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Ball-milled and chemically activated pitch-based carbon fibers (PCF) were prepared for use as electrode materials. Ball milling altered the structure of PCF from fibers to micro-sized particles with loss of porosity. In contrast, chemical activation using KOH facilitated the development of pore structures. The supercapacitive behavior of treated PCF was assessed using cyclic voltammetry and galvanostatic charge/discharge experiments in 6 M KOH electrolytic solution. BAPCF900, the sample subjected to combined ball milling and chemical treatment, activated at 900 °C, exhibited a specific capacitance of about 80 F/g at a current density of 0.2 A/g; this good capacitance is attributed to a specific surface area of 803 m2/g and a total pore volume of 0.352 cm3/g, and is related to the appropriate pore structure for electrode application, comprising mesopores and micropores.

A β-diketiminatophosphane-palladium complex was found to act as an efficient and general catalyst in the Stille coupling reaction of various aryl and heteroaryl chlorides with organostannanes. The results show that this catalytic system allows for the use of less reactive substrates such as deactivated or sterically hindered aryl chlorides. A catalyst loading of 0.5 mol% was sufficient to achieve excellent performance under relatively mild reaction conditions. Furthermore, the scope of catalyst was extended to the coupling of vinyl chlorides.

Thermally expandable core–shell microcapsules (TEM) were fabricated with an organic steric stabilizer and an inorganic Pickering emulsifier. In order to fabricate a TEM, acrylonitrile (AN) and metacrylonitrile (MAN) were used as monomers. Halloysite nanotubes (HNTs) and poly(vinylpyrrolidone) (PVP) were used as the inorganic Pickering emulsifier and the organic stabilizer, respectively. The liquid hydrocarbon content in the core, and the thermal and expansion properties, of TEMs with two different emulsifiers were compared. The mechanical properties of polypropylene (PP) foams containing TEMs prepared with two types of stabilizers were analyzed. The TEMs polymerized with PVP showed a finer expanded cell, while those fabricated with HNTs resulted in a larger expanded cell in the PP matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44247.

Silicon carbide was incorporated in poly(dimethyl siloxane) (PDMS) in combination with multiwall carbon nanotubes (MWCNTs) to improve the thermal conduction behavior. The amount of silicon carbide was increased from 0 to 150 phr and the amount of MWCNTs was increased from 0 to 8 phr at a fixed amount of silicon carbide (150 phr). The thermal conductivity of the PDMS composite was increased with increasing amount of the MWCNTs and fine dispersibility of the incorporated MWCNTs was achieved without pretreatment. The rheological properties of the PDMS composites incorporating silicon carbide and MWCNTs were investigated and the activation energy of the composites was calculated during thermal decomposition using the Horowitz-Metzger method. Importantly, unexpected thermal decomposition behavior as indicated by the reduction in activation energy from 361.63 to 194.18 kJ mol−1, namely acceleration of decomposition of the PDMS matrix caused by MWCNTs, was observed for the first time. Copyright © 2011 Society of Chemical Industry

Amphiphilic copolymer microspheres of poly(styrene-co-4-vinylpyridine) were prepared by dispersion polymerization in an alcohol/water medium. The synthesis of poly(styrene-co-4-vinylpyridine) microparticles was successfully carried out, and the latexes had a spherical morphology with good monodispersity. The degree of conversion in the early stage of polymerization decreased with increasing 4-vinylpyridine (4VP) monomer content, but the final conversions were similar (>95%). The copolymerization rate decreased with increasing 4VP content, and a broad particle size distribution was observed with 20 wt % 4VP because of the prolonged nucleation time. With the 4VP concentration increasing, the molecular weight of the copolymer microspheres decreased, and the glass-transition temperature of the copolymers increased; this indicated that all the copolymers were random and homogeneous. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Two different polyurethane-based macromonomers, a polyurethane macromonomer with methacrylamide (PUM-M) and a polyurethane macromonomer with acrylamide (PUM-A), were synthesized from poly(ethylene glycol)s (PEGs) of various molecular weights and two different amides, methacrylamide and acrylamide, and they were used for the dispersion polymerization of styrene. The structures of the macromonomers and polystyrene (PS) particles were verified with 13C-NMR and Fourier transform infrared. The weight-average molecular weights of the PS particles increased with the macromonomer concentration but decreased with the PEG molecular weight. The average diameter of the PS particles increased with the PEG molecular weights but decreased with the macromonomer concentration. The thermal stability of PUM-A–PS was enhanced, and its grafting ratio with 30 wt % PUM-A was much higher than that of PUM-M–PS. Thus, this study suggested that the polyurethane-based macromonomers act not only as reactive stabilizers but also as grafting agents in the dispersion polymerization. In addition, the acrylamide end group provided better thermal stability than methacrylamide. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Multiwalled carbon nanotubes (MWNTs) were effectively functionalized with KMnO 4 in the presence of a phase-transfer catalyst at room temperature. The hydroxyl functionalized MWNTs were reacted with a vinyl-group carrying silane-coupling agent and the terminal vinyl groups were used to fabricate polystyrene (PS) brushes by solution polymerization. Finally, PS-encapsulated MWNTs were obtained. The synthesis results were verified from FT-Raman, thermal gravimetric analysis, energy dispersive X-ray analysis, and transmission electron microscope. PS-encapsulated MWNTs had much improved dispersion stability in hydrophobic medium, toluene since grafted hydrophobic PS interacts with media and has improved compatibility. This functionalization technique would provide a facile route to prepare various polymer brushes on the surface of MWNTs to improve the dispersion of MWNTs for potential applications.

A novel approach to fabricate polymer brushes on the surface of carbon nanotubes (CNTs) is proposed. Carboxyl groups on the surface of chemically oxidized CNTs were reacted with hexamethylene diisocyanate, followed by a reaction with methacrylamide to give terminal vinyl groups-functionalized CNTs, so called "CNT-mer." The synthetic procedure was investigated step-by-step and the synthesized CNT-mer was used to grow polystyrene (PS) from CNTs by a simple in situ polymerization in the presence of a thermal initiator. By employing 1 H NMR, X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and light scattering, the experimental results were verified. Using this approach, 45% PS with respect to CNTs are grafted on the surface of CNTs with about 4.0 nm thickness. This novel technique would provide a facile route to prepare tailormade polymer brushes on the surface of CNTs.

A novel bifunctional vinyl-terminated polyurethane macromonomer was applied to the dispersion polymerization of styrene in ethanol. Monodisperse polystyrene (PS) microspheres were successfully obtained above 15 wt % of macromonomer relative to styrene. The steep slope from the reduction of the average particle size reveals that the macromonomer can efficiently stabilize higher surface area of the particles when compared with a conventional stabilizer, poly(N-vinylpyrrolidone). The stable and monodisperse PS microspheres having the weight-average diameter of 1.2 μm and a good uniformity of 1.01 were obtained with 20 wt % polyurethane macromonomer. The grafting ratio of the PS calculated from 1H NMR spectra linearly increased up to 0.048 with 20 wt % of the macromonomer. In addition, the high molecular weights (501,300 g/mol) of PS with increased glass transition and enhanced thermal degradation temperature were obtained. Thus, these results suggest that the bifunctional vinyl-terminated polyurethane macromonomer acts as a reactive stabilizer, which gives polyurethane-grafted PS with a high molecular weight. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3566–3573, 2005

The TEMPO-mediated polymerization of styrene in the presence of camphorsulfonic acid (CSA) is carried out using controlled radical dispersion polymerization. In the absence of TEMPO and CSA, 92% of conversion was achieved within 3 h of polymerization. When TEMPO is solely used, broadening of particle size with narrow PDI was observed because of the prolonged polymerization time. However, when 1:1 molar ratio of CSA/TEMPO was added, the fairly monodisperse PS microspheres having 5.83 μm average size and 3.42% CV (coefficient of variation) were successfully achieved because of the narrow molecular weight of intermediate oligomers and shortening of the polymerization time. This result obviously indicates that the addition of CSA in TEMPO-mediated dispersion polymerization not only shortens the polymerization time but also greatly improves the uniformity of the microspheres. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 62–68, 2006

The desorption behavior of a surfactant in a linear low-density polyethylene (LLDPE) blend at elevated temperatures of 50, 70, and 80 °C was studied with Fourier transform infrared spectroscopy. The composition of the LLDPE blend was 70:30 LLDPE/low-density polyethylene. Three different specimens (II, III, and IV) were prepared with various compositions of a small molecular penetrant, sorbitan palmitate (SPAN-40), and a migration controller, poly(ethylene acrylic acid) (EAA), in the LLDPE blend. The calculated diffusion coefficient (D) of SPAN-40 in specimens II, III, and IV, between 50 and 80 °C, varied from 1.74 × 10 11 to 6.79 × 10 11 cm 2 /s, from 1.10 × 10 11 to 5.75 × 10 -11 cm 2 /s, and from 0.58 x 10 11 to 4.75 x 10 - 11 cm 2 /s, respectively. In addition, the calculated activation energies (E D ) of specimens II, III, and IV, from the plotting of In D versus 1/T between 50 and 80 °C, were 42.9, 52.7, and 65.6 kJ/mol, respectively. These values were different from those obtained between 25 and 50 °C and were believed to have been influenced by the interference of Tinuvin (a UV stabilizer) at elevated temperatures higher than 50 °C. Although the desorption rate of SPAN-40 increased with the temperature and decreased with the EAA content, the observed spectral behavior did not depend on the temperature and time. For all specimens stored over 50 °C, the peak at 1739 cm 1 decreased in a few days and subsequently increased with a peak shift toward 1730 cm 1 . This arose from the carbonyl stretching vibration of Tinuvin, possibly because of oxidation or degradation at elevated temperatures. In addition, the incorporation of EAA into the LLDPE blend suppressed the desorption rate of SPAN-40 and retarded the appearance of the 1730 cm 1 peak.

The effect of the stearic acid coated fillers and their geometry on the shear/dynamic viscosity and complex viscosity has been investigated using polypropylene (PP) compounds filled with stearic acid uncoated and coated talc, calcite, and mixed talc/calcite particles. The viscosity was measured over a wide range of shear rates (10−8 to 103) using a capillary, cone-plate and sandwich rheometer. Overall, the rheological properties of the compounds exhibited different behavior upon different filler systems, stearic acid involvement, shear stress or strain, and frequencies due to stearic acid involvement. This implies that the stearic acid lowers the interfacial force between the filler surface and the resin matrix, followed by a favorable processing. In addition, at very low shear stresses, the viscosity of talc(un) compounds was higher than calcite(un) ones; at very high shear stresses, on the other hand, talc compounds became lower than calcite(un) compounds. This is interpreted as due to the different geometry between talc and calcite. The yield value as a function of shear stress was observed for all filler systems and exhibited lower than that obtained from the extrapolation. Furthermore, the Cox–Merz relation between the complex and shear viscosity for both the stearic acid uncoated and coated compounds is found not valid. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2105–2113, 2004

The comparative tensile and impact properties and fracture morphologies between calcite and calcite/zeolite (hybrid) filled linear low-density polyethylene (LLDPE) and polypropylene (PP) composites have been studied. The incorporation of fillers into LLDPE, whether calcite or calcite/zeolite hybrid fillers, does not alter the Tm of LLDPE, but slightly reduces the Tm of PP. The melting peak area representing the heat of fusion of the crystal decreases with fillers; the effect of the calcite and the hybrid filler would be the same. The impact strength, Young's modulus, and yield stress of the calcite and the hybrid filled LLDPE increased, indicating a reinforcing effect of the fillers. In addition, the filled LLDPE decreases in elongation at break (EB) and ultimate tensile strength. However, the hybrid LLDPE composite exhibits slightly higher Young's modulus and ultimate tensile strength than the calcite one, while the same values of impact strength and yield stress were observed. In the PP system, the Young's modulus is enhanced, whereas the rest of the mechanical properties were reduced. From SEM photomicrographs of the hybrid filled composites, the tensile fractured surface

Fully crosslinked, stable poly(styrene-co-divinylbenzene) microspheres were prepared by precipitation polymerization, and a new mechanism is proposed, based on the morphology, circularity, and specific surface area. Once the stable particles were generated by aggregation of the primary nucleus particles, they grew in size by absorbing oligomeric species without generating substantial pores. The investigation was carried out characterizing the particles in the polymerization time and in various concentrations of the polymerization ingredients. Particle size continuously grew, but the uniformity and circularity of the microspheres were reduced with polymerization time because of the higher reactivity of divinylbenzene. The measured specific surface areas of the microspheres all were less than 10 m2/g, which showed good agreement with calculated values under an assumption of no pores on the surface of the microspheres. Thus, the specific surface area of the microspheres supported the proposed mechanism. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3967–3974, 2004

Fully crosslinked, stable poly(styrene-co-divinylbenzene) microspheres, which are composed of various concentrations of divilylbenzene from 5 to 75 mol % based on styrene monomer, were prepared without a significant particle coagulation by the precipitation polymerization. The number-average particle diameter ranged from 3.5 to 2.8 μm and decreased with an increasing concentration of divinylbenzene in monomer. In addition, the coefficient of variation of the microspheres was slightly reduced with the increasing concentration of divinylbenzene. The circularity and the measured specific surface area indicated that lesser particles are coagulated because of the improved stability of individual particles at a high divinylbenzene concentration and that the resulting particles have a smooth surface without micropores. The glass-transition temperature was not observed for all microspheres formed from the range of divinylbenzene concentrations. In addition, the onset of the thermal-degradation temperature was increased from 339.8 to 376.9 °C upon higher contents of divinylbenzene. On the basis of the DSC and thermogravimetric data, the polymer microspheres prepared by the precipitation polymerization possessed a fully crosslinked structure and highly enhanced thermal stability. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 835–845, 2004

The effects of the presence of water on ultrasonic devulcanization of 30 phr silica-filled polydimethylsiloxane (PMDS) were investigated at increasing feed rates and different die gap sizes. The results showed that the initial die entrance pressure without ultrasound for wet rubber was higher than in the case without water and then it decreased monotonously with applying ultrasound. The die pressure for wet rubber decreased significantly even at low ultrasonic amplitude, while that for dry rubber changed little at low amplitude. The power consumption at an amplitude of 10 μm, where devulcanization was most effectively achieved, was lower for wet rubber even though the pressure was lower. The crosslink density and gel fraction after the devulcanization of wet rubber were lower than those of dry rubber, indicating that the presence of water facilitates the devulcanization process under the same devulcanization conditions. The good mechanical properties of recycled silica-filled PDMS were obtained at higher feed rates and at lower ultrasound amplitudes, which are directly related to the economics of a recycling process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2630–2638, 2003

We used NMR relaxation and pulsed-gradient diffusion measurements at 70 °C in precipitated silica-filled poly(dimethylsiloxane) (PDMS; silicone rubber) after crosslinking, after subsequent devulcanization by intense ultrasound, and after subsequent revulcanization. As in unfilled PDMS, transverse relaxation displays three distinct rate components attributed to an entangled and crosslinked network (similar in T2), light sol plus dangling network fragments, and unreactive trace oligomers. Ultrasound produces copious amounts of extractable sol. The T2 relaxation times decreased modestly with increasing filler content, but they and the components' proportions correlated mainly with the sol fraction, that is, the network degradation. In rupturing the network, devulcanization produces large diffusing fragments and dangling ends; revulcanization largely reverses these effects. The rates and amplitudes of the bimodal diffusivity distribution confirmed this conclusion. The weakness of the effects of filler suggests that ultrasound devulcanization is easily adaptable to the recycling of the preponderantly particulate-filled industrial rubbers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 454–465, 2003

Micron-sized monodisperse crosslinked polystyrene (PS) beads have been prepared by a multistage emulsion polymerization using styrene monomer, divinylbenzene crosslinking agent, and potassium persulfate initiator in the absence of emulsifier. In the first stage of the reaction, the lower the reaction temperature, the larger the bead size obtained. In the later stages of the reaction, the particle size is increased with the initiator concentration and monomer content. Particle nucleation of the preexisting polymer seed of 0.7–0.8 μm in diameter is prepared at 60°C, then the monodisperse crosslinked PS beads > 2 μm are synthesized up to the third stage of the reaction. As the particle size grows, the number of free radicals in the growing particles increases, and the conversion of the next stage is continuously increased. The reaction mechanism is suggested that the continuous polymerization be conducted due to the diffusion of monomer into the preexisting particles to induce spherical beads in the later stages of the reaction. Otherwise, phase separation or the formation of protrusion by the capture of free radicals will be taking place. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2259–2269, 1999

The use of the highly active catalyst PPA renders possible the coupling of deactivated or sterically hindered aryl chlorides and vinyl chlorides with organostannanes to provide a variety of coupling products (44 examples).