Laser-initiated polymerization of epoxies in the presence of maleic anhydride

Laser-initiated polymerization of cyclohexene oxide in the presence of maleic anhydride was investigated. The influences of solvents laser irradiation time and the monomer feed ratio on the polymer yield and composition were evaluated. The rate of polymerization increased with an increase in the molar concentration of maleic anhydride in the monomer feed. Short irradiation times of 1–3 min duration gave very high yield of epoxy polymer (>80% conversion). Infrared spectral studies of the polymer product indicated the formation of polyether linkage at lower levels of conversion and an adduct of polyether and maleic anhydride at higher polymer conversions. The quantitative chemical analyses results also showed similar results. The results indicated that the polymerization was initiated by the excited charge transfer complex between the electron donor, cyclohexane oxide, and the electron acceptor–maleic anhydride. In the initial stages of polymerization, cyclohexene oxide undergoes a cationic polymerization in the presence of the radical anion of maleic anhydride. Laser-initiated polymerization of cyclohexene oxide/maleic anhydride is several hundred times more efficient than UV-initiated polymerization, as measured by the energy absorbed by the polymer system.     

Photoinduced polymerization of maleic anhydride in dioxane

Maleic anhydride (MAn) was irradiated with ultraviolet light in dioxane at 35°C without initiator, and predominantly a MAn oligomer was obtained with a small quantity of cyclic dimer of MAn. Mass spectrometric, NMR, and elementary analysis investigation of the oligomer showed that it is composed of about four MAn units and one dioxane molecule per molecule.     

Melt-photografting polymerization of maleic anhydride onto LDPE film

Maleic anhydride (MAH) was photografted onto low density polyethylene substrates at temperatures above the melting point of MAH. The effects of some principal factors including irradiation temperature, photoinitiators, the intensity of UV radiation, and the far UV radiation on the grafting polymerization were investigated in detail. Percent conversion and grafting efficiency of the polymerizations were determined by the gravimetric method. The contact angles of the grafted film PE-g-PMAH against water and the FTIR spectrum of the grafted film were measured as characterization. The results show that the photografting polymerization of MAH can proceed smoothly at temperatures higher than the melting point of MAH; the far UV radiation and the intensity of the UV radiation affect the grafting polymerization greatly; the photoinitiators also have influence on the polymerization. According to the FTIR spectra, it is clearly confirmed that the grafted film samples contain anhydride groups. The contact angles demonstrate that the wettability of the grafted films is enhanced obviously, especially to those grafted film samples through hydrolysis.     

Polymerization of cyclic ethers in the presence of maleic anhydride. Part II. Investigation of the polymerization mechanism

In order to elucidate the reaction mechanism of both the radiation-induced and benzoyl peroxide-catalyzed polymerizations of cyclic ethers in the presence of maleic anhydride, the development of color during reaction and copolymerization of oxetane derivatives were investigated. Upon addition of a small amount of the γ-ray or ultraviolet-irradiated equimolar solution of a cyclic ether and maleic anhydride to isobutyl vinyl ether, a rapid polymerization took place, and the resulting polymer was confirmed to be a homopolymer of isobutyl vinyl ether. A heated solution of dioxane, maleic anhydride, and a small amount of benzoyl peroxide can initiate the polymerization of isobutyl vinyl ether in the same manner. The electrical conductivity of a 1:1 mixture of maleic anhydride and dioxane is increased by about a factor of ten after ultraviolet irradiation. These results indicate that some cationic species are actually formed in the system by irradiation or the decomposition of added benzoyl peroxide. The mechanism of formation of the cationic species responsible for the initiation may be explained as follows. A free radical of an ether is formed by abstraction of a hydrogen atom attached to the carbon adjacent to oxygen atom, followed by a one-electron transfer from the resulting radical to maleic anhydride, an electron acceptor, to yield the cationic species of the ether and the anion-radical of maleic anhydride, respectively. The resulting cationic species as well as the counteranion-radical are resonance-stabilized. Therefore, the present polymerization may be designated a radical-induced cationic polymerization.     

Electronitiated polymerization of maleic anhydride by direct electron transfer

Controlled potential electrolysis was employed to accomplish homopolymerization of maleic anhydride, by direct electron transfer. The solvent used in the polymerization studies was acetonitrile–dimethylformamide mixture (1 : 1) with the supporting electrolyte tetrabutylammonium tetra fluroborate, A brown paramagnetic polymer was obtained from the catholyte, upon electroreduction of monomer.     

Radical-catalyzed homopolymerization of maleic anhydride in presence of polar organic compounds

Polar organic compounds either (1) inhibit the peroxide-catalyzed bulk homopolymerizations of both MAH and MMA at 80°C, (2) do not inhibit the polymerization of either MAH or MMA, or (3) inhibit the polymerization of MAH but not that of MMA. Compounds generally used as polymerization inhibitors or antioxidants inhibit the polymerizations of both MAH and MMA, presumably by interaction with peroxide decomposition products. Ketones, ethers, acids, esters, nitriles, imides, sulfones, sulfonates, sulfonamides, and acyl disulfides do not inhibit either MAH or MMA polymerization. However, amides, lactams, carbamates, amine oxides, phosphites, phosphates, phosphonates, phosphoramides, phosphine oxides, monosulfides, sulfoxides, aryl disulfides, and thiazyl disulfides inhibit the polymerization of MAH but not that of MMA. Inhibition presumably occurs as a result of electron transfer from the nitrogen-, phosphorous- or sulfur-containing electron donor compound to the MAH carbocation which is an intermediate in the polymerization of MAH.     

Calorimetric analysis of the graft polymerization of maleic anhydride onto liquid polybutadienes

The kinetics of the reaction of maleic anhydride with liquid polybutadienes of various microstructures was studied by using differential scanning calorimetry (DSC). The kinetic results of thermal maleinization show a dependence from m.w. and polybutadiene microstructure. The introduction of a gel inhibitor as copper naphthenate has proved that crosslinking reactions also occur during the maleinization. On the other hand, the maleinization in the presence of a radical initiator as dicumyl peroxide (DCP) shows thermal effects higher than pure thermal reaction with a partial overlap of the calorimetric peaks due to maleinization and crosslinking. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ring-opening copolymerization of maleic anhydride with epoxides: a chain-growth approach to unsaturated polyesters

We report the ring-opening copolymerization of maleic anhydride with a variety of epoxides catalyzed by a chromium(III) salen complex. Quantitative isomerization of the cis-maleate form of all polymers affords the trans-fumarate analogues. Addition of chain transfer reagents yields low M(n), narrow PDI polymer samples. This method provides access to a range of new unsaturated polyesters with versatile functionality, as well as the first synthesis of high molecular weight poly(propylene fumarate).     

High temperature copolymerization of styrene and maleic anhydride in propagating polymerization front

The synthesis of poly(styrene‐maleic anhydride) copolymers by frontal polymerization is reported. The propagating front can be achieved if the mole fraction of styrene (St) is 0.3 ≤ St ≤ 0.7 in the feed. Depending on the St/MA mole ratio alternating St‐MA‐St‐MA copolymers (St/MA ≤ 1) or (St‐MA)_n‐(St‐St‐St)_m block copolymers (St/MA > 1) are formed. The microstructure of the copolymers obtained was estimated by means of ¹³C NMR spectroscopy.     

Cyclic acetal-photosensitized polymerization—15. Photopolymerization of maleic anhydride in the presence of 2,4,8,10-tetraoxaspiro[5,5]undecane compounds

The photopolymerization of maleic anhydride (Manh) was carried out in the presence of 2,4,8,10-tetraoxaspiro[5,5]undecane (TU) at 40 in vacuo without initiator to give the hygroscopic oligomer of Manh having a TU unit as each of the end-groups and a small amount of the cyclic dimer of Manh. The initiation mechanism for this oligomerization was discussed.     

Modification of deproteinized natural rubber via grafting polymerization with maleic anhydride

Modification of natural rubber (NR) via grafting polymerization with maleic anhydride (MA) has received wide attention as it could improve the hydrophilicity of NR and extend its application to a wider application field. However, the grafting efficiency of MA onto NR in either the molten state or solution state is low and is accompanied with undesired high gel content in the grafts. In this work a novel technical route was developed in that a deproteinization operation was conducted before carrying out the grafting process and a differential microemulsion polymerization technique was applied for the grafting reaction. The effects of initiator and monomer concentration, reaction temperature, and reaction time on the grafting efficiency and gel fraction were investigated, and a comparison of the reaction performance was conducted for deproteinized NR (DPNR) and NR. The results indicated that the deproteinization operation could significantly improve the grafting efficiency and reduce the gel content, and a 29% yield of MA grafted onto the rubber backbone could be achieved at a condition of a DPNR:MA:initiator ratio of 85:9:6 (wt%) at 60 °C for 8 h.     

Synthesis of divinylbenzene–maleic anhydride microspheres using precipitation polymerization

Narrow disperse micron-range divinylbenzene-maleic anhydride microspheres have been prepared in near quantitative yields using precipitation polymerization. A variety of solvents were investigated for use as the reaction medium with a 40:60 mixture of methyl ethyl ketone and heptane providing the best results. The effects of solvent composition on particle size and morphology and monomer loading effects were also investigated. Particle size decreased with increasing solvency (increasing MEK fraction) while increases in monomer loading caused larger particle sizes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2223–2227, 1998     

Potentiometric determination of maleic anhydride in the presence of cis-3,6-endomethylene-1,2,3,6-tetrahydrophthalic (endic) anhydride

A procedure is developed for the determination of maleic anhydride in the presence of endic anhydride by potentiometric titration in aqueous-organic solutions. It is found that separate titration of a hydrolyzed mixture of anhydrides is most efficient in the system acetonitrile-water (3 : 2).     

Self‐initiating performance of maleic anhydride on surface photografting polymerization

Maleic anhydride (MAH) was photografted onto low‐density polyethylene (LDPE) films with a grafting efficiency of about 70% in the absence of a photoinitiator. The self‐initiating performance was attributed to a mechanism of abstracting hydrogen atoms from LDPE chains by excited MAH dimers. The supporting experimental results were as follows: (1) the far‐UV radiation (200–300 nm) was indispensable for the graft polymerization and 2) the crosslinking reaction of LDPE inevitably accompanied the grafting of MAH. In addition, the initiation performance of MAH was further confirmed by surface photografting of acrylic acid in the presence of MAH, where MAH was used as the photoinitiator. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3246–3249, 2001     

马来酸酐均聚反应机理的理论研究Ⅱ: α-羟基丁二酸酐碳阴离子和碱催化下的阴离子聚合机理

用AM1方法计算了马来酸酐、氢氧根阴离子及其加成物α-羟基丁二酸酐碳阴离子的电子结构、电荷分布和键级。应用前线轨道理论和成键三原则研究了碱(NaOH)催化条件下马来酸酐均聚过程中α-羟基丁二酸酐碳阴离子活性中间体参与反应的可能性及其阴离子聚合机理。计算结果能很好地阐明实验事实。     

Peroxide-catalyzed grafting of maleic anhydride onto molten polyethylene in the presence of polar organic compounds

The crosslinking of LDPE resulting from reaction with dicumyl peroxide at 180°C is increased in the presence of maleic anhydride (MAH). The presence of electron-donating nitrogen-containing compounds (amides, lactams, disubstituted aromatic amines, and amine oxides), phosphorous-containing compounds (phosphites, phosphates, phosphonates, phosphoramides, and phosphine oxides) and sulfur-containing compounds (sulfoxides, aryl disulfides, and thiazyl disulfides) which inhibit the homopolymerization of MAH but not that of methyl methacrylate, prevents crosslinking and yields soluble PE containing MAH units. Crosslinking, due to coupling of PE^˙ macroradicals formed by hydrogen abstraction from PE by excited MAH, is prevented by electron donation from the additive to the MAH⁺ cation which is present in the MAH+?MAH excimer as well as in the excimer which is appended to the PE.     

Effect of the initial maleic anhydride content on the grafting of maleic anhydride onto isotactic polypropylene

A series of ¹³C‐enriched maleic anhydride grafted isotactic polypropylene samples were prepared in solution at 170 °C by changes in the initial maleic anhydride content. The NMR spectra of the samples showed that the signals of the maleic anhydride attached to the tertiary carbons of the isotactic polypropylene chains increased considerably with increasing maleic anhydride content, whereas the signals of the maleic anhydride on the radical chain ends (with a single bond) arising from β scission did not. On the other hand, the signals of the maleic anhydride on the radical chain ends with double bonds increased markedly with increasing maleic anhydride content, and this suggested that β scission could occur extensively after maleic anhydride was attached to the tertiary carbons. As a result, the molecular weight of the grafted polypropylene decreased significantly with increasing maleic anhydride content in this study. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5529–5534, 2005     

羟基自由基引发的马来酸酐聚合反应机理AM1研究

用AM1方法计算了马来酸酐、羟基自由基及其加成产物α-羟基丁二酸酐基自由基的电子结构、电荷分布和键级.应用前线轨道理论和成键三原则研究了羟基自由基引发下马来酸酐聚合过程中α-羟基丁二酸酐基自由基活性中间体参与反应的可能性及其自由基聚合反应机理.计算结果表明:马来酸酐基态分子的HOMO和LUMO分别对应于双键CC的成键π-MO和反键π -MO;马来酸酐的羟基自由基加成反应活化能计算值为55 7kJ/mol;马来酸酐在羟基自由基引发下的自由基聚合产物是链式结构,与实验事实相符.     

Plasma polymerization in the design of new materials: looking through the lens of maleic anhydride plasma polymers

Plasma polymerization is a well-established process for the deposition of thin polymeric films on various types of substrates. The potential of this technique for promoting changes of substrate’s wettability constitutes one of the most basic and often reported applications. However, as novel technological demands emerge, and with it the range of available characterizations, plasma polymers are having their niche of applications and properties expanded. The properties of these materials are commonly tailored through the variation of polymer chemistry, postfunctionalization, or other post-treatment processes. That chemical versatility allows the use of plasma polymers in adhesives, water treatment, biomedicine, and many other fields. The creation of nanostructures via lithography or during the deposition process itself constitutes other dynamic fields for new plasma polymer materials. In the current review, the design of materials through plasma polymerization is addressed with the direction given by our expertise in maleic anhydride plasma polymers (MAPP). A non-exhaustive number of applications of plasma polymers is provided to non-specialists as an overview of the materials coming out from the field of this chemical-vapor deposition process. A complete analysis of the literature on maleic anhydride plasma polymers is also performed.     

Radiation-induced graft polymerization of maleic acid and maleic anhydride onto ultra-fine powdered styrene–butadiene rubber (UFSBR)

The functionalization of ultra-fine powdered styrene–butadiene rubber (UFSBR) was carried out using gamma radiation-induced graft polymerization of maleic acid (MA) and maleic anhydride (MAH), respectively. It was found that the graft yield of MA onto UFSBR increased rapidly up to the peak and then decreased with increasing MA content. Moreover, the peak shifted to the direction of lower MA content with increasing absorbed dose. Similarly, there was the peak of graft yield with increasing MAH content for grafting of MAH onto UFSBR, whereas the peak of graft yield was achieved at 10 wt% MAH content at different absorbed doses. On the other hand, increasing absorbed dose and decreasing monomer contents are useful to improve the graft efficiency of MA and MAH. At high dose and low monomer content, the graft yield of MAH onto UFSBR is higher than that of MA. FTIR spectra confirmed that both MA and MAH can be grafted successfully onto the UFSBR under gamma irradiation, respectively. Comparing with maleation of rubber by melt grafting, the graft yield of MAH on UFSBR is higher, which can be attributed to the network structure and nanometer size of UFSBR as well as high energy provided by radiation.