Copolymers of 1,4-Dienes with Monoolefins via a Cyclocopolymerization Mechanism

The copolymerizations of divinyl ether, divinyl sulfone, and 1,4-pentadiene with certain monoolefinic monomers were studied. High molecular weight (inherent viscosity ≥ 1.0) copolymers of divinyl ether with maleic anhydride could be prepared using dichlorobenzoyl peroxide as the initiator. Derivatives of this copolymer were also prepared and studied. Divinyl sulfone and 1,4-pentadiene also gave soluble polymers with maleic anhydride but the inherent viscosities were much lower. Copolymerizations of these three dienes with dimethyl maleate, acrylonitrile, or vinyl acetate gave either low molecular weight materials at low conversions or cross-linked polymer at higher conversion. All of the soluble copolymers obtained showed little aliphatic unsaturation in the infrared, supporting the cyclocopolymerization theory.     

Studies in cyclocopolymerization. V. Further evidence for charge-transfer complexes in cyclocopolymerization

Previous work from this laboratory has shown that certain 1,4-dienes which readily undergo cyclocopolymerization with certain alkenes also form charge-transfer complexes with the same alkenes. The results observed and the proposed cyclocopolymerization mechanism are consistent with participation of the charge-transfer complex as a distinct species in the copolymerization. It was the purpose of this investigation to determine whether there was a dilution effect on the relative reactivities of the monomers in support of the charge-transfer participation concept, and whether the results of a suitable terpolymerization study would also support this postulate. In the divinyl ether–fumaronitrile system, the maximum rate of copolymerization occurred at a monomer feed ratio of 1:2 and the composition of the copolymer was also 1:2 at a total monomer concentration of 3 mole/l. However, when the concentration was progressively lowered to 0.5 mole/l. at the same monomer feed ratio, the fumaronitrile content of the copolymer decreased in a linear manner. In a series of terpolymerization experiments with the divinyl ether–maleic anhydride–acrylonitrile system, it was shown that the divinyl ether–maleic anhydride ratio in the terpolymer was always less than 1:1 and had an upper limit of 1:2, regardless of the feed ratio of the termonomers. These results are consistent with the participation of the charge-transfer complex of divinyl ether and maleic anhydride in a copolymerization process with either maleic anhydride or acrylonitrile as the comonomer.     

Copolymerization of divinyl monomers with maleic and fumaric acid derivatives

The process of formation of reticular copolymer molecular structures produced in free radical copolymerization of divinyl monomers (divinyl ethers of diethylene glycol and hydroquinone, divinyl sulfide, p-divinylbenzene, etc.) with maleic and fumaric acid derivatives is studied. The basic factor that determines the features of molecular and network structures of copolymers is reactivity of the divinyl monomer in copolymerization with monovinyl monomer. The network of copolymers of maleic anhydride with the divinyl ether of hydroquinone is formed out of oligomer microgels. Divinyl sulfide in copolymerization with maleic acid is disposed to cyclocopolymerization; also crosslinking reactions occur. Formation of a network structure of copolymers of divinylbenzene with maleic and fumaric acid derivatives is shown to proceed via an alternating copolymerization mechanism. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36 : 371–378, 1998     

Silver recovery with complexing sorbents based on 1-vinyl-1,2,4-triazole

The sorption activity of copolymers based on 1-vinyl-1,2,4-triazole toward silver ions was studied in relation to the copolymer structure and to the kind and concentration of acids. The copolymers were prepared by radical copolymerization of 1-vinyl-1,2,4-triazole with 1,1,3-trihydrotetrafluoropropyl methacrylate and divinylbenzene, with 1,1,3-trihydrotetrafluoropropyl methacrylate, methyl methacrylate, and N,N′-methylenebisacrylamide, with diethylene glycol divinyl ether, and with divinyl sulfide. The copolymers exhibit high sorption activity. They efficiently recover silver cations from acid solutions and behave as anion exchangers.     

A study of the ring size in the copolymer of divinyl ether and maleic anhydride by H-NMR spectroscopy

The well-known alternating 1:2 cyclocopolymer of divinyl ether (DVE) and maleic anhydride (MA) possesses a wide spectrum of biological activities, including antitumor. Recent research on the structure of a variety of cyclopolymers has raised a question about the ring size of this cyclocopolymer. In this article we report on an extensive spectroscopic study of its structure. By use of deuterated monomers the H-NMR peaks at δ 2.31, 3.47, 4.06, and 4.49 ppm with an area ratio of 2:1:1:1 were assigned to the hydrogens of methylenes, methines on the backbone anhydride unit, methines on the ring anhydride unit, and methines adjacent to oxygen on the cyclic ether ring, respectively. By examination of the possible isomeric structures of the bicyclic ring, the splitting of each peak group was further assigned for cis and trans disubstitutions on the anhydride unit. The splitting pattern from the 300-MHz NMR spectrum of the DVE-2,3-dideuteriomaleic anhydride (DMA) copolymer confirmed the unsymmetrical ring structure. ¹³C-NMR spectra were consistent with the conclusion from the H-NMR spectra. A chair-form, six-membered ring with predominantly trans geometry in the anhydride ring was assigned to the structure of DVE–MA copolymer. On the basis of little or no change in the ¹³C-NMR spectra of the copolymers prepared at different temperatures it was concluded that there was no significant change in structure with temperature. This led to the assignment of the energetically favored, six-membered ring structure to the copolymer prepared under these conditions. A mechanism for cyclocopolymerization, based on the HOMO–LUMO interaction of the comonomers and the intramolecular radical addition on the preoriented double bond, was proposed. This mechanism leads to the formation of the six-membered ring structure of the copolymer as the only product. A ¹³C-NMR study of the structure of the copolymer prepared in chloroform by Kunitake and Tsukino is being published as a companion article.     

New network copolymers of 1-vinyl-1,2,4-triazole as efficient sorbents of mercury

The possibility of preparing copolymers by radical copolymerization of 1-vinyl-1,2,4-triazole with divinyl sulfide and divinyl diethylene glycol ether in the bulk was examined. The sorption characteristics of the new cross-linked copolymers with respect to mercury(II) ions under static conditions in acid solutions were studied.     

Type of bond in products of the interaction between primary amines and the copolymer of divinyl ether and malefic anhydride

The nature of the bond in the products of the interaction between primary amines and the copolymer of divinyl ether and malefic anhydride has been studied by IR and electron spectroscopy. The reaction in acetone proceeds with the formation of H-bonded ionic charge transfer complexes where p--conjugation is possible. It is proposed that the biological activity of macromolecular therapeutic systems based on copolymers of maleic anhydride and drugs containing a primary amino group is due to their ability to reversibly dissociate and the presence of local fragments of p--conjugation stabilizing the negative charge.     

Studies in Cyclocopolymerization. X. Cyclocopolymerization of Tetrahydronaphthoquinone and Dimethyl Tetrahydronaphthoquinone with Divinyl Ether

Abstract

Tetrahydronaphthoquinone (THNQ) and dimethyl tetrahydronaphthoquinone (DMTHNQ) were found by UV spectroscopy to form donor-acceptor complexes with divinyl ether (DVE), the latter being the electron donor. Since the participation of such complexed species has been considered in the cyclocopolymerization of a 1,4-diene with a monoolefin such as DVE-maleic anhydride (MA) and DVE-fumaronitrile (FN) systems, radical copolymerization of THNQ and DMTHNQ with DVE was studied. It was found that these copolymers have constant 1:1 composition regardless of the feed composition. The terpolymerization of DVE-THNQ-DMTHNQ confirmed the 1:1 donor-acceptor composition in the polymer. The integration of the NMR spectrum was used in determining the copolymer composition. The spectroscopic data suggest a cyclized repeating unit in which the copolymer main chain consists of only DVE units. There is a marked difference between these copolymers and the typical cyclo-copolymers, such as DVE-MA and DVE-FN, in which the copolymer main chains consist of DVE and the comonomer alternately, with the overall composition being 1:2. These results are interpreted in terms of the steric effect by the bulky acceptor monomers and the electronic interaction between the comonomers. The competition between an acceptor monomer and the charge-transfer (CT) complex toward the cyclized DVE radical in the propagation step appears to favor the CT complex.     

Radical cyclocopolymerization of divinyl ether and maleic anhydride. A 13C-NMR study of the polymer structure

The structure of the 1:2 copolymer of divinyl ether and maleic anhydride was investigated by ¹³C-NMR spectroscopy. The polymer contains the bicyclic unit composed of one molecule of each monomer and the maleic anhydride unit. The carbon chemical shift for these units was calculated on the basis of the chemical shift of many model compounds. The major peaks of the cyclopolymer prepared in chloroform were consistent with the presence of the symmetrical bicyclic unit with cis junction and the trans monocyclic anhydride unit. The carbonyl carbon spectrum for the copolymer obtained in a mixed solvent of acetone and CS₂ suggested the predominant formation of the unsymmetrical bicyclic unit. The polymerization process was discussed on the basis of these results.     

Quasi “Tacticity” of Rigidly Alternating Copolymers of Isobutyl Vinyl Ether and Maleic Anhydride

Since the copolymers of maleic anhydride, a cyclic monomer, and vinyl ethers, such as isobutyl vinyl ether, are made of rigidly alternating monomer unit sequences, quasi "isotactic" and quasi "syndiotactic" configurations for the monomer unit diads and triads are proposed considering the relative orientation of the cyclic anhydride group and the ether side chain with respect to the copolymer backbone.     

Synthesis and sorption activity of copolymers of vinyltriazole with diethylene glycol divinyl ether

New cross-linked insoluble polyfunctional copolymers with triazole fragments and vinyloxy groups in the side chain were synthesized by radical copolymerization of 1-vinyl-1,2,4-triazole with diethylene glycol divinyl ether. The dependence of the sorption activity with respect to the gold ions in acidic solutions on their nature and concentration was studied. The copolymers obtained were found to possess high sorption activity; they efficiently extracted gold ions from solutions of complex composition.     

Synthesis and application of novel degradable crosslinkers

A novel divinyl ether was synthesized by a convenient method with high yield.Then the divinyl ether was combined with 2- hydroxyethyl methacrylate and acrylic acid,respectively,generating difunctional polymeric crosslinkers with(hemi)acetal structure that was labile in acid.The chemical structures of the divinyl ether and crosslinkers were confirmed by ~1H NMR and elemental analysis.The crosslinkers were employed in free-radical polymerization to prepare polymer gel and gel particles. Due to the(hemi)acetal structure in the crosslinking segment,the polymer gel and particles exhibited degradable ability in strong acid.     

Cyclocopolymerization of dicyclic dienes and maleic anhydride to fused ring systems

The cyclocopolymerization of maleic anhydride and four 1,5- and 1,6-dienes (bicyclopentene, bicyclohexene, dicyclopentenyl ether, and dicyclohexenyl ether) and one tetraene (quartercyclopentene) is described. Soluble, low molecular weight copolymers were obtained from all five compounds. Their compositions approach 2:1 copolymer ratios. Fused ring structures are proposed as the main repeating units. Among the compounds listed, bicyclopentene copolymerized most easily and gave good conversions for monomer ratios of 2:1. Quartercyclopentene and dicyclopentyl ether, the other five-membered ring compounds, also polymerized to good-to-fair yields. However, a monomer ratio of about 4:1 was required to obtain conversions comparable to a 2:1 maleic anhydride—bicyclopentene polymerization. The six-membered systems, bicyclopentene and dicyclopentenyl ether, gave consistently low conversions, even with a 4:1 monomer ratio. The influence of the initiator system, initiator concentration, and reaction medium was studied on copolymerizations of bicyclopentene. Best results were obtained in acetic anhydride with azobisisobutyronitrile as the initiator.     

Characterization of amphiphilic hydrocarbon modified Poly(ethylene glycol) synthesized through ring-opening reaction of 2-(1-octadecenyl)succinic anhydride

Poly(ethylene glycol) (PEG) triblock and diblock amphiphilic block copolymers were synthesized from poly(ethylene glycol) and poly(ethylene glycol) monomethyl ether, respectively. The hydroxyl groups of PEG readily react with 2-(1-octadecenyl) succinic anhydride (OSA) at 140 °C through ring-opening reaction of the succinic anhydride. Both the PEG-OSA diblock and triblock copolymers are produced without use of any solvent or catalyst. The molecular structure of the copolymers was characterized by ¹H NMR and FTIR spectroscopy, and the thermal properties by DSC. The behavior of the copolymers in selective and nonselective solvents was studied by ¹H NMR spectroscopy in deuterium oxide and d-chloroform. The aggregation of the polymers in water was studied with a particle size analyzer and a transmission electron microscope (TEM) in bright field mode. The results show that the hydrophobic C₁₈ chain with intramolecular succinic anhydride linker can be attached to the hydrophilic PEG chain, an ester bond forming between the blocks. The copolymers exhibit flexible, liquid-like hydrophobic blocks even in water, which is a nonsolvent for OSA. PEG-OSA block copolymers self-organize in water, forming micellar polymer aggregates in nanoscale.     

Gel formation in cationic polymerization of divinyl ethers. III. Effect of oligooxyethylene chain versus oligomethylene chain as central spacer units

Cationic polymerizations of two series of divinyl ethers were carried out to clarify the effects of their central spacer chain structure on their crosslinking polymerization behavior. One series of the monomers involves divinyl ethers with an oligooxyethylene central spacer chain: diethylene glycol divinyl ether ( O‐3 ), triethylene glycol divinyl ether ( O‐4 ), tetraethylene glycol divinyl ether ( O‐5 ), pentaethylene glycol divinyl ether ( O‐6 ), and heptaethylene glycol divinyl ether ( O‐8 ) (see Scheme 1 ). The other series includes divinyl ethers with an oligomethylene central spacer chain: 1,4‐butanediol divinyl ether ( C‐4 ), 1,6‐hexanediol divinyl ether ( C‐6 ), and 1,8‐octanediol divinyl ether ( C‐8 ). Cationic polymerizations of these monomers were carried out with the hydrogen chloride/zinc chloride (HCl/ZnCl₂) initiating system in methylene chloride (CH₂Cl₂) at ?30 °C ([Monomer]₀ = 0.15 M; [HCl]₀ = 5.0 mM; [ZnCl₂]₀ = 0.5 mM). The polymerizations of the oligomethylene‐based divinyl ethers C‐6 and C‐8 caused gel formation at high monomer conversions (～90%), whereas C‐4 formed soluble polymers even at almost 100% monomer conversion. The oligooxyethylene‐based divinyl ethers O‐3 , O‐4 , O‐5 , and O‐6 underwent gel‐free polymerizations up to 100% monomer conversion and O‐8 did so at least up to ～80% conversion. The content of unreacted pendant vinyl groups of the obtained soluble polymers was measured by ¹H NMR spectroscopy. In the polymerizations of the oligomethylene‐based divinyl ethers ( C‐4 , C‐6 , and C‐8 ), the vinyl contents of the polymers decreased monotonously with increasing monomer conversion, and their number‐average molecular weights (M_n's) and polydispersity ratios (M_w/M_n's) increased considerably just before the gelation occurred. On the contrary, the vinyl contents of the polymers obtained from the oligooxyethylene‐based divinyl ethers ( O‐3 , O‐4 , O‐5 , O‐6 , and O‐8 ) decreased steeply even in the early stage of the polymerizations and almost all the pendant vinyl ether groups were consumed in the soluble polymers at the final stage of the polymerizations. The oligooxyethylene spacer units adjacent to the pendant unreacted vinyl ether groups may solvate intramolecularly with the carbocationic active center to accelerate frequent occurrence of intramolecular crosslinking reactions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3729–3738, 2004     

Studies in Cyclocopolymerization. IX. A Systematic Kinetic Study on the Cyclocopolymerization of Vinyl Ethers with Maleic Anhydride in Different Solvents

Abstract

The kinetics of the AIBN-initiated copolymerization of divinyl ether (DVE) and ethyl vinyl ether (EVE) with maleic anhydride (MA) was extensively studied in seven different solvents. The yield at 100% conversion as a function of the feed composition when the total monomer concentration is kept constant gave a confirmation of the composition of these copolymers: DVE/MA=½ and EVE/MA=1/1. The study of the initial rate as a function of the feed composition made it possible to determine the relative values of the different propagation rate constants consistent with a mechanism by successive and selective additions: in the EVE-MA system, the addition of EVE is slower than the addition of MA; in the DVE-MA system, the addition of DVE is slower than the addition of the first MA molecule, while the addition of the second MA molecule is slower than the first one. The study of the dependence of the monomer concentration, of the AIBN concentration, and of the efficiency of the initiator, on the rate of polymerization, shows finally that the true order of the monomer concentration is close to 1 while its apparent order varies from 1 to 2. From all the kinetic data it was observed that the mechanism of these co polymerizations can be explained without reliving upon the concept of participation of the charge-transfer complex formed between the monomers. However, participation of the complex in a competing mechanism with the above cannot be completely excluded.     

聚缩醛药物载体的合成表征及其降解动力学的NMR研究

在对甲苯磺酸催化下, 将聚乙二醇2000(PEG2000)和氨基保护的丝胺醇与三甘醇二乙烯基醚三元共聚, 再脱去丝胺醇的氨基保护基团, 合成了4种氨基含量不同的聚缩醛PA1, PA2, PA3和PA4, 用1H NMR表征了其结构. 同时, 利用1H NMR监测了聚缩醛PA3在pH值为7.4, 6.5和5.7的磷酸缓冲液及pH值为4.7, 4.1和3.8的醋酸缓冲液中的降解行为. 结果表明, PA3在酸性缓冲液介质中的降解反应符合一级反应动力学方程, 且随着介质pH值的减小降解速率常数增大, 降解半衰期减小.     

Modified copolymers of bifunctional vinyl ethers with methyl vinyl sulfide as active matrices of solid superbases

Reactive linear and crosslinked copolymers of diethylene glycol divinyl ether and ethylene glycol vinyl glycidyl ether with methyl vinyl sulfide have been synthesized in the presence of 2,2′-azobis(isobutyronitrile) (2%, 60 °C, 45–55 h) in ∼53% yield. The hydrolyzed at the residual vinyloxy and epoxy groups and oxidized at the methylthio groups copolymers upon treatment with KOH afford alkoxide (complex) and crown-like superbases. They are capable of catalyzing the acetone ethynylation, as well as the prototropic isomerization of methyl propargyl ether to allenyl methyl ether and vinylation of ethylene and diethylene glycols with acetylene.     

Synthesis and characterization of anionic graft copolymers containing poly(ethylene oxide) grafts

Anionic graft copolymers were synthesized through grafting of poly(ethylene glycol) monomethyl ether (MPEG) onto terpolymers containing succicinic anhydride groups. The backbone polymers were prepared through radical terpolymerization of maleic anhydride, styrene, and one of the following monomers: methyl methacrylate, ethylhexyl methacrylate, and diethyl fumarate. MPEG of different molecular weights were grafted onto the backbone through reactions with the cyclic anhydride groups. In this reaction one carboxylic acid group is formed together with each ester bond. The molecular weights of MPEG were found to influence the rate of the grafting reaction and the final degree of conversion. The graft copolymers were characterized by IR, GPC, and ¹H-NMR. Thermal properties were examined by DSC. Graft copolymers containing 50% w/w of MPEG 2000 grafts were found to be almost completely amorphous, presumably because of crosslinking, and hydrogen bonding between carboxylic acid groups in the backbone and the ether oxygens in MPEG grafts. © 1995 John Wiley & Sons, Inc.     

SYNTHESIS AND CHARACTERIZATION OF TITANOCENE POLYMER DERIVATIVES

Titanocene polymer derivatives with potential antitumor properties were synthesized by interfacial condensation. The preformed polymers used are PAA (polyacrylic acid), CPSMA (1:1 alternating copolymer of styrene and maleic anhydride) and DVEMA (1:2 copolymer of divinyl ether and maleic anhydride). The ratio of practical and theoretical titanium content is 73.6%, 92.2% and 86.2% for PAA, CPSMA and DVEMA polymer derivatives respectively. The IR spectra of the polymer derivatives possess the characteristic absorptions of titanocene. XPS (X-ray photoelectron spectroscopy) of O_(1s) and Ti_(2p3/2) supports the existence of Ti-O bonding.