Surface analysis of cotton fabrics fluorinated in radio‐frequency plasma

Cotton fabrics were treated by radio‐frequency plasma with tetrafluoromethane (CF₄) and hexafluoropropene (C₃F₆) gases under different exposure times, pressures, and power levels. The hydrophobicity and water repellency were analyzed with measurements of the cosine of the contact angle (cos θ) and wet‐out time. The hydrophobicity was enhanced with treatments of both gases. X‐ray photoelectron spectroscopy (XPS) revealed increases in the surface fluorine content of 1–2% for CF₄ plasma and of 2.3–7.8% for C₃F₆ plasma. The relative chemical composition of the C_1s spectra after CF₄ and C₃F₆ plasma treatments showed increases in the relative amounts of ? C? O? C? and fluorocarbon groups (? CF, ? CF₂, and ? CF₃), whereas peak areas for ? COH and ? COOH decreased. The hydrophobicity was enhanced by the increase in the fluorine content and fluorocarbon groups. C₃F₆ plasma treatment resulted in higher hydrophobicity than CF₄ plasma treatment according to not only cos θ and wet‐out measurements but also XPS analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2038–2047, 2003     

Tailored surface properties of semi-fluorinated block copolymers by electrospinning

Diblock copolymers based on polystyrene (PS) macroinitiators and four different fluorinated monomers (perfluorooctyl ethyl methacrylate (FMA), pentafluorostyrene (FS), perfluorooctyl-ethylene oxymethyl styrene (EMS), 2,3,5,6-tetrafluoro-4-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecaoxy)styrene (FSF)) were synthesized via atom transfer radical polymerization (ATRP). The lengths of the PS and fluorinated blocks were altered and the surface and self-assembling properties of the polymers were compared with respect to the fluorinated monomer used and the fluorine content. The surface properties, contact angles and surface tension, were enhanced by the existence of the CF₃ groups at the end of the alkyl chains compared with poly(pentafluorostyrene). Hydrophobicity of the surfaces was further enhanced by electrospinning the polymer solutions, which yielded superhydrophobic surfaces with water contact angles >150° for polymers having CF₃ groups.     

Halogen bonding at the active sites of human cathepsin L and MEK1 kinase: efficient interactions in different environments

In two series of small‐molecule ligands, one inhibiting human cathepsin L (hcatL) and the other MEK1 kinase, biological affinities were found to strongly increase when an aryl ring of the inhibitors is substituted with the larger halogens Cl, Br, and I, but to decrease upon F substitution. X‐ray co‐crystal structure analyses revealed that the higher halides engage in halogen bonding (XB) with a backbone C?O in the S3 pocket of hcatL and in a back pocket of MEK1. While the S3 pocket is located at the surface of the enzyme, which provides a polar environment, the back pocket in MEK1 is deeply buried in the protein and is of pronounced apolar character. This study analyzes environmental effects on XB in protein–ligand complexes. It is hypothesized that energetic gains by XB are predominantly not due to water replacements but originate from direct interactions between the XB donor (C_aryl? X) and the XB acceptor (C?O) in the correct geometry. New X‐ray co‐crystal structures in the same crystal form (space group P2₁2₁2₁) were obtained for aryl chloride, bromide, and iodide ligands bound to hcatL. These high‐resolution structures reveal that the backbone C?O group of Gly61 in most hcatL co‐crystal structures maintains water solvation while engaging in XB. An aryl? CF₃‐substituted ligand of hcatL with an unexpectedly high affinity was found to adopt the same binding geometry as the aryl halides, with the CF₃ group pointing to the C?O group of Gly61 in the S3 pocket. In this case, a repulsive F₂C? F???O?C contact apparently is energetically overcompensated by other favorable protein–ligand contacts established by the CF₃ group.     

Aging of fluorocarbon thin films deposited on polystyrene from hyperthermal C3F+5 and CF+3 ion beams

Fluorocarbon films grown on polystyrene (PS) in vacuum from 25-100 eV CF⁺ ₃ and C₃F⁺ ₅ ions are aged by exposure to atmosphere for 4 and 8 weeks, then analyzed by X-ray photoelectron spectroscopy, atomic force microscopy, and water contact angle measurements. These fluorocarbon films oxidize with time, showing an increase in their oxygen/ carbon ratio and a decrease in their fluorine/carbon ratio. The decrease in fluorine/carbon ratio with aging is due not only to increased oxygen content, but also to surface restructuring and release of low molecular weight oxidized material from the surface. The higher oxidation and surface restructuring observed upon aging for 100 eV C₃F⁺ ₅ and 50 eV CF⁺ ₃ ion-modified PS can be additionally attributed to higher surface bond breakage and active site formation. 100 eV C₃F⁺ ₅ and 50 eV CF⁺ ₃ ion-modified PS surfaces are rougher than the 50 eV C₃F⁺ ₅ ion-modified PS. Overall, the aging process of these ion-deposited films appears similar to that of plasma-deposited films.     

Permeability of dried gases and gases dissolved in water through polyimide membranes modified by immersing in amino compound solutions

Membranes of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA)?2,3,5,6‐tetramethyl‐1,4‐phenylene diamine (TeMPD) polyimide, a fluorine‐containing polyimide synthesized using 6FDA and TeMPD, were modified by immersing them in various amino compound solutions for application in artificial lungs. Permeabilities of dried gases (P_G) and gases dissolved in water (P_L) through the membranes were investigated. The surface reaction ratios of all the modified membranes were higher than the total reaction ratio, indicating that the modified membranes exhibited graded structures that were reacted with amino compounds from both surfaces toward the interior. Both P_L (O₂) and P_L (CO₂) of the base membrane and amine‐modified membranes, except the membrane where d ‐glucamine was used, were lower than or equal to P_G (O₂) and P_G (CO₂), respectively. Both P_L (O₂) and P_L (CO₂) of the amine‐modified membranes decreased with increasing water content, which suggests that water content strongly affected permeability in liquid phase. Results indicate that water molecules interrupted gas permeation. Moreover, CO₂/O₂ permselectivity in liquid phase increases with high‐polarity amino compounds compared with the base membrane. POLYM. ENG. SCI. 56:178–186, 2016. © 2015 Society of Plastics Engineers     

Construction of ultra‐stable perovskite–polymer fibre membranes by electrospinning technology and its application to light‐emitting diodes

Recently, organometallic halide perovskites have shown attractive application prospects in photoelectric devices depending on their excellent electro‐optic properties. However, their poor stability has greatly limited their practical applications. Here, methylammonium lead tribromide (MAPbBr₃) crystals are protected by polystyrene (PS) fibre membranes using electrospinning technology. The MAPbBr₃@PS composite fibre membranes fabricated in this work not only show strong photoluminescence properties but also excellent stability: 70% of the fluorescence intensity of MAPbBr₃@PS is maintained after soaking in water for 30 days, 85% after leaving at 95 °C for 350 min, and 90% after irradiating under UV light for 100 h. The excellent stability of the MAPbBr₃@PS fibre membranes may be attributed to the hydrogen bonds between the MAPbBr₃ crystal and the PS fibre. In addition, a high‐brightness white‐light‐emitting diode based on MAPbBr₃@PS fibre was fabricated, which fully demonstrates its application prospects in the field of colour conversion. © 2020 Society of Industrial Chemistry     

Modified polydimethylsiloxane/polystyrene blended IPN pervaporation membrane for ethanol/water separation

In this article a modified polydimethylsiloxane (PDMS) blended polystyrene (PS) interpenetrating polymer network (IPN) membranes supported by Teflon (polytetrafluoroethylene) ultrafiltration membrane were prepared for the separation of ethanol in water by pervaporation application. The relationship between the surface characteristics of the surface‐modified PDMS membranes and their permselectivity for aqueous ethanol solutions by pervaporation are discussed. The IPN supported membranes were prepared by sequential IPN technique. The IPN supported membrane were tested for the separation performance on 10 wt % ethanol in water and were characterized by evaluating their mechanical properties, swelling behavior, density, and degree of crosslinking. The results indicated that separation performance, mechanical properties, density, and the percentage of swelling of IPN membranes were influenced by degree of crosslink density. Depending on the feed temperature, the supported membranes had separation factors between 2.03 and 6.00 and permeation rates between 81.66 and 144.03 g m^?2 h^?1. For the azeotropic water–ethanol mixture (10 wt % ethanol), the supported membrane had at 30°C a separation factor of 6.00 and a permeation rate of 85 g m^?2 h^?1. Compared to the PDMS supported membranes, the PDMS/PS IPN supported blend membrane ones had a higher selectivity but a somewhat lower permeability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Sulfonation of solid polystyrene using gaseous sulfur trioxide

Kinetics of the heterogeneous sulfonation of polystyrene (PS) beads using gaseous SO₃ was investigated. Scanning electron microscopy (SEM) and electron diffraction scattering spectroscopy (EDS) was employed to study the kinetics of diffusion of SO₃ into the PS particles. The diffusion of SO₃ through the barrier of sulfonated polystyrene (SPS) on the beads surface was the primary parameter determining the rate and the yield of the sulfonation reaction. The measurement of the time dependence of the thickness of sulfonated layer formed on the solid PS surface provided for the hypothesis that the sulfonation in heterogeneous phase was diffusion controlled. Diffusion coefficients of SO₃ in PS at ?5°C, 22°C, and at 50°C and activation energy of SO₃ diffusion to the solid PS were determined from these experimental data assuming in the first approximation a simple diffusion unaffected by the ongoing sulfonation reaction. The experimental data were fitted using Johanson‐Mehl‐Avrami‐Jerofyeev‐Kolgomorov's equation to obtain an overall rate constant of heterogeneous sulfonation on solid PS surface. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

A continuous method to prepare porous polystyrene membranes with high adsorption ability for polycyclic aromatic hydrocarbons

A convenient and continuous method to prepare porous polystyrene (PS) membranes via a microlayer coextrusion and template method is proposed. The porous PS membranes can be obtained via the acid etching of a CaCO₃ template embedded in the membranes. Scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy of the porous PS membranes show that most of the CaCO₃ particles can be etched away. The effects of etching time, CaCO₃ content, and membrane thickness on the porous structures are investigated, which can be used to regulate and control the porous structure. To demonstrate the adsorption performance of porous PS membranes on polycyclic aromatic hydrocarbons, pyrene is used as the model compound. Compared with that of solid PS membranes, porous PS membranes exhibit much higher adsorption performance for trace pyrene. The adsorption kinetics and isotherm of porous PS membranes can be well fit by pseudo‐second‐order kinetics and a Freundlich isotherm model. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45917.     

Graft polymerization of octafluoropentyl acrylate on polycaproamide thread

Octafluoropentyl acrylate [H(CF₂CF₂)₂CH₂‐ C(O)CH?CH₂] and polycaproamide (PA‐6) thread were copolymerized with a tert‐butyl hydroperoxide initiator. The fluorine content of the thread was 0.87–1.33% after copolymerization. The creation of ester polyfluorinated alkyl groups on the end of the polyamide macromolecules by the homolytical substitution of hydrogen atoms in the α‐CH₂? group of the ? HN? CH₂? (CH₂)₄? C(O)? chain led to an increase in the tensile strength of the PA‐6 thread. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4028–4029, 2006     

Facile fabrication of superhydrophobic raspberry‐like SIO2/polystyrene composite particles

A facile and novel strategy was reported on the fabrication of raspberry‐like SiO₂/polystyrene (SiO₂/PS) composite particles by emulsion polymerization in the presence of vinyl‐functionalized silica (vinyl‐SiO₂) particles, which were prepared via a one‐step sol–gel process using vinyltriethoxysilane as the precursor. The submicron vinyl‐SiO₂ particles were used as the core, and nanosized PS particles were then adsorbed onto the vinyl‐SiO₂ particles to form raspberry‐like composite particles during the polymerization process. The composition, morphology, and structure of the vinyl‐SiO₂ particles and the SiO₂/PS hybrid particles were characterized by thermogravimetric analysis, nuclear magnetic resonance, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. Superhydrophobic surface can be constructed by directly depositing the raspberry‐like SiO₂/PS composite particles on glass substrate, and the water contact angle can be adjusted by the styrene/SiO₂ weight ratio. In addition, the superhydrophobic film possessed a strong adhesive force to pin water droplet on the surface even when the film was turned upside down. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Solid‐phase photocatalytic degradation of polystyrene with TiO2/Fe(St)3 as catalyst

A novel photodegradable TiO₂‐Fe(St)₃‐polystyrene (TiO₂‐Fe(St)₃‐PS) nanocomposite was prepared by embedding TiO₂ and Fe(St)₃ into the commercial polystyrene. Ferric stearate was added into polymer as cocatalyst in order to improve the dispersion in polystyrene and photocatalytic efficiency of TiO₂ nanoparticles. Solid‐phase photocatalytic degradation of the TiO₂‐Fe(St)₃‐PS nanocomposite was carried out in an ambient air at room temperature under ultraviolet lamp. The properties of TiO₂‐Fe(St)₃‐PS composite film were compared with that of the pure PS film and the TiO₂‐PS composite film, through weight loss monitoring, scanning electron microscope, gel permeation chromatogram, and FTIR spectroscopy. The photodegradation efficiency of TiO₂‐Fe(St)₃‐PS composite film was higher than that of the pure PS film and the TiO₂‐PS composite film under the UV light irradiation. The average molecular weight (M_w) of TiO₂‐Fe(St)₃‐PS composite film decreased 63.08%, and the number of average molecular weight (M_n) decreased 79.49% after UV light irradiation for 480 h. Photo‐oxidation leads to an increase in the low molecular weight fraction by chain scission, thereby facilitating biodegradation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Silica/polystyrene and silica/polystyrene‐b‐polymethacryloxypropyltrimethoxysilane hybrid nanoparticles via surface‐initiated ATRP and comparison of their wettabilities

Both silica/polystyrene (SiO₂/PS) and silica/polystyrene‐b‐polymethacryloxypropyltrimethoxysilane (SiO₂/PS‐b‐PMPTS) hybrid nanoparticles were synthesized via surface‐initiated atom transfer radical polymerization (SI‐ATRP) from SiO₂ nanoparticles. The growths of all polymers via ATRP from the SiO₂ surfaces were well controlled as demonstrated by the macromolecular characteristics of the grafted chains. Their wettabilities were measured and compared by water contact angle (WCA) and surface roughness. The results show that the nanoparticles possess hydrophobic surface properties. The static WCA of SiO₂/PS‐b‐PMPTS hybrid nanoparticles is smaller than that of SiO₂/PS hybrid nanoparticles, meanwhile, the surface roughness of SiO₂/PS‐b‐PMPTS hybrid nanoparticles is yet slightly rougher than that of SiO₂/PS hybrid nanoparticles, which shows that the combination and competition of surface chemistry and roughness of a solid material can finally determine its wettability. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Flexible and flame‐retardant S‐SEB‐S triblock copolymer/PPE nano‐alloy

We observed that modified polyphenylene ether (PPE) was solubilized in thermoplastic styrenic elastomer (TPS) and that a two‐phase lacy structure formed on nanometer scales when the TPS composition was 67 wt % and modified PPE and polystyrene‐block‐poly(styrene‐co‐ethylene‐co‐butylene)‐block‐polystyrene (S‐SEB‐S triblock copolymer) were blended. However, the molecular weight of the outer PS block segments M_outPS and the content of the outer PS block segments ?_outPS were <10,000 g/mol and 20 wt %, respectively. The resulting S‐SEB‐S/modified PPE nano‐alloy exhibited both flexibility and flame retardancy, unlike other materials, where a trade‐off exists between these two properties; that is, the flame retardancy was excellent when the phosphorus additive was present. This combination of properties might be attributed to the two‐phase nanometer‐scale structure consisting of flame‐retardant styrene/PPE domains and a continuous soft, lacy SEB matrix. The results for polystyrene‐block‐poly(ethylene‐co‐butylene)‐block‐polystyrene (S‐EB‐S triblock copolymer)/modified PPE blends were presented for comparison. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40446.     

Fabrication of alumina based electrically conductive polymer composites

Novel electrically conductive composites were synthesized by incorporating Cu coated alumina (Cu‐Al₂O₃) powder prepared via electroless plating technique as filler (0–21wt %) into polystyrene‐b‐methylmethacrylate (PS‐b‐PMMA) and polystyrene (PS) matrices. XRD analysis depicted maximum Cu crystallite growth (26.116 nm～ plating time 30 min) onto Al₂O₃ along with a significant change in XRD patterns of composites with Cu‐Al₂O₃ inclusion. SEM–EDX analyses exhibited uniform Cu growth onto Al₂O₃ and confirmed presence of Cu, Al, Pd in Cu‐Al₂O₃, and C, O, Al, Cu, and Pd in PS‐b‐PMMA and PS composites. Increasing filler loadings exhibited increased electrical conductivity (5.55 × 10^?5S/cm for PS‐b‐PMMA; 5.0 × 10^?6S/cm for PS) with increased Young's modulus (1122MPa for PS‐b‐PMMA; 1053.9MPa for PS) and tensile strength (27.998MPa for PS‐b‐PMMA; 30.585MPa for PS) and decreased % elongation. TGA demonstrated increased thermal stability and DTG revealed two‐step degradation in composites while DSC depicted pronounced increment in T_g of Cu‐Al₂O₃/PS‐b‐PMMA with increased filler loading. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42939.     

Modification of polyolefin films by photochlorination

Composite polyolefin membranes with graded chlorination gradient were obtained by photochlorination of polyethylene, polypropylene, and polystyrene films using ultraviolet and visible light. The maximum chlorine contents of these membranes were 12%, 8.5%, and 6.5%, respectively. As for polyethylene, the surface photochlorination reduced gas permeation of carbon dioxide and oxygen down to 1/30 and 1/21 of the original polyethylene; it also improved the wettability without changing substantially other favorable physical properties such as tensile strength, elongation, and water vapor permeation. The water contact angle of chlorinated polyethylene was comparable to that of poly(vinyl chloride). The infrared spectra suggest the presence of the chlorine of the ? CHCl? CHCl? type rather than of the ? CCl₂? type in the photochlorination of polyethylene. In an effort to obtain useful membranes with a photocrosslinking functional group as a side chain, surface-photochlorinated polyethylene was allowed to react with sodium N,N-dimethyldithiocarbamate or sodium N-methyl-N-carboxymethyldithiocarbamate in dimethylformamide at 50°C for 48 hr according to the procedure by which poly(vinyl chloride) was previously reacted. The polymer thus obtained has 4.1 mole-% ? SCS? NMe₂ and 3.4 mole-% ? SCS? N(CH₃)CH₂COONa groups.     

Syntheses of an azo‐group‐bound silica initiator and silica–polystyrene composites

In this article, we present a facile method for the synthesis of an azo‐group‐bound silica (SiO₂–azo) initiator. The azo groups were introduced onto the surface of silica (SiO₂) nanoparticles via facile condensation between 4,4′‐azobis‐4‐cyanopentanoic acid and the alkyl–hydroxyl groups ‐ immobilized on the SiO₂ nanoparticle surface under ambient conditions. The polystyrene (PS) chains were grafted onto the SiO₂ nanoparticle surface by in situ polymerization with the resulting SiO₂–azo as an initiator, and then, the SiO₂–PS composite was prepared. The syntheses and properties of the SiO₂–azo initiator and the composite were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, thermogravimetric analysis, gel permeation chromatography, and differential scanning calorimetry techniques. The results confirm that the SiO₂–azo initiator and the composite were synthesized successfully. Styrene was polymerized with the initiation of SiO₂–azo, and the resulting PS domain accounted for 48.6% of the total amount of composite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Amino‐functional electrospun nanofibrous membrane for detecting nitroaromatic compounds

A novel amino‐functionalized polystyrene copolymer (PS‐NH₂) was designed and synthesized with styrene and 4‐vinylbenzyl amine. Additionally, an amino modified glass (G‐NH₂) was obtained as a carrier. (PS‐NH₂/pyrene)/G‐NH₂ fluorescent nanofibrous membrane [named (PS‐NH₂/pyrene)/G‐NH₂] was designed and prepared via electrospinning technique to detect representative saturated nitroaromatic (NAC) explosive vapor. The (PS‐NH₂/pyrene)/G‐NH₂ showed highly fluorescence stability in ambient condition and further displayed a high quenching efficiency of 70.9% toward trinitrotoluene (TNT) vapor (～10 ppb) with an exposure time of 150 s at room temperature. The abundance of amino groups could effectively adsorb NACs and the binding of electron‐deficient NACs to the amino groups on the (PS‐NH₂/pyrene)/G‐NH₂ surface led to the formation of charge‐transfer complexes. The quenching constant (K_SV) to TNT was obtained to be 1.07 × 10¹¹ mL/g in gaseous phase with a limit of detection up to 2.76 × 10^?13g/mL. Importantly, the (PS‐NH₂/pyrene)/G‐NH₂ showed notable selectivity toward TNT and 2,4‐dinitrotoluene vapors. Straightforwardly, the colorimetric sensing performance can be visualized by naked eye with a color change for detecting of different vapor phase NACs explosives. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46708     

Preparation and characterization of semi‐interpenetrating network polystyrene/PVDF cation exchange alloy membranes

The polystyrene‐DVB/PVDF alloy particles were prepared by pulverizing the polymerization product of styrene/DVB/PVDF in DMF, and then sulfonated with concentrated sulfuric acid to gain the cation exchange alloy powder, which was directly thermoformed by a hot‐press machine to form the titled cation exchange alloy membranes with the structure of semi‐interpenetrating polymer network. The effects of the polystyrene‐DVB to PVDF mass ratio and the DVB content in the monomers on the physical and electrochemical properties of the prepared alloy membranes were investigated. While the Fourier transform infrared spectroscopy (FTIR) confirms the components of membranes, the scanning electron microscopy (SEM) reveals that the alloy membranes possess a uniform distribution of functional groups, and a more dense structure with the increases of DVB content and PVDF content. The optimal prepared membranes have the area electrical resistance values within 3.0–6.6 Ω·cm², obviously superior to the commercial heterogeneous cation exchange membrane, as well as the moderate water contents of 35–40% and the desirable permselectivity with a transport number more than 0.95. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1220‐1227, 2013     

Polystyrene composites of single‐walled carbon nanotubes‐graft‐polystyrene

Single‐walled carbon nanotubes (SWCNTs) dispersed in N‐methylpyrrolidone (NMP) were functionalized by addition of polystyryl radicals from 2,2,6,6‐tetramethyl‐1‐piperidinyloxy‐ended polystyrene (SWCNT‐g‐PS). The amount of polystyrene grafted to the nanotubes was in the range 20‐25 wt% irrespective of polystyrene number‐average molecular weight ranging from 2270 to 49 500 g mol^?1. In Raman spectra the ratios of D‐band to G‐band intensity were similar for all of the polystyrene‐grafted samples and for the starting SWCNTs. Numerous near‐infrared electronic transitions of the SWCNTs were retained after polymer grafting. Transmission electron microscopy images showed bundles of SWCNT‐g‐PS of various diameters with some of the polystyrene clumped on the bundle surfaces. Composites of SWCNT‐g‐PS in a commercial‐grade polystyrene were prepared by precipitation of mixtures of the components from NMP into water, i.e. the coagulation method of preparation. Electrical conductivities of the composites were about 10^?15 S cm^?1 and showed no percolation threshold with increasing SWCNT content. The glass transition temperature (T_g) of the composites increased at low filler loadings and remained constant with further nanotube addition irrespective of the length and number of grafted polystyrene chains. The change of heat capacity (ΔC_p) at T_g decreased with increasing amount of SWCNT‐g‐PS of 2850 g mol^?1, but ΔC_p changed very little with the amount of SWCNT‐g‐PS of higher molecular weight. The expected monotonic decrease in ΔC_p coupled with the plateau behavior of T_g suggests there is a limit to the amount that T_g of the matrix polymer can increase with increasing amount of nanotube filler. Copyright © 2012 Society of Chemical Industry