Unusual Stepwise Protonation and J‐Aggregation of meso‐Tetrakis(N‐methylpyridinium‐4‐yl)porphine on Binding Poly(sodium vinylsulfonate)

The binding of a tetracationic porphyrin to a highly charged polymer like poly(sodium vinylsulfonate) has been investigated over a wide pH range and under various experimental conditions. We present evidence that, depending on the pH, the high electrostatic field exerted by the polymer stabilizes the diprotonated form of the free base porphyrin at unusual pH values or otherwise causes the formation of H‐type aggregates. In particular, at a low polymer concentration, lowering the pH at first allows the formation of the diacid species then it determines its reorganization in close‐packed J‐type aggregates. The employment of various metallo‐derivatives of the title porphyrin enables a better insight into the nature of all the detected species.     

Multifunctional poly(2,5‐benzimidazole)/carbon nanotube composite films

The AB‐monomer, 3,4‐diaminobenzoic acid dihydrochloride, was recrystallized from an aqueous hydrochloric acid solution and used to synthesize high‐molecular‐weight poly(2,5‐benzimidazole) (ABPBI). ABPBI/carbon nanotube (CNT) composites were prepared via in situ polymerization of the AB‐monomer in the presence of single‐walled carbon nanotube (SWCNT) or multiwalled carbon nanotube (MWCNT) in a mildly acidic polyphosphoric acid. The ABPBI/SWCNT and ABPBI/MWCNT composites displayed good solubility in methanesulfonic acid and thus, uniform films could be cast. The morphology of these composite films was studied by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The results showed that both types of CNTs were uniformly dispersed into the ABPBI matrix. Tensile properties of the composite films were significantly improved when compared with ABPBI, and their toughness (～200 MPa) was close to the nature's toughest spider silk (～215 MPa). The electrical conductivities of ABPBI/SWCNT and ABPBI/MWCNT composite films were 9.10 × 10^?5 and 2.53 × 10^?1 S/cm, respectively, whereas that of ABPBI film was 4.81 × 10^?6 S/cm. These values are ～19 and 52,700 times enhanced by the presence of SWCNT and MWCNT, respectively. Finally, without acid impregnation, the ABPBI film was nonconducting while the SWCNT‐ and MWCNT‐based composites were proton conducting with maximum conductivities of 0.018 and 0.017 S/cm, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1067–1078, 2010     

Synthesis of thermo‐responsive 4‐arm star‐shaped porphyrin‐centered poly(N,N‐diethylacrylamide) via reversible addition‐fragmentation chain transfer radical polymerization

Tetrafunctional porphyrins‐containing trithiocarbonate groups were synthesized by an ordinary esterification method. This tetrafunctional porphyrin (TPP‐CTA) could be used as a chain transfer agent in a controlled reversible addition‐fragmentation chain transfer (RAFT) radical polymerization to prepare well‐defined 4‐arm star‐shaped polymers. N,N‐Diethylacrylamide was polymerized using TPP‐CTA in 1,4‐dioxane. Poly(N,N‐diethylacrylamide) (PDEA) is known to be a thermo‐responsive polymer, and exhibits a lower critical solution temperature (LCST) in water. The star‐shaped PDEA polymer (TPP‐PDEA) was therefore also thermo‐responsive, as expected. The LCST of this polymer depended on its concentration in water, as confirmed by turbidity, dynamic light scattering (DLS), static light scattering (SLS), and ¹H NMR measurements. The porphyrin cores were compartmentalized in PDEA shells in aqueous media. Below the LCST, the fluorescence intensity of TPP‐PDEA was about six times larger than that of a water‐soluble low molecular weight porphyrin compound (TSPP), whose fluorescence intensity was independent of temperature. Above the LCST, the fluorescence intensity of TPP‐PDEA decreased, while the intensity was about three times higher than that of TSPP. These observations suggested that interpolymer aggregation occurred due to the hydrophobic interactions of the dehydrated PDEA arm chains above the LCST, with self‐quenching of the porphyrin moieties arising from these interactions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009     

Fabrication of Pyrene and Tetraphenylethylene Nanostructures by a Hydrolysis‐Assisted Co‐Assembly

The poly(allylamine hydrochloride)‐g‐pyrene‐tetraphenylethylene (PAH‐g‐Py‐g‐TPE) copolymers with different ratios of Py and TPE are synthesized by grafting 1‐pyrenecarboxaldehyde (Py‐CHO) and tetraphenylethylenecarboxaldehyde (TPE‐CHO) to PAH via a Schiff base reaction in methanol. The PAH‐g‐Py‐g‐TPE forms spherical micelles in water regardless of the ratios of Py and TPE, which can transform into different nanostructures after being incubated in pH 0 and pH 2 solutions, respectively. These nanomaterials including nanoparticles (NPs), nanorods (NRs), nanotubes (NTs) and nanoribbons (NBs) are composed of Py‐CHO and TPE‐CHO with different ratios, and emit fluorescence with colors different from the pure Py NRs and NTs, and TPE NPs.     

Preparation,Characterization, and Bioelectrocatalytic Properties of Hemoglobin Incorporated Multiwalled Carbon Nanotubes‐Poly‐L‐lysine Composite Film Modified Electrodes Towards Bromate

The present work describes preparation of hemoglobin‐incorporated multiwalled carbon nanotubes‐poly‐L ‐lysine (MWCNT‐PLL)/Hb) composite modified electrode film modified glassy carbon electrode (GCE) and its electrocatalytic behavior towards reduction of bromate ( ) in 0.1 M acetate buffer (pH 5.6). The modified electrode has been successfully fabricated by immobilizing hemoglobin on MWCNT dispersed in poly‐L ‐lysine. The surface morphologies of MWCNT, PLL and Hb were characterized using atomic force microscopy (AFM). The voltammetric features suggested that the charge transport through the film was fast and the electrochemical behavior resembles that of surface‐confined redox species. Cyclic voltammetry was used to investigate the electrocatalytic behavior of the modified electrode towards bromate and was compared with that of the CNT‐modified as well as bare electrode. The analytical determination of bromate has been carried out in stirred solution at an optimized potential with a sensitivity of 7.56 μA mM^?1 and the calibration curve was linear between 1.5×0^?5 to 6.0×0^?3 M.     

Arginine Side Chains as a Dispersant for Individual Single‐Wall Carbon Nanotubes

Charged peptides and proteins disperse single‐wall carbon nanotubes (SWCNTs) in aqueous solutions. However, little is known about the role of their side chains in their interactions with SWCNTs. Homopolypeptide–SWCNT systems are ideal for investigating the mechanisms of such interactions. In this study, we demonstrate that SWCNTs are individually dispersed by poly‐L ‐arginine (PLA). The debundled SWCNTs exhibited a distinct fluorescence. The dispersibility of SWCNTs with PLA was greater than that of SWCNTs with poly‐L ‐lysine (PLL). Molecular dynamics simulations suggest that the side chains of PLA have stronger interactions with the sidewalls of SWCNTs compared with those of PLL. The guanidinium group at the end of the side chain of an arginine residue plays an important role in the interaction with SWCNTs, likely through hydrophobic, van der Waals, and π–π interactions. PLA can be useful as a tool for the dispersion of SWCNTs and can be used to non‐covalently anchor materials to SWCNTs with strong binding.     

Supramolecular micellization and pH‐inducible gelation of a hydrophilic block copolymer by block‐specific threading of α‐cyclodextrin

A poly(ethylene glycol)‐b‐poly(L ‐lysine) diblock copolymer (PEG‐b‐PLL) was synthesized. Micellization of this hydrophilic copolymer due to the block‐specific threading of α‐cyclodextrin (α‐CD) molecules onto the polyethylene glycol (PEG) block yielded supramolecular‐structured nanoparticles, which undergoes pH‐inducible gelation in aqueous media. The pH‐inducible gelation of supramolecular micelle in water appeared to be completely reversible upon pH changes. The synergetic effect of selective complexation between PEG block and α‐CD and the pH‐inducible hydrophobic interaction between PLL blocks at pH 10 was believed to be the driving force for the formation of the supramolecular hydrogel. ¹H NMR and wide angle X‐ray diffraction (WAXD) were employed to confirm the inclusion complexation between α‐CD and PEG block. Meanwhile, the morphology of the micellized nanoparticles was investigated by transmission electron microscopy (TEM). The thermal stability of inclusion complexes (ICs) was investigated and the rheologic experiment was conducted to reveal the micelle‐gel transition. Such pH‐induced reversible micelle‐gel transition of the supramolecular aggregates may find applications in several fields, for example as advanced biomedical material possessing stimulus‐responsiveness. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 782–790, 2008     

Allyloxyporphyrin‐Functionalized Multiwalled Carbon Nanotubes: Synthesis by Radical Polymerization and Enhanced Optical‐Limiting Properties

Allyloxyporphyrin‐functionalized multiwalled carbon nanotubes (MWCNT‐TPP) were synthesized by radical polymerization and characterized by FTIR, UV/Vis absorption, and X‐ray photoelectron spectroscopy; elemental analysis; TEM; and thermogravimetric analysis. Z‐scan studies revealed that this nanohybrid exhibits enhanced nonlinear optical (NLO) properties compared to a control sample consisting of a covalently unattached physical blend of MWCNTs and porphyrin, as well as to the separate MWCNTs and porphyrin. At the wavelengths used, the mechanism of enhanced optical limiting likely involves reverse saturable absorption, nonlinear scattering, and photoinduced electron/energy transfer between the MWCNTs and the porphyrin. The role of electron/energy transfer in the NLO performance of MWCNT‐TPP was investigated by Raman and fluorescence spectroscopy.     

Effect of pH and Temperature on Adsorption of Dimethyl Phthalate on Carbon Nanotubes in Aqueous Phase

Adsorptions of dimethyl phthalate (DMP) on carbon nanotubes (CNTs) in aqueous phase at various pH and temperatures were studied. The increase in pH results in the increase in adsorption coefficient. The adsorption is governed by the π-π electron interaction which is affected by the changes in pH of the medium. The outer diameter of the CNTs greatly influences the adsorption behavior of CNT for DMP. Under the same working temperature, the adsorption capacity of CNTs for DMP is inversely related to the average outer diameter of the CNT: single-walled SWCNT (1.4 nm)>multi-walled MWCNT10 (9.4 nm)>MWCNT30 (27.8 nm)>MWCNT40 (42.7 nm). The larger surface area of CNTs provides many active sites for adsorption of DMP molecules. The Freundlich model can describe well the adsorption isotherms of DMP on CNTs. The thermodynamic parameters of standard free energy, standard enthalpy (ΔH), and standard entropy changes are determined, showing that the adsorption of DMP on CNTs is an endothermic and spontaneous reaction. The ΔH value of 27.8 nm-sized MWCNT (22.69 kJ/mol) is higher than 1.4 nm-sized SWCNT (6.05 kJ/mol), inferring that the adsorption process becomes more endothermic with the increase in the outer diameter of CNTs.     

四-(对-磺基苯基)卟啉二酸(H_4~(2+)TSPP)分子聚集体的共振喇曼光谱研究

研究了四－（对－磺基苯基）卟啉二酸（Ｈ２＋４ＴＳＰＰ）的Ｊ－聚集体共振喇曼光谱,用氘代法考察了各喇曼谱带的同位素位移．指认３条低波数喇曼带为分子聚集体的晶格模．喇曼光谱退偏比测量表明,聚集体中Ｈ２＋４ＴＳＰＰ的对称性较分子态降低．比较游离碱Ｈ２ＴＳＰＰ和分子态Ｈ２＋４ＴＳＰＰ共振喇曼光谱讨论了聚集体中Ｈ２＋４ＴＳＰＰ的结构变化．Ｈ２＋４ＴＳＰＰ在聚集体中以接近面对面方式排列     

Simultaneous Detection of Dopamine and Uric Acid on Indium Tin Oxides Modified with Cost‐effective Gas‐phase Synthesized Single Walled Carbon Nanotubes

Cost‐effective gas‐phase synthesized single walled carbon nanotubes (SWCNTs) were first employed for the surface modification of indium tin oxides (ITO) via electrostatic coating of poly‐l‐lysine (PLL). Compared with control substrates of bare ITO and SWCNT‐PLL‐slide glasses, SWCNT‐PLL‐ITO, with high catalytic properties associated with large surface areas, showed significant improvement of electro catalytic activity toward the oxidation of dopamine (DA) and uric acid (UA). The cyclic voltammetric (CV) peak separation of oxidation for both DA and UA was estimated to be ∼ 0.13 V, which renders them capable of simultaneously detecting DA and UA in a mixed solution. The differential pulse voltammetry (DPV) technique was further performed to obtain a linear detection range of DA from 1.0 μM to 100 μM, and a detection limit of 1.0 μM was confirmed in the mixed solution. Furthermore, the practical analytical ability of the method was finally confirmed by selective detection of both DA and UA in human urine samples without any preliminary treatment, implying the feasibility of applying bio‐sensors in a low‐cost manner.     

Counterion-dependent excitonic spectra of tetra(p-carboxyphenyl)porphyrin aggregates in acidic aqueous solution

Aggregates of the diacid form of tetra(p-carboxyphenyl)porphyrin (TCPP) are found to be stabilized in aqueous solution at low pH in the presence of poly(vinyl alcohol). At pH values in the range from about 1 to 4, a split Soret band is observed which is independent of counterion and tentatively assigned to a dimer species. As the pH is made lower than 1, the spectra evolve to reveal the presence of porphyrin aggregates. As in the case of the well-known aggregates of the related tetra(p-sulfonatophenyl)porphyrin (TSPP) diacid, the concentration of spectroscopically distinguishable aggregates increases with increasing ionic strength or decreasing pH. Unlike aggregates of TSPP, however, TCPP aggregates below pH 1 have visible absorption spectra which depend on the counterion, which is Cl(-) or NO(3)(-) in this study. In this work, we present visible absorption, light-scattering, and resonance Raman spectra of TCPP diacid in its monomer, dimer, and aggregated forms and attempt to understand the structural basis for counterion-dependent structure and excitonic coupling in the aggregates. Evidence is presented for intercalation of inorganic counterions between porphyrin molecules in the aggregate, an effect which to our knowledge has not been previously reported.     

Poly(γ‐benzyl‐L‐glutamate)‐functionalized single‐walled carbon nanotubes from surface‐initiated ring‐opening polymerizations of N‐carboxylanhydride

Single‐walled carbon nanotubes (SWCNTs) have been functionalized with poly(γ‐benzyl‐L ‐glutamate) (PBLG) by ring‐opening polymerizations of γ‐benzyl‐L ‐glutamic acid‐based N‐carboxylanhydrides (NCA‐BLG) using amino‐functionalized SWCNTs (SWCNT‐NH₂) as initiators. The SWCNT functionalization has been verified by FTIR spectroscopy and transmission electron microscopy. The FTIR study reveals that surface‐attached PBLGs adopt random‐coil conformations in contrast to the physically absorbed or bulk PBLGs, which exhibit α‐helical conformations. Raman spectroscopic analysis reveals a significant alteration of the electronic structure of SWCNTs as a result of PBLG functionalization. The PBLG‐functionalized SWCNTs (SWCNT‐PBLG) exhibit enhanced solubility in DMF. Stable DMF solutions of SWCNT‐PBLG/PBLG with a maximum SWCNTs concentration of 259 mg L^?1 can be readily obtained. SWCNT‐PBLG/PBLG solid composites have been characterized by differential scanning calorimetry, thermogravimetric analysis, wide/small‐angle X‐ray scattering (W/SAXS), scanning electron microscopy, and polarized optical microscopy for their thermal or morphological properties. Microfibers containing SWCNT‐PBLG and PBLG can also be prepared via electrospinning. WAXS characterization reveals that SWCNTs are evenly distributed among PBLG rods in solution and in the solid state where PBLGs form a short‐range nematic phase interspersed with amorphous domains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2340–2350, 2010     

Templated nanostructured PS‐b‐PEO nanotubes

With anodic aluminum oxide (AAO) membranes as wetting templates, nanotubes of the cylinder‐forming polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) copolymer were generated. The PS‐b‐PEO solution was introduced into the cylindrical nanopores of an AAO membrane by capillary force and polymeric nanotubes formed after solvent evaporation. Because of the water solubility of the cylindrical PEO microdomains and the orientation of the cylindrical PEO microdomains with respect to the nanotube walls, the nanotubes were permeable to aqueous media. PS‐b‐PEO nanotubes were also prepared on the interior walls of amorphous carbon nanotubes (a‐CNTs). Because of the unique water permeability of the PEO microdomains, an avenue for functionalizing the interior of the a‐CNTs is enabled. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2912–2917, 2007     

Double‐Wall Carbon Nanotube–Porphyrin Supramolecular Hybrid: Synthesis and Photophysical Studies

Double‐wall carbon nanotubes (DWCNTs) with pyridyl units covalently attached to the external wall through isoxazolino linkers and carboxylic groups that have been esterified by pentyl chains are synthesized. The properties of these modified DWCNTs are then compared with an analogous sample based on single‐wall carbon nanotubes (SWCNTs). Raman spectroscopy shows the presence of characteristic radial breathing mode vibrations, confirming that the samples partly retain the integrity of the nanotubes in the case of DWCNTs, including the internal and external nanotubes. Quantification of the pyridyl content for both samples (DWCNT and SWCNT derivatives) is based on X‐ray photoelectron spectroscopy and thermogravimetric profiles, showing very similar substituent load. Both pyridyl‐containing nanotubes (DWCNTs and SWCNTs) form a complex with zinc porphyrin (ZnP), as evidenced by the presence of two isosbestic points in the absorption spectra of the porphyrin upon addition of the pyridyl‐functionalized nanotubes. Supramolecular complexes based on pyridyl‐substituted DWCNTs and SWCNTs quench the emission and the triplet excited state identically, through an energy‐transfer mechanism based on pre‐assembly of the ground state. Thus, the presence of the intact inner wall in DWCNTs does not influence the quenching behavior, with respect to SWCNTs, for energy‐transfer quenching with excited ZnP. These results sharply contrast with previous ones referring to electron‐transfer quenching, in which the double‐wall morphology of the nanotubes has been shown to considerably reduce the lifetime of charge separation, owing to faster electron mobility in DWCNTs compared to SWCNTs.     

Facile Synthesis and Enhanced Nonlinear Optical Properties of Porphyrin‐Functionalized Multi‐Walled Carbon Nanotubes

Two multi‐walled carbon nanotube (MWCNT)‐based nanohybrids, MWCNT–ZnTPP and MWCNT–TPP (TPP=5‐[4‐{2‐(4‐formylphenoxy)‐ ethyloxy}phenyl]‐10,15,20‐triphenylporphyrin, ZnTPP=5‐[4‐{(4‐formylphenyl)ethynyl}phenyl]‐10,15,20‐triphenylporphinatozinc(II)), were prepared directly from pristine MWCNTs through 1,3‐dipolar cycloaddition reactions. Covalent attachment of the porphyrins to the surfaces of the MWCNTs was confirmed by Fourier transform infrared spectroscopy, ultraviolet/visible absorption, fluorescence, Raman, and X‐ray photoelectron spectroscopy, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin moieties to the surface of the MWCNTs significantly improves the solubility and ease of processing of these MWCNT–porphyrin composite materials. Z‐scan studies reveal that these MWCNT–porphyrin nanohybrids exhibit enhanced nonlinear optical properties under both nanosecond and picosecond laser pulses at λ=532 nm in comparison with free MWCNTs and the free porphyrin chromophores, whereas superior optical limiting performance was displayed by MWCNT–porphyrin composite materials rather than MWCNTs/ZnTPP and MWCNTs/TPP blends, which is consistent with a remarkable accumulation effect as a result of the covalent linkage between the porphyrin and the MWCNTs.     

Matrix‐polymer‐functionalized multiwalled carbon nanotubes as a highly efficient toughening agent for matrix polymers

Matrix‐polymer‐functionalized multiwalled carbon nanotubes (MWCNTs) are demonstrated as a highly efficient toughening agent for matrix polymers. With poly(vinylidene fluoride) (PVDF) as the matrix polymer, the PVDF/MWCNT‐PVDF nanocomposite films show high toughness. With a small load amount of MWCNT‐PVDF (0.07 wt %), the nanocomposite film shows a yield point and a constant‐stress extension region in stress–strain tests, compared with the typical low‐extensibility feature of neat PVDF film. The PVDF/MWCNT‐PVDF‐0.7 film exhibits a 180‐fold increase of toughness and about 38‐fold increase in strain at break compared with neat PVDF film. This toughening effect is attributed to (a) homogeneous dispersion of MWCNT‐PVDF in PVDF, (b) the high efficiency of load‐transfer across MWCNT/PVDF interface, and (c) the long length of the MWCNTs. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Tetrakis(4-sulfonatophenyl)porphyrin fluorescence as reporter of human serum albumin structural changes induced by guanidine hydrochloride

The interaction of the drug carrier protein human serum albumin (HSA) with the ionic, free base porphyrin tetrakis(4-sulfonatophenyl)porphyrin (TSPP) was investigated under chemical denaturation conditions using guanidine hydrochloride (Gdn-HCl) in aqueous solution at pH 7 and 2.5. Protein stability was studied by fluorescence spectroscopy using intrinsic tryptophan fluorescence, whereas far-UV circular dichroism gave information regarding conformational changes. Steady-state and time-resolved fluorescence as well as extinction and induced visible CD of TSPP were also monitored in the presence of the denaturant.The addition of 1.0 M Gdn-HCl inhibited the FRET process between the sole tryptophan residue of HSA and the porphyrin as inferred by an increase in the intrinsic fluorescence of the former together with a drop in the fluorescence of the latter. Simultaneously, an induced bisignate CD band was detected in the Soret region of TSPP extinction following the changes in the monomer ? aggregate equilibrium of TSPP. The features in the extinction spectra pointed to the formation of J-aggregates at pH = 2.5 and were confirmed by fluorescence lifetime measurements. At pH = 7, no TSPP dimers were detected in the absence of the protein or in the presence of native HSA. However, H-dimers or higher aggregates of TSPP associated to HSA were induced at concentrations of Gdn-HCl below 2 M.The main unfolding transition probed by HSA intrinsic fluorescence took place between 2 and 3 M Gdn-HCl at pH = 7, whereas at pH = 2.5 it was detected only above 2.8 M Gdn-HCl, coinciding with TSPP release into solution which occurs at high denaturant concentration for both pH studied. The results suggest that the chemical unfolding of HSA is a multistep process. The free base porphyrin contributes to an increase in the protein stability, particularly important under acidic conditions, where the protein is known to be in an expanded form in the absence of TSPP.The analysis of TSPP fluorescence fluctuations in the autocorrelation functions obtained using fluorescence correlation spectroscopy (FCS) in the presence of HSA at different denaturant concentrations showed that the porphyrin only interacts with the native form of the protein.Both fluorescence and circular dichroism data confirmed that in the noncovalent complex HSA–TSPP the free base porphyrin can act as a reporter of the protein structural changes induced either by pH or chemical denaturation.     

Preparation and Cellular Uptake of pH‐Dependent Fluorescent Single‐Wall Carbon Nanotubes

Fluorescent single‐wall carbon nanotubes (SWCNTs) were prepared by mixing cut SWCNTs with acridine orange (AO). The optical absorbance and fluorescence characteristics of AO–SWCNT conjugates display interesting pH‐dependent properties. Fluorescence microscopy in combination with transmission electron microscopy proves that AO–SWCNTs can enter HeLa cells and are located inside lysosomes. The endocytosis‐inhibiting tests show that the clathrin‐mediated endocytosis is a key step in the internalization process. The internalized AO–SWCNTs remain inside lysosomes for more than a week and have little effect on cell proliferation. These findings may be useful in understanding the SWCNT‐based intracellular drug delivery mechanism and help to develop new intracellular drug transporters.     

Thermal curing behavior of MWCNT modified vinyl ester‐polyester resin suspensions prepared with 3‐roll milling technique

This study aims to investigate the curing behavior of a vinyl ester‐polyester resin suspensions containing 0.3 wt % of multiwalled carbon nanotubes with and without amine functional groups (MWCNTs and MWCNT‐NH₂). For this purpose, various analytical techniques, including Differential Scanning Calorimetry (DSC), Fourier infrared spectroscopy (FTIR), Raman Spectroscopy, and Thermo Gravimetric Analyzer (TGA) were conducted. The resin suspensions with carbon nanotubes (CNTs) were prepared via 3‐roll milling technique. DSC measurements showed that resin suspensions containing CNTs exhibited higher heat of cure (Q), besides lower activation energy (E_a) when compared with neat resin. For the sake of simplicity of interpretation, FTIR investigations were performed on neat vinyl ester resin suspensions containing the same amount of CNTs as resin. As a result, the individual fractional conversion rates of styrene and vinyl ester were interestingly found to be altered dependent on MWCNTs and MWCNT‐NH₂. The findings obtained from RS measurements of the cured samples are highly proportional to those obtained from FTIR measurements. TGA measurements revealed that CNT modified nanocomposites have higher activation energy of degradation (E_d) compared with the cured polymer. The findings obtained revealed that CNTs with and without amine functional groups alter overall thermal curing response of the surrounding matrix resin, which may probably impart distinctive characteristics to mechanical behavior of the corresponding nanocomposites achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1511–1522, 2009