of 2,2′,6,6′-tetramethylpiperidinyl-1-oxy (TEMPO). For this purpose, firstly, macroinitiator having thermally unstable azo groups was obtained with reaction of partial glycerides (PGs) mixture and 4,4′-azobis-4-cyanopentanoyl chloride (ACPC). Then, the macroinitiator was subjected to polymerization with styrene in the presence of TEMPO in order to obtain a copolymer with controlled structure and low polydispersity. The products thus obtained were characterized by GPC, 1H NMR and FT-IR measurements. A classical styrenated oil was also prepared for comparison. The film properties of the products were determined according to the related standards and compared with each other. The product obtained at the end of the 72 h in the presence of TEMPO showed to some extent brittle film properties. To improve the film properties, this product was further reacted with the oil-based vinyl macromonomer (MM). The styrenated oil samples prepared by the controlled polymerization method, exhibited relatively low polydispersity (<1.5) and showed good film properties.

Polystyrene-b-polydimethyl siloxane (PDMS) multicomponent polymer networks: Styrene polymerization with macromonomeric initiators (macroinimers) having PDMS units

A new macromonomeric initiator (macroinimer) was synthesized and evaluated for the bulk polymerization of styrene at 60 and 80°C. The macroinimer containing poly(dimethylsiloxane), PDMS, was synthesized via condensation reactions between 4,-4′-azobis-4-cyanopentanoyl chloride (ACPC), PDMS and methacryloyl chloride. The product (MIM I) was thermally homopolymerized and copolymerized with styrene in bulk. Kinetics of radical polymerization of styrene with MIM I at 60°C and at low conversion was studied. Rate constant K, k p( fk d/ k t) 1/2, was estimated from kinetic data as 1.15 × 10 −4 1 1/2 mol −1/2 s. Bulk polymerization of styrene with macroinimers at 80°C gave crosslinked block copolymers. D.s.c. measurements showed that crosslinked block copolymers had a glass transition temperature around 45°C. This is evidence of a plasticizing effect of flexible polysiloxane segments in copolymers. Crosslinked PDMS-b-PS block copolymers obtained using macroinimers may be an interesting group of thermoplastic elastomers.

Photopolymerization of Styrene with Azo-Containing Polydimethylsiloxane as Photoinitiator

Azo-containing polydimethylsiloxane (PDMS-ACP), prepared by polycondensation reaction of bis(hydroxybutyl) polydimethylsiloxane (PDMS) with 4,4′-azobis-4-cyanopentanoyl chloride (ACPC), was used as the photoinitiator for the polymerization of styrene (St) in bulk. Polymerization of styrene with azobisisobutyronitrile (AIBN) as photoinitiator was conducted for comparision. The propagation and termination rate constants (kp and kt), and the fractions β of primary radicals entering into termination were calculated. The values of kp and kt in St/PDMS-ACP system were in agreement with that in St/AIBN system. However, the photoinitiator efficiency Φ of PDMS-ACP was found to be smaller than that of AIBN. The ratio σkt/ki of the rate constants for chain termination and chain initiation by primary radicals were determined.

Synthesis of new macro‐azo‐initiators having two kinds of azo linkages in repeating unit and block copolymerization by two‐step radical polymerization initiated with them

Two kinds of new macro-azo-initiator (MAI) having dual decomposition temperatures were synthesized by polycondensation between 4,4′-azobis-4-cyanopentanoyl chloride (ACPC) and 2,2′-azobis-2-cyanopentanol (ACPO) (MAI [2A]), and between ACPC and 2,2′-azobis-2-methyl-N-2-hydroxyethylpropionamide (AHPA) (MAI [2B]). MAI [2A] and [2B] were compared with MAI [1] having a single decomposition temperature synthesized by polycondensation between ACPC and bisphenol-Z. Two step polymerization of styrene and methyl methacrylate initiated with MAI [1], [2A], and [2B] was carried out. It was confirmed that the new MAI [2A] and [2B] initiated effectively at each step of polymerization due to their dual decomposability, resulting in higher conversion of the comonomers to yield block copolymers than the case initiated with MAI [1]. © 1997 John Wiley & Sons, Inc.

Synthesis of new macro-azo-initiators having two kinds of azo linkages in repeating unit and block copolymerization by two-step radical polymerization initiated with them

Two kinds of new macro-azo-initiator (MAI) having dual decomposition temperatures were synthesized by polycondensation between 4,4'-azobis-4-cyanopentanoyl chloride (ACPC) and 2,2'-azobis-2-cyanopentanol (ACPO) (MAI [2A]), and between ACPC and 2,2'-azobis-2-methyl-N-2-hydroxyethylpropionamide (AHPA) (MAI [2B]). MAI [2A] and [2B] were compared with MAI [1] having a single decomposition temperature synthesized by polycondensation between ACPC and bisphenol-Z. Two step polymerization of styrene and methyl methacrylate initiated with MAI [1], [2A], and [2B] was carried out. It was confirmed that the new MAI [2A] and [2B] initiated effectively at each step of polymerization due to their dual decomposability, resulting in higher conversion of the comonomers to yield block copolymers than the case initiated with MAI [1].

Preparation and characterization of block and graft copolymers using macroazoinitiators having siloxane units

α,ω-Amine terminated organofunctional polydimethylsiloxane (PDMS) was condensed with 4,4′-azobis-4-cyanopentanoyl chloride (ACPC) to prepare macroazoinitiators containing siloxane units. Interfacial polycondensation reaction at room temperature was applied: ACPC was slightly dissolved in carbon tetrachloride and it was poured on aqueous NaOH solution of PDMS. Block copolymers containing PDMS as a block segment combined with polystyrene (PS) have been derived by the polymerization of styrene monomer initiated by these macroazoinitiators. PS-b-PDMS block copolymers were characterized by using nuclear magnetic resonance and infrared spectroscopy. Thermal and mechanical properties of the block copolymers were studied by using thermogravimetric analysis, differential scanning calorimetry, and a Tensilon stress-strain instrument. The morphology of block copolymers was investigated by scanning electron microscopy. PDMS-g-polybutadiene (PBd) graft copolymers were also prepared by reaction of PBd with the above macroazo-initiator. Increase in the amount of macroazoinitiator in the mixture of PBd (52% w/w) leads to the formation of crosslinked graft copolymers. Molecular weights of soluble graft copolymer samples were between 450 and 600 K with a polydispersity of 2.0–2.3. © 1996 John Wiley & Sons, Inc.

Preparation and characterization of block and graft copolymers using macroazoinitiators having siloxane units

α,ω-Amine terminated organofunctional polydimethylsiloxane (PDMS) was condensed with 4,4′-azobis-4-cyanopentanoyl chloride (ACPC) to prepare macroazoinitiators containing siloxane units. Interfacial polycondensation reaction at room temperature was applied: ACPC was slightly dissolved in carbon tetrachloride and it was poured on aqueous NaOH solution of PDMS. Block copolymers containing PDMS as a block segment combined with polystyrene (PS) have been derived by the polymerization of styrene monomer initiated by these macroazoinitiators. PS-b-PDMS block copolymers were characterized by using nuclear magnetic resonance and infrared spectroscopy. Thermal and mechanical properties of the block copolymers were studied by using thermogravimetric analysis, differential scanning calorimetry, and a Tensilon stress-strain instrument. The morphology of block copolymers was investigated by scanning electron microscopy. PDMS-g-polybutadiene (PBd) graft copolymers were also prepared by reaction of PBd with the above macroazo-initiator. Increase in the amount of macroazoinitiator in the mixture of PBd (52% w/w) leads to the formation of crosslinked graft copolymers. Molecular weights of soluble graft copolymer samples were between 450 and 600 K with a polydispersity of 2.0–2.3. © 1996 John Wiley & Sons, Inc.

Characterization of azo-containing polydimethylsiloxanes and their copolymers with methyl methacrylate

Azo group-containing polydimethylsiloxanes (PDMS-ACP), macroazoinitiators, were prepared by polycondensation reaction of 4,4'-azobis-4-cyanopentanoyl chloride (ACPC) with hydroxybutyl-terminated polydimethylsiloxane (PDMS) of varying molecular weights. The activation energy (E a ), activation enthalpy (ΔH ?), and activation entropy (ΔS ?) of the thermodecomposition of PDMS-ACP in toluene increased with increase in poly-dimethylsiloxane chain length (SCL) in PDMS moieties, while the activation free energy (ΔG ?) was independent on the SCL. The polydimethylsiloxane-poly(methyl methacrylate) block copolymers (PDMS-b-PMMA) were prepared by the use of PDMS-ACP macroazoinitiators, and they were characterized by 1 H-, 29 Si-, and 13 C-nuclear magnetic resonance (NMR) spectroscopies. The microstructure and morphology of copolymers were investigated by proton spin-spin relaxation measurements and scanning electron microscopy (SEM).

Characterization of azo‐containing polydimethylsiloxanes and their copolymers with methyl methacrylate

Azo group-containing polydimethylsiloxanes (PDMS–ACP), macroazoinitiators, were prepared by polycondensation reaction of 4,4′-azobis-4-cyanopentanoyl chloride (ACPC) with hydroxybutyl-terminated polydimethylsiloxane (PDMS) of varying molecular weights. The activation energy (Ea), activation enthalpy (ΔH‡), and activation entropy (ΔS‡) of the thermodecomposition of PDMS-ACP in toluene increased with increase in poly-dimethyl-siloxane chain length (SCL) in PDMS moieties, while the activation free energy (ΔG‡) was independent on the SCL. The polydimethylsiloxane-poly(methyl methacrylate) block copolymers (PDMS-b-PMMA) were prepared by the use of PDMS-ACP macroazoinitiators, and they were characterized by 1H-, 29Si-, and 13C-nuclear magnetic resonance (NMR) spectroscopies. The microstructure and morphology of copolymers were investigated by proton spin–spin relaxation measurements and scanning electron microscopy (SEM). © 1996 John Wiley & Sons, Inc.

Photopolymerization of Methyl Methacrylate with Azo-Containing Polydimethylsiloxane as Photoinitiator

Abstract Azo-containing polydimethylsiloxane (PDMS-ACP), prepared by the polycondensation reaction of hydroxybutyl-terminated polydimeth-ylsiloxane (PDMS) with 4,4′-azobis-4-cyanopentanoyl chloride (ACPC), was used as the photoinitiator for the polymerization of methyl meth-acrylate (MMA) in bulk. Polymerization of MMA with azobisisobutyronitrile (AIBN) as the photoinitiator was conducted for comparison. The propagation and termination rate constants (K p and Kt ), and the fraction β of primary radicals entering into termination were evaluated. The termination rate constant 4.5 × 107 mol·L−1·s−1 in the MMA/PDMSACP system was smaller than 9.1 × 107 mol·L−1·s−1 in the MMA/AIBN system. The photoinitiator efficiency φ of PDMS-ACP was found to be smaller than that of AIBN. The ratio [sgrave]kt /ki of the rate constants for chain termination and chain initiation by primary radicals were determined to be 7.9 × 107 and 5.8 × 107 for PDMS-ACP and AIBN, respectively.