Synthesis and characterization of graft copolymers of syndiotactic polystyrene with polybutadiene and 4‐methylstyrene

The basic method for synthesizing syndiotactic polystyrene‐g‐polybutadiene graft copolymers was investigated. First, the syndiotactic polystyrene copolymer, poly(styrene‐co‐4‐methylstyrene), was prepared by the copolymerization of styrene and 4‐methylstyrene monomer with a trichloro(pentamethyl cyclopentadienyl) titanium(IV)/modified methylaluminoxane system as a metallocene catalyst at 50°C. Then, the polymerization proceeded in an argon atmosphere at the ambient pressure, and after purification by extraction, the copolymer structure was confirmed with ¹H‐NMR. Lastly, the copolymer was grafted with polybutadiene (a ready‐made commercialized unsaturated elastomer) by anionic grafting reactions with a metallation reagent. In this step, poly(styrene‐co‐4‐methylstyrene) was deprotonated at the methyl group of 4‐methylstyrene by butyl lithium and further reacted with polybutadiene to graft polybutadiene onto the deprotonated methyl of the poly(styrene‐co‐4‐methylstyrene) backbone. After purification of the graft copolymer by Soxhlet extraction, the grafting reaction copolymer structure was confirmed with ¹H‐NMR. These graft copolymers showed high melting temperatures (240–250°C) and were different from normal anionic styrene–butadiene copolymers because of the presence of crystalline syndiotactic polystyrene segments. Usually, highly syndiotactic polystyrene has a glass‐transition temperature of 100°C and behaves like a glassy polymer (possessing brittle mechanical properties) at room temperature. Thus, the graft copolymer can be used as a compatibilizer in syndiotactic polystyrene blends to modify the mechanical properties to compensate for the glassy properties of pure syndiotactic polystyrene at room temperature. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of diblock copolymer PBA-<Emphasis Type="Italic">b</Emphasis>-PSt by DPE method in emulsion

Diblock copolymer poly (butyl acrylate)-b-polystyrene (PBA-b-PSt) was prepared by two steps in a complete emulsion system, using DPE (1, 1-diphenylethylene) as free radical control agent. In the first step, butyl acrylate (BA), initiator potassium peroxodisulfate (KPS) and DPE were emulsion polymerized to form P(BA-DPE) precursor. Then the precursor was heated in the presence of a second monomer styrene (St), and block copolymer was synthesized successfully. The structures, molecular weight of precursor and block copolymer were characterized by FTIR, UV–VIS, ¹H-NMR and SEC/MALLS. Influence of DPE on polymerization kinetics was also investigated. Meantime, thermal properties of block copolymer were analyzed by TGA and DSC.     

Syndiospecific Polymerization of Styrene Using Half-Titanocene Catalyst Covalently Supported on MgCl<Subscript>2</Subscript>/AlEt<Subscript>n</Subscript>(OEt)<Subscript>3-n</Subscript>

The novel half-titanocene catalyst bearing reactive functional amino group, η⁵-pentamethylcyclopentadienyltri(p-amino-phenoxyl) titanium [Cp^∗Ti(p-OC₆H₄NH₂)₃], was easily synthesized by the reaction of η⁵-pentamethylcyclopentadienyltrichloride titanium (Cp^∗TiCl₃) with p-amino phenol in the presence of triethyl amine (NEt₃). Cp^∗Ti(p-OC₆H₄NH₂)₃ covalently anchored on MgCl₂/AlEt_n(OEt)_3-n support obtained from the reaction of triethylaluminium (AlEt₃) with the adduct of magnesium chloride (MgCl₂) and ethanol (EtOH), has been investigated and used to catalyze syndiospecific polymerization of styrene. Influences of the support structure, cocatalyst, and the molar ratio of Al in methylaluminoxane (MAO) and Ti (Al_MAO/Ti) on catalytic activity, syndiotacticity and molecular weight of the resultant polystyrene were investigated. Compared with the corresponding Cp^∗Ti(p-OC₆H₄NH₂)₃ homogeneous catalyst, a considerable increase in activity and molecular weight of syndiotactic polystyrene (sPS) was observed for the Cp^∗Ti(p-OC₆H₄NH₂)₃-MgCl₂/AlEt_n(OEt)_3-n supported catalyst even at a relatively low Al_MAO/Ti ratio of 50, and the kinetics of polymerization was stable during the reaction process.     

Synthesis of <Emphasis Type="Italic">p</Emphasis><Emphasis Type="Bold">-</Emphasis> and <Emphasis Type="Italic">n</Emphasis>-type Gels Doped with Ionic Charge Carriers

In this study, we synthesized the new kinds of semiconducting polymeric gels having negative (n-type) and positive (p-type) counter ions as charge carriers. The polyacrylamide gel was doped with pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt), having \textSO₃ ^- {\text{SO}}_{3}^{ - } ions as side groups and Na⁺ as counter ions, so-called p-type semiconducting gel. The doping process was performed during the polymerization where the pyranine binds to the polymer strands over OH group chemically via radical addition. In a similar way, N-isopropylacrylamide (NIPA) gel was doped with methacrylamidopropyltrimethyl ammonium chloride (MAPTAC), having Cl⁻ as counter ions, so-called n-type semiconducting gel. Here MAPTAC was embedded by copolymerization within the polymer network (NIPA). These semiconducting gels can show different electrical properties by changing the concentration of the doping agents, swelling ratio etc. We have shown that the pn junction, formed by combining p-type and n-type gels together in close contact, rectifies the current similar to the conventional Si and Ge diodes.     

Synthesis and characterization of functionalized syndiotactic polystyrene copolymers

Functionalized syndiotactic polystyrene copolymers were synthesized and characterized. The syndiotactic polystyrene copolymers, poly(styrene‐co‐4‐methylstyrene) (sPSMS), were prepared by styrene with 4‐methylstyrene with a metallocene/methylaluminoxane catalyst. In addition, grafted copolymers, chemically grafted with isoprene onto an sPSMS backbone [poly(styrene‐co‐4‐methylstyrene)‐g‐polyisoprene (sPSMS‐g‐PIP)] were synthesized by anionic grafting polymerization with a metallation reagent. In this study, we also examined the effect of the degree of functionalization (epoxidation) on the polymer structure of the sPSMS‐g‐PIP copolymers. Experimental results indicate that the crystallinity of the sPSMS‐g‐PIP copolymer was lower than that of the ungrafted sPSMS copolymer. Moreover, the epoxy‐containing sPSMS‐g‐PIP copolymer effectively increased the thermal stability more than did the sPSMS‐g‐PIP copolymer alone. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1038–1045, 2002     

Ultralow ppm <Emphasis Type="Italic">se</Emphasis>ATRP synthesis of PEO-<Emphasis Type="Italic">b</Emphasis>-PBA copolymers

Poly(ethylene oxide)-block-poly(butyl acrylate) copolymers were prepared via simplified electrochemically mediated atom transfer radical polymerization (seATRP) utilizing only 1 ppm of Cu^II complex, which is the limit of a successful well-controlled polymerization. The presented seATRP system works under potentiostatic and galvanostatic conditions. The polymerization results showed similar molecular weight evolution while maintaining a narrow molecular weight distribution throughout the reactions. ¹H NMR results confirm chemical structure of synthesized diblock copolymers. This ultralow ppm technique is promising candidate for polymerization from nanoparticles, flat surfaces, proteins, and DNA.     

Molecular-hydrodynamic study of poly(<Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="Italic">N</Emphasis>-vinylacetamide) macromolecules

High-velocity sedimentation, translational isothermal diffusion, and viscometry in H₂O and DMF are used to investigate the samples and fractions of poly(N-methyl-N-vinylacetamide) synthesized by free-radical polymerization and fractionated in a chloroform-diethyl ether system. Molecular masses M and the Mark-Kuhn-Houwink-Sakurada relations are obtained for the fractions in the molecular mass range M × 10⁻³ = 3.5−540.0. The negative temperature coefficient of intrinsic viscosity is revealed for both solvents. The length of the Kuhn statistical segment and the hydrodynamic diameter of poly(N-methyl-N-vinylacetamide) macromolecules are estimated; the hydrodynamic volumes occupied by water-soluble poly(N-methyl-N-vinylacetamide), poly(1-vinyl-2-pyrrolidone), poly(vinylformamide), and pullulan molecules are compared.     

Corrosion inhibition of mild steel in acidic medium by poly (aniline-co-<Emphasis Type="Italic">o</Emphasis>-toluidine) doped with <Emphasis Type="Italic">p</Emphasis>-toluene sulphonic acid

The corrosion behaviour of mild steel in 0.5 M H₂SO₄ solution containing various concentrations of a p-toluene sulphonic acid doped copolymer formed between aniline and o-toluidine was investigated using weight loss, polarization and electrochemical impedance techniques. The copolymer acted as an effective corrosion inhibitor for mild steel in sulphuric acid medium. The inhibition efficiency has been found to increase with increase in inhibitor concentration, solution temperature and immersion time. Various parameters like E _a for corrosion of mild steel in presence of different concentrations of inhibitor and ΔG _ads, ΔH ⁰, ΔS ⁰ for adsorption of the inhibitor, revealed a strong interaction between inhibitor and mild steel surface. The adsorption of this inhibitor on the mild steel surface obeyed the Langmuir adsorption equation.     

Preparation and characterization of the molecular weight controllable poly(lactide-<Emphasis Type="Italic">co</Emphasis>-glycolide)

A series of poly(d,l-lactide-co-glycolide) (PLGA) polymers with various molecular weight were synthesized by a ring-opening polymerization method using stannous 2-ethyl hexanoate (Sn(Oct)₂) as the catalyst. The molecular weight of these polymers was controlled in a novel way, using t-butyldimethylsilanol (TBDS) or triphenylsilanol (TPS). The silicon-end group attached to the PLGA copolymer was removed at room temperature using either hydrochloric acid (HCl) or trifluoroacetic acid (TFA). The structures of these polymers before and after end group removal were characterized by ¹HNMR spectroscopy, while the molecular weight and polydispersity index (PDI) were determined by viscosity method and gel permeation chromatography (GPC). The residual amounts of stannum in PLGA and the glass transition temperature (T _g) of copolymer before and after end group removal were determined by the atomic absorption spectrum (AAS) and differential scanning calorimetry (DSC), respectively. The results showed that the removal method was effective. This study demonstrated that the molecular weight of PLGA could be easily controlled by altering the monomers/silanol molar ratio and the molecular weight and the purity of PLGA copolymer materials after silicon-end group removal could meet the demand of drug release.     

Synthesis,characterization and antibacterial activity of quaternized <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">O</Emphasis>-(2-carboxyethyl) chitosan

N,O-(2-carboxyethyl)chitosan (N,O-2-CEC) was prepared from chitosan with 3-chloropropionic acid as modifying agent and NaOH as catalyst. Different quaternary ammonium groups were introduced into N,O-2-CEC by the reaction between N,O-2-CEC and different 2,3-epoxypropyl trialkyl ammonium chlorides in the presence of 25% NaOH aqueous solution, and obtained different quaternized N,O-2-carboxyethyl chitosans (QCECs). Structures of QCECs were characterized by FT-IR, ¹HNMR and gel permeation chromatography (GPC). Antimicrobial activity of QCECs was evaluated against a gram-negative bacterium Escherichia coli and a gram-positive bacterium Staphylococcus aureus. Compared with N,O-2-CEC and quaternized chitosans, the QCECs had much stronger antimicrobial activity, which increased with increasing chain length of the alkyl in the quaternary ammonium groups. The presence of benzyl in quaternary ammonium groups could endow QCECs with much better antimicrobial activity.     

Acidic ionic liquid polymers: <Emphasis Type="Italic">poly</Emphasis>(<Emphasis Type="Italic">bis</Emphasis>-imidazolium-<Emphasis Type="Italic">p</Emphasis>-phenylenesulfonic acid) and applications as catalysts in the preparation of 1-amidoalkyl-2-naphthols

A new class of polymeric acidic ionic liquids with imidazolium hydrogen sulfate and p-phenylene sulfonic acid units built into the main polymer chain were prepared by a simple two step method in 87–89% yield. These new polymers were characterized by elemental analysis, ¹H, ¹³C NMR, FT-IR, TGA and GPC. The catalytic activity of sulfonic acid group functionalized ionic liquid polymers was demonstrated through the synthesis of 1-amidoalkyl-2-naphthols in 78–90% yield by condensation of 2-naphthol, benzaldehyde and amides without a solvent at 100 °C.     

Aqueous radical polymerization of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylacrylamide redox-initiated by aerobically catalytic oxidation of water-soluble tertiary amines

Catalytic oxidation of water-soluble tertiary amines by complexes of Cu^II, Fe^III and Co^II was utilized to initiate radical polymerization of N,N-dimethylacrylamide (DMAAm) in aqueous solution at 70–80 °C. The oxidation of tertiary amines by Cu^II was studied by proton nuclear magnetic resonance spectroscopy and online ultraviolet–visible spectrophotometry. The polymerization kinetics was monitored by gas chromatography, and molecular weight of the PDMAAm was measured by gel-permeation chromatography coupled with multi-angle laser light scattering. Oxidation of tertiary amines occurs predominantly via formation of C_alpha·radicals to initiate polymerization of electron-deficient monomers and N-dealkylation, and redox equilibrium between Cu^I/L and Cu^II/L is established at a faster rate in aqueous media. Fe^III and Cu^II complexes are efficient catalysts as each catalyst molecule could generate above 10 propagating radicals in 5 h, while Co^II complex might involve in oxidation of tertiary amines in non-radical pathway, leading to a low catalytic efficiency. Water-soluble tertiary amines such as N,N-dialkylethanolamine (alkyl = methyl, ethyl etc.) are reducing agents of a higher activity in aqueous media than those primary or secondary analogues. Our strategy renders it possible to prepare polymer of alpha-amino functionality via one-pot process from commercially available commodity reagents under practical conditions with negligible catalyst residue.     

Microspheres of copolymeric <Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone and 2-ethoxyethyl methacrylate for the controlled release of nifedipine

Free radical copolymerization of N-vinyl-2-pyrrolidone (NVP) with 2-ethoxyethyl methacrylate (EOEMA) was carried out with 2,2′-azobisisobutyronitrile (AIBN) initiator in 1,4-dioxane solvent at 60 °C. The resulting copolymers were characterized by FTIR, ¹H-NMR and ¹³C-NMR methods. Microspheres were prepared by varying the amount of NVP with respect to EOEMA. Nifedipine (NFD), a water-insoluble antihypertensive drug, was loaded into these microspheres by the oil in water emulsion technique followed by solvent evaporation. The effect of the proportion of NVP in the NVP/EOEMA copolymer on the controlled release of NFD from the microsphere matrix was investigated. Scanning electron micrographs (SEM) of the microspheres indicated spherical shapes in the size range 17–47 μm, even after loading with NFD. In vitro studies of the release of NFD from the NVP/EOEMA microspheres in pH 7.4 medium showed that the rate of NFD release was enhanced when the NVP content of the copolymer was high; the size of the microspheres also increased with increasing NVP content of the copolymer. Release data were analyzed using an empirical relation in order to elucidate the kinetics of the NFD release. This analysis indicated that a Fickian transport mode operates in this system.     

Selective separation of water from aqueous alcohol mixtures through functionalized syndiotactic poly(styrene‐co‐4‐methylstyrene) membranes by pervaporation

The pervaporation performances of a series of functionalized syndiotactic poly(styrene‐co‐4‐methylstyrene) (SPSM) membranes for various alcohol mixtures were investigated. The syndiotactic polystyrene copolymers, poly(styrene‐co‐4‐methylstyrene) (SPSM), were prepared by styrene with 4‐methylstyrene using a Cp*Ti(OCH₃)₃/methyl aluminoxane (metallocene/MAO) catalyst. The effect of functionalization on the thermal properties and polymer structure of the SPSM membranes were also investigated. The crystallinity of the functionalized SPSM membrane is lower than that of the unfunctionalized SPSM membranes. The water molecules preferentially permeate through the SPSM membranes. Compared with unfunctionalized SPSM membranes, the functionalized SPSM membrane effectively increases the membrane formation performances and the pervaporation performances. The optimun pervaporation performance (a separation factor of 510 and permeation rate of 220 g/m²h) was obtained by the bromination of SPSM (SPSMBr) membrane with a 90 wt % aqueous ethanol solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2247–2254, 2002     

An Improved Method for Synthesis of <Emphasis Type="Italic">N</Emphasis>-stearoyl and <Emphasis Type="Italic">N</Emphasis>-palmitoylethanolamine

Certain N-acylethanolamines interact with cannabinoid receptors and have anorexic and neuroprotective effects. Traditional methods for the synthesis of N-acylethanolamines use fatty acid chlorides, fatty acid methyl esters, free fatty acids and triacylglycerols as acyl donors to react with ethanolamine. In the present study, we investigated the feasibility of using fatty acid vinyl esters as the acyl donor to synthesize N-stearoyl and N-palmitoylethanolamine. Theoretically, the use of fatty acid vinyl esters should lead to an irreversible reaction because the volatile acetaldehyde by-product is easily removed. Four reaction conditions, i.e. catalyst concentration, substrate ratio, temperature, and time were evaluated. The reaction performed at mild temperatures and with an excess amount of ethanolamine which acted as both reactant and solvent resulted in the formation of high purity N-stearoyl and N-palmitoylethanolamine. When 20 mmol ethanolamine was reacted with 1 mmol vinyl stearate at 80 °C for 1 h with 1% sodium methoxide as catalyst, N-stearoylethanolamine with 96% purity was obtained after the removal of excess ethanolamine without further purification, while N-palmitoylethanolamine with 98% purity was obtained by reacting with the same substrate ratio at 60 °C for 1.5 h with 3% catalyst. Complete conversion of vinyl stearate and palmitate was achieved.     

Effect of Impurities on the Syndiospecific Coordination Polymerization of Styrene

Summary: The effect of impurities on the coordination polymerization has generally been classified and discussed in different ways and has been investigated in detail in the syndiospecific homo‐ and copolymerization of styrene. With regard to impurities of styrene, phenylacetylene as an unpolar impurity containing separate multiple bonds, 1‐phenyl‐1,2‐ethanediol and ω‐hydroxyacetophenone as examples of polar impurities, and ethylbenzene as an other unpolar impurity have been investigated regarding the effect on the polymerization rate and the influence on the molecular properties of the syndiotactic polystyrenes. In the syndiospecific copolymerization with p‐methylstyrene, indene shows a different behavior regarding the decrease of the polymerization conversion depending on the comonomer concentrations present in the monomer mixture. Additionally, the effect of impurities of the catalyst system on the syndiospecific styrene polymerization has been demonstrated, particularly of octahydrofluorene as a component of the transition metal compound and of trimethylaluminium as a component of the cocatalyst methylaluminoxane. All results have been discussed with respect to the mechanisms of the effects on polymerization behavior and on polymer properties.

Dependence of the relative polymerization conversion on the amount of indene added to the monomer mixture in styrene (ST)/p‐methylstyrene (PMS) copolymerization (catalyst n‐ratio: 0.5; molar ratio MAO:Ti = 110:1; polymerization temperature: 60 °C; polymerization time: 45 min).     

Synthesis of poly(ethylene glycol)-<Emphasis Type="Italic">b</Emphasis>-poly(mercapto ethylacrylamide) diblock copolymer via atom transfer radical polymerization

Atom transfer radical polymerization was used to synthesize a well-defined poly(ethylene glycol)-b-poly(mercapto ethylacrylamide) (PEG-b-PMEAAm) diblock copolymer. Poly(ethylene glycol)-b-poly[N-(acryloxysuccinimide)](PEG-b-PNAS) was synthesized at 80 °C using methoxy-poly(ethylene glycol)-2-bromo propanoate (PEG-Br) and CuBr/2,2′-bipyridine as a macroinitiator and catalyst, respectively. The monomer conversion was determined by ¹H nuclear magnetic resonance (NMR) spectroscopy. The resulting PEG-b-PNAS diblock copolymer was characterized by gel permeation chromatography, Fourier transform infrared (FT-IR), and ¹H NMR spectroscopy. Disulfide groups were introduced by a simple reaction through the N-acryloxysuccinimide (NAS) moieties of the PEG-b-PNAS diblock copolymer with cystamine dihydrochloride in the presence of triethylamine. FT-IR spectroscopy was used to confirm the introduction of disulfide moieties into the polymer repeating units. Subsequently, a thiol-functionalized block copolymer was prepared using DL-dithiothreitol (DTT) as the reducing agent and the reduction step was monitored by ¹H NMR spectroscopy. This thiol group was transformed easily to a disulfide bond using FeCl₃ as an oxidizing agent. The transformation into disulfide could be visualized easily as insoluble polymeric particles formed from a clear solution of PEG-b-PMEAAm after oxidation.     

<Emphasis Type="Italic">m</Emphasis>-Cresol-substituted triethyl aluminum/MoCl<Subscript>5</Subscript>/TBP catalytic system for coordination polymerization of butadiene

Coordination polymerization of butadiene was initiated by a catalyst system consisting of tributyl phosphate (TBP) as ligand, molybdenum pentachloride as primary catalyst and triethyl aluminum substituted by m-cresol as co-catalyst. The effects of the substitution of m-cresol on the activity of the catalyst system, molecular weight and molecular weight distribution, intrinsic viscosity and microstructures of the resulting polymers were investigated in details. The molecular weight and molecular weight distribution of the polymerization products were determined by GPC. The microstructure of the polymerization products was characterized by FTIR, ¹³C NMR and DSC techniques. The experimental results indicated that the polymerization activity of the reaction system and the molecular weight of the polymerization products gradually increased with the increase of the substitution content of m-cresol, namely, Al(OPhCH₃)₂Et?>?Al(OPhCH₃)Et₂?>?Al(OPhCH₃)_0.5Et_2.5>AlEt₃. The 1,2-structure contents of the polymerization products could be adjusted between 89 and 91% through the control of the substitution of m-cresol, and there was minute quantities of crystalline structures in the resulting polymers due to the increasing content of the syndiotactic 1,2-polybutadiene. In a word, the existence and increase of steric hindrance of m-cresol made it easier for polymerization products to form interdisciplinary 1,2-structure.     

<Emphasis Type="Italic">N</Emphasis>-Acylated Bacteriohopanehexol-Mannosamides from the Thermophilic Bacterium <Emphasis Type="Italic">Alicyclobacillus acidoterrestris</Emphasis>

Identification of molecular species of various N-acylated bacteriohopanehexol-mannosamides from the thermophilic bacterium Alicyclobacillus acidoterrestris by semipreparative HPLC and by RP-HPLC with ESI is described. We used triple-quadrupole type mass spectrometer, ¹H and ¹³C NMR for analyzing this complex lipid. CD spectra of two compounds (model compound—7-deoxy-d-glycero-d-allo-heptitol obtained by stereospecific synthesis, and an isolated derivative of hopane) were also measured and the absolute configuration of both compounds was determined. On the basis of all the above methods, we identified the full structure of a new class of bacteriohopanes, represented by various N-acylated bacteriohopanehexol-mannosamides.     

In-situ generation of a well-dispersed multiwall carbon nanotube/syndiotactic polystyrene composite using pentamethylcyclopentadienyltitanium trimethoxide anchored to multiwall carbon nanotubes

A well-dispersed multiwall carbon nanotube (MWCNT)/syndiotactic polystyrene (sPS) composite was prepared by simple in-situ polymerization of styrene using pentamethylcyclopentadienyltitanium(IV) trimethoxide (Cp*Ti(OMe)₃) attached to the shortened and functionalized MWCNT (f-MWCNT). The attachment of Cp*Ti(OMe)₃ to the f-MWCNT was confirmed by thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy, and energy dispersive X-ray spectroscopy. Cp*Ti(OMe)₃ attached to pristine MWCNT in the presence of methylaluminoxane (MAO) did not produce PS, whereas Cp*Ti(OMe)₃ attached to f-MWCNT showed a high catalytic activity for the syndiospecific polymerization of styrene under the same polymerization conditions. Obtained sPS showed a narrow molecular weight distribution (PDI ≈ 2), a high SI value (≥90%), and a high melting point (≈272 °C). Scanning electron microscopy and transmission electron microscopy images showed that MWCNT strands were well dispersed in the MWCNT/sPS composite. Such composites had greatly improved thermal stability compared to normal sPS polymers.