Mechanical properties of crosslinked polyurethane elastomers based on well‐defined prepolymers

This article presents research findings for selected mechanical properties of polyurethane elastomers. The studied elastomers were synthesized with the prepolymer‐based method with the use of controlled molecular weight distribution (MWD) urethane oligomers and with the classical single‐stage method. Prepolymers with defined MWDs were obtained with the use of a multistage method, that is, step‐by‐step polyaddition. To produce elastomers, isocyanate oligomers were then crosslinked with triethanolamine, whereas hydroxyl oligomers were crosslinked with 4,4′,4′′‐triphenylmethane triisocyanate (Desmodur RE). The tensile strength of the obtained elastomers ranged from 1.0 to 7.0 MPa, the ultimate elongation approached 1700%, the Shore A hardness varied from 40 to 93°, and the abrasion resistance index fell within 15–140. The effects of the types of raw materials used, the chemical structures, the production methods, and the supermolecular structures on the mechanical properties of the obtained polyurethane elastomers were examined. When the obtained findings were generalized, it was concluded that the structural changes in the polyurethanes, which were favorable for intermolecular interactions, improved the tensile strength, hardness, and abrasion resistance of the materials and impaired their ultimate elongation at the same time. More orderly supermolecular structures and, therefore, superior mechanical properties were found for polyurethane elastomers produced with the prepolymer method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of fullerene derivatives on the gas permeability of thermoplastic polyurethane elastomers

In an effort to improve the gas barrier properties of thermoplastic polyurethane (TPU) elastomers, fullerene derivatives were added as fillers, and the resulting O₂ and CO₂ permeabilities were analyzed. The addition of 5 wt % polyhydroxylated fullerene {fullerenol [C₆₀(OH)_n] mixture, where n = 6–12} decreased the gas permeability by approximately 10–20%. According to the hole volumes computed with the results from positron annihilation lifetime spectroscopy, the addition of fullerene derivatives did not produce any changes in the hole volumes of the TPUs. Thus, the reduction in the TPU gas permeability was not caused by changes in the hole volumes. Instead, an inhibited diffusion of gas molecules by fullerene particles was deduced as the cause of the decrease in gas permeability from changes in the diffusion coefficient with temperature. The addition of urethanized fullerene, prepared through the chemical modification of fullerenol, markedly affected the TPU gas barrier properties. As compared to fullerenol addition, the gas barrier properties improved approximately fourfold for O₂ and approximately fivefold for CO₂. These results suggest that the dispersability of urethanized fullerene in TPU was higher than that of fullerenol. We found that the gas barrier properties were independent of the structure of polyol. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39986.     

Preparation,hydrogen bonding and properties of polyurethane elastomers with 1,2,3-triazole units by click chemistry

Two kinds of diols containing 1,2,3-triazole units were synthesized through the azide-alkyne cycloaddition reaction between propargyl alcohol and 1,4-diazidobutane. One of the diols, (butane-1,4/1,5-diylbis[1H-1,2,3-triazole-1,4/1,5-diyl])dimethanol (BDTDO-1), containing 1,4/1,5-disubstituted 1,2,3-triazole regioisomers, was directly prepared under thermal condition without Cu(I) catalyst. The other diol, (butane-1,4-diylbis[1H-1,2,3-triazole-1,4-diyl])dimethanol (BDTDO-2), containing 1,4-disubstituted 1,2,3-triazoles, was prepared by Cu(I) catalyzed click chemistry. Then, two kinds of 1,2,3-triazole modified polyurethane elastomers (PUEs) were prepared from the reaction of 4,4′-methylenebis(phenyl isocyanate) and poly(tetramethylene ether) glycol, with BDTDO-1 or BDTDO-2 as the chain extender (CE). It was found that the introduction of 1,2,3-triazoles and their substitution positions had significant influences on the hydrogen bonding, thermal and mechanical properties of PUEs. Compared with the PUE prepared from 1,4-butanediol as the CE, the PUE containing symmetric 1,4-disubstituted 1,2,3-triazoles units in the main chains shows higher values of hydrogen bonding, physical crosslinking density, Young's modulus, tensile strength and melting temperature, while lower glass transition temperature, resulting from the rigid structure and the ability to form more hydrogen bonds. However, the introduction of asymmetric 1,4/1,5-disubstituted 1,2,3-triazole moieties decreases the values of hydrogen bonding, thermal and mechanical properties of PUE appreciably due to the destruction of the ordered structure of the hard segments.     

Dielectric properties of C60 and Sc3N@C80 fullerenol containing polyurethane nanocomposites

Polymer–fullerene nanocomposites consisting of linear polyurethane (PU) chains crosslinked via increasing loadings of polyhydroxylated fullerenes (C₆₀ and Sc₃N@C₈₀, a metallic nitride fullerene) were prepared and characterized for their mechanical and dielectric properties using dynamic mechanical analysis (DMA) and broadband dielectric spectroscopy (BDS). Fullerene–polymer networks [C₆₀‐PU and Sc₃N@C₈₀‐PU] having high gel fractions, good mechanical properties and thermal stabilities were produced. Polyhydroxylated fullerenes C₆₀(OH)₂₉ and Sc₃N@C₈₀(OH)₁₈ were synthesized in high yield through a high‐speed vibration milling method and characterized using FTIR, matrix‐assisted laser desorption/ionization mass spectroscopy, and thermal gravimetric analysis. DMA of fullerene–PU networks indicates T_g ～ ?50°C, with a sub‐T_g relaxation due to local chain motions. BDS analyses of the fullerenes, before and after hydroxylation and before incorporation into the networks, revealed one relaxation and large real permittivity (ε′) values for C₆₀(OH)₂₉ relative to C₆₀. Analogous samples for Sc₃N@C₈₀ exhibit two relaxations, where the extra relaxation is attributed to motions of the cage‐encapsulated Sc₃N clusters. ε′ values for Sc₃N@C₈₀‐PU at a given frequency are higher than corresponding values for C₆₀‐PU, likely because of the rotationally mobile Sc₃N encapsulates. Surface and bulk resistivities of fullerene–PU networks were found to have a modest dependence on relative humidity. Capacitance versus voltage characteristics of the fullerene–PUs were also studied in the range of the applied dc bias voltage of ?30 to +30 v. It is generally concluded, based on all the evidence that this class of materials can be rendered quite polarizable and could be used as high dielectric permittivity materials in capacitance applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40577.     

Novel method for preparation of polyurethane elastomers with improved thermal stability and electrical insulating properties

A novel method was developed for the preparation of polyurethane with enhanced thermal stability and electrical insulation properties via the reaction of epoxy‐terminated polyurethane prepolymer (EPU) and poly(amic acid) (PAA). EPUs were synthesized from the reaction of glycidol with NCO‐terminated polyurethane prepolymers, which were prepared from the reaction of polycaprolactone‐based polyol (CAPA) of different molecular weights and some commercially available diisocyanates including hexamethylene diisocyante, toluene diisocyanate, and 4,4′‐methylene bis(phenyl isocyanate). PAA was prepared from the reaction of equimolar amounts of pyromellitic dianhydride and oxydianiline. The effects of PAA content, the nature of diisocyanate, and the molecular weight of CAPA on the mechanical, thermal, thermomechanical, and electrical properties of the final networks were investigated. The crosslink density of the samples was determined according to an equilibrium swelling method using the Flory–Rehner equation and was correlated to the structure of the final polymers. Gel content and activation energy of network formation in the absence and the presence of a tertiary amine catalyst were also studied. The results showed considerable improvement in the thermal, electrical, and mechanical properties compared to those of other common polyurethanes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1776–1785, 2007     

Block architecture influence on the structure and mechanical performance of drawn polyurethane elastomers

Some natural biopolymers such as spider silk exhibit superb mechanical properties, characterised by their great toughness. Synthetic polyurethane (PU) copolymers also endow great toughness but lack silk's stiffness and strength. The aim of this work was to elucidate the role of segment block architectural features that influence PU stiffness and strength after cold drawing. For this purpose PUs with varied soft segment character, crystalline versus rubbery, as well as with different hard segment chemistries, 4,4′‐diphenylmethane diisocyanate/1,4‐butanediol versus 1,6‐hexamethylene diisocyanate/1,4‐butanediol, were synthesised by a two‐step polymerisation method. We found that the architecture of both block segments has a dramatic influence on drawn PU mechanical performance, in which PUs with crystallisable soft segments and crystalline hard segments are shown to have a greater impact on developing stiffer and stronger materials. © 2013 Society of Chemical Industry     

Green polyurethane from dimer acid based polyether polyols: Synthesis and characterization

In this study, dimer acid (DA) obtained from waste soybean oil was used together with propylene oxide (PO) to obtain novel polyether polyols [prepolymers for polyurethanes (PUs)] through ring‐opening polymerization reaction. The average molecular weight of polyols was estimated by gel permeation chromatography and titration method. The substantial reaction between DA and PO was evident from FTIR and nuclear magnetic resonance spectroscopy. Subsequently, the polyols were reacted with chain extender [ethylene glycol, (EG)] and 4, 4 ‐ Diphenylmethane diisocyanate (MDI) to prepare green PUs. The effect of molar ratio variation of EG and MDI with a fixed amount of polyols was estimated by measuring hydrophobicity and mechanical strength of PUs. The molar ratio such as 1 : 4 : 5.7 of polyol : EG : MDI was found to exhibit maximum hydrophobicity and improved mechanical strength that were comparable with typical PU sample prepared from commercially available polyol, such as polypropylene glycol. FTIR spectroscopic analysis confirmed the chemical changes and possible crosslinking in PUs. Thermalgravimetric analysis and differential scanning calorimetry analysis also showed substantial thermal stability of the green PUs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41410.     

Mechanical and thermal properties of polyurethane elastomers based on hydroxyl‐terminated polybutadienes and biopitch

Biopitch is a renewable source of polyol obtained from Eucalyptus tar distillation, which was studied as an active component of polyurethane (PU). The polymerization occurred in one step, with a mixture of biopitch and hydroxyl‐terminated polybutadiene polyols reacted with 4‐4′‐diphenyl methane diisocyanate in the presence of dibutyltin dilaurate. Solid‐state ¹³C‐NMR, IR spectroscopy, elemental analysis, and thermal analysis [thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC)] were used to characterize the biopitch. The biopitch sample showed an aromatic and oxygenated structure with great thermal stability at high temperatures. Multiphasic PUs were synthesized and characterized by IR spectroscopy (attenuated total reflectance), elemental analysis, thermal analysis (TGA and DSC), mechanical assays (tensile strength, elongation at break, toughness, hardness, and resilience), and water absorption resistance (ASTM D 570‐81). In a comparative study of the synthesized elastomers, biopitch content increased tensile strength and hardness and decreased thermal stability, elongation at break, and water absorption. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 759–766, 2003     

Synthesis and properties of liquid crystalline polyurethane elastomers

Novel type of mesogenic chain extenders used in this study are N,N′‐bis(4‐hydroxyphenyl)‐3,4,3′,4′‐biphenyldicarboxyimide (BPDI) and N,N′‐bis[4‐(6‐hydroxyhexyloxy) phenyl]‐3,4,3′,4′‐biphenyldicarboxyimide (BHDI). BHDI has a flexible spacer of 6‐methylene units but BPDI does not. The liquid crystalline polyurethane elastomers were synthesized from BPDI or BHDI as a mesogenic chain extender, 4,4′‐diphenylmethane diisocyanate, and poly(oxytetramethylene)glycol (MW 1000) as a soft segment. Polyurethane based on BHDI exhibited two melting transitions. However, any melting behavior was not shown in the BPDI‐based polyurethanes because of higher melting temperature than decomposition temperature. The composition of polyurethanes was varied as a means of manipulating liquid crystalline behavior and physical properties. The BHDI‐based polyurethanes containing above 50 wt % of hard segment content exhibited nematic liquid crystal behaviors. As the hard segment content of the BHDI‐based polyurethanes increased, the glass transition temperature (T_g), strength, modulus, and the amount of hydrogen bonding increased. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 577–585, 2000     

Synthesis and thermomechanical characterization of polyurethane elastomers extended with α,ω‐alkane diols

A series of polyurethane (PU) elastomers was prepared by the reaction of poly(?‐caprolactone) and 4,4′‐diphenylmethane diisocyanate, which was extended with a series of chain extenders (CEs) having 2–10 methylene units in their structure. The completion of the reaction was confirmed by Fourier transform infrared spectroscopy. The chemical structures of the synthesized PU samples were characterized with Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR spectroscopy, and the thermal properties were determined by thermogravimetric analysis, DSC, and dynamic mechanical thermal analysis techniques. The mechanical properties were also studied and are discussed. The thermogravimetric analysis and DSC analysis showed that CE length had a considerable effect on the thermal properties of the prepared samples. The dynamic mechanical thermal analysis and damping peaks were also affected by the number of methylene units in the CE length. The elastomer extended with 1,2‐ethane diol exhibited optimum thermal properties, whereas the elastomer based on 1,10‐decane diol displayed the worst thermal properties. Tensile strength and elongation at break decreased with increasing CE length, whereas hardness showed the opposite trend. The glass‐transition temperature moved toward lower temperatures with increasing CE length. The decrease in the glass‐transition temperature and tensile properties were interpreted in terms of decreasing hard segments and increasing chain flexibility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of polyurethane urea based on fluorine‐containing bisphenoxydiamine

A fluorine‐containing bisphenoxydiamine, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (BAPF₆P), was synthesized and characterized by means of Fourier transform infrared spectrometry (FTIR), NMR, and elemental analysis. The obtained BAPF₆P was used as a chain extender to prepare polyurethane urea (PUU), whose morphology and properties were measured through FTIR, differential scanning calorimetry, thermogravimetric analysis, tensile measurements, and atomic force microscopy. The results show that the PUU elastomers based on BAPF₆P exhibited good mechanical properties and thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1863–1869, 2006     

Vinyl ether‐based polyacetal polyols with various main‐chain structures and polyurethane elastomers prepared therefrom: Synthesis,structure, and functional properties

Novel acid degradable polyacetal polyols and polyacetal polyurethanes able to controlled acid degradation were developed. Polyacetal polyols with various main‐chain structures were synthesized by polyaddition of various vinyl ethers with a hydroxyl group [4‐hydroxy butyl vinyl ether (CH₂?CH? O? CH₂CH₂CH₂CH₂? OH), 2‐hydroxy ethyl vinyl ether (CH₂?CH? O? CH₂CH₂? OH), diethylene glycol monovinyl ether (CH₂?CH? O? CH₂CH₂OCH₂CH₂? OH), and cyclohexanedimethanol monovinyl ether (CH₂?CH? O? CH₂? C₆H₁₀? CH₂? OH)] with p‐toluenesulfonic acid monohydrate (TSAM) as a catalyst in the presence of the corresponding diols [1,4‐butandiol (HO? CH₂CH₂CH₂CH₂? OH), ethylene glycol (HO? CH₂CH₂? OH), diethylene glycol (HO? CH₂CH₂OCH₂CH₂? OH), and 1,4‐cyclohexanedimethanol (HO? CH₂? C₆H₁₀? CH₂? OH)], respectively. Polyacetal polyurethanes were prepared by a two‐step polymerization, using the synthesized polyacetal polyols, 4,4′‐diphenylmethane diisocyanate (MDI), and 1,4‐butandiol (BD) as a chain extender. Depending on the main‐chain structures, these polyurethanes had different glass transition temperature (from ?44 to 19 °C) and properties such as hydrophobic or hydrophilic. Polyurethanes containing the hydrophilic main‐chain exhibited the thermoresponsiveness and had the certain volume phase transition temperature (VPTT). The polyacetal polyurethanes were flexible elastomers around room temperature (～25 °C) and thermally stable (T_d ≥ 310 °C) and additionally exhibited smooth degradation with a treatment of aqueous acid in THF at room temperature to give the corresponding raw material diols. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44088.     

热熔胶用聚氨酯弹性体的合成

以4,4’-二苯基甲烷二异氰酸酯（MDI）、聚乙二醇（PEG）和I,4-丁二醇（BIDO）为原料合成聚氨酯弹性体,采用流延法制备了热熔胶膜。考察了预聚反应的温度、时间对聚氨酯弹性体性能的影响,并对预聚体中NCO含量、异氰酸酯指数（R）、聚醚多元醇的种类以及相对分子质量等进行了探讨。确定了最佳反应条件：反应温度为（80±5）℃;反应时间为1．5～2．0h。预聚体中NCO质量分数控制在9％～10％,R值取1．02,选用相对分子质量为1500的PEG制备的热熔胶用聚氨酯弹性体性能优异。     

Synthesis of new anionic HTPB‐based polyurethane elastomers: Aqueous dispersion and physical properties

New segmented polyurethane (PU) anionomers based on hydroxytelechelic polybutadiene (HTPB) were synthesized via an environment‐friendly chemical route. Incorporation of carboxylated functions on the PU soft segment was carried out using a thiol‐ene reaction on HTPB vinyl double bonds with thioglycolic acid. PU water dispersions were obtained by addition of a water dispersible polyisocyanate, i.e., Bayhydur® 3100, to the modified ionic HTPB water dispersions. The key factor of this formulation is the control of ionic concentration apart from the hard segment content, oppositely to all other PU anionomer formulations. The influence of ionic content was studied through all steps of the PU material synthesis, from aqueous dispersions upto crosslinked materials' physical properties. For fully neutralized precursors, the stability of the ionic aqueous dispersions was higher than that was in six months. In all cases, particles were smaller than 200 nm. PU glass transition temperature, surface hydrophily and swelling increased with ionic content. But, however, PUs exhibit hydrophobic surface properties with a maximum surface tension of 45 mN m^?1 and a limited water uptake. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3312–3322, 2006     

Study on antistatic modification of polyurethane elastomer surfaces by grafting with vinyl acetate and antistatic agent

Under UV light, vinyl acetate (VAc) was grafted onto polyurethane (PU) elastomer membrane, using benzoyl peroxide as photoinitiator. After surface alcoholysis reaction, hydroscopic hydroxyl formed on the surface of PU, and under catalysis of MgCl₂, the antistatic agent combined with hydroxyl by chemical linkage, so that the antistatic durability of PU improved. The ATR‐FTIR spectrum, X‐ray photoelectron spectroscopy, and SEM characterized the grafted copolymers and verified the occurrence of grafting copolymerization. The effect of grafting degree of VAc on the antistatic ability of PU surface was also investigated in this study. Experimental results showed that after modification the surface electric resistivity of PU elastomer reached the nearly 10⁸ Ω class, with little change in spite of a washing‐fastness experiment, although its mechanical ability was slightly decreased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3617–3624, 2003     

Synthesis and photoconducting properties of C60‐bonded polystyrene initiated with C60Cln

C₆₀‐bonded polystyrene was produced with a novel initiator system, C₆₀Cl_n/CuCl/2,2′‐bipyridine (where the average value of n is 20). The molar ratio of styrene/C₆₀Cl_n/CuCl/bpy was 100:1/20:1:2, and the polymerization temperature was 130°C. Gel permeation chromatography detected with an ultraviolet detector demonstrated that C₆₀ was chemically bonded to polystyrene. The linear increase in the number‐average molecular weight (by gel permeation chromatography) with the conversion indicated that this novel initiator system had some characteristics of living polymerization. A possible polymerization mechanism was examined. The photoconducting properties of C₆₀‐bonded polystyrene were better than those of polystyrene initiated with CCl₄. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3001–3004, 2002     

Synthesis and investigation of properties of thiacalix[4]arene‐based polyurethane elastomers

A series of polyurethane elastomers (PUEs) derived from three thiacalix[4]arene derivatives (TC4As), namely p‐tert‐butylthiacalix[4]arene, tetrasodium thiacalix[4]arenetetrasulfonate and thiacalix[4]arenetetrasulfonic acid, as a portion of chain extender in a mixture with glycerol were synthesized. The effects of the chemical structure of TC4As used as chain extenders on the various properties of the prepared PUEs were investigated and compared with PUE extended with only glycerol as chain extender using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), scanning electron microscopy and a universal tensile tester. Moreover, the effect of the introduction of TC4As as a portion of chain extender on the hydrophobicity of the PUEs was also evaluated. DSC, FTIR spectroscopy and XRD revealed that the degree of phase separation and crystallinity in TC4A‐based PUEs was much higher than that of the glycerol‐based ones. Thus, it was concluded that the presence of TC4As in TC4A‐based PUEs seems to favour the formation of a more ordered structure due to an increase in the degree of phase separation. The TGA results also showed that, with incorporation of TC4As into the polyurethane backbone, the thermal stability of PUEs was improved. © 2014 Society of Chemical Industry     

Properties of thermoplastic polyurethane elastomers chemically modified by rosin

Thermoplastic polyurethane elastomers (TPUs) are prepared including different amounts of rosin in their composition. Rosin is used either as an additive, mixed in the TPU solutions, or as a reactant in the chain‐extension step of polymer synthesis. The properties of the materials are studied using solution viscosity measurements, size‐exclusion chromatography, stress‐controlled rheometry, differential scanning calorimetry, wide‐angle X‐ray diffraction, and contact angle determinations. Rosin as an additive does not markedly change the polymer properties. On the contrary, the use of rosin in the chain‐extension step leads to sharp increases of viscosity and molar mass as well as improvements of rheological properties and changes in morphology: the crystalline regions are more affected (variations in the softening temperature and enthalpy) than the amorphous ones (quite constant glass‐transition temperature). The conclusion is that rosin acts as an actual chain extender and that it modifies the organization of both the hard and the soft segments of the polymers. Furthermore, the TPUs are used as raw materials of solvent‐based adhesives, which adhesion properties are characterized by T‐peel tests of PVC/TPU adhesive joints. Rosin as an additive cannot improve the low tack (initial adhesive strength) of TPU, although as a chain extender or cochain extender (together with butane diol) rosin allows development of significant initial adhesive strengths, while keeping a high level of actual (maximal) adhesive strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3402–3408, 2001     

Degradation behavior of an ultraviolet and hygrothermally aged polyurethane elastomer: Fourier transform infrared and differential scanning calorimetry studies

The degradation behavior of an elastomeric polyurethane (PU) was investigated with accelerated ultraviolet (UV) and hygrothermal (HT) techniques. Samples were subjected to UV exposure and HT conditions for 3 or 5 months and were removed in 1‐month intervals from the test chambers. Their chemical structure was evaluated with Fourier transform infrared (FTIR) spectroscopy. The thermal transitions of the aged samples were evaluated with differential scanning calorimetry (DSC). Both FTIR and DSC results showed no evidence of significant structural damage to the HT‐aged PU throughout exposure. FTIR analysis of the UV‐aged samples showed a noticeable change in the chemical structure of the polymer after 1 month of UV exposure. The results from DSC correlated with the FTIR analysis of the UV‐aged samples. Spectroscopic and thermal analysis of the aging of the PU samples was correlated to mechanical analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Transformation of methano[60]fullerenes in dihydrofullerofuranes induced by electron transfer

The electrochemical reduction of methano[60]fullerenes (61-acetyl-61-(diethoxyphosphoryl)methano-60-fullerene 1, 61-acetyl-61-(diisopropoxyphosphoryl)methano-60-fullerene 2, 61-(2,2-diethoxyacetyl)-61-(diethoxy-phosphoryl)methano-60-fullerene 3, 61-phenyl-61-(1,2-dioxo-3,3-dimethyl-buthyl)methano-60-fullerene 4) in o-dichlorobenzene-DMF (3:1 v/v)/0.1 M Bu₄NBF₄ on a glass-carbon electrode proceeds in a few steps. The reversible transfer of the first electron results in the formation of radical anions registered by ESR method. The subsequent reduction proceeds differently because of the various stability of anionic intermediates. The radical anions of the methanofullerenes 3 and 4 are less stable than the radical anions of compounds 1 and 2 and less stable than the radical anions of methanofullerenes, which contain an ester and/or a phosphonate group. The opening of a cyclopropane ring occurs during the stage of the formation of radical trianions of methanofullerenes 1, 2. The same process for compounds 3, 4 proceeds slowly in radical anions and fast in dianions. The opening of cyclopropane ring for all compounds is not accompanied by the elimination of methanogroup and results in the formation of dihydrofullerenofurane derivatives. The transformation of methanofullerene 3 induced by single electron transfer proceeds via a chain reaction mechanism.