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Time dependence of the heat evolution rate on the radical polymerization of plain MMA (curve 1) and its polymerization in the presence of 1 (curve 2), 2 (curve 3), 4 (curve 4), 10 (curve 5)
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Free radical initiated polymerization of methyl methacrylate containing 1–15 wt% of dissolved polyimide is studied by a calorimetric method. It is shown that polyimide (up to 10 wt%) addition leads to a shifting of the initial autoacceleration and initial autoretardation conversions to lower conversion values than those for polymerization of plain...
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Copolymerizations of dibenzofulvene (DBF) with methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), methyl acrylate (MA), and 2-hydroxyethyl acrylate (HEA) were conducted under free radical conditions in toluene using α,α′-azobisisobutylonitrile (AIBN) as the initiator. In the copolymerizations, DBF indicated much higher reactivity than t...
Citations
... Previously, we performed investigations of free radical thermal homo-and copolymerization of (meth)acrylates, styrene and N-vinyl-2-pyrrolidone containing dissolved polyheteroarylenes including PIs [37][38][39][40][41][42][43][44]. It was found that the obtained polymer systems differ from the corresponding homopolymers in terms of molecular weight characteristics, thermal and mechanical properties. ...
... The study of the kinetics of free radical thermal and photopolymerization (meth)acrylates in the presence of polyimide, polyarylate and their model compounds by differential scanning photocalorimetry, FTIR, ESR spectroscopy, etc. [38,[41][42][43][44][45][46][47] allowed us to identify the mechanism of copolymer formation due to the chain transfer reaction to functional groups of polyheteroarylenes, in particular to imide cycles [42,43,46,47]. The introduction of polyheteroarylenes into the monomer(s) and subsequent polymerization in situ contributed to an increase in the thermal and mechanical properties of the copolymers formed compared to unmodified carbon-chain homopolymers [37][38][39][40][41][42][43][44][45][46][47], opening up wide possibilities for obtaining various functional materials. ...
... Based on previous results [38][39][40]46,47,58], it was suggested that the introduction of FCPI into di(meth)acrylates will improve the thermal stability and strength properties of corresponding polymer compositions, which is important for the formation of protective coatings of silica optical fibers. To investigate these properties, films were prepared from unmodified monomers and their blends with FCPI (see the details in the experimental section). ...
The development of photocurable compositions is in high demand for the manufacture of func-tional materials for electronics, optics, medicine, energy, etc. The properties of the final pho-to-cured material are primarily determined by the initial mixture, which needs to be tuned for each application. In this study we propose to use simple systems based on di(meth)acrylate, polyimide and photoinitiator for the preparation of new photo-curable compositions. It was es-tablished that a fluorinated cardo copolymide (FCPI) based on 2,2-bis-(3,4-dicarboxydiphenyl)hexafluoropropane dianhydride, 9,9-bis-(4-aminophenyl)fluorene and 2,2-bis-(4-aminophenyl)hexafluoropropane (1.00:0.75:0.25 mol) has excellent solubility in di(met)acrylates. This made it possible to prepare solutions of FCPI in such monomers, to study the effect of FCPI on the kinetics of their photopolymerization in situ and the properties of the resulting polymers. According to the obtained data, the solutions of FCPI (23 wt.%) in 1,4-butanediol diacrylate (BDDA) and FCPI (15 wt.%) in tetraethylene glycol diacrylate were tested for the formation of the primary protective coatings of the silica optical fibers. It was found that the new coating of poly(BDDA–FCPI23%) can withstand prolonged annealing at 200°C (72 h), which is comparable or superior to the known most thermally stable photo-curable coatings. The proposed approach can be applied to obtain other functional materials.
... The free-radical in situ (co)polymerization of MMA [111][112][113], ethyl acrylate [114,115], fluoro(meth)acrylates [116,117], MMA with bifunctional comonomers [118], styrene [119], styrene with MMA [119], N-vinyl-2-pyrrolidone [120,121] in the presence of PI (4-85 wt %) afforded the molecular composites of different formulations. The mechanism of copolymer formation that consists in the interaction of free radicals of the reaction system with macromolecules of PI has been established by DSC and EPR [111,114]. ...
... The free-radical in situ (co)polymerization of MMA [111][112][113], ethyl acrylate [114,115], fluoro(meth)acrylates [116,117], MMA with bifunctional comonomers [118], styrene [119], styrene with MMA [119], N-vinyl-2-pyrrolidone [120,121] in the presence of PI (4-85 wt %) afforded the molecular composites of different formulations. The mechanism of copolymer formation that consists in the interaction of free radicals of the reaction system with macromolecules of PI has been established by DSC and EPR [111,114]. The products of thermal or photopolymerization are the copolymers that strongly differ in the properties from the corresponding homopolymers and their mixtures [111][112][113][114][115][116][117][118][119][120][121]. ...
... The mechanism of copolymer formation that consists in the interaction of free radicals of the reaction system with macromolecules of PI has been established by DSC and EPR [111,114]. The products of thermal or photopolymerization are the copolymers that strongly differ in the properties from the corresponding homopolymers and their mixtures [111][112][113][114][115][116][117][118][119][120][121]. ...
This review presents the current achievements in the ecologically friendly synthesis of polyimides. The progress in the formulation and applications of different nanocomposites based on polyimides are highlighted. The enormous potential of the polymers and composites under consideration in environmentally benign synthesis and various application fields is shown.
... The result obtained is quite different from our previous data on radical polymerization of other vinyl monomers such as (meth)polyacrylates, styrene, etc., where the homopolymer formation is not observed even in presence of small amounts of the introduced condensation polymer [24][25][26][27]. We have established the graft copolymer formation by the polymerization of vinyl monomers containing different condensation polymers is due to the interaction of free radicals with functional groups of the added polymers [25,27,28]. ...
... On the other hand the research into the radical thermal polymerization of acrylates [5][6][7][8] and styrene [9] containing dissolved polyheteroarylenes, particularly polyimides, including the three-dimensional copolymerization of MMA with various difunctional monomers [10,11], has shown the possibility to synthesize copolymers containing fragments of polyheteroarylenes and of carbon-chain polymers based on the vinyl monomers. In a previous work, using styrene as the vinyl monomer, it has been established that the styrene homopolymer was not formed even in the presence of a small (4 wt.%) content of PI in the monomer [9]. ...
... MMA and monomers for the synthesis of polyimides and model diimides were purified by common methods [7]. Photoinitiator (Pht) IRGACURE-1700 was supplied by CIBA-GEIGY and used as received. ...
New copolymers have been synthesized by anionic or radical photopolymerization of ε-caprolactam or methyl methacrylate (MMA) in the presence of dissolved polyimides bearing hexafluoroisopropylidene, fluorene or other groups. Using diimides as models it was shown that the kinetics of anionic polymerization of ε-caprolactam depends on the nature of spacer between the imide cycles. The mechanical and tribological properties of copolymers, their water absorbance and the microstructure of copolymer films were studied. It was found that upon the selection of polyimide activator it was possible to gain the desirable control over the polymer properties, namely, the gel fraction content, phase composition, compression modulus, notched Izod impact strength, friction coefficient and temperature of frictional contact. The kinetics of radical polymerization of MMA in the presence of polyimide and model diimide has been studied by differential scanning photocalorimetry and infrared spectroscopy. From the results of the reaction kinetics and the study of polymer structures by Fourier transform infrared spectroscopy, nuclear magnetic resonance, size-exclusion chromatography and thermogravimetric analysis it has been established that radical photopolymerization of MMA in the presence of polyimide leads to the formation of copolymers owing to chain transfer reactions and/or chain termination by the relevant condensation polymer. It has been established that the imide cycles play a significant role in the formation of both copolymers with ε-caprolactam and MMA, respectively.
... Research into the radical thermal polymerization of acrylates [1][2][3][4] and styrene [5] containing dissolved polyheteroarylenes (PHA), including the three-dimensional copolymerization of methyl methacrylate (MMA) with various difunctional monomers [6,7], has shown the possibility to synthesize copolymers containing fragments of polyheteroarylenes and of carbon-chain polymers based on the vinyl monomers. In previous work using styrene as the vinyl monomer it has been established that the styrene homopolymer is not formed even in the presence of only a small (4 wt%) content of polyimide (PI) in the monomer [5]. ...
... Materials. Vinyl monomers, solvents, and monomers for the synthesis of polyheteroarylenes and model Diimide were purified by literature methods [3]. Photoinitiator (Pht) IRGACURE-1700 was supplied by CIBA-GEIGY and used as received. ...
... In our earlier work it was shown that both PAr and PI cause significant changes in the kinetics of thermal polymerization of vinyl monomers [4] and in the properties of the polymers formed [3,5]. ...
Radical photopolymerization of (meth)acrylates in the presence of dissolved polyheteroarylenes has been investigated. The kinetics of radical polymerization of unsaturated monomers in the presence of polyheteroarylenes and model compounds has been studied by Differential Scanning Photocalorimetry and Infrared Spectroscopy. From the results of investigations into the kinetics and the polymer structures (Fourier Transform Infrared Spectroscopy, Nuclear Magnetic Resonance, Size-exclusion Chromatography, Thermogravimetric analysis), it has been established that radical photopolymerization of vinyl monomers in the presence of polyheteroarylenes leads to the formation of copolymers owing to chain transfer reactions and/or chain termination by the relevant condensation polymer. Using Electron Spin Resonance Spectroscopy the novel radicals upon the addition of model compounds for the polyheteroarylenes have been detected, and a mechanism of copolymer formation has been proposed.
Crosslinked copolymers capable of swelling in organic solvents were synthesized by the free-radical copolymerization of methyl methacrylate and 2-10 wt % allyl methacrylate in the presence of polyimide (4 wt %, ηinh = 0.38-1.02 dl/g), soluble in the starting reaction mixture, and without polyimide. Using isothermal calorimetry at 70°C, it was shown that, as the concentration of a crosslinking agent increases, conversions that correspond to the onset of autoacceleration and autoretardation and the intensity of the gel effect decrease. It was demonstrated that the addition of an aromatic polyimide to the system also influences the parameters of the gel effect in copolymerization and the homogeneity of the resulting polymer samples. Swelling of the polymer systems of interest in chloroform and toluene was studied, and the parameters of their network structure were determined. It was found that the thermal stability of PMMA was enhanced upon the addition of aromatic polyimide. When the amount of allyl methacrylate was reduced to 2 wt %, the compressive and flexural strength and moduli of the resulting polymers increased.
Polymer systems were prepared through the free-radical polymerization of methyl methacrylate in the presence of 4 wt % dissolved poly(arylates). The latter polymers were shown to affect the parameters of the gel effect. It was demonstrated that, as the molecular mass of poly(imide) dissolved in methyl acrylate grows, the conversion corresponding to the onset of autoacceleration and the rate of polymerization at all stages of the process decrease. The data on the free-radical polymerization of methyl methacrylate carded out in the presence of model compounds (diimide and diester) provide evidence that the reactions of chain transfer to the benzene nuclei of poly(heteroarylenes) are not the only path of copolymer formation.
The free-radical polymerization of styrene and its copolymerization with MMA in the presence of polyheteroarylenes of various structures yielded new polymers that differed in molecular mass characteristics, solubility, and thermal and mechanical properties from the corresponding homopolymers. The properties of the as-synthesized polymers were compared with those of analogous polymer systems based on various (meth)acrylates and polyheteroarylenes. The free-radical polymerization of styrene in the presence of a model aromatic diimide and its copolymerization with MMA in the presence of an aromatic polyimide (PI) at various initiator concentrations was studied by calorimetry under isothermal conditions. Based on the experimental data obtained, a reaction scheme, including the formation of chemical bonds between PI macromolecules and styrene units in polystyrene (PS)-PMMA copolymers, was suggested.
