Preparation and application of sulfonated poly(1‐octene‐co‐styrene)

In this article, 1‐octene and styrene was copolymerized by the supported catalyst (TiCl₄/ID/MgCl₂). Subsequently, by sulfonation reaction, sulfonated poly(1‐octene‐co‐styrene)s which were amphiphilic copolymers were prepared. The copolymerization behavior between 1‐octene and styrene is moderate ideal behavior. Copolymers prepared by this catalyst contain appreciable amounts of both 1‐octene and styrene. Increase in the feed ratio of styrene/1‐octene leads to increase in styrene content in copolymer and decrease in molecular weight. As the polymerization temperature increases, the styrene content in the copolymers increases, however, the molecular weight decreases. Hydrogen is an efficient regulator to lower the molecular weights of poly(1‐octene‐co‐styrene)s. The sulfonation degree of the sulfonated poly(1‐octene‐co‐styrene)s increased as the styrene content in copolymer increased or the molecular weight decreased. Thirty‐six hour is long enough for sulfonation reaction. The sulfonated poly(1‐octene‐co‐styrene)s can be used as effective and durable modifying agent to improve the wettability of polyethylene film and have potential application in emulsified fuels and for the stabilization of dispersions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of various reaction media on the thermal and rheological properties of poly(acrylamide‐co‐N‐hexadecylacrylamide)

A hydrophobically modified polyacrylamide (PAM) was synthesized by the copolymerization of acrylamide (Am) and N‐hexadecylacrylamide (hAm) through solution copolymerization in a polar organic solvent. Polymer synthesis was performed in three nonaqueous media, including dimethyl sulfoxide (DMSO), a mixture of DMSO and an anionic surfactant such as sodium dodecyl sulfate, and a mixture of DMSO and an acidic surfactant such as dodecyl benzene sulfonic acid. The obtained copolymer, poly(acrylamide‐co‐N‐hexadecylacrylamide) [poly(Am‐co‐hAm)], was characterized by ¹H‐NMR. The physical properties of poly(Am‐co‐hAm)s synthesized in different media were compared with those of PAM and with each other by viscosity measurement, X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. We investigated the ways in which the polymerization medium affected the hydrophobic distribution within the resulting copolymer structure. This aspect, in turn, should have altered the solution properties and the microstructure of the copolymer. For this purpose, we studied the viscometric behavior in diluted solutions, the thermal behavior and thermal stability of the copolymers, and finally, the crystalline structure of the copolymers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39939.     

Copolymerization of styrene with an α‐olefin via atom transfer radical polymerization

This investigation reports the preparation of styrene–α‐olefinic random copolymers, using 1‐octene as an α‐olefin, via atom transfer radical polymerization. Atom transfer radical copolymerization of styrene with 1‐octene was successfully carried out using phenylethyl bromide as initiator and CuBr as catalyst in combination with N, N, N′, N″, N″‐pentamethyldiethylenetriamine as ligand. The copolymers had controlled molecular weight, narrow dispersity and well‐defined end groups with significant 1‐octene incorporation in the polymer. Incorporation of 1‐octene in the copolymers was confirmed using ¹H NMR and matrix‐assisted laser desorption ionization time‐of‐flight mass spectroscopy. An increase in 1‐octene content in the monomer feed led to an increase in the level of incorporation of the α‐olefin in the copolymer. An increase in the concentration of 1‐octene led to a decrease in the rate of polymerization and an increase in dispersity. The glass transition temperature of the copolymer gradually decreased as the incorporation of 1‐octene increased. Copyright © 2011 Society of Chemical Industry     

Preparation of ethylene/1‐octene copolymers from ethylene stock with tandem catalytic system

Tandem catalysis offers a novel synthetic route to the production of linear low‐density polyethylene. This article reports the use of homogeneous tandem catalytic systems for the synthesis of ethylene/1‐octene copolymers from ethylene stock as the sole monomer. The reported catalytic systems involving a highly selective, bis(diphenylphosphino)cyclohexylamine/Cr(acac)₃/methylaluminoxane (MAO) catalytic systems for the synthesis of 1‐hexene and 1‐octene, and a copolymerization metallocene catalyst, rac‐Et(Ind)₂ZrCl₂/MAO for the synthesis of ethylene/1‐octene copolymer. Analysis by means of DSC, GPC, and ¹³C‐NMR suggests that copolymers of 1‐hexene and ethylene and copolymers of 1‐octene and ethylene are produced with significant selectivity towards 1‐hexene and 1‐octene as comonomers incorporated into the polymer backbone respectively. We have demonstrated that, by the simple manipulation of the catalyst molar ratio and polymerization conditions, a series of branched polyethylenes with melting temperatures of 101.1–134.1°C and density of 0.922–0.950 g cm^?3 can be efficiently produced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Amphibious water‐soluble copolymer. I. Its synthesis and dispersing ability on barium titanate

An amphibious water‐soluble copolymer, polyacrylamide/(α‐N,N‐dimethyl‐N‐acryloyloxyethyl) ammonium ethanate (PAAM/DAAE), was synthesized and used as a dispersion agent for BaTiO₃ particles. PAAM/DAAE was prepared from acrylamide and (α‐N,N‐dimethyl‐N‐acryloyloxyethyl) ammonium ethanate under basic conditions through a free‐radical polymerization. The structure of this copolymer was verified with IR and ¹H‐NMR spectra. The dispersing effects of PAAM/DAAE were examined through the measurement of the viscosity and sedimentation of BaTiO₃ suspensions and the green density. The results indicated that this copolymer could uniformly disperse the particles, reduce the viscosity, stabilize the suspensions, and produce high‐density green compacts. In comparison with a commercial dispersant, the ammonium salt of poly(methylacrylic acid), PAAM/DAAE was clearly more effective. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2232–2239, 2004     

Amphoteric water‐soluble copolymer for barium titanate slurries. I. Synthesis and dispersing ability

An amphoteric water‐soluble copolymer, polyacrylamide/[α‐N,N‐dimethyl‐N‐(3‐(β‐carboxylate)acrylamino)propyl] ammonium ethanate (PAM/DAE) was synthesized and used as a dispersion agent for BaTiO₃ particles. PAM/DAE was prepared from acrylamide and [α‐N,N‐dimethyl‐N‐(3‐(β‐carboxylate)acrylamino)propyl] ammonium ethanate in a basic condition through a free‐radical polymerization. The structure of this copolymer was verified by IR and ¹H‐NMR spectra. The dispersing effects of PAM/DAE were examined by measuring the viscosity and sedimentation of BaTiO₃ suspensions, and by analyzing the particle size. The results indicate that this copolymer could uniformly disperse the particles, and the resulting suspensions were less viscous, more stabilized, and contained powder with smaller particle size. The dispersing/stabilizing ability of PAM/DAE is close to, or slightly better than, that of a commercial dispersant, ammonium salt of poly(methacrylic acid). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1443–1450, 2005     

Copolymerization of propylene with 1‐octene catalyzed by MgCl2/TiCl4/diether catalyst

MgCl₂/TiCl₄/diether is a fifth‐generation Ziegler–Natta catalyst for the commercial polymerization of propylene. The outstanding features of this catalyst are the high activity and high isotacticity for propylene polymerization without using an external electron donor. In this study, we explored the copolymerization of propylene and 1‐octene with MgCl₂/TiCl₄/diether catalyst. It was found that MgCl₂/TiCl₄/diether catalyst showed higher polymerization activity and led to greater 1‐octene content incorporation, compared with a fourth‐generation Ziegler–Natta catalyst (MgCl₂/TiCl₄/diester). With an increase in 1‐octene incorporation in polypropylene chains, the melting temperature, glass transition temperature and crystallinity of the copolymers decreased distinctly. The microstructures of the copolymers were characterized using ¹³C NMR spectroscopy, and the copolymer compositions and number‐average sequence lengths were calculated from the dyad concentration and distribution. This result is very important for the in‐reactor polyolefin alloying process, especially for the case of a single catalyst and two‐step (or two‐reactor) process. Copyright © 2011 Society of Chemical Industry     

Study of the compositional heterogeneity of ethylene/1–hexene copolymers produced over supported catalysts of different composition

Separation into narrow MWD fractions (liquid–liquid fractionation) and preparative TREF (temperature rising elution fractionation) with subsequent analysis of fractions by GPC, FTIR, and ¹³C NMR spectroscopy were used to study the comonomer distribution of ethylene/1–hexene copolymers produced over highly active supported titanium‐ and vanadium‐magnesium catalysts (TMC and VMC) and a supported zirconocene catalyst. These catalysts produce PE with different MWD: M_w/M_n values vary from 2.9 for zirconocene catalyst, 4.0 for TMC, and 15 for VMC. 1‐Hexene increases polydispersity to 25 for copolymer produced over VMC and hardly affects MWD of the copolymer produced over TMC and zirconocene catalysts. The most broad short chain branching distribution (SCBD) was found for ethylene/1–hexene copolymers produced over TMC. VMC and supported zirconocene catalyst produce copolymers with uniform profile of SCB content vs. molecular weight in spite of great differences in M_w/M_n values (22 and 2.5 respectively). TREF data showed that majority of copolymer produced over supported zirconocene catalyst was eluted at 70–90°C (about 85 wt %). In the case of VMC copolymer's fractions were eluted in the broad temperature interval (40–100°C). Accordingly, TREF data indicate a more homogeneous SCBD in copolymer, produced over supported zirconocene catalyst. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

(Co)polymerization of ethylene via nonmetallocene catalysts with diphenyl phosphoroso schiff‐base ligand

A series of novel nonmetallocene catalysts [N, O, P] with diphenyl phosphoroso ligands were synthesized by the treatment of phthaldialdehyde, substituted phenols, chlorodiphenyl phosphine with metal halides of TiCl₄ and ZrCl₄. The catalyst microstructure was characterized by ¹H NMR and EA. After activated by methylaluminoxane (MAO), these [N, O, P] catalysts were utilized to catalyze the polymerization of ethylene and the copolymerization of ethylene with 1‐octene. The results indicated that the obtained catalysts were highly efficient for ethylene polymerization and ethylene/1‐octene copolymerization. Structures and properties of the obtained polymers were measured by WAXD, DSC, GPC, and ¹³C NMR. The results indicated that polyethylene catalyzed by Cat. 3 possessed the highest weight‐average molecular weight of 1.025 × 10⁶ g/mol and the highest melting point of 136.3°C. The copolymer of ethylene/1‐octene catalyzed by Cat. 1 exhibited the highest 1‐octene incorporation content of 0.63 mol %. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42225.     

Silica‐supported (nBuCp)2ZrCl2: effect of catalyst active center distribution on ethylene–1‐hexene copolymerization

Metallocenes are a modern innovation in polyolefin catalysis research. Therefore, two supported metallocene catalysts—silica/MAO/(ⁿBuCp)₂ZrCl₂ (Catalyst 1) and silica/ⁿBuSnCl₃/MAO/(ⁿBuCp)₂ZrCl₂ (Catalyst 2), where MAO is methylaluminoxane—were synthesized, and subsequently used to prepare, without separate feeding of MAO, ethylene–1‐hexene Copolymer 1 and Copolymer 2, respectively. Fouling‐free copolymerization, catalyst kinetic stability and production of free‐flowing polymer particles (replicating the catalyst particle size distribution) confirmed the occurrence of heterogeneous catalysis. The catalyst active center distribution was modeled by deconvoluting the measured molecular weight distribution and copolymer composition distribution. Five different active center types were predicted for each catalyst, which was corroborated by successive self‐nucleation and annealing experiments, as well as by an extended X‐ray absorption fine structure spectroscopy report published in the literature. Hence, metallocenes impregnated particularly on an MAO‐pretreated support may be rightly envisioned to comprise an ensemble of isolated single sites that have varying coordination environments. This study shows how the active center distribution and the design of supported MAO anions affect copolymerization activity, polymerization mechanism and the resulting polymer microstructures. Catalyst 2 showed less copolymerization activity than Catalyst 1. Strong chain transfer and positive co‐monomer effect—both by 1‐hexene—were common. Each copolymer demonstrated vinyl, vinylidene and trans‐vinylene end groups, and compositional heterogeneity. All these findings were explained, as appropriate, considering the modeled active center distribution, MAO cage structure repeat units, proposed catalyst surface chemistry, segregation effects and the literature that concerns and supports this study. While doing so, new insights were obtained. Additionally, future research, along the direction of the present work, is recommended. © 2013 Society of Chemical Industry     

Micellar Effects in Olefin Hydroformylation Catalysed by Neutral,Calix[4]arene‐Diphosphite Rhodium Complexes

The combination of calixarene‐derived surfactants and neutral rhodium complexes containing a hemispherical “1,3‐calix‐diphosphite” ligand led to efficient catalysts for the hydroformylation of octene and other olefins in water. While the surfactants allowed the formation of micelles that dissolve both the catalyst and the alkene, thereby resulting in high olefin:rhodium ratios, the diphosphite provided a tight envelope about the catalytic centre able to drive the reaction towards the linear aldehydes. Best results in the hydroformylation of 1‐octene were obtained when using [tetra(p‐sulfonato)]‐(tetra‐n‐butoxy)‐calix[4]arene as surfactant. With this additive remarkable linear to branched aldehyde ratios of up to 62 were obtained, the corresponding activities being higher than those observed when operating in an organic solvent [turnover frequencies (TOFs) up to 630 mol(converted 1‐octene)⋅ mol(Rh)⁻¹⋅h⁻¹].     

NMR characterization of absorbed water in equilibrium swollen hydrogel P(AM‐NaA)

The behavior of absorbed water in equilibrium‐swollen poly(acrylamide‐co‐sodium acrylate) [P(Am‐NaA)] hydrogel is studied with ¹H nuclear magnetic resonance (¹H‐NMR). The observed non‐exponential decay of the spin–spin relaxation data manifests at least two distinguishable environmental states of the absorbed water in all samples. The component, characterized by the relatively shorter T₂, is associated with the more tightly bound water; whereas the other, characterized by longer T₂, might be a combination of near normal and loosely bound water. Attention is directed to the way in which relaxation times and the corresponding fraction of each type of water behave as a function of the crosslink density at 25°C. There is evidence of a sudden change of the crosslink state in P(Am‐NaA) hydrogel at crosslink density of about 1.0%. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1203–1207, 1999     

Poly(1‐octene) synthesis using high performance supported titanium catalysts

Poly(1‐octene) was synthesized by polymerization of 1‐octene using high performance MgCl₂‐supported TiCl₄ in combination with triethyl aluminum (TEAl) as cocatalyst in n‐hexane for 2 h. Two catalysts, C₁ (diester catalyst) having di‐isobutyl phthalate as internal donor and C₂ (monoester catalyst) having ethyl benzoate as internal donor were utilized for the atmospheric polymerizations to evaluate the influence of structurally different internal donors on the productivity, rate of polymerization and molecular weight profiles. The kinetic profile assessed in terms of variation of reaction parameters like temperature, cocatalyst to catalyst molar ratio and monomer concentration was found to be dependent on them. From these kinetic analyses, optimize conditions for polymerizations of 1‐octene using diester as well as monoester catalyst were elucidated. The difference in the performance of diester and monoester catalyst system can be explained in terms of stability of active titanium species and chain transfer process. NMR spectroscopy of synthesized poly(1‐octene) indicate predominantly isotactic nature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Alumina‐supported microwave synthesis of Cassia marginata seed gum‐graft‐polyacrylamide

In this article, we report the alumina‐supported, microwave (MW)‐induced synthesis of Cassia marginata seed gum‐graft‐polyacrylamide (MWS‐GP). No initiator or catalyst was required in the synthesis, and the conditions for the grafting were optimized by variation of the acrylamide concentration, MW power, and exposure time. At an identical monomer concentration, a higher level of grafting was observed in the solid‐supported method than under aqueous conditions (the MW‐assisted or redox‐initiated thermal method). The used alumina support was easily separated from MWS‐GP and reused for another three cycles without any significant loss in its efficiency as a solid support. MWS‐GP synthesized under optimum conditions was characterized with Fourier transform infrared spectroscopy, ¹³C‐NMR, thermogravimetric analysis, and X‐ray diffraction, with C. marginata gum as a reference. The properties of MWS‐GP and its saponified derivative were studied to explore the applicability areas of the copolymer in hydrogel formation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of a linear low‐density polyethylene/MgO@Mg(OH)2 nanocomposite using modified in situ polymerization

Composites of linear low‐density polyethylene were obtained in toluene slurry by in situ copolymerization of ethylene and 1‐octene in the presence of untreated magnesium oxide–hydroxide nanoparticles (MgO@Mg(OH)₂) of ±50 nm and such treated with dibutylmagnesium (DBM) as support for a bis(n‐butylcyclopentadienyl)zirconium dichloride–methylaluminoxane (MAO) catalyst system. Treatment of the nanoparticles with DBM (0.5–6 mmol g^?1 MgO@Mg(OH)₂) allows one to decrease the amount of MAO by 1.2 mmol Al g^?1 MgO@Mg(OH)₂, while reaching the same average catalyst activity and a finer distribution of the particles. Energy‐dispersive X‐ray mapping shows that the MAO is mainly associated with the filler. The crystallinity of the matrix polymer decreases with filler content. © 2018 Society of Chemical Industry     

Temperature responsive fibers with anisotropic transitional behavior

Temperature sensitive polymer hydrogels are being extensively studied because of their potential applications in the biomedical, robotics, and chemical industries. However, major hurdles in their development have been their slow response, low efficiency (swelling/deswelling ratios), and poor mechanical properties due to difficulty in processing them into mechanically strong and fine structures. Fibers made from such polymers would be highly desirable. A temperature sensitive random linear copolymer of N‐tert‐butylacrylamide (NTBA) and acrylamide (Am) was synthesized by the solution polymerization method, using regulated dosing of comonomers. Using a novel approach, a high molecular weight poly(N‐tert‐butylacrylamide‐ran‐acrylamide::27 : 73) has been converted to insoluble strong fibers with fineness of 30–50 microns by solution spinning, drawing, and subsequent crosslinking. Fibers were solution spun in acetone using a 14% copolymer solution in acetic acid with polycarboxylic acid as a crosslinker and sodium hypophosphite as a catalyst. The crosslinks were formed, subsequent to drawing, between reactive amide side groups of the acrylamide moiety of the polymer and the carboxylic acid group of the crosslinker by thermal treatment at 160°C. The transition temperatures of the crosslinked fibers were found to shift towards the lower temperature from 37°C (in linear copolymer) to 22–25°C. These engineered fibers display sharp temperature sensitivity, extremely high reversible change in dimensions (1000% in diameter and ～ 70% in length), and extremely fast response time (< 20 s for expansion and < 2 s for contraction). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 681–688, 2005     

Efficiencies of various metallocene/reducing agent catalyst systems in the hydrogenation of polystyrene‐b‐polybutadiene‐b‐polystyrene block copolymers

Various metallocenes, including bis(η⁵‐cyclopentadienyl)cobalt, bis(η⁵‐cyclopentadienyl)nickel, and bis(η⁵‐cyclopentadienyl)titanium dichloride, combined with various reducing agents, including n‐butyllithium, phenyllithium, and triethylaluminum, have been evaluated for their catalytic efficiencies in the hydrogenation of polystyrene‐b‐polybutadiene‐b‐polystyrene (SBS) block copolymer. The efficiencies were determined by monitoring the extent of saturation of double bonds on the polybutadiene segment of the copolymer using FTIR and ¹H‐NMR spectroscopy. The cobaltocene/n‐butyllithium catalyst system was found the most active. The effects of H₂ pressure and the ratio of n‐butyllithium to cobaltocene ratio on the hydrogenation efficiency were also investigated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1807–1815, 1999     

Water‐soluble copolymers of 1‐vinyl‐2‐pyrrolidone and acrylamide derivatives: synthesis,characterization, and metal binding capability studied by liquid‐phase polymer‐based retention technique

Radical copolymerizations of 1‐vinyl‐2‐pyrrolidone with acrylamide and N,N′‐dimethylacrylamide at different feed ratios were investigated. The copolymers were characterized by Fourier transform infrared spectroscopy, ¹H NMR, and ¹³C NMR spectroscopy. The copolymer composition was determined from the ¹H NMR spectra and found to be statistical. The metal complexation of poly(acrylamide‐co‐1‐vinyl‐2‐pyrrolidone) and poly(N,N′‐dimethylacrylamide‐co‐1‐vinyl‐2‐pyrrolidone) for the metal ions Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Pb(II), Fe(III), and Cr(III) were investigated in an aqueous phase. The liquid‐phase polymer‐based retention method is based on the retention of inorganic ions by soluble polymers in a membrane filtration cell and subsequent separation of low‐molecular compounds from the polymer complex formed. The metal ion interaction with the hydrophilic polymers was determined as a function of the pH and the filtration factor. Poly(N,N‐dimethylacrylamide‐co‐1‐vinyl‐2‐pyrrolidone) showed a higher affinity for the metal ions than poly(acrylamide‐co‐1‐vinyl‐2‐pyrrolidone). According to the interaction pattern obtained, Cr(III) and Cu(II) formed the most stable complexes at pH 7. Pb(II) and Zn(II) were not retained. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 741–750, 1999     

Volume phase transition behavior of N‐isopropyl acrylamide–N‐cyanomethyl acrylamide copolymer gel particles: The effect of crosslinking density

We prepared submicron‐sized N‐isopropyl acrylamide (NIPA)–N‐cyanomethyl acrylamide (NCMA) copolymer gel particles by precipitation polymerization. Volume phase transition behaviors of gel particles with various compositions and crosslinking density were observed by using photon correlation spectroscopy (PCS). The experimental data showed that both the volume transition temperature and the swelling ratio of copolymer gel particles were varied with the mole ratio of NCMA and NIPA. We compared the swelling behaviors of given systems with the thermodynamic model based on the extended Flory–Huggins theory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1091–1099, 1999     

Synthesis of ethylene/1‐octene copolymers with controlled block structures by semibatch living copolymerization

A kinetic model was developed for the living copolymerization of ethylene/1‐octene using the fluorinated FI‐Ti catalyst system, bis[N‐(3‐methylsalicylidene)‐2,3,4,5,6‐pentafluoroanilinato] TiCl₂/dried methylaluminoxane is presented. The model was first validated by batch polymerization experiments. Kinetic parameters were estimated from the model correlations with online ethylene consumption rates and end‐of‐batch copolymer molecular weight. The model was then used to calculate the microstructural properties of ethylene/1‐octene copolymers with controlled composition profiles (uniform, diblock, and step triblock), which were synthesized using sequential comonomer feeding policies in semibatch copolymerization. The synthesized block copolymers had the exact composition distributions and molecular weights as the model simulated. It was demonstrated that the polymer chain microstructure in the living copolymerization of olefins could be precisely regulated by using semibatch comonomer feeding policies. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4686–4695, 2013