Methylaluminoxane‐activated neodymium chloride tributylphosphate catalyst for isoprene polymerization

The polymerization of isoprene was examined by using a novel binary catalyst system composed of neodymium chloride tributylphosphate (NdCl₃·3TBP) and methylaluminoxane (MAO). The NdCl₃·3TBP/MAO catalyst worked effectively in a low MAO level ([Al]/[Nd] = 50) to afford polymers with high molecular weight (M_n ～10⁵), narrow molecular weight distribution (M_w/M_n = 1.4–1.6), and high cis‐1,4 stereoregularity (> 96%). The catalytic activity increased with an increasing [Al]/[Nd] ratio from 30 to 100 and polymerization temperature from 0 to 50°C, while the M_n of polymer decreased. The presence of free TBP resulted in low polymer yield. Polymerization solvent remarkably affected the polymerization behaviors; the polymerizations in aliphatic solvents (cyclohexane and hexane) gave polymer in higher yield than that in toluene. The M_w/M_n ratio of the producing polymer remained around 1.5 and the gel permeation chromatographic curve was always unimodal, indicating the presence of a single active site in the polymerization system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40153.     

Polymerization of 1,3‐dienes containing functional groups: 8. Free‐radical polymerization of 2‐triethoxysilyl‐ 1,3‐butadiene

The presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene ( 1 ) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ( ) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (R_p) was found to be R_p = k[AIBN]^0.5[ 1 ]^1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol^?1. The monomer reactivity ratios in copolymerization with styrene were r ₁ = 2.65 and r_st = 0.26. The glass transition temperature of the polymer of 1 was found to be ?78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry     

Homogeneous neodymium iso-propoxide/modified methylaluminoxane catalyst for isoprene polymerization

The neodymium iso-propoxide [Nd(Oi-Pr)₃] catalyst activated by modified methylaluminoxane (MMAO) is homogeneous and effective in isoprene polymerization in heptane to provide polymers with high molecular weight (M_n∼10⁵), narrow molecular weight distribution (M_w/M_n=1.1-2.0) and mainly cis-1,4 structure (82-93%). The polymer yield increased with increasing [Al]/[Nd] ratio (50-300 mole ratio) and polymerization temperature (0-60 °C), while the molecular weight and cis-1,4 content decreased. On the other hand, the same catalyst resulted in relatively low polymer yield and low molecular weight in toluene. The cyclized polyisoprene was formed in dichloromethane, which is attributable to the cationic active species derived from MMAO alone. When chlorine sources (Et₂AlCl, t-BuCl, Me₃SiCl) were added, the cis-1,4 stereoregularity of polymer improved up to 95% even at a high temperature of 60 °C, though the polymer yield decreased.     

Laser-initiated homogeneously photocatalytic polymerization of phenylacetylene by W(CO)6-CH3I system

Summary The polymerization of phenylacetylene at room temperature by UV laser activated W(CO)₆ in CH₃I solvent was investigated. The weight-average molecular weight of the polymer is 10³, and the ¹H NMR spectra of polymers indicate that the polyphenylacetylene has a cis-transoidal structure. The experimental data show that not only laser wavelength, energy and irradiation time influence on the yield of polymer but also the laser energy influences the structure of polymer.     

Investigation of kinetics of 4‐methylpentene‐1 polymerization using Ziegler–Natta‐type catalysts

The kinetics of 4‐methylpentene‐1 (4MP1) polymerization by use of Ziegler–Natta‐type catalyst systems, M(acac)₃‐AlEt₃ (M = Cr, Mn, Fe, and Co), are investigated in benzene medium at 40°C. The effect of various parameters such as Al/M ratio, reaction time, aging time, temperature, catalyst, and monomer concentrations on the rate of polymerization and yield are examined. The rate of polymerization increased linearly with increasing monomer concentration with first‐order dependence, whereas the rate of polymerization with respect to catalyst concentration is found to be 0.5. For all cases, the polymer yield is maximum at an Al/M ratio of 2. The activation energies obtained from linear Arrhenius plots are in the range of 25.27–33.51 kJ mol^?1. It is found that the aging time to give maximum percentage yield of the polymer varies with the catalyst systems. Based on the experimental results, a plausible mechanism is proposed that envisages a free‐radical mechanism. Characterization of the resulting polymer product, for all the cases, through FTIR, ¹H‐NMR, and ¹³C‐NMR studies, showed isomerized polymeric structures with 1,4‐structure as dominant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2468–2477, 2003     

Synthesis,characterization and thermal properties of phenylene–disiloxane polymers obtained from catalytic cross‐dehydrocoupling polymerization of bis(dimethylsilyl)benzene isomers and water

Phenylene–disiloxane polymers were prepared from 1,4‐bis(dimethylsilyl)benzene and 1,3‐bis(dimethylsilyl)benzene with water in various ratios by catalytic cross‐dehydrocoupling polymerization. Each isomer showed almost equal reactivity in the polymerization as verified by the analysis of the composition by ¹H NMR. Crystallinity observed in the polymer obtained from the 1,4‐isomer was removed by incorporating a small amount of 1,3‐isomer. © 2001 Society of Chemical Industry     

Polymerization of allyl methacrylate with nylon 6 using benzoyl peroxide as initiator

Polymerization of allyl methacrylate with nylon 6 using benzoyl peroxide as initiator was carried out under different conditions. The polymer add-on was dependent upon allyl methacrylate and benzoyl peroxide concentrations, polymerization time and temperature as well as addition of metallic salts or organic solvents. The polymer add-on increased by increasing benzoyl peroxide concentration up to 0.5 mmol/l then decreased by further increase in peroxide concentration, whereas it increased as the allyl methacrylate concentration increased from 80 – 300 mmol/l. A polymerization temperature of 85°C constituted the optimal temperature, below or above this temperature resulted in lower polymer add-on. The effect of polymerization time was related to the polymerization temperature, no induction period occured at 95°C in contrast to 15 and 30 minutes at 85°C and 75°C, respectively. The incorporation of Cu^{+ +}ions in the polymerization system improved the magnitude of polymer add-on. A similar situation was encountered with Fe^{+ + +} and Li⁺ ions. Using a water/organic solvent mixture as a polymerization medium was advantageous in enhancing polymer add-on provided that the organic solvent did not exceed 1% in case of ethanol and isopropanol and 4% in case of methanol.     

酸性膦酸酯钕盐催化丁二烯在苯乙烯溶剂中的选择性聚合

以酸性膦酸酯钕盐Nd(P507)3(简称Nd)、氢化二异丁基铝(简称Al)和倍半乙基铝(简称Cl)为催化剂体系,研究了丁二烯在苯乙烯溶剂中的选择性聚合,考察了溶剂种类、Al/Nd、Cl/Nd及温度对聚合的影响。结果表明,该催化剂体系可在苯乙烯溶剂中实现丁二烯的选择性聚合,在Al/Nd(摩尔比)为10、Cl/Nd(摩尔比)为2.0及聚合温度为50℃的条件下,丁二烯的转化率可达90%以上;聚合物中苯乙烯链节的摩尔分数在4%以下,丁二烯链节的顺式-1,4-结构摩尔分数为90%左右,1,2-结构摩尔分数为4%左右。     

立构嵌段聚丁二烯的研制Ⅳ．立构二嵌段与三嵌段共混聚丁二烯的研究

在以ｎ－Ｂｕｌｉ为引发剂，环己烷为溶剂，二哌啶乙烷和二乙基锌为调节剂的丁二烯负离子聚合过程中，采用高分子设计，分别以二甲基二氯硅烷、苯甲酸乙酯和乙酸乙酯为偶联剂，合成了不同分子量、不同嵌段比及共混比的１，４－１，２／１，４－１，２－１，４及１，２－１，４／１，２－１，４－１，２立构嵌段聚丁二烯（ＰＢ），考察了共混物的微观相分离、流变性及屈服强度。结果表明，嵌段共混ＰＢ的分子量、嵌段比、共混比值只有在一定范围时，共混物才产生微观相分离，分相的嵌段共混ＰＢ具有较好的流变性、加工性，较小的冷流性和较高的屈服强度。     

Ring‐opening polymerization of styrene oxide with Maghnite‐H+ as ecocatalyst

The polymerization of styrene oxide was carried out at 20°C in chloroform with an acid‐exchanged montmorillonite as acid solid ecocatalyst (Mag‐H⁺). The effect of the amount of catalyst, solvent, and concentration of monomer on yield and molecular weight of polymer was studied. A typical reaction product (PSTO) was analyzed by infrared and nuclear magnetic resonance spectroscopy, as well as by gel‐permeation chromatography and MALDI‐TOFMS. The mechanism of the polymerization appears to be cationic. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1681–1687, 2006     

Poly(β-amino ester) based solid polymer electrolytes for lithium-ion batteries

In this paper, we present the synthesis of poly(β-amino ester)-based solid polymer electrolytes (SPE) from off-stoichiometric acrylate-amine formulations using one-step, catalyst and solvent free aza-Michael addition. By varying the monomers, the pendant functionality of the polymer chain structure could be altered. All synthesized polymers yield freestanding and easy to handle electrolyte films and hence are evaluated as a new class of SPEs. The SPE with 1,4-butanediol diacrylate and propylamine showed the highest conductivity of 1.15 × 10⁻⁷ S cm⁻¹ at 30°C with 10 wt% lithium bis(trifluoromethanesulfonyl)imide. Because of the presence of the various functional groups in the structure, the polymer chain aids in the movement of both the anion and the cation.     

Synthesis of polymers having 1,3-cyclobutanedione unit in the main chain by cycloaddition polymerization of bisketene

Summary A novel polymer having 1,3-cyclobutanedione unit in the main chain was prepared by cycloaddition polymerization of the bisketene derived from 1,4-cyclohexanedicarbonyl chloride. The polymer was soluble in MeOH, acetone, and CHCl₃. The structure of the polymer was confirmed by IR, ¹H-, and ¹³C-NMR spectroscopies compared with those of the model compounds. The polymer was found to contain anhydride bond as well as 1,3-cyclobutanedione unit in the main chain. The anhydride bond in the polymer was cleaved by MeOH under reflux condition in benzene. Received: 8 February 1999/Accepted: 16 March 1999     

Ring opening polymerization of 2-aminothiazole with iron(III) chloride

Poly(2-aminothiazole), PAT, was synthesized by the chemical polymerization of 2-aminothiazole, AT, with FeCl₃·6H₂O in 1,4-dioxane. The effect of temperature, monomer, and initiator concentration and polymerization time on the rate of polymerization was studied. The structural analysis of the polymer was carried out by elemental analysis and ¹H-NMR, FTIR, and UV–VIS spectroscopies. Thermal properties were studied by DSC and TGA. Conductivity measurements were carried out by four-probe technique and the number average molecular weight, M _n, of the polymer was determined by cryoscopy.     

Synthesis and properties of ionic conjugated polymer with spiroxazine moiety

A noble conjugated ionic polymer with photochromic spiroxazine moiety, poly[2-ethynyl-N-hexyloxyspiroxazine pyridinium bromide] (PEHSPB) 6 was prepared by the activated polymerization of 2-ethynylpyridine 5 with 1,3,3-trimethyl-6′-bromohexyloxyspiro[2H]-indol-2,3′-[3H]-naphth[2,1-b][1,4]oxazine 4 without any additional initiator or catalyst. The polymerization reaction was performed in DMF solvent at the temperature of 120 °C. As the polymerization proceeded, the reaction solution became more viscous and black in colour. The polymer yield and inherent viscosity were 75% and 0.15 dL/g, respectively. The instrumental analysis data on the chemical structure of PEHSPB 6 indicated that the present PEHSPB 6 have a conjugated polymer backbone system with the spiroxazine-hexyl substituents. X-ray diffraction analyses of the polymers indicated that the present polymers are mostly amorphous. The photoluminescence peak is located at 515 nm corresponding to the photon energy of 2.41 eV. Upon UV irradiation, closed spiroxazine form is transformed into the open merocyanine form that reverts back to the colourless spiro form in dark.     

Polymer-based fluorescence sensor incorporating triazole moieties for Hg detection via click reaction

The polymer could be obtained by the polymerization of 1,4-dibutoxy-2,5-diethynylbenzene (M-1) with 1,4-diazidobenzene (M-2)via click reaction. The polymer show blue fluorescence. The responsive optical properties of the polymer on various transition metal ions were investigated by fluorescence spectra. Compared with other cations, such as Co²⁺, Ni²⁺, Ag⁺, Cd²⁺, Cu²⁺ and Zn²⁺, Hg²⁺ can exhibit the most pronounced fluorescence response of the polymer Hg²⁺ can exhibit the most pronounced fluorescence response of the polymer due to triazole moiety in the polymer main chain as the metal binding ligand. The results indicate this kind of conjugated polymer with triazole moiety synthesized by click reaction can be used as a selective fluorescence sensor for Hg²⁺ detection.     

Polymerization of bicyclic ethers: 2. N.m.r. structure study of the polymer formed from 3-oxabicyclo[3,2,2]nonane

The polymerization of 3-oxabicyclo[3.2.2] nonane (I) was carried out in methylene chloride with phosphorus pentafluoride and epichlorohydrin at temperatures ranging from ?25° to +25°C. Slow polymerization rates were generally observed, leading to low molecular weight amorphous polymers. By ¹³C n.m.r. and ¹H n.m.r. analysis of the monomer and polymer compounds, it was possible to assign the polymer the structure of a poly(1,4-cyclohexylene-dimethylene there). By comparing the polymer n.m.r. spectra with the proton spectra of two reference compounds, it was possible to establish a microstructure for the repeating unit of the polymer in which the methylenether groups on positions 1 and 4 of the cyclohexane ring are cis to each other. A propagation scheme through oxonium ions is proposed in order to explain the formation of cis polymer.     

Biodegradable poly(ester‐ether)s: ring‐opening polymerization of D,L‐3‐methyl‐1,4‐dioxan‐2‐one using various initiator systems

The synthesis and detailed characterization of racemic 3‐methyl‐1,4‐dioxan‐2‐one (3‐MeDX) are reported. The bulk ring‐opening polymerization of 3‐MeDX, to yield a poly(ester‐ether) meant for biomedical applications, in the presence of various initiators such as tin(II) octanoate, tin(II) octanoate/n‐butyl alcohol, aluminium tris‐isopropoxide and an aluminium Schiff base complex (HAPENAlOⁱPr) under varying experimental conditions is here detailed for the first time. Polymerization kinetics were investigated and compared with those of 1,4‐dioxan‐2‐one. The studies reveal that the rate of polymerization of 3‐MeDX is less than that of 1,4‐dioxan‐2‐one. Experimental conditions to achieve relatively high molar masses have been established. Thermodynamic parameters such as enthalpy and entropy of 3‐MeDX polymerization as well as ceiling temperature have been determined. Poly(D ,L ‐3‐MeDX) is found to possess a much lower ceiling temperature than poly(1,4‐dioxan‐2‐one). Poly(D ,L ‐3‐MeDX) was characterized using NMR spectroscopy, matrix‐assisted laser desorption ionization mass spectrometry, size exclusion chromatography and differential scanning calorimetry. This polymer is an amorphous material with a glass transition temperature of about ?20 °C. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of water soluble poly(N‐acetyl)iminoethylene and poly(ethyleneimine) by ion‐exchanged clay montmorillonite

The cationic polymerization of 2‐méthyl‐2‐oxazoline was carried out at 0°C in acetonitrile using an acid‐exchanged montmorillonite as acid solid ecocatalyst (Maghnite‐H⁺). The effect of the amount of catalyst, solvent, and times of polymerization on yield and viscosity of polymer was studied. A typical reaction product (PMOX) was analyzed by infrared and nuclear magnetic resonance spectroscopy as well as by gel‐permeation chromatography and MALDI‐TOF MS. The polymers presented similar spectrometric results and narrow molecular weight distribution. The poly(N‐acetyl)iminoethylene was hydrolyzed in acid medium obtaining a linear poly(ethyleneimine). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3741–3750, 2006     

Synthesis and properties of a functional copolymer from N-ethylaniline and aniline by an emulsion polymerization

A series of functional copolymers was synthesized by an emulsion polymerization of N-ethylaniline (EA) and aniline (AN) in the presence of sodium dodecylbenzene sulfonate in HCl. Several important polymer parameters including the polymerization yield, molecular weight, solubility, film formability, solvatochromism, thermochromism, and alterable electrical conductivity were systematically studied by changing the comonomer ratio, emulsifier/monomer ratio, oxidant/monomer ratio, solvent, and temperature. The resulted copolymers were characterized in detail by infrared and UV-vis spectroscopies. It is found that these copolymers exhibit narrow molecular weight distribution, good solubility, excellent film flexibility, colorful solvatochromism in various solvents, reversible thermochromism in a wide temperature range, and widely controllable conductivity from 2.03×10⁻¹⁰ to 0.161 S/cm with changing the polymerization conditions and doping states.     

Preparation of polynorbornene with β-diketonate titanium / MAO catalysts

Summary Polynorbornene was synthesized by β -diketonate titanium / MAO (methylaluminoxane) catalysts. The polymerization activity was up to 8 × 10³ g polymer/(mol Ti h). FT-IR, ¹H NMR, ¹³C NMR and WAXD analyses showed that the polynorbornenes contained both ring-opening metathesis (trans and cis) and addition polymer chain structures and they are amorphous. The portions of trans- and cis- double bonds decreased when the polymerization temperature and Al/Ti molar ratio decreased. In addition, using 1,2-dichlorobenzene, instead of toluene, as the polymerization solvent increased the activity and produced the polymer containing more cis-double bonds. The glass transition temperature of the elastic polymers ranged from 330°C ∼ 400°C. Received: 10 September 2001/Revised version: 15 October 2001/Accepted: 10 December 2001