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A series of wholly aromatic copolyesters P-IPAx with low melting point (Tm) derived from hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA), 4,4'-dihydroxy-biphenyl (BP), terephthalic acid...

Previously impregnated and stored carbon fibres i.e. prepregs are a breakthrough in the composites industries. Prepregs are extremely convenient for industrial growth. Until now epoxy-based CFRP has been the focus of the industries. This report discusses a new conductive yet inexpensive resin which can be utilized in the form of prepregs owing to its long-term stability. The major prepreg enabling properties like thermal stability, rheological properties and storage effect are studied in detail. Finally, the preliminary results of the mechanical and electrical properties of the CFRP are also encompassed in this report.

Methacrylate group containing acid is explored as a curable dopant material for the synthesis of structural composites with polyaniline (PANI). The performance of this material is evaluated using various characterisation techniques to analyse how the material behaves with PANI. Thermal microscopy, UV–Vis spectroscopy, FTIR spectroscopy, differential scanning calorimetry show promising results of doping of PANI and subsequent curing of the composite. After detailed quantification, the composites were also tested to verify the electrical and mechanical properties, which gave significantly enhanced results with suitable viscosity of the resin.

Polystyrene (PS) has low impact strength and also shows poor strain hardening. In this work, poly(styrene–butadiene–styrene) triblock copolymer (SBS) was solution- and melt-blended with PS in the presence of a free-radical polymerization initiator, dicumyl peroxide (DCP), to enhance PS’s thermal stability, mechanical properties, impact resistance, and strain hardening. The solution-blended PS/SBS containing 0.1% DCP annealed at 180 °C showed strong strain hardening, but the melt-blended PS/SBS annealed at the same temperature and time showed poor strain hardening. The change in the blending temperature, DCP concentration, and PS-to-SBS ratio had minimal effect on the strain hardening of melt-blended PS/SBS. The tensile strength increased with an increase in the concentration of DCP up to 0.1%, and beyond that level, the tensile strength started decreasing. The impact resistance considerably improved with an increase in the SBS loading in the PS matrix, and the enhancement was more than double of the impact resistance shown by the neat PS.

This work establishes the fact that Polyaniline (PANI) contributes to cationic scavenging on the polymerization of a cross linking polymer, i.e. Divinylbenzene (DVB), resulting in a significant change in the properties of the PANI-based DVB resin system. Furthermore, it is also shown that the cationic scavenging is directly related to the degree of doping of PANI and its dispersion state. Various intermediate doped PANI was added with a fixed amount of DVB to prepare thermosetting matrices. The degree of doping of PANI was assessed with the DSC, FT-IR, and UV-VIS-NIR analyses before mixing with DVB matrix. It has been shown that the Polyaniline (PANI) agglomerates broke and a uniform dispersion was obtained with an increased degree of doping, which led to more exposed amines groups of PANI. These groups acted as scavengers to the cationic polymerization of the DVB monomer. DSC and viscosity measurement of the uncured PANI-DBSA/DVB resin system confirmed the scavenging effect of PANI on the curing profile and subsequently to the electrical and mechanical properties of the cured composites. This paper presents a detailed analysis of the advantages and disadvantages of the scavenging behavior of PANI in the context of preparing PANI-based polymer composites.

A liquid crystalline polymethacrylate having two cyclohexylphenyl mesogens on its side-chain (PMG0) was synthesized by the radical polymerization of the corresponding methacrylate monomer (MG0). PM...

Solution processing of thin film encapsulation (TFE) has been a long anticipated technology to bridge the big idea of flexible organic electronics to become real world values, since only small-sized flexible devices are currently achieved with expensive multilayered TFE by complex vacuum processing. Highly demanding conditions are to carry out the process under inert gas, at a low temperature, and without aggressive chemicals to avoid damages to the organic materials. Here we show for the first time a solution-processed TFE to totally equal the level of conventional glass-cap encapsulation to achieve a "ready-to-be-used" stability of an organic light emitting diode (OLED). A seamless organic/inorganic multilayer in a structure such as polydimethylsiloxane (PDMS)/SiO

Electrowetting on dielectric (EWOD) devices were fabricated using two hydrophobic organic fluoropolymers, comprising CYTOP (a product name) having different chemical structures only at the terminal functional groups. These devices were subsequently characterized by applying a range of direct current (DC) voltages. The data demonstrated that the EWOD performance was dramatically improved upon incorporating a CYTOP polymer having highly polar terminal functional groups, as compared to a polymer having terminal groups with lower polarity. The new finding about the positive effect of highly polar terminal functional groups on the enhancement of EWOD was exhibited through various careful experiments, changing only the quantitative amount of polar terminal functional groups while keeping other factors constant (thickness, substrate, etc.).

Carbon fiber reinforced plastics (CFRPs) are prone to severe damages by lightning strikes due to their low electrical conductivity. Current lightning strike protection (LSP) technology generally consists of metal foils/films on the surface of composite airframe structures. The present work aims to introduce all polymeric conductive layer for LSP of CFRP structures. Intrinsic conductive polymer i.e. Polyaniline (PANI) is used to make a thermosetting polymer mixture. CFRPs coated with this electrically conductive, all polymeric layer was tested against simulated lighting strike. It has been shown that PANI-LSP specimens dissipated the lightning current effectively and provided enough residual mechanical properties of CFRPs.

A roll milled complex of Polyaniline (PANI) and Dodecylbenzenesulphonic acid (DBSA) is used with a cross-linked polymer Divinylbenzene (DVB), to prepare a conductive thermoset matrix with good environmental stability at room temperature. Upon heating, thermal doping of PANI-DBSA and curing of DVB occur simultaneously. Different amounts of DVB are used to prepare different samples and their properties are determined. Electrical & mechanical properties are measured. It has been shown that the electrical properties and mechanical properties of the composites are inversely proportional. It is demonstrated that the flexural modulus increases with an increase in DVB content, while the conductivity increases with an increase in PANI-DBSA content. The composite using roll-milled PANI-DBSA complex has shown better stability but lower electrical and mechanical properties as compared to the composite prepared using centrifugally mixed PANI-DBSA complex. An environmentally stable PANI-DBSA/DVB conductive thermosetting matrix is introduced in this work. FTIR spectra and UV–vis–NIR spectra are obtained to explain the effect of roll milling on PANI-DBSA and also the effect of DVB concentration on the composite. Thermal stability of the composites is determined using TGA analysis. The morphology of the samples is studied using SEM and the conductivity behavior is explained.

Conductive polymers have garnered extensive attention over the last few decades owing to their vast applications and relative ease of production. One such polymer is PANI; with versatile thermo-mechanical, chemical, and electrical properties, has been researched for varied applications in the field of electronics, electrodes and corrosion protection. In this study, we focus on an alternative route to process semi-doped PANI/DBSA complexes with special focus on material properties for improved processability. This study investigates the influence of two different material preparation techniques: roll-milling and thermal-doping, on the formability and processability of such polymer-complex systems. Results confirm similar doping levels achieved in both processes and shear-thinning behavior was only observed for roll-milled samples. These results underline the formability of roll-milled PANI/DBSA with thermosetting resins. It essentially explains the production route and offers a perspective for commercial manufacturing.

Polyaniline (PANI) is one of the most studied intrinsic electrically conductive polymer in recent years. In the present work, PANI-based conductive composites have been prepared using dodecylbenzenesulphonic acid (DBSA) as a dopant and divinylbenzene (DVB) as a cross-linking polymer to enhance the rigidity. In this mixture, DBSA acts as the dopant of PANI as well as the curing agent of DVB, and this means that doping and curing of the composite occur simultaneously. PANI–DBSA mixture has been prepared by physical mixing using centrifugal mixer. The ratio of PANI and DBSA has been kept constant in weight ratio 30:70. Furthermore, DVB content has been varied to prepare the different samples. It has been found that with the increase in DVB content, a good dispersion of PANI–DBSA/DVB solution is achieved. However, significant improvement in the electrical conductivity of the samples is observed with the increase in PANI content. Mechanical flexural test has been performed on the prepared samples using a three-point bending configuration. It has been found that the flexural modulus and brittleness of the prepared samples increase with the increase in the content of DVB in the composite. Morphology of the composite surfaces has been also studied and it has been found that low concentration of DVB results into a poor dispersion and hence agglomeration of PANI–DBSA in composite can be seen clearly in the images.

Si O C ceramics were prepared from a methyl silicone preceramic polymer and rice bran by a simple method. Dried rice bran powder was blended with a molten preceramic polymer (Silres 610) at various ratios by a Brabender-type static mixer. Composites were made from them by crosslinking at 250 °C in a hot press and porous ceramics were made by pyrolysing them at 900 °C. The produced porous ceramics were characterised by measuring their density, ceramic yield, volume shrinkage, hygroscopic expansion, and compressive strength. Additionally, the fabricated ceramics were examined by SEM, and FTIR. Ceramics made from Silres 610/rice bran 50/50 ratio showed the highest compressive strength (2.7 MPa) along with the highest ceramic yield (47.8%), but the lowest hygroscopic expansion, and volume shrinkage. On the other hand, the 20/80 ratio showed the lowest ceramic yield and compressive strength but the volume shrinkage higher than the 50/50 ratio. All ceramics showed negligible hygroscopic expansion.

Rice bran (RB), rich in carbon and silicone, is an agricultural waste that is abundantly available in rice producing countries. In this work, composites of a preceramic methyl silicone resin (MSR) and RB were prepared by blending powdered RB with a molten MSR at 110 °C at various ratios in a Brabender-type static mixer. Composites were made from them by compression molding and cross-linking at 260 °C under 20 MPa pressure. The thermal, mechanical, and chemical properties of the produced composites were assessed by thermogravimetric analysis, scanning electron microscopy, and FT-IR and by measuring compressive strength and hygroscopic expansion. It was found that RB was partially ceramized and decomposed to carbonaceous materials during cross-linking. The water absorption and hygroscopic expansion of the MSR/RB composites were increased but the compressive strength was decreased with an increase in the weight % of RB. The highest compressive strength was shown by the composites made from the 50/50 blends, ...

Nematic liquid crystals (LCs) dropped via micro-dispenser (3 μL) on a vertical alignment (VA) polyimide coated indium tin oxide glass substrate have been observed under crossed polarisers. The wettability between the LC and the VA polyimide layer was extremely low. The contact angle of the LC droplet was around 33° and the droplet diameter was much smaller than the LC on the parallel-aligned polyimide layer. The contact angle of the droplet increased, and the droplet diameter decreased, on increasing the molar fraction of the side group of the polyimide. The flow behaviour of the LC by assembling between the two substrates has been directly observed under crossed polarisers. The droplet spread out keeping a cross-extinction pattern during assembling. After assembling to a 5 μm gap, a dark field was observed in whole area on the polyimide alignment layer with 50 mol% side group. Increasing the side group enhanced aligning the LC perpendicular to the substrate, and no disclination appeared.

The influence of temperature during reactive extrusion of poly(L-lactide) (PLLA) on the molecular architecture and crystallization behavior was investigated for OO-(t-butyl) O-(2-ethylhexyl) peroxycarbonate-modified polymer. The long chain–branched PLLA (LCB-PLLA) content and its structure in the resulting slightly crosslinked PLLA (χ-PLLA) containing linear and LCB-PLLA were characterized by both analyses, size exclusion chromatography equipped with multiangle laser light scattering and rheological measurements. A reduction of LCB-PLLA content in χ-PLLA and an increase of number of branches in LCB-PLLA were found with increasing the extrusion temperature. An increase of extrusion temperature induces different process in the polymer: decrease of the lifetime of peroxide, increase of the radical concentration due to rapid peroxide decomposition rate, and increase of the chain diffusion to the amorphous phase. Among these indices, the lifetime of peroxide is a good index for crosslinking behavior of PLLA during extrusion. As for the isothermal crystallization behavior from the melt, the Avrami crystallization rate constant of χ-PLLA increases as an increase of LCB-PLLA content in χ-PLLA. This implies that LCB-PLLA acts as a nucleating agent for PLLA. Furthermore, regime analysis and the free energy of nucleus of χ-PLLA were investigated using Hoffman–Lauritzen theory. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Electrically conducting samples of polyaniline (PANI) were prepared by doping with dodecylbenzene sulfonic acid (DBSA) using a thermal doping method without the application of shear. Besides characterizing the samples using optical microscopy, SEM, UV-vis-NIR, the degree of doping and the electrical conductivity were also measured. The pure PANI powder consisted of aggregates of PANI particles and was non-conducting. In the shear-free thermal doping of the PANI/DBSA mixture, the original aggregates were progressively broken up into smaller pieces with increasing temperature while maintaining the original primary particle shape and size and which were dispersed rather uniformly in the DBSA matrix. The electrical conductivity of doped PANI increased with increasing doping temperature. This increase strongly mirrored the increase in the levels of DBSA directly associated with PANI and suggested that the increasing levels of PANI doping were directly responsible for the increase in electrical conductivity as a function of the doping temperature. Despite the absence of the absorption peak at around 800 nm, the sample absorbed strongly in the near-infrared. Moreover, PANI/DBSA samples possessing a higher ratio of absorbance at 2600 nm to that at 800 nm showed higher electrical conductivity. These results suggest that shear-free thermal doping provides a simple route to controlling the morphology of the mixture by enabling the disintegration of the micron scale aggregates present in the as-purchased PANI. This in turn can be used to control the degree of doping of the PANI and consequently the conductivity of the sample. Copyright © 2011 John Wiley & Sons, Ltd.

Ethene-/α-olefin copolymers having a wide range of comonomers between 8 and 26 carbon atoms in length were characterized by wide angle X-ray diffraction (WAXD). It was found that the crystallinities for the shorter comonomers (C8, C12) matched fairly well with the crystallinities from DSC and volumetric measurements, while for the longer comonomers (C18, C26) distinct differences between the three methods were found. This was explained by the presence of an additional crystalline phase of the side chains slightly deforming the amorphous peak.

Fabrication of CNT-dispersed epoxy under various conditions using the ball milling process is performed as a fundamental research on the application of CNT-dispersed resin to CFRP composites. CNT length in compounds and viscosity of CNT-dispersed resin are measured in relation to process conditions. Viscosity characteristics on CNT-dispersed compounds and relationship between CNT length and viscosity are clarified in this paper.

Several techniques are introduced to enhance the interlaminar fracture toughness of CFRP laminates using cup-stacked carbon nanotubes (CSCNTs). Prepared CSCNT-dispersed CFRP laminates are subject to Double Cantilever Beam (DCB) and End Notched Flexure (ENF) tests in order to obtain mode-I and mode-II interlaminar fracture toughness. The measured fracture toughnesses are compared to that of CFRP laminates without CSCNT to evaluate the effectiveness of CSCNT dispersion for the improvement of fracture toughness. All CSCNT-dispersed CFRP laminates exhibit higher fracture toughness, and specifically, CSCNT-dispersed CFRP laminates with thin epoxy interlayers containing short CSCNTs have three times higher fracture toughness than CFRP laminates without CSCNT. SEM observation of fracture surfaces is also conducted to investigate the mechanisms of fracture toughness improvement. Crack deflection mechanism is recognized in the CSCNT-dispersed CFRP laminates, which is considered to contribute the enhancement of interlaminar fracture toughness.

Vapor-grown carbon fiber (VGCF)/silicon oxycarbide ceramic composites have been prepared by pyrolysis of a VGCF/methylsilicone precursor (MSR) composite produced through polymer melt-mixing. The electrical resistivity of the composite before and after pyrolysis was drastically reduced by VGCF (above 5 wt% in MSR), and reached the order of 100 Ω cm. However, the ceramic composite could not always maintain its shape because of shrinkage from the weight loss of MSR during pyrolysis. To overcome this difficulty, polymethyl methacrylate (PMMA) microbeads were added as a sacrificial processing aid during melt-mixing to enable the material to maintain its shape through the microporous structure generated. The microcellular VGCF/ceramics obtained from VGCF/MSR/PMMA were characterized in terms of their shrinkage, mechanical, structural and electrical properties, and their composition was optimized. It was found that microcellular VGCF/ceramics derived from an optimal VGCF/MSR/PMMA composition of 5/45/45 (by weight) gave a low electrical volume resistivity (around 1.0 Ω cm), comparable to that of VGCF/ceramics from 10/90 (by weight) VGCF/MSR.

The influence of filler types and concentration on the foaming structure was investigated using a batch method to penetrate CO2 in ABS polymer matrix. Vapor grown carbon fiber (VGCF®, averaged diameter = 150 nm), and calcium carbonate (averaged particle diameter = 1.8 μm) were used as fillers and the concentration was changed from 5 to 15 wt %, respectively. Vapor grown carbon fiber or calcium carbonate was compounded with ABS using an extruder and samples were made by hot press method. Foamed samples, whose density reduction showed about 30–40%, were made by controlling preparation conditions.In the case of vapor grown carbon fiber/ABS systems, the average diameter of foaming cell decreased, and the cell density increased as a function of fiber concentration. On the other hand, by the incorporation of calcium carbonate, the diameter increased, and density decreased with higher concentration. The initial nucleation stages of foaming from fillers were carefully observed for fillers having large aspect ratio and particle shape. Based on the evidences from optical microscope observation, the different tendency of cell diameter between the two systems as a function of concentration was discussed.

A facile method of simultaneous alignment and micropatterning of multi-wall carbon nanotubes (MWCNTs) is presented. The method uses the combination of the magnetic alignment and patterning techniques. Due to their diamagnetic nature, MWCNTs suspended in a liquid medium are trapped at the minima of the magnetic field created by a field modulator and at the same time they align due to their magnetic anisotropy. The achieved patterning and alignment is fixed by solidification of the matrix. The alignments both parallel and perpendicular to the film surface have been achieved.

A trace amount of vapor-grown carbon fibers (VGCFs) were dispersed in polydimethylsiloxane (0.097 Pa s) by mechanical stirring. A magnetic field (0.23 T) was applied to the dispersion while in situ optical microscope observation was performed. The alignment rate was determined through analysis of the VGCF orientation. Using this suspension method, the diamagnetic anisotropic susceptibility of VGCF was estimated to be 3.11 × 10 −4 (–). From this value, the alignment time of VGCFs was estimated as a function of viscosity or magnetic field. The anisotropic susceptibility of VGCFs was compared with those of conventional carbon fibers.

紫外線硬化型高分子液体中で Vapor-Grown Carbon Fiber(VGCF®)の分散状態が異なる分散液を調整し，複合体フィルムを作製した．一つは紫外線硬化型高分子液体に VGCF®を均一分散させた．もう一つは前者に熱処理し，VGCF®のネットワーク構造を誘起させた．これら 2 種の分散液に磁場(1 T, 10 T)を膜厚方向に印加した．VGCF®が均一分散した系に磁場印加した場合，均一分散状態で磁場方向に配向した(1 T, 10 T ともに同じ配向構造)．一方，VGCF®ネットワーク構造を有した系に磁場印加した場合，ネットワーク構造を保持し，磁場方向に配向した．特に 10 T の方が高度に配向した．また，VGCF® 1.0 wt%が均一分散した膜厚方向の体積抵抗率は磁場印加前後で変化なく 1010 Ω・cm 以上であった．一方，ネットワーク構造を有するフィルムは磁場無印加，1 T, 10 T でそれぞれ 4.2×105 Ω・cm, 2.1×105 Ω・cm, 9.6×103 Ω・cm と抵抗率が減少した．

Microcellular silicon oxycarbides have been produced by pyrolysis of methylsilicone resin with the help of sacrificial microbeads of polymethyl methacrylate (PMMA). The PMMA microbeads were added in the range from 0 to 80 wt%, and the pyrolysis was performed at 800–1200 °C. The volume shrinkage resulting from the polymer-to-ceramic conversion becomes constant at the pyrolysis temperature above 1000 °C, and the shrinkage value reaches about 60% by a PMMA addition of 80 wt%. In the all range of PMMA additive ratios, the spherical micro pores with the wide range diameter from 1 to 10 μm are produced in the matrix. The open-cells, which are formed above 30 wt% of PMMA addition, have the open pores size bigger than 0.5 μm. The bending strength and the elastic modulus of the product exhibit the maximum values, i.e., 24.1 MPa and 16.0 GPa, respectively, when PMMA addition is 50 wt%.

The high temperature stability, and the dynamic melt rheological properties of poly(ethylene-co-acrylic acid) (EAA), zinc salt of EAA, and sodium salt of EAA were evaluated in the molten state over broad ranges of shear rates and temperatures using ARES (Rheometrics). The master curves of G′ and G″ as a function of angular frequency (ω) were constructed for each material. The influence of ionic groups on the storage modulus (G′), loss modulus (G″), complex viscosity (η∗), and flow activation energy (Ea) were analyzed. The results of EAA based ionomers are discussed with those of the ionomers based on poly(ethylene-co-methacrylic acid) (EMAA). The linear visco-elastic spectra, and flow activation energies of the two series of ionomers show differences.

A trace amount of vapor-grown carbon fibers (VGCFs), which, as received, had an aggregated lump form, was completely dispersed in polydimethylsiloxane, a nonpolar viscous liquid, at room temperature by mechanical stirring. Using this uniformly dispersed sample as a starting material, a dc electric or magnetic field was applied to induce the formation of an aligned structure. In situ transmission optical microscopy was carried out to observe the structural development of VGCFs in polydimethylsiloxane under the dc electric or magnetic field, which was applied both parallel and perpendicular to the observation direction. Upon application of a dc electric field, an aligned ramified network structure of VGCFs developed between the electrodes. In the formation of the network structure, ends of VGCFs became connected to ends of other VGCFs, which was followed by rotation and orientation of the VCGFs. On the other hand, upon application of a magnetic field, the VGCFs were only rotated, without the formation of a network. The electric resistivity of the network structure was evaluated. Additionally, the influence of the viscosity of the polydimethylsiloxane matrix on the structural formation process was examined.

Vapor-grown carbon fibers (VGCFs) have outstanding mechanical, thermal, and electric characteristics, and it has strong anisotropy. To take advantage of the enhanced properties, the orientation control of VGCFs should be important. In recent years, the orientational control of VGCFs by magnetic processing has received considerable attention. We have performed the magnetic processing of polymer composite films including VGCFs by using magnetic processing apparatus with permanent magnets (1 T) and superconductive magnet (10 T). We have studied the orientation of VGCFs along the thick-ness direction of the film. It was demonstrated that the oriented VGCFs/polymer composite films were successfully produced even by permanent magnets (1 T). The volume resistivity (Ω·cm) of the film (vertically oriented VGCFs, 1.0 wt %, 10 lim thickness) showed 3.2 × 1012 and 2.1 × 100 Ω·cm along surface and thickness direction, respectively. Vertically oriented VGCFs / polymer composite film could be utilized as an alternative material having anisotropic electric conductive property.

Uniaxial elongational flow behavior was examined for polystyrene(PS)/styrene-butadiene-styrene(SBS) triblock copolymer by using a Meissner type rheometer under uniaxial elongational flow at constant strain rates. The mixtures of PS and SBS were prepared by means of a solution blending method. Pure PS did not exhibit strain-hardening. Elongational viscosity was quite similar among the mixtures of PS/SBS without heat treatment. However, large enhancement of strain-hardening was observed for PS/SBS blends treated at temperatures higher than 220 °C, and the magnitude of enhancement reached ten times or more. To analyze the cause of the enhancement of strain-hardening, we examined pure SBS itself using a combination of uniaxial elongation and FT-IR spectroscopy. Change in uniaxial elongational flow behavior, i.e., from strain-softening to strain-hardening, was observed corresponding to heat treatment temperatures. From FT-IR spectroscopy of SBS treated at various temperatures, the correlation between enhancement of strain-hardening and crosslinking of butadiene was obtained. From shear stress relaxation measurement of PS/SBS(90/ 10) treated at 260 °C for 60 min, convergence of relaxation modulus was observed in a strain range of γ 2 at long times. Thus, the increase of strain-hardening of PS/SBS blends treated at high temperatures is likely to result from affine deformation of crosslinked SBS component.

We have tried to form a variety of oriented structures in liquid crystalline materials and composites by magneto-processing. Using photo-curable liquid crystal (LC), homogeneous, homeotropic, and bend oriented structures were fixed in the films. Moreover, UV light was irradiated to the LC monomers through a photomask under the magnetic field. The pattern was successfully recorded in the film by molecular orientation. Low viscous branched LC molecules, LCs based on calix [4] resorcinarene and dendrimer, synthesized in this study could be highly aligned under the magnetic fields. The smectic structures of these LC materials were demonstrated from X-ray diffraction results of the magneto-oriented samples. Carbon nanotubes (CNTs) were aligned parallel to the field direction in polycarbonate (PC). Moreover, magneto-oriented CNTs remarkably enhanced the recrystallization of the PC during annealing.

Carbon nanotube (CNT) /polymer composites have been expected for a promising application of CNT and have received considerable attention in fundamental studies. Recent progress of Carbon nanotube/polymer composites is reviewed from polymer material point of view for utilizing CNTs into polymer matrix.

It is known that polycarbonate (PC) is categorized as amorphous polymer and pure PC crystallizes extremely slowly. However, we have recently found that the crystallization of PC was substantially accelerated around 200 °C in the presence of vapor grown carbon fiber (VGCF), having ultra thick multi-walled carbon nanotube (MWCNT) structure. To examine the accelerated crystallization by VGCF, the effect of pre-graphitized VGCF, carbon black, and mesophase pitch based carbon fiber (CF) on the crystallization was evaluated. In addition, polarized optical microscope observation was performed by using PC including magnetically oriented VGCF. It was suggested that the surface of ordered graphite structure from VGCF or CF induced the oriented crystallization of PC along the axial direction of VGCF or CF. To utilize the accelerated oriented crystallization of PC by CF, PC sheet having oriented crystallized surface PC layer was made by annealing the stacked structure of PC sheet and oriented CF sheet at 200 °C. The PC sheet, whose surface was crystallized along CF axial direction, was successfully produced, showing retardation property by polarized optical microscope.

We present a percolation study of a two-dimensional crossbar networks and investigate the percolation behavior in fiber-reinforced composites. A modified model of sticks with a finite width is proposed for predicting percolation threshold of volume fraction of the fiber-reinforced composites. Based on the presented model and Monte Carlo simulations, the influences of fiber aspect ratio and orientation on the percolation behavior were investigated. It was found that the percolation threshold had a linear dependence with aspect ratio more than 40 in double-logarithmic plot. The percolation threshold had larger dependence on the orientation angle less than 30 ∘ . In terms of a model considering the tunneling effect, furthermore, the composite system filled with carbon nanotubes predicted to obtain lower percolation threshold. For lower fiber aspect ratios, fiber ends strongly affected the connection of crossbar networks.

A novel polystyrene(PS) with an incorporation of a small mass fraction of styrene-butadine-styrene(SBS) and dicumyl peroxide(DCP) has been developed to enhance strain-hardening significantly under elongational flow. Here, strain-hardening is defined as steep increase of elongational viscosity at large strain which deviates from linear viscoelastic curve. The content of SBS was in a range from 1wt% to 10wt%, and the content of DCP was in a range from 0.01wt% to 0.1wt%. Pure PS at 180 °C did not exhibit any strain-hardening. Whereas, significant enhancement of strain-hardening was observed for PS blended only 1wt% SBS and 0.1wt% DCP. The magnitude of strain-hardening (SH) was over 10 up to Hencky strain of 3. Note that the parameter, SH, is defined as elongational viscosity at large strain to linear viscoelastic envelope at the same time. Enhancement of strain-hardening was in the order of SBS content and DCP content. The magnitude of strain-hardening(SH) for PS/SBS/DCP(SH~70 at the maximum) was much more remarkable than that of any other PS such as PS/UHMW-PS and branched PS reported before(SH

Carbon fiber (CF) has outstanding mechanical, thermal, and electric characteristics, and it has strong anisotropy. To take advantage of the enhanced properties, the orientation control of CFs should be important. In recent years, the aligned carbon nanotube (CNT) /polymer composites have been produced by the application of high magnetic field. However, there are few reports about magnetically oriented CF/polymer composites. We have performed the magnetic processing of polymer composite films including CFs by using our magnetic processing machine (0.9 T) with permanent magnets, and a commercially available superconductive magnet (10 T). We have studied the orientation of CFs along the thickness direction of the film. The orientational distribution of CFs was analyzed by three dimensional optical microscope analysis in addition to X-ray diffraction. It was demonstrated that the oriented CF/polymer composite films were produced even by permanent magnets. The electric resistance of the film (vertically oriented CFs, 10wt.%), after magnetic processing (0.9T), was improved by the order of 109Ω·cm. It was also found that the film showed anisotropic electric property.

The strain hardening of blends of polystyrene (PS) and ultra-high molecular weight polystyrene (UHMW-PS) in elongational flow is modeled by the molecular stress function (MSF) theory. Assuming that the ratios of strain energies stored in polydisperse and monodisperse polymers are identical for linear and nonlinear deformations, the value of the only non-linear parameter of the theory in extensional flows, the maximum molecular stress fmax, can be determined and is shown to be related to steady-state compliance Je0. Using only linear-viscoelastic data, the elongational viscosity of PS/UHMW-PS blends is consistently predicted by the MSF theory.