Maleimide Copolymers Research Articles

Contact angle measurements by axisymmetric drop shape analysis and an automated polynomial fit program

Low-rate dynamic contact angles of eight liquids on an inert (non-polar) FC-722 surface and a non-inert (polar) poly(propene- alt- N-methylmaleimide) copolymer are reported using two different contact angle methods: axisymmetric drop shape analysis (ADSA) and an automated polynomial fit (APF) scheme. The latter technique was found to be more sensitive to minute surface heterogeneity and/or roughness of the surface. For the non-inert solid–liquid systems, very complex contact angle responses were observed with both methods. If one omits these inconclusive contact angle measurements, the values of γ lv cos θ change smoothly with γ lv for these polymers, independent of which of the two methods is used. When comparing with previously studied maleimide copolymer surfaces, a consistent change in the wettability was observed as the length of the side chains decreases from hexyl to methyl groups.

Methyl methacrylate-N-chlorophenyl maleimide copolymers: Effect of structure on properties

The article describes the preparation of cast acrylic sheets by copolymerizing methyl methacrylate (MMA) with varying mole fractions of N-o-chlorophenyl maleimide (OC), N-m-chlorophenyl maleimide (MC), and N-p-chlorophenyl maleimide (PC) using benzoyl peroxide as an initiator. The effect of incorporation of varying mole fraction of N-chlorophenyl maleimides in poly(methyl methacrylate) backbone on the optical, physicomechanical, and thermal properties of cast acrylic sheets were evaluated. Vicat softening temperature, glass transition temperature (Tg) and thermal stability of the copolymers increased with an increase in the maleimide content. The solar transmittance and percentage of transmittance of the copolymer sheets having low mole fractions of N-chlorophenyl maleimides (i.e., 0.025–0.085) were found to be comparable with that of PMMA. Further increase in the comonomer content resulted in a decrease in the percentage of transmittance. Copolymer sheets having low mole fractions of N-chlorophenyl maleimides (0.025–0.108) have tensile strength comparable to that of PMMA, whereas the percentage of elongation decreased. Tensile modulus increased with increasing mole fraction of N-chlorophenyl maleimides. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 527–534, 1998

Synthesis and characterization of styrene-N-butyl maleimide copolymers using iniferters containing thiyl end groups

The radical homopolymerization of styrene or copolymerization of styrene (S) with N-butyl maleimide (I) initiated by tetraethylthiuram disulfide was used to prepare macroinitiators having thiyl end groups. The S–I copolymers from the feeds containing 30–70 mol % I showed approximately alternating composition. The rate of copolymerization and molecular weights decreased with increasing maleimide derivative concentration in the feed; homopolymerization of I alone did not proceed. The macroinitiators served for synthesis of further S–I copolymers. Using polystyrene macroinitiator and the S–I copolymer with thiyl end groups in the polymerization of S–I mixture and styrene, respectively, the copolymers containing blocks of both polystyrene and alternating S–I copolymer were obtained. The copolymerization of S–I mixture initiated with the S–I copolymer bearing thiyl end groups led to the extension of macroinitiator chains by the blocks of alternating copolymer. The presence of the blocks in the polymer products was corroborated using elemental analysis, size exclusion chromatography, and differential scanning calorimetry. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 755–762, 1998

Synthesis and characterization of styrene–N-butyl maleimide copolymers using iniferters containing thiyl end groups

Synthesis and characterization of styrene–<i>N</i>-butyl maleimide copolymers using iniferters containing thiyl end groups

Photo-induced orientation and micropattern imaging of maleimide copolymers containing azobenzene side groups

Photo-induced birefringence properties of azobenzene containing maleimide copolymers P[DR1PMI-co-St]1 and P[DR1MSt-co-PMI]2 are investigated. These polymers show reversible photo-induced birefringence and the rate parameters for the induction and relaxation processes are obtained. Photoimage patterns of the polymers with narrowest line width of 2 µm are obtained. The micro patterns are relatively stable for over a month at room temperature.

Poly(sulfobetaine)s and corresponding cationic polymers. VII. Thermal degradation of copolymers derived from poly(acrylamideco-N,N-dimethylaminopropylmaleimide)

The copolymer prepared by copolymerizing acrylamide and maleic anhydride was imidized with N,N-dimethylaminopropylamine. The obtained acrylamide-N,N-dimethylaminopropylmaleimide (ADMAPM) copolymer was then reacted with propane sultone to yield an acrylamide-N,N-dimethylmaleimidopropyl ammoniopropane sulfonate (ADMMAPS) copolymer or then reacted with methyl iodide to yield a poly(methyl iodide quaternized acrylamide-N,N-dimethylaminopropyl maleimide) copolymer [poly(MIQADMAPM)]. The kinetic parameters, such as the reaction order, the activation energy, and the preexponential factor, of the thermal degradation were evaluated from thermal gravimetric curves for these two copolymers. The activation energy and preexponential factor of the poly(ADMMAPS) were higher than those of poly(MIQADMAPM) for Ozawa's method and van Krevelen's method. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 95–103, 1997

Poly(sulfobetaine)s and corresponding cationic polymers: 3. Synthesis and dilute aqueous solution properties of poly(sulfobetaine)s derived from styrene-maleic anhydride

The copolymer prepared by copolymerizing styrene and maleic anhydride was imidized with N,N′-dimethylaminopropyl amine. The styrene- N,N′-dimethylaminopropyl maleimide (SDMAPM) copolymer obtained was then reacted with propane sultone to yield a styrene-[ N,N′-dimethyl(maleimidopropyl)ammonium propane sulfonate] (SDMMAPS) copolymer. The cloud point and intrinsic viscosity of this ampholytic SDMMAPS copolymer were determined in aqueous salt solutions. The effects of counter ions on the cloud point and intrinsic viscosity of SDMMAPS were similar to their effects on these properties of other zwitterionic poly(sulfobetaine)s. The Huggins constants for SDMMAPS in aqueous salt solutions, however, were quite different than those of other sulfobetaine homopolymers, such as poly[ N,N′-dimethyl(acrylamidopropyl) ammonium propane sulfonate], [poly(DMAAPS]. The value of the constant was negative and increased as the intrinsic viscosity and salt concentration increased. This phenomenon is mainly attributed to the presence of the styrene segment, a hydrophobic group, in the SDMMAPS copolymer.

Partially fluorinated maleimide copolymers for Langmuir films of improved stability, 1. Synthesis, copolymerisation behaviour and bulk properties

AbstractVarious new partially fluorinated polymers on the basis of substituted N‐phenylmaleimides are prepared by radical copolymerisation. Nearly alternating copolymers are produced with vinyl ethers and styrene derivatives. The copolymers show high stability against thermal degradation in comparison to conventional vinyl and vinylidene polymers, and high glass transition temperatures. Highest thermal stability is found for copolymers in which the classical hydrophilic and hydrophobic fragments are reduced to a minimum.

Modification of thermosetting plastics by maleimide copolymers

Modification of thermosetting plastics by maleimide copolymers

Partially Fluorinated Maleimide Copolymers for Langmuir Films of Improved Stability. 2. Spreading Behavior and Multilayer Formation

The spreading behavior and multilayer formation of partially fluorinated alternating copolymers are studied. The copolymers are based on substituted N-phenylmaleimides which lack standard hydrophilic groups as well as aliphatic hydrophobic chains. The stability of such vinyl copolymers against thermal degradation is exceptionally high, as are their glass transition temperatures. Despite their unconventional structure, the copolymers form stable monolayers with high collapse pressures. The surface potential of monolayers can be adjusted between positive and negative potentials by well-placed fluorinated substituents. Also, multilayers can be built up by the Langmuir-Blodgett technique.

A new class of transparent polymeric materials. II. Synthesis and properties of poly(N-cyclohexylmaleimide-alt-isobutene) modified with lauryl methacrylate

Transparent polymeric materials with high heat resistance and low water absorption were designed based on the alternating copolymers of N-substituted maleimide (RMI) with isobutene (IB). The N-substituent of the maleimide significantly affected the glass transition temperature (Tg) and water absorption of the copolymers. Poly(N-cyclohexylmaleimide-alt-JB) [poly(CHMI-IB)] showed a Tg value as high as 192°C and relatively low water absorption. Furthermore, the incorporation of a small amount of lauryl methacrylate in the copolymers was confirmed to reduce the water absorption of the copolymer drastically, although it decreased the Tg of the copolymers at the same time. Poly(CHMI-IB), containing 4 mol % lauryl methacrylate, showed a good balance of excellent transparency, high heat resistance, acceptable mechanical properties, and low water absorption. The heat deflection temperature was as high as 141°C. The water absorption at 23°C after immersion for 14 days was 0.56% and the dimensional change after 7 days was 0.06%. They are half and one-quarter of those of poly(methyl methacrylate), respectively. © 1996 John Wiley & Sons, Inc.

Simultaneous TA and MS analysis of alternating styrene-maleic anhydride and styrene-maleimide copolymers

The thermal behaviours of alternating styrene-maleic anhydride copolymer (St/MAn), styrene-methyl maleimide copolymer (St/MMI) and copolymers with different contents of MMI were studied by means of a simultaneous thermal analyser and quadrupole mass spectrometer system (STA/QMS). In addition, special measurements were carried out by a pyrolysis-gas chromatography-mass spectrometer (Py-GC-MS) and a differential scanning calorimeter (DSC). The glass transition of the copolymers in influenced by the degree of imidization. The decomposition behaviour of pure styrene-maleic anhydride copolymer differs from that of styrene-methyl maleimide copolymer. The favoured process of degradation of maleic anhydride-rich structures is reaction in the chains, and that of methyl maleimide-rich structures is the random chain break.

Thermally stable maleimide copolymer for second-order nonlinear optics

Second-order nonlinear optical copolymer containing p-hydroxyphenyl maleimide as a comonomer was newly synthesized. Second-order nonlinear optical properties of the poled films were investigated in terms of the second harmonic generation (SHG) and linear electrooptic (EO) coefficient measurement. SHG coefficient, d33 was found to be 14 pm/V at the fundamental wavelength of 1064 nm and EO coefficient, r33 was found to be 25-30 pm/V at 633 nm wavelength. To prevent the orientational relaxation of poled polymer, the thermal crosslink reaction was induced using diisocyanate as a crosslinker between the side chains themselves. Temporal stabilities of second-order NLO coefficients of crosslinked polymer systems were proved much better than that of guest-host system or other side chain polymers. © 1996 John Wiley & Sons, Inc.

Synthesis and biological activities of copolymers of N‐glycinyl maleimide with methacrylic acid and vinyl acetate

AbstractCopolymerizations of N‐glycinylmaleimide (GMI) with methacrylic acid (MA) and vinyl acetate (VAc) were carried out in 2‐butanone using lauroylperoxide as an initiator at 70°C. Synthesized GMI, poly(GMI‐co‐MA), and poly(GMI‐co‐VAc) were characterized by IR and 1H‐NMR spectroscopies, elemental analysis, and gel permeation chromatography. The in vitro cytotoxicities of poly(GMI‐co‐MA) and poly(GMI‐co‐VAc) were evaluated using K‐562 human leukemia cells and HeLa cells. From the cytotoxicity data against HeLa cells, the copolymers are less cytotoxic than monomeric GMI at dosage of 0.02, 1.0, and 5.0 mg/mL. Copolymers were very effective at any dosage tested. The in vivo antitumor activities of poly(GMI‐co‐MA) and poly(GMI‐co‐VAc) were also evaluated against mice bearing sarcoma 180. Monomeric GMI and its copolymers showed higher antitumor activity than 5‐fluorouracil (5‐FU) at any dosage tested. © 1995 John Wiley &amp; Sons, Inc.

Electrically Induced Structural Changes in Quaternized Methyl Methacrylate-N-[2-methyl-5-(dimethylamino)phenyl]maleimide Copolymer Membranes

Homogeneous membranes were prepared by casting chloroform solutions of methyl methacrylate-N-[2-methyl-5-(dimethylamino)phenyl]maleimide copolymers containing 2.3-8.7 mole % of the imide. After quaternization with methyl iodide, diffusive permeabilities and electric resistances (both with alternating and direct current) of the membranes were determined. During the passage of electric current a substantial decrease (2-10 fold) in the membrane resistance was observed; the lower the imide content was, the greater was the effect. The decrease suggests structural changes in the membranes due to electrohydrodynamic convection of unstable polymer chains caused by electric force. Significant correlations between the imide content and the resistance, both before and after the treatment with electric current, were found. According to oriented concentration potentials, the internal symmetry of the membranes was also affected by electric current.

Preparation, characterization, and thermal behavior of MMA–N‐aryl maleimide copolymers

AbstractThe work describes the synthesis and characterization of copolymers of methyl methacrylate (MMA) and N‐o‐tolyl maleimide (MO)/N‐p‐tolyl maleimide (MP)/4‐maleimido benzoic acid (MB). The copolymers were synthesized by varying the mol fraction of N‐aryl maleimides from 0.1 to 0.5 in the initial feed using azobisisobutyronitrile (AIBN) as an initiator and tetrahydrofuran as the solvent. The copolymer composition was determined from the 1H‐NMR spectra by taking the ratio of proton resonance signals due to OCH3 of MMA (δ=3.59 ppm) and the aromatic protons (δ=7.0–7.3 ppm) of N‐aryl maleimides. The monomer reactivity ratios of MMA–MP were r1=0.926±0.001 and r2=0.47±0.03 and MMA–;MO were r1=1.37±0.005 and r2=0.31±0.01. The initial decomposition temperature of copolymers and glass transition temperatures increased with increasing N‐aryl maleimide content in the backbone. © 1994 John Wiley &amp; Sons, Inc.

Pervaporation of Ethanol and Water Through Polymeric Membranes with Incorporated N-(Halogenophenyl)maleimide Units

Styrene N-(chloro- or bromophenyl)maleimide and methyl methacrylate N-(chloro- or bromophenyl)maleimide copolymers were synthesized. Membranes casted from the copolymer solutions were used for the pervaporation of ethanol water mixtures at 35 °C. The membranes were characterized by the separation factor related to the preferentially transported water and by the permeate flux. The pervaporation characteristics were dependent on the hydrophilicity or polarity of the polymer chains, on the kind and position of the halogen and on the composition of the mixture to be separated. Membranes made from the copolymers of styrene with N-(2-chlorophenyl)maleimide or N-(2-bromophenyl)maleimide show the highest separation factors in the separation of concentrated ethanol solutions. The permeate flux through membranes made from the copolymers of methyl methacrylate with N-(halogenophenyl)maleimide was by one order of magnitude higher than through membranes made from similar styrene copolymers.

A study of the thermal and dynamic mechanical properties of functionalized aryl cyanate esters and their polymers

AbstractDifferential scanning calorimetry (DSC) was employed to examine the thermally initiated and catalysed polymerizations of a number of cyanate ester monomers. Rigorous purification by preparative HPLC was found to have marked effects on the thermal polymerization characteristics of these compounds as determined by DSC. The effects on the thermal behaviour of varying the heating rate and level of catalysis were also examined. The thermal polymerization of the cyanate ester monomers was found to obey a first order model over wide apparent conversion limits. Functionalized cyanate ester/bis‐maleimide copolymers were prepared and the thermal stabilities of these were evaluated by thermogravimetric analysis (TGA) alongside a variety of commercial blends and homopolymers. The dynamic mechanical properties of the cured neat resins were also investigated.

Molecular ordering in electrochemically synthesized conducting copolymer of pyrrole with N-phenyl maleimide

An unusual molecular ordering, as evidenced by number and sharpness of X-ray diffraction peaks, has been observed in electrochemically synthesized conducting copolymer of pyrrole with N -phenyl maleimide. The comonomer N -phenyl maleimide is hitherto unused in the synthesis of conducting polymers. The copolymer formation has been established by X-ray photoelectron spectroscopy. As derived from wide angle X-ray diffraction data, this novel copolymer possesses an orthorhombic structure with unit cell dimensions of a =9.28 A ̊ , b =7.1 A ̊ and c =8.4 A ̊ . From these parameters, it is inferred that the comonomers are placed in an alternate manner maintaining isotactic stereoregular conformation. Quite interestingly, this pyrrole N -phenyl maleimide copolymer, even with the absence of extended π conjugation, exhibits electrical conductivity comparable to pyrrole homopolymer itself.

Free-Radical-Initiated Copolymerization of A-Methylstyrene with Maleimide

Abstract Alternating copolymers of α-methylstyrene (α-MeSt) and maleimide (MI) were prepared by free-radical initiated polymerization at different monomer-to-monomer concentrations in the feed in CHCl3, as solvent. The equilibrium constant of -MeSt and MI was determined by the transformed Benesi-Hildebrand NMR method in CDCl3, and has a value of 0.03 L/mol. From the equation Rp = Rp(f) + Rp(CT) proposed by Shirota and coworkers, Rpf) and RpCT) were calculated, and it was found that the copolymerization of -MeSt with MI proceeds predominantly through participation of the CT complex. Alternating copolymers have a glass transition temperature of 567 K (DSC method). Alternating copolymer decomposes via a one-step reaction at 350°C.