Polymerization of tert-alkylacetylenes by Mo- and W-based catalysts

Polymerization of three tert-alkylacetylenes (3,3-dimethyl-1-pentyne, 3,3-dimethyl-1-nonyne, 1-adamantylacetylene) by Mo- and W-based catalysts provided new polymers in virtually quantitative yields. In contrast, Ziegler catalysts did not polymerize these monomers. Every polymer had a form of white solid, and had alternating double bonds along the main chain. Though some of poly(3,3-dimethyl-1-pentyne)s contained a toluene-insoluble fraction, the polymer was totally soluble when proper polymerization conditions were chosen. The molecular weights of soluble fractions were as high as 3 × 10⁵. Poly(3,3-dimethyl-1-nonyne) was also partly insoluble in toluene, and the quantity of soluble fraction was less than that of poly(3,3-dimethyl-1-pentyne). The geometric structure of these two polymers could be controlled by the choice of suitable polymerization conditions. Poly(1-adamantylacetylene) was insoluble in any organic solvents. Copolymerization of 1-adamantylacetylene with suitable comonomers afforded soluble copolymers.     

Polymeric arylsulfonylmethyl isocyanide,a novel polymer reagent

p-Vinylphenylsulfonylmethyl isocyanide (1M) was synthesized starting with sodium p-styrenesulfinate via p-vinylphenylsulfonylmethylformamide (4M). Free-radical polymerization of 1M provided cross-linked insoluble polymers (1), whereas 4M provided soluble polymers, which could be converted to soluble polymer 1. Conversions of carbonyl compounds to nitriles and Schiff bases to 1,5-disubstituted imidazoles with both soluble and cross-linked polymers 1 as reagents proceeded almost as efficiently as with their low molecular weight analog. Reusability of polymer 1 was fairly good.     

Soluble and Colorless Polyimides from Alicyclic Diamines

Abstract

A series of novel polyimides was synthesized from alicyclic diamines and various aromatic dianhydrides by one-step polymerization in m-cresol without a catalyst. The polymerization was conducted for 4 hours with refluxing, which was enough to obtain the polymers with high molecular weight. The inherent viscosities of the resulting polyimides were in the range of 0.30 ～1.29 dL/g. The prepared polyimides showed excellent thermal stabilities and good solubility. All the polymers were readily soluble in common organic solvents such as chloroform, tetrachloroethane (TCE), dimethylacetamide (DMAc), etc and the glass transition temperatures were observed at 199 to 311°C. UV-visible spectra were obtained to measure the transparency of polymer films. All the polymers showed high transmission above 90% in the wavelength of 400 ～700 nm.     

Horseradish peroxidase-catalyzed polymerization of<Emphasis Type="Italic"> p</Emphasis>-hydroxycinnamic acid for synthesis of reactive microspheres

In this article, we report the experimental synthesis of reactive polymer microspheres of poly(p-hydroxycinnamic acid). Enzyme-catalyzed polymerization of poly(p-hydroxycinnamic acid) using horseradish peroxidase as a catalyst and hydrogen peroxide as an oxidant took place in a mixture solution of methanol and phosphate buffer solution; it was found that the fraction of methanol in the mixture solution strongly affected the yield of powdery polymer materials. The chemical structure of the polymers was characterized by ¹H-NMR and FT-IR spectroscopies, and the molecular weight was measured by gel permeation chromatography. The ¹H-NMR chart of the obtained polymer was almost the same as that of the monomer; FT-IR spectra indicated the existence of carboxyl groups. The weight-average molecular weight of the soluble part in tetrahydrofuran was found to be 1,451. Dispersion polymerization of p-hydroxycinnamic acid was carried out in a mixture solution of methanol and phosphate buffer solution by adding a dispersion stabilizer. Of the several such polymers tested, poly(vinyl alcohol) was found to be the most effective in producing reactive poly(p-hydroxycinnamic acid) microspheres.     

C3 cyclopolymerization. I. Is the cyclopolymerization of 1,3-bis(p-vinylphenyl)-propane by means of radical or anionic initiators possible?

Polymerization of 1,3-bis(p-vinylphenyl) propane (St-C₃-St) was investigated by using radical and anionic initiators. Radical polymerization yielded linear polymer with pendant styryl groups in pertinent conditions without gelation. Anionic polymerization with n-butyllithium and sodium naphthalene produced insoluble polymers that, according to infrared (IR) spectroscopy, had no cyclized units. On the other hand, phenylmagnesium bromide gave soluble polymer in HMPA-benzene mixed solvent. Zero-valent nickel catalyst also gave soluble polymer. The soluble polymers could be analyzed by several spectroscopies, and it was confirmed that those obtained by anionic and coordination polymerization had no [3.3]paracyclophane units in the main chain. From these results it was concluded that cationic propagation could be assumed if the polymer Of St-C₃-St contained [3.3]paracyclophane units in the main chain.     

Epoxide polymers: Synthesis,stereochemistry, structure,and mechanism

Epoxide polymerization studies have yielded technically important catalysts and polymers. The polymers were studied by cleaving them with Group IA organometallics to monomer, dimer, and trimer glycol fragments. The identification of these glycol fragments has established that the crystalline polymers from the cis- and trans-2,3-epoxybutanes are respectively racemic and meso-diisotactic and that the amorphous polymer from the cis-oxide is disyndiotactic. These studies also showed that the amorphous fraction from propylene oxide polymerization with coordination catalysts contains substantial head-to-head and tail-to-tail segments. This work has led to a much better understanding of the mechanism of epoxide polymerization. These facts were established: (1) epoxides polymerize with inversion of configuration of the ring-opening carbon atom; (2) monosubstituted epoxides polymerize largely by attack on the primary carbon with a coordination catalyst; and (3) two or more metal atoms must be involved in the coordination polymerization of epoxides.     

Polymerization of N,N-Dialkylacrylamides with Anionic Initiators Modified by Diethylzinc

Abstract

N,N-Dimethyl-, diethyl-, and dipropylacrylamides were polymerized with 1,1-bis(4′-trimethylsilylphenyl)-3-methylpentyllithium (I) in the presence and absence of diethylzinc in THF. Although the polymers produced with I in the absence of diethylzinc have rather broad molecular weight distributions, the addition of diethylzinc to the polymerization systems causes narrow molecular weight distributions of the polymers. The addition of diethylzinc also affect the stereospecificities of the polymers obtained. The poly(N,N-diethylacrylamide) produced with I/diethylzinc (molar ratio of 1/3-15) is highly syndiotactic, while the one obtained with I is isotactic. The configuration of the poly(N,N-dimethylacrylamide) is changed from isotactic to syndio and heterotactic rich by the addition of diethylzinc to the polymerization mixture. Little effect of diethylzinc is observed on the stereospecificity of the polymerization of N,N-dipropylacrylamide. The stoichiometric additive effect of Et₂Zn toward the initiator in the polymerization of DEAA suggests that the coordination of Et₂Zn aggregates with the propagating carbanionic species narrows the molecular weight distribution and controls the tacticity of the polymer.     

Synthesis and polymerization of o-hexylaniline: Characterization of the corresponding polyaniline

In the field of research on soluble conducting polymers, the poly(o-alkylanilines) are very interesting because we can expect them to give more soluble polymers and new properties. Like poly(o-propylaniline) (POP), which is more soluble than polyaniline (PANi), poly(o-hexylaniline) (POH) appears to be more soluble in organic solvents than POP because of the longer alkyl groups in the 2-position. The higher solubility confers better processability on this new polymer, and because of this solubility, an NMR study in solution became possible.The nitration of hexylbenzene and the reduction of the resulting product to o-hexylaniline were performed according to the literature. The chemical polymerization was easy and it is possible to produce this polymer in large quantities.The polymerization carried out in anhydrous NH₄F, 2.35 HF medium and in 5 M perchloric acid gave a polymer with almost quantitative yield. The electrochemical behaviour of POH displayed faster electron transfers than PANi in organic solvents, depending on the acido-basicity level of the aqueous solutions. Unlike PANi, fractal growth was not observed.     

Cationic polymerization of γ-methyl- and α-methylphenylallene

The cationic polymerizations of γ-methylphenylallene ( 1 ) and α-methylphenylallene ( 2 ) were carried out with some Lewis acids at 25 and 0°C in dichloromethane to obtain the corresponding polymers through allyl cations, respectively. Tin (IV) chloride was found to be an effective catalyst for the cationic polymerization of both allenes 1 and 2 compared with other Lewis acids. Thus, in the polymerization of 1 , methanol-insoluble polymer was only obtained using Tin (IV) chloride, and M?_n of methanol-insoluble polymer obtained by Tin (IV) chloride was the highest in the polymerization of 2 . From the analysis of ¹H- and ¹³C-NMR spectra of the obtained polymers, the polymer from 1 consisted of two kinds of units polymerized by each double bonds of allene 1 , whereas the polymer from 2 consisted of only one unit polymerized by terminal double bond of allene 2 . Moreover, effect of solvent on the cationic polymerizations of 1 and 2 were discussed.     

An experimental study on the kinetics and mechanisms of styrene polymerization in oil‐in‐water microemulsion initiated by oil‐soluble initiators

In order to clarify the kinetic role of oil‐soluble initiators in microemulsion polymerization, the oil‐in‐water (O/W) microemulsion polymerizations of styrene are carried out using four kinds of azo‐type oil‐soluble initiators with widely different water‐solubility. The results are compared with those observed when a water‐soluble initiator, potassium persulfate (KPS) is used. For all the oil‐soluble initiators used, the molecular weight of polymers and the average size of polymer particles do not change with the monomer conversion and the initial initiator concentration. The monomer conversion is expressed as a function of r_i^0.5t, where r_i is the rate of radical generation in the whole reaction system and t is the reaction time. These characteristics are quite the same as those observed when KPS is used as an initiator. When the polymerizations are carried out with the rate of radical generation in the whole reaction system fixed at the same value, the rates of polymerization are almost the same for all the oil‐soluble initiators employed, irrespective of their water‐solubility, but are significantly lower (ca. 1/3) than that with KPS. Then, the following conclusions are given: (1) The radicals generated not only in the aqueous phase, but also in the micelle and polymer particle phase are almost equally effective for the polymerization. However, (2) only a small portion (ca. 1/9) of the radicals generated in both phases participate in the polymerization. (3) Bimolecular termination of a growing radical in the polymer particle with an entering radical and with a pair of radicals generated in the polymer particles is negligible, and hence, the molecular weight of polymers is determined only by chain transfer to monomer.     

茂金属催化聚合的聚1-丁烯的结构表征

以 η5 五甲基茂基三苄氧基钛 (Cp Ti(OBz) 3 和改性甲基铝氧烷 (mMAO)为催化剂 ,合成立体嵌段聚 1 丁烯 ,分子量高 ,分子量分布窄 ( Mw/ Mn=1 1～ 1 2 ) .聚合产物经沸乙醚、沸庚烷连续抽提分离 ,聚合物在两种溶剂中都能部分溶解 .各级份经13C NMR ,WAXD ,DSC和GPC等手段分析 ,结果表明乙醚可溶级份是无规聚 1 丁烯 ,庚烷可溶级份是立体嵌段聚 1 丁烯 ,庚烷不溶级份是等规聚 1 丁烯 .聚合温度较低 (0℃和30℃ )时 ,聚合物有结晶性 ,结晶度达 30 %以上 ,DSC分析有两个吸热峰 ;聚合温度较高 (4 0℃ )时 ,聚合物无结晶尖锐X射线衍射峰 ,也无熔融吸热峰 .     

Morphospecific polymer from the copolymerization of trioxane and ethylene oxide

Recently, we have observed the following phenomena during the copolymerization of trioxane and ethylene oxide using a boron trifluoride initiator. In almost all of the polymerization cases, all polymers were soluble in a p-chlorophenol-tetrachloroethane mixed solvent at 90°C. However, in some polymerization cases, a small portion of the polymer was insoluble at this temperature, and this mixed solvent-insoluble fraction showed a higher melting point than that of the other fractions. Scanning electron microscope (SEM) photographs of the polymer showed that a highly fibrous structure was formed for the mixed solvent-insoluble fraction, and this highly packed structure is thought to be the origin of the high melting fraction. The nature of this high melting fraction was further examined using X-ray diffraction and Raman spectra. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2479–2486, 1997     

Synthesis and polymerization of (E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene with Ziegler–Natta,rhodium, and palladium complexes

The synthesis and polymerization of (E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene was carried out with a homogeneous vanadium acetylacetonate/aluminum triethyl catalyst system, a bis(rhodium chloride cycloocta‐1,5‐diene) complex, and a palladium/trimethylsilyl complex. In all cases, the main fraction was a polymer with a stereoregular structure. The polymerization with the vanadium catalyst gave a polymer fraction in a low yield. The polymerization of (E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene with the soluble rhodium complex gave a polymer in a high yield. The soluble palladium/chlorotrimethylsilane complex gave a polymer in a good yield. On the basis of the spectroscopic data, the poly{(E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene)} obtained, in all cases, showed a cis–transoidal stereoregular structure. The molecular mass of poly{(E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene)} was determined by the matrix‐assisted laser desorption/ionization time‐of‐flight technique. The kinetics of the reaction were analyzed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6438–6444, 2005     

Polymerization of allyl(vinyl phenyl) ethers and reactions of the resulting polymers

Solution polymerizations of allyl(o-vinyl phenyl)ether and allyl(p-vinyl phenyl)ether with cationic and radical initiators were investigated. Soluble polymers were formed in polymerizations with boron trifluoride etherate and with benzoyl peroxide. In polymerization with azobisisobutyronitrile the polymerization in dilute solution gave a soluble polymer, whereas that in concentrated solution gave a crosslinked, insoluble one. For informationon the polymerization behavior some infrared and ultraviolet spectroscopic investigations of the soluble polymers were made. From these results it appears that polymers with pendant allyl groups are formed in polymerization with boron trifluoride etherate at low temperature, and polymers containing pendant vinyl groups and allyl groups are obtained with the two types of radical initiator. Copolymerizations of these monomers with ethyl vinyl ether and styrene with the use of boron trifluoride etherate were sucessfully effected. Such reactions as Claisen rearrangement, crosslinking induced with radical initiators, and epoxidation with perbenzoic acid were examined for the polymers prepared in the polymerization with boron trifluoride etherate. Good results were obtained for the former two reactions. However, the latter was unsuccessful.     

Polymerization of n-octadecene-1 with catalysts derived from titanium tetrachloride and triethylaluminum

The effects of variation in Al/Ti mole ratio, catalyst concentration, reaction time, and temperature on the yield and some physical properties of polymers of n-octadecene-1 obtained with the use of Ziegler catalyst systems derived from titanium tetrachloride and triethylaluminum have been investigated. Results show many features similar to those obtained by other workers with lower olefins. In general, the yield of polymer shows a distinct maximum at an Al:Ti mole ratio of 2.8:1 and total catalyst concentration (at the stated mole ratio) of 4%, based on monomer; the yield increases sharply with polymerization temperature to a maximum at about 40°C. and with time up to about 12 hr. at 25°C. Polymer intrinsic viscosity also shows a strong dependence on Al:Ti mole ratio and catalyst concentration, increasing between Al:Ti mole ratios of 2.0–3.4, and showing a maximum at catalyst concentration of 3.5% on monomer. Polymer intrinsic viscosity shows a decrease with increasing reaction temperature and an increase with time of polymerization. The polymer densities, melting points, and fraction soluble in hexane (at 25°C.) appear to show much less dependence on the variables under consideration, and no firm conclusions are drawn. An important reaction concurrent with polymerization is the formation of a trans nonterminal isomer of octadecene. This certainly affects the yield (the nonterminal isomer not being polymerizable under the same conditions); the effect of the presence during polymerization of isomerized monomer on the physical characteristics of the polymer is less clear, and further work is proceeding.     

Controlled Cationic Polymerization of 1‐Methoxy‐1,3‐Butadiene: Long‐Lived Species‐Mediated Reaction and Control over Microstructure with Weak Lewis Bases

Controlled cationic polymerization of trans‐1‐methoxy‐1,3‐butadiene was achieved through the design of appropriate initiating systems, yielding soluble polymers with controllable molecular weights. The combined use of SnCl₄ or GaCl₃ as a Lewis acid catalyst and a weak Lewis base in conjunction with HCl as a protonogen resulted in efficient and controlled polymerization. The M_n values of the product polymers increased linearly along the theoretical line, which indicates that intermolecular crosslinking reactions negligibly occurred. In addition, the polymer microstructure was critically dependent on the weak Lewis base employed. In particular, the use of tetrahydrofuran as an additive resulted in the highest 4,1/4,3‐structure ratio (96/4). Weak Lewis bases also affected the polymerization rates but exhibited unique trends that differed from their effects on the cationic polymerization of alkyl vinyl ethers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 288–296     

Synthesis of heteroarm star polymers comprising poly(4-methylphenyl vinyl sulfoxide) segment by living anionic polymerization

<正>A series of 3-arm ABC and AA'B and 4-arm ABCD,AA'BC and AA′A″B heteroarm star polymers comprising one poly(4-methylphenyl vinyl sulfoxide) segment and other segments such as polystyrene,poly(α-methylstyrene), poly(4-methoxystyrene) and poly(4-trimethylsilylstyrene) were synthesized by living anionic polymerization based on diphenylethylene(DPE) chemistry.The DPE-functionalized polymers were synthesized by iterative methodology,and the objective star polymers were prepared by two distinct methodologies based on anionic polymerization using DPE-functionalized polymers.The first methodology involves an addition reaction of living anionic polymer with excess DPE-functionalized polymer and a subsequent living anionic polymerization of 4-methylphenyl vinyl sulfoxide(MePVSO) initiated from the in situ formed polymer anion with two or three polymer segments.The second methodology comprises an addition reaction of DPE-functionalized polymer with excess sec-BuLi and a following anionic polymerization of MePVSO initiated from the in situ formed polymer anion and 3-methyl-1,1-diphenylpentyl anion as well.Both approaches could afford the target heteroarm star polymers with predetermined molecular weight,narrow molecular weight distribution (M_w/M_n1.03) and desired composition,evidenced by SEC,~1H-NMR and SLS analyses.These polymers can be used as model polymers to investigate structure-property relationships in heteroarm star polymers.     

Stereospecific polymerization of 9-fluorenyl methacrylate: Tacticity effects on the thermal and photophysical properties of the polymers

Poly(9-fluoreneyl methacrylate) was obtained through anionic polymerization with t-BuLi and t-BuMgBr and through radical polymerization with α,α′-azobisisobutyronitrile. Anionic polymerization with t-BuLi in tetrahydrofuran and radical polymerization afforded syndiotactic polymers (rr ∼ 90%), whereas anionic polymerization with Li and Mg initiators in toluene and CH₂Cl₂ led to isotactic polymers. The thermal and photophysical properties of the polymers were examined. A syndiotactic polymer tended to show higher glass transition and decomposition temperatures than an isotactic polymer. However, polymers with different tacticities were not likely to assume specific, distinctive conformations such as a helix or a π-stacked conformation in solution. An isotactic polymer showed stronger interactions in a CH₂Cl₂ solution with 2,4,7-trinitro-9-fluorenylidenemalononitrile, an electron-acceptor molecule, than a syndiotactic polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4656–4665, 2004     

Polymerization of oriented monomers. V. Radiation-induced polymerization of 3n-dodecyl-1-vinylimidazolium iodide in micellar aggregates

In the present study radiation-induced polymerization of 3n-dodecyl-1-vinylimidazolium iodide (I) in micellar aggregates was investigated. For comparison, the corresponding isotropic polymerization of I was also studied. Micellization was obtained in concentrated aqueous solutions; that is, above the monomer's critical micelle concentration (CMC) polymers obtained by both modes of polymerization were treated similarly and subsequently subjected to physical characterization. The main purpose of this study was to investigate whether the degree of organization of the monomer in micelles would affect polymer properties. Attempts to determine tacticity by ¹³C-NMR spectrometry failed because of the particular structure of the polymer. Crystallization of these polymers from ethyl alcohol or acetone was not possible as indicated by x-ray powder diffraction patterns that were characteristic of amorphous polymers. On the other hand, viscosity data of polymers do not depend on the mode of polymerization. It is therefore concluded that micellar aggregates are not sufficiently organized to affect polymer properties.