Synthesis of novel tetrahydrofuran‐epichlorohydrin [poly(THF‐b‐ECH)] macromonomeric peroxy initiators by cationic copolymerization and the quantum chemically investigation of initiation system effects

Cationic polymerization of tetrahydrofuran (THF) and epichlorohydrin (ECH) was performed with peroxy initiators synthesized from bis (4,4′‐bromomethyl benzoyl peroxide (BBP) or bromomethyl benzoyl t‐butyl peroxy ester (t‐BuBP) and AgSbF₆ or ZnCl₂ system at 0 °C to obtain the poly(THF‐b‐ECH) macromonomeric peroxy initiators. Kinetic studies were accomplished for poly(THF‐b‐ECH) initiators. Poly(THF‐b‐ECH‐b‐MMA) and poly(THF‐b‐ECH‐b‐S) block copolymers were synthesized by bulk polymerization of methyl methacrylate (MMA) and styrene (S) with poly(THF‐b‐ECH) initiators. The quantum chemical calculations for the block copolymers, the initiating systems of the cationic polymerization of THF and ECH were achieved using HYPERCHEM 7.5 program. The optimized geometries of the polymers were investigated with the quantum chemical calculations. Poly(THF‐b‐ECH) initiators having peroxygen groups were used for graft copolymerization of polybutadien (PBd) to obtain poly(THF‐b‐ECH‐g‐PBd) crosslinked graft copolymers. The graft copolymers were investigated by sol‐gel analysis. Swelling ratio values of the graft copolymers in CHCl₃ were calculated. The characterizations of the polymers were achieved by FTIR, ¹H NMR, GPC, SEM, TEM, and DSC techniques. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2896–2909, 2010     

Polymerization of β‐cyclodextrin in the presence of bentonite clay to produce polymer nanocomposites for removal of heavy metals from drinking water

New hybrid organic–inorganic nanocomposites consist of β‐cyclodextrin (β‐CD)/epichlorohydrin (ECH), and bentonite clay were prepared by direct intercalation through one step emulsion polymerization. The structure and thermal stability of prepared nanocomposites were investigated by Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), field emission‐scanning electron microscopy (FE‐SEM), energy dispersive X‐ray analysis (EDAX), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), differential of differential scanning calorimetry (DDSC), thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analyses. The observed results show that the β‐CD polymer/clay nanocomposites (β‐CD–ECH polymer/clay) with higher thermal stability than β‐CD–ECH polymer were successfully prepared. The removal of heavy metals such as Cu(II), Zn(II) and Co(II) ions from drinking water was studied using a batch method at ambient temperature. The removal percentage and distribution coefficients (Kd) were determined for the adsorption system. It was found that the β‐CD–ECH polymer/clay nanocomposites showed higher removal capacity for Co²⁺, Cu²⁺ and Zn²⁺ ions in comparison with β‐CD–ECH polymer. The selectivity order could be given as Zn²⁺ > Cu²⁺ > Co²⁺. Copyright © 2016 John Wiley & Sons, Ltd.     

Photo and thermal polymerization sensitized by donor–acceptor interaction. I. N-vinyl-carbazole–acrylonitrile and related systems

Spontaneous photo and thermal polymerization of N-vinylcarbazole (VCZ)–acrylonitrile (AN), VCZ–acetonitrile, AN-N-ethylcarbazole, and AN-ferrocene were studied. These combinations of electron donor with acceptor were thermally rather stable but showed prominent photopolymerizability when the systems were irradiated by near ultraviolet light. The VCZ–AN system showed multireactivity producing VCZ polymer and a copolymer of VCZ with AN. The composition of copolymer was approximately the same as that of polymer produced in radical copolymerization. The effects of additives (DPPH, NH₃, H₂O, air) indicated simultaneous occurrence of cationic and radical polymerization in the AN–VCZ and acetonitrile–VCZ systems. The results were interpreted on the assumption of initial formation of a cation radical–anion radical pair. The ratio of cationic to radical polymerization differed for photo and thermal polymerization. In no case was anionic polymerization detected.     

杂多酸引发四氢呋喃开环聚合反应Ⅵ.以环氧氯丙烷为促进剂

在以低浓度杂多酸(ＨＰＡ)催化四氢呋喃(ＴＨＦ)聚合反应中,我们曾采用环氧乙烷(ＥＯ)和环氧丙烷(ＰＯ)为促进剂,发现它们都具有很好的促进效果[1,2],并且活性相近.在以三氟化硼(ＢＦ3)为催化剂的四氢呋喃正离子开环聚合反应中,促进剂的活性次序为:ＥＣＨ(环氧氯丙烷)>ＰＯＥＯ[3].在ＨＰＡ催化ＴＨＦ聚合反应中,ＥＣＨ是否仍具有高的促进活性是本文研究的目的.1　原料及聚合操作ＴＨＦ的纯化见文献[4],ＥＣＨ的纯化见文献[5],十二磷钨杂多酸(ＰＷ12)的处理见文献[1],三氟醋酸酐的合成方法和聚合反应的操作均见前文[2].2　分析测试核磁共振…     

环氧化物稀土络合催化开环聚合动力学研究

用膨胀计方法研究环氧丙烷、环氧氯丙烷在稀土络合催化剂 Nd(P_(204))_3-Al(i-Bu)_3-H_2O作用下的聚合反应动力学,表明聚合反应速度对催化剂浓度及单体浓度均呈一级关系。环氧丙烷、环氧氯丙烷开环聚合反应活化能分别为61.3kJ/mol和48.9kJ/mol。在同样的聚合反应条件下,环氧氯丙烷聚合反应速度大于环氧丙烷聚合反应速度。 研究还发现,催化剂组成摩尔比Al/Nd及H_2O/Al对聚合反应速度均有一定影响;各种稀土元素络合催化剂催化活性顺序为:Nd>La>Dy>Yb>Eu;稀土络合物中配体对活性的影响为:acac>P_(204)>P_(507)>naph;烷基铝的影响为:Al(i-Bu)_3>AlEt_3。     

三异丁基铝-亚乙基脲-三苯基膦三元体系对环氧氯丙烷的催化聚合

<正> 利用环氧氯丙烷(ECH)的开环聚合,制备特种耐油合成橡胶,是近十余年发展起来的。本文发现由三异丁基铝(Al)、亚乙基脲(Eu)和三苯基膦(TPP)组成的三元催化剂是ECH聚合用的优良催化剂,其催化活性高,可获得分子量达70—130万的无定形聚合物,聚合速率受温度的影响较小,适宜在室温下聚合。     

Photopolymerization initiated by charge–transfer complex. X. Photopolymerization of methyl methacrylate with the use of isoquinoline–sulphur dioxide charge–transfer complex

Aqueous polymerization of methyl methacrylate in visible light was studied using isoquinoline–sulphur dioxide (IQ–SO₂) charge–transfer complex as the photoinitiator. Analysis of kinetic and other data indicate that the polymerization proceed via a radical mechanism and the termination is dependent on the initiator concentration. Chain–termination via degradative chain (initiator) transfer appears to be predominant here.     

Synthesis of Novel Polyether Polyol by Using Double Metal Cyanide

Hydroxyl-terminated novel polyether polyols were synthesized by polymerization of epichlorohydrin (ECH) catalyzed by double metal cyanide (DMC) catalyst. The effects of reaction temperature and catalyst concentration on the polymerization of Polyether Polyol were studied. The molecular structure and the damping properties were measured by IR spectra, ¹H-NMR spectra and the dynamic mechanical analysis.     

Synthetic routes to block copolymerization by changing mechanism from cationic polymerization to free radical polymerisation

Polymers containing thermolabile groups were synthesized by various cationic polymerization initiation mechanisms, namely; oxo–carbenium, promoted cationic and activated monomer polymerization. These polymers used in a subsequent blocking step in which azo groups were decomposed and converted into initiating centres from which blocks were grown by means of free radical polymerization. This procedure was applied to specific systems in which cationic polymerizable monomers are tetrahydrofuran (THF), cyclohexene oxide (CHO) and epichlorohydrin (ECH), respectively, and the free radical polymerizable monomer is styrene (St).     

Polymerization of acrolein and methyl vinyl ketone induced by amine–water and pyridine–phenol systems

It was reported that acrolein (AL) in tetrahydrofuran (THF) polymerizes at temperatures below 0°C in the presence of pyridine (Py) and water. To clarify this polymerization mechanism the polymerization of AL and methyl vinyl ketone (MVK) by an initiation system such as Py–water, triethylamine (Et₃N)–water, or Py–phenol(Ph) was carried out. The polymerization rate (R_p) of MVK in the Et₃N–water system was expressed by the same equation, R_p = k [Et₃N] [H₂O] [MVK]², used for AL in the Py–water system. Meanwhile, β-hydroxypropionaldehyde, β-phenoxypropionaldehyde, γ-ketobutanol, and β-phenoxy-1-methylpropionketone were obtained as the initial addition products. The polymer of AL obtained was composed of polymer units of vinyl and aldehyde polymerization, but the structure of MVK polymer obtained by the Py–water system was composed of only vinyl polymerization units. The polymerization of MVK by the Py–Ph system did not occur, however. These results were discussed in terms of the initiation and propagation mechanisms.     

Polymerization of acrylonitrile by V5+–lactic acid system in aqueous sulfuric acid

Kinetics of polymerization of acrylonitrile by the redox system V⁵⁺–lactic acid in sulfuric acid at 20–35°C was studied. Oxidation of lactic acid by V⁵⁺ in the absence of monomer was also carried out under identical conditions. The rates of polymerization, V⁵⁺ disappearance and the chainlengths of polyacrylonitrile were measured. From the results it is concluded that the polymerization reaction is initiated by an organic free radical arising from the V⁵⁺–lactic acid reaction with termination by V⁵⁺ ions. Mutual termination of active polymer radicals does not appear to operate under the conditions studied. The various rate parameters were evaluated.     

Polymerization of vinyl monomers by alkali metal–thiobenzophenone complexes

The polymerization of vinyl monomers by use of alkali metal (Li, Na, K)–thiobenzophenone complexes was studied. Monoalkali metal complexes of thiobenzophenone (thioketyls) induced the polymerization of vinyl monomers such as acrylonitrile (AN) and methyl methacrylate (MMA), and dialkali metal complexes of thiobenzophenone (dianion) induced the polymerization of styrene (St), butadiene (Bd), and isoprene (Ip) as well as AN and MMA. The polymerization of MMA with the dianion was initiated by both the mercaptide and the carbanion of the dianion, but that of styrene was initiated by the carbanion alone. In the case of polymerization of MMA by the thioketyl, the initial rate of polymerization depended on the catalyst concentration and the square of the monomer concentration. Similar results were obtained in the case of the dianion. The polymer yield increased with increasng polarity of sovents. In the copolymerization of AN with MMA, the copolymer obtained consisted almost of AN units. From these results, it was concluded that the polymerization proceeded by anionic mechanisms.     

Mechanism of the three-dimensional polymerization of glycol methacrylates. II. The system glycol monomethacrylate–glycol dimethacrylates–solvents

The three-dimensional polymerization of the system glycol monomethacrylate–glycol dimethacrylates–solvents has been studied. The kinetic dependences thus obtained were interpreted in terms of the dependence of rate constants of the individual reactions on the properties of the medium used. The three-dimensional polymer formed was characterized in the range from medium to the highest conversions.     

Spontaneous polymerization of the nitroethylene–isobutyl vinyl ether system

Initiation and propagation mechanisms of the spontaneous polymerization of the system nitroethylene–isobutyl vinyl ether were studied. An equimolar mixture of these two monomers gives white precipitates below room temperature, though they react explosively to give viscous products at higher temperature. The precipitate was found to be composed of a polynitroethylene and a cycloadduct of these two monomers. The isolated cycloadduct product is so reactive that it not only polymerizes itself spontaneously but also initiates the polymerization of nitroethylene. The polymerization of the cycloadduct was revealed to proceed without termination to produce an alternate copolymer of these two monomers. These results indicate that the explosive spontaneous polymerization of this system consists of three elementary reaction processes; (1) cycloaddition reaction between two monomers, (2) anionic polymerization of nitroethylene induced by the cycloadduct, and (3) the living ring-opening polymerization of the cyclo-adduct.     

Controlled/living polymerization of MMA promoted by heterogeneous initiation system (EPN‐X–CuX–bpy)

The polymerization of methyl methacrylate (MMA) promoted by heterogeneous initiation system (ethyl‐2‐halopropionate (EPN‐X)–CuX–2,2′‐bipyridyl (bpy), where X = Br or Cl) is studied in detail. The results show that ethyl‐2‐bromopropionate (EPN‐Br) is an efficient initiator as expected, and that CuCl–bpy, instead of CuBr–bpy, is a better catalyst for the controlled polymerization of MMA. The solvents with a high value of dielectric constant (ε) will lead to fast initiation and narrow molecular weight distribution (MWD). As a result, the controlled, living polymerization of MMA with EPN‐Br–CuCl–bpy can be got in ethyl acetate (EAc) at 100°C and in acetonitrile at 80°C. All results suggest that the initiation reaction is a controlling step in the controlled polymerization of MMA. The relationship between the UV spectra of CuCl–bpy and the performances of the polymerization in EAc or acetonitrile suggest that the formation of bis‐bpy complex, [Cubpy₂]X⁻, will lead to fast initiation and good control of the polymerization. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1255–1263, 1999     

Kinetics of polymerization initiated by Mn3+–substrate redox system. I

The kinetics and mechanism of polymerization of acrylamide (AM) initiated by manganese (III) acetate (MTA)–diglycolic acid (DGA) redox system in aqueous sulfuric acid were studied in the temperature range 20-35°C. The overall rates of polymerization and the disappearance of Mn³⁺ and the kinetic chain lengths of polyacrylamide were determined. The polymerization reaction is initiated by the organic free radical arising from the Mn³⁺–diglycolic acid reaction and the termination is by the metal ions. The rate of polymerization of acrylamide was found to be proportional to the first power of monomer and diglycolic acid and independent of manganese(III) acetate. The various rate parameters were evaluated.     

Methyl methacrylate polymerization initiated by triethylborane–peroxide mixtures

The polymerization of methyl methacrylate initiated by triethylborane or triethylborane–peroxide mixtures was studied. The rate of initiation by a mixture of triethylborane and tert-butyl peroxide was found to be first-order in peroxide. The order in triethylborane changes from one at low triethylborane/peroxide to nearly zero at high triethylborane/peroxide. The possibility of a mechanism involving a fast reaction followed by a slow reaction that would initiate the polymerization is discussed.     

Preparation of liquid–crystal thermosets: In situ photopolymerization of oriented liquid–crystal diacrylates

The photoinitiated polymerization of 2-chloro-1,4-phenylene bis[4-[6-(acryloyloxy)hexyloxy]benzoate] (1M) was studied. The monomer 1M exhibited a broad nematic phase between 24.9 and 113.7 °C on a DSC cooling scan. It was oriented in its nematic phase at a substrate coated with polyimide and unidirectionally rubbed with a nylon cloth. During polymerization, the ordering of the liquid–crystal molecules was fixed, yielding a uniaxially crosslinked network. The clear liquid–crystal networks (LCNs) exhibited a birefringence between 0.14 and 0.19, depending on the polymerization temperature. Finally, a nonmesogenic diluent, tetra(ethylene glycol)diacrylate, was mixed with 1M, subsequently decreasing the birefringence of the obtained LCNs. The LCNs containing nonmesogenic diluent exhibited not only a smaller birefringence but also a weaker birefringence dispersion in the visible region. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3929–3935, 1999     

Polymerization of acrylonitrile initiated by thiourea–chromium(VI) redox system

The kinetics of polymerization of acrylonitrile initiated by Cr(VI)–thiourea and Cr(VI)–ethylene thiourea have been studied at 35, 40, and 45°C in nitrogen. The rates of polymerization and of disappearance of Cr(VI) were measured. Chromic acid alone did not initiate the polymerization under deaerated and undeaerated conditions. On the basis of the experimental observation of the dependence of the rate of polymerization R_p, the rate of Cr(VI) disappearance, –R_m, etc., on various variables, a suitable kinetic scheme was proposed and various rate and energy parameters were evaluated.     

Polymerization of methyl methacrylate by the binary system of the copper–amine complex type resin and carbon tetrachloride

The polymerization of vinyl monomers initiated by binary initiator systems composed of a copper–amine complex type resin and organic halides has been studied. These binary systems initiated the polymerization of various vinyl monomers. A kinetic study of the polymerization of methyl methacrylate initiated by the copper–amine complex resin–CCl₄ system was carried out, and it was found that the polymerization proceeds by way of a radical mechanism. This fact was also supported by the copolymerization of methyl methacrylate with styrene. The overall activation energy of the polymerization of methyl methacrylate was estimated as 8.4 kcal/mole. The activity of the initiator systems was greatly dependent upon the dissociation energy of carbon–halogen bonds in the organic halides. A possible initiation mechanism with the binary systems is proposed and discussed.