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Volume 74 (2017)
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Volume 74, Issue 6
Displaying 1-24 of 24 articles from this issue
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Special Topic on Conductive Polymers
Comprehensive Papers
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Shotaro HAYASHI, Yuki TOGAWA, Atsushi ASANO, Koji NISHI, Shin-ichi YAM ...2017 Volume 74 Issue 6 Pages 453-459
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: June 22, 2017JOURNAL FREE ACCESSThe direct arylation synthesis of π-conjugated network polymers (conjugated microporous polymers: CMP) containing fluoroarene and triazine moieties was successfully achieved. The direct arylation of 1,2,4,5-tetrafluorobenzene or 1,3,5-trifluorobenzene with a tribromoarene having a triazine core under two reaction conditions (Conditions a: in DMAc, Conditions b: in toluene) gave four types of CMPs (CMP1a, CMP1b, CMP2a and CMP2b). Brunauer-Emmett-Teller (BET) surface area of CMP2a and CMP2b was higher than that of CMP1a and CMP1b because of a higher number of branches. The solvents used for the direct arylation polycondensation thus strongly affected the structure of the resulting CMPs.View full abstractDownload PDF (748K) -
Yuki KOIZUMI, Shinsuke INAGI2017 Volume 74 Issue 6 Pages 460-472
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 20, 2017JOURNAL FREE ACCESSBipolar electrochemistry, which involves redox reactions on a wireless electrode (bipolar electrode) in low concentration of supporting electrolyte, has attracted much attention due to its versatile use in interdisciplinary fields ranging from analytical chemistry to materials science. What makes bipolar electrochemistry unique is not only its site-selective and wireless way of inducing reactions, but also its applicability for various sizes of conducting materials as bipolar electrodes. In this article, we focus on the recent progress in electropolymerization using bipolar electrochemistry. Site-selective modification of conductors as well as conducting polymer fiber formation are included.View full abstractDownload PDF (1903K) -
Toru AMAYA, Toshikazu HIRAO2017 Volume 74 Issue 6 Pages 473-481
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: August 16, 2017JOURNAL FREE ACCESSIn this comprehensive paper, syntheses and properties of self-doped conducting polyanilines bearing phosphonic acid moieties are summarized. Poly(2-methoxyaniline-5-phosphonic acid) (PMAP), a polyaniline bearing phosphonic acid moieties which are directly bonded to the main chain, was synthesized by oxidative polymerization of 2-methoxyaniline-5-phosphonic acid. The synthesis could be scaled up by improving the synthetic scheme. Poly(2-methoxyaniline-5-phosphonic acid monoester) (PMAPE), a monoester form of PMAP, was also synthesized. Self-doping of PMAP and PMAPE was confirmed from their absorption, ESR, and XPS spectra. The conductivity of PMAP and PMAPE was 1.9 × 10−1 and 1.0 × 10−2 S/cm, respectively. Unlike a typical conducting polyaniline, PMAP showed the efficient delocalization of polarons under basic conditions (ca. pH 10). We also achieved to prepare the self-doped conducting polyaniline that is soluble in organic solvents by forming salts with quaternary ammonium cations possessing long alkyl chains. PMAP exhibited properties that make it useful as an antistatic agent in electron beam lithography.View full abstractDownload PDF (1071K) -
Makoto MORIYA2017 Volume 74 Issue 6 Pages 482-493
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 04, 2017JOURNAL FREE ACCESSMolecular crystals (MCs) consisting of an ordered arrangement of supramolecules are attractive compounds to develop novel materials because of the structural versatility of component units and their hierarchical structures. Lithium ion conductivity is one of the most important functions of such MCs because of their potential applications as solid electrolytes for next-generation batteries. Although it is known that the ionic conduction path is one of the most attractive key structures to generate solid-state ion diffusivity, lithium ion conducting MCs show limited ion conductivity that is not sufficient for practical applications at present. The authors investigated the systematic structural control of the ionic conduction paths in MCs through the modification of the component molecules. In this review, the structure-conductivity relationships of the molecular crystalline electrolytes synthesized by the authors are described, together with a guideline to develop molecular-based solid electrolytes exhibiting fast and selective lithium ion conduction.View full abstractDownload PDF (1550K)
Original Papers
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Yoshito YAMADA, Yoshimasa MATSUMURA, Mahito ATOBE2017 Volume 74 Issue 6 Pages 494-501
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: June 21, 2017JOURNAL FREE ACCESSA rotating disk electrode (RDE), which is often used for electrochemical analysis, was applied for electrochemical polymerization in order to control the structure of the obtained conducting polymer films, such as polyaniline films. As result, a polyaniline films with smooth surface could be obtained by the RDE method. In addition, it was also found that the film density and conductivity of the polyaniline films increased with an increase in the rotating speed. These facts suggest that the use of RDE is extremely useful for preparation of polyaniline films with highly-regulated structures.View full abstractDownload PDF (927K) -
Kozo MATSUMOTO, Daisuke TSUTSUMI, Makoto KUWAJIMA, Takeshi ENDO2017 Volume 74 Issue 6 Pages 502-507
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: August 18, 2017JOURNAL FREE ACCESSThe title polysiloxane was prepared by polycondensation of 2-(1,3-dioxolan-2-only)ethyldimethoxymethylsilane. Ionic conductivity of the polymer was measured after addition of lithium trifluoromethanesulfonate (LiOTf) or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). In the case of LiOTf, the maximum value of ionic conductivity was reached when 2.0 equivalents of LiOTf per carbonate group were added, but the value was rather low (3.6 × 10−8 S/cm at 30°C). In the case of LiTFSI, on the other hand, the conductivity increased with the increase of LiTFSI amount, and it reached 7.7 × 10−5 S/cm at 30°C when 4.0 equivalents of LiTFSI were added.View full abstractDownload PDF (857K) -
Kyusun KIM, Hiroaki ITOI, Shinji KANEHASHI, Kenji OGINO2017 Volume 74 Issue 6 Pages 508-516
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: August 31, 2017JOURNAL FREE ACCESSIn order to develop thermally stable hole transporting polymers, the N-arylcarbozole moiety, which was connected at 3,9-positions, was incorporated into 4-butyltriphenylamine based polymers via Pd-catalyzed C-N coupling polymerization. The synthesized copolymers have number average molecular weights in the range from 7.3 to 12 kg/mol, and are soluble in chloroform and chlorobenzene. UV-vis spectra revealed that the introduction of carbazole moiety leads to the blue-shift of wavelength at the absorption maximum, and thus to the extension of the band gap. Other optical and electrochemical properties were evaluated by fluorescent spectroscopy and cyclic voltammetry. From DSC measurements, it is found that the glass transition temperatures of copolymers are higher than that of the homopolymer consisting of 4-butyltriphenylamine units. The copolymer with 70 mol% of carbazole units shows a glass transition at 267°C. Investigation of space-charge limited current characteristics in the hole-only devices reveals that the introduction of carbozole unit improves the hole mobility, and the above-mentioned copolymer shows a hole mobility of 1.5 × 10−5 cm2 V−1 s−1.View full abstractDownload PDF (847K) -
Takashi KUWAHARA, Takao YOSHIDA, Hikaru ISHIKAWA, Mizuki KONDO, Masato ...2017 Volume 74 Issue 6 Pages 517-523
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 13, 2017JOURNAL FREE ACCESSThis study presents the influence of the preparation conditions of conducting polymer films on the bioelectrocatalytic currents generated with enzyme electrodes composed from those films and glucose oxidase. The films were prepared by electrochemical polymerization of 3-methylthiophene and thiophene-3-acetic acid. The enzyme electrodes were finalized by covalently immobilizing glucose oxidase on the film surface. The bioelectrocatalytic current was measured in a phosphate buffer solution (pH 7.0) containing glucose and p-benzoquinone. By switching the polymerization solvent from acetone to acetonitrile, the bioelectrocatalytic current increased by a factor of 7.2. The monomer concentration had an optimum range (0.25–1.0 M) for the bioelectrocatalytic current. The polymerization current increased accompanying an increase in applied potential during the electrochemical polymerization. In contrast, the bioelectrocatalytic current showed a plateau in a higher potential range. The primary factor to influence the bioelectrocatalytic current is considered to be the surface morphology of the films that is closely related to the electrochemical polymerization conditions.View full abstractDownload PDF (837K) -
Manabu YAMAZAKI, Eiichi AKIYAMA, Shinji OZOE2017 Volume 74 Issue 6 Pages 524-533
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: October 23, 2017JOURNAL FREE ACCESSPoly(styrenesulfonate)-poly(dialkylacrylamide) block copolymers (PSS-block-copolymers) were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. Poly(3,4-ethylenedioxythiophene):PSS-block-copolymer (PEDOT:PSS-block-copolymer) composites were obtained by oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) in PSS-block-copolymer aqueous solutions. Good conductivity and stability of PEDOT composite film were maintained by using PSS-poly(acryloylmorpholine) block copolymer as compared to the statistical copolymer or the blend as a polyanion, even when the amount of sulfonate groups was reduced. PEDOT:PSS-block-copolymers, prepared by using 4-acryloylmorpholine, N,N-diethylacrylamide or N,N-dimethylacrylamide as a hydrophilic comonomer, showed good conductivity. On the other hand, the conductivity decreased in PEDOT:PSS-block-copolymers, prepared by using N,N-dipropylacrylamide or 4-acryloylpiperidine as a hydrophobic comonomer.View full abstractDownload PDF (816K) -
Shigetaka HAYANO, Rie ARAI, Hiroshi SUGIMOTO2017 Volume 74 Issue 6 Pages 534-541
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: October 30, 2017JOURNAL FREE ACCESSAlternating copolymerization of carbon dioxide and epichlorohydrin, followed by quaternization of obtained polymers with pyridine was carried out to give alternating copolymers containing pyridinium chloride groups, of which ionic conductivity was investigated. The alternating copolymer, poly[4-(chloromethyl)-1,3-dioxolan-2-one] (poly(ECH-alt-CO2)) (Mw = 17,000), was formed when zinc glutarate was employed as a catalyst. Degradation was dominant when 1-methylimidazole or n-butyldimethylamine were employed for quaternization. In the case of pyridine, the cationized polycarbonate was formed with moderate selectivity in the early period of quaternization. Volume resistivity of the partially cationized (11.6 mol%) polycarbonate was 1.87 × 107 Ω cm and much lower than that of the non-ionic poly(ECH-alt-CO2) (1.21 × 1014 Ω cm).View full abstractDownload PDF (822K) -
Jun ISHII, Yuko TAKEOKA, Masahiro RIKUKAWA, Masahiro YOSHIZAWA-FUJITA2017 Volume 74 Issue 6 Pages 542-548
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 22, 2017JOURNAL FREE ACCESSColorless and transparent polybetaine-type ion gels (PEG100CL2BTx (x = 0, 1, 3, 5, and 10) (the numbers indicate mole percent)) composed of poly(ethylene glycol) methyl ether methacrylate (PEGMA), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (BT) as the polymer matrix, N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)amide/lithium bis(trifluoromethylsulfonyl)amide (IL/Li) as the electrolyte, and a cross-linker (CL) were synthesized by in situ polymerization. These ion gels exhibited a glass transition temperature (Tg) at approximately −70°C, and their ionic conductivity was almost the same regardless of the x value. On the other hand, the oxidation stability of ion gels increased with increasing BT content. All ion gels exhibited a reduction peak for Li+ and an oxidation peak for Li. The current density and coulombic efficiency of PEG100CL2BT5 were higher than those of PEG100CL2BT0.View full abstractDownload PDF (972K) -
Nobutaka TANIGAKI2017 Volume 74 Issue 6 Pages 549-556
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: October 27, 2017JOURNAL FREE ACCESSOriented thin films were fabricated on substrates from a conducting polymer, poly(p-phenylene) (PPP), by the friction transfer method. When these films were immersed into a benzene polymerization reaction solution, newly polymerized molecules were deposited on the friction-transferred films as orienting templates. We call this process “homoepitaxial polymerization”. We investigated the dependence of thickness and orientation degree of the polymerized films on various reaction conditions, such as catalyst concentration, monomer concentration, reaction time and reaction temperature. The mechanism of oriented growth of the PPP films is discussed. Moreover, homoepitaxial polymerization of polyaniline (PANI) was examined with friction-transferred PANI as a template, for which an acceleration of the polymerization on the surfaces of the friction-transferred films was observed. We call this “surface-enhanced polymerization”. These processes are useful for the formation of patterned conducting polymers films.View full abstractDownload PDF (965K) -
Jun MORITA, Morito YAGI, Takanori GOTO, Shinji KANEHASHI, Takeshi SHIM ...2017 Volume 74 Issue 6 Pages 557-564
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: October 11, 2017JOURNAL FREE ACCESSWe fabricated complementary devices with a pn junction between p-type nanofiber/PMMA composite film and n-type nanofiber/PMMA composite film and evaluated the temperature dependence. This full-organic pn junction, fabricated in this study showed rectification, but, as the temperature decreased, the current in forward direction became smaller and the ideal coefficient tended to increase. In addition, the energy gap obtained from the temperature dependence of the reverse saturation current of the fabricated pn junction was influenced by the leakage current in the negative voltage region and the impurity of the dopant to compensate for n-type carrier deficiency, which was very small. Even in the case of using a flexible substrate, this pn junction showed rectifying properties. However, this rectification was lost by bending.View full abstractDownload PDF (766K) -
Maki HORIKAWA, Tomohiro SHIROSAKI, Naoya RYU, Yoshiro OHGI, Hideo SAKU ...2017 Volume 74 Issue 6 Pages 565-571
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 14, 2017JOURNAL FREE ACCESS
Supplementary materialSome kinds of sulfated cellulose (CS) with various degrees of substitution of sulfate groups (DS) were prepared through direct sulfation of cellulose. PEDOT/CS were prepared via in situ chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) in aqueous solution of CS. The PEDOT/CS films were formed on glass substrates by spin-coating. The electrical conductivity of the PEDOT/CS film with a DS of 1.03 was 0.576 S cm−1. Through TEM images of PEDOT/CS, the nanocrystalline morphology depending on CS was observed. Using X-ray diffraction, we studied the crystallinity of cellulose chains in the PEDOT/CS. The electrical conductivity of PEDOT/CS tended to increase with the crystallinity of the cellulose. Thus, EDOT molecules can polymerize and form a complex, lining up around the nanocrystalline cellulose. Using Raman spectroscopy, we studied the conformation of PEDOT chains in the PEDOT/CS and PEDOT/PSS films. We attributed the increased electrical conductivity of the PEDOT/CS film to an increase in the proportion of the quinoid structure in the PEDOT.View full abstractDownload PDF (929K) -
Asuka NODA, Hisaki KOBAYASHI, Hidenori OKUZAKI2017 Volume 74 Issue 6 Pages 572-576
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 11, 2017JOURNAL FREE ACCESSFlexible and transparent electric shielding was fabricated by bar-coating of a poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) water dispersion on poly(vinylidene difluoride) (PVDF) films and subsequent treatment with sulfuric acid. The thickness (d), sheet resistance (Rs), electrical conductivity (σ), total light transmittance (TT), and haze of the sulfuric acid treated (SA) films were 60~208 nm, 112~24 Ω/□, 1450~2300 S/cm, 73~95%, and <2.9%, respectively, where the figure-of-merit (FOM) as transparent electrodes was found to be 58. The electric shielding characteristics of the SA film (d = 94 nm, TT = 92%) showed that the shielding effect (SE) attained as high as −40 dB, while the electrical and optical properties of the PEDOT:PSS were crucially important for the flexible and transparent electric shielding.View full abstractDownload PDF (757K) -
Maito KOGA, Keisuke HASHIMOTO, Yoichi TOMINAGA2017 Volume 74 Issue 6 Pages 577-583
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: October 23, 2017JOURNAL FREE ACCESSSolid polymer electrolytes (SPEs) have been expected as solid-state electrolytes in electrochemical applications. However, ionic conductivity of SPEs are lower than that of common liquid and gel electrolytes. In this study, random and block copolymers were synthesized from CO2 and propylene oxide, and the ion conductive properties of block copolymers that consist of a polypropylene oxide central block connected to poly(propylene carbonate) (PPC) segments at both ends were investigated. We used three types of random copolymers containing different amount of ether units and one block copolymer. SPE samples were prepared by adding 20–100 mol% LiTFSI to the polymers. All copolymers showed a lower glass transition temperature and higher ion conductivity than those of PPC electrolytes. On the other hand, the random copolymers showed a lower ion conductivity than that of the block copolymer.View full abstractDownload PDF (681K)
Notes
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Shotaro HAYASHI, Toshio KOIZUMI2017 Volume 74 Issue 6 Pages 584-587
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: June 22, 2017JOURNAL FREE ACCESSThe direct arylation polycondensation of 3,3′-dihexyl-2,2′-bithiophene (BT6) with dibromoisoindigo (ID) was achieved by using PITS, palladium immobilized on thiol-modified silica gel. The polycondensation of BT6 with ID using PdCl2 for 1 h gave PBT6ID (Mn = 6900) in 74% yield. On the other hand, the polycondensation for 2 h gave PBT6ID (Mn = 5600) in low (12%) yield along with insoluble polymer products. This is probably due to chain branching based on β-defects of the polymers. The polycondensation of BT6 with ID for 12 h was performed with PITS-Cl catalyst, furnishing PBT6ID (Mn = 9800) in 79% yield. The optical and electrochemical properties of PBT6ID are also described.View full abstractDownload PDF (509K) -
Shotaro HAYASHI, Hiroki SHIMIZU, Yoshihisa KOJIMA, Shin-ichi YAMAMOTO, ...2017 Volume 74 Issue 6 Pages 588-593
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 07, 2017JOURNAL FREE ACCESSPalladium-catalyzed direct arylation polycondensation of 3,4-ethylenedioxythiophene (EDOT) with dibromocarbazole was investigated by varying heating conditions and microwave heating conditions. The polycondensation of EDOT with 3,6-dibromocarbazole resulted in the alternating copolymer (Mn = 6600) in high yield. In contrast, 2,7-dibromocarbazole shows low reactivity and the polycondensation of EDOT with 2,7-dibromocarbazole resulted in an oligomeric product (Mn < 4000) in low yield.View full abstractDownload PDF (565K)
Regular Topics
Original Papers
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Mei ABE, Kazuyuki SAKAI, Hironori TAMAMUSHI, Masaru KAWAKAMI, Hidemits ...2017 Volume 74 Issue 6 Pages 594-602
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: August 18, 2017JOURNAL FREE ACCESSParticle double-network gels (P-DN gels) consist of two kinds of network structure. The first structure is made by hard and rigid particles of polyelectrolyte gels and the second structure is made by a soft and elastic network of neutral gels. Recently, we have developed improved P-DN gels for 3D gel printers by grinding the 1st gel particle to be finer. In this work, we report the internal structure of P-DN gels by Scanning Microscopic Light Scattering (SMILS) and the mechanical properties by tensile tests and repeated tensile tests. From the results of SMILS measurements, we infer the motion of the 2nd gels network. Increasing the concentration of crosslinking agents for 2nd gels, the motion slowed down. From the tensile tests of P-DN gels, we observed that the fracture strain of P-DN gels depends on the size of 1st gel particles. This implies that the hardness of P-DN gels can be changed easily by changing the size of 1st gel particles. Furthermore, we observed the hysteresis of P-DN gels due to plasticity by repeated tensile tests.View full abstractDownload PDF (1183K) -
Shuto TOKUNAGA, Shinichi MOCHIZUKI, Noriko MIYAMOTO, Kazuo SAKURAI2017 Volume 74 Issue 6 Pages 603-607
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: August 08, 2017JOURNAL FREE ACCESSNucleic acid has attracted attention as a next generation drug. However, since the nucleic acid is a natural molecule, it is degraded by nucleases in vivo. Therefore, to overcome these problems, a drug delivery system (DDS) is indispensable. There is a DNA structure that can precisely control particle size and shape by using DNA nanotechnology. According to recent studies, tetrahedral DNA containing CpG sequences can stimulate the immune system without being degraded by nuclease. This research aims at new DDS carriers with pH responsiveness, using tetrahedral DNA. Tetrahedral DNA induced TNF-α more than CpG-DNA alone, indicating that tetrahedral DNA is an efficient nucleic acid adjuvant.View full abstractDownload PDF (610K) -
Suzuka MATSUMOTO, Arihiro KANAZAWA, Shokyoku KANAOKA, Sadahito AOSHIMA2017 Volume 74 Issue 6 Pages 608-615
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: July 26, 2017JOURNAL FREE ACCESSDegradable alternating copolymers with distinctly fluorous characteristics were synthesized via controlled cationic copolymerization of perfluoroalkyl vinyl ethers (VEs) and conjugated aldehydes. Well-defined alternating copolymers were obtained using the EtSO3H/GaCl3 initiating system in the presence of 1,4-dioxane as an added base and 2,6-di-tert-butylpyridine as a proton trap in a fluorine solvent at −78°C. Various conjugated aldehydes and fluorine-containing VEs were also investigated for controlled alternating cationic copolymerization. The solubility of the obtained alternating copolymers improved compared to the fluorine-containing VE homopolymer. In particular, copolymers underwent upper critical solution temperature-type phase separation behavior in various solvents. In addition, polymer thin films of the alternating copolymers exhibited high water and oil repellency. All alternating copolymers were decomposed into small molecules under an acidic condition without residual oligomers in both solution and thin film state.View full abstractDownload PDF (879K) -
Marehito SHIBATA, Masahiko MAEDA2017 Volume 74 Issue 6 Pages 616-620
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 19, 2017JOURNAL FREE ACCESSWhen TiO2 particle doped PVDF sheets are irradiated with UV-light, the sheets become cloudy, because local photocatalytic decomposition of PVDF leads to an increase in the surface roughness on a sub-micrometer scale. This is called “chalking”. Chalking results in decreased photocatalytic activity of the sheet. In this study, we investigated the chalking process of TiO2 doped PVDF sheets using SEM/EDX and AFM. In the first stage of chalking, minute cavities appear everywhere in the PVDF sheet surface. With UV-light irradiation, it is found that the density of minute cavities increases until they are connected laterally and then grow into minute cracks. When the decomposition of the PVDF progresses, TiO2 particle aggregates, which show cracks, are exposed on the surface. These results suggest that tensile stress builds up because of the PVDF decomposition.View full abstractDownload PDF (678K) -
Shigeki HIKASA, Kouichi KOUKA2017 Volume 74 Issue 6 Pages 621-630
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 12, 2017JOURNAL FREE ACCESSFor high density polyethylene (HDPE)/CaCO3 composites, CaCO3 inclusion influenced the mechanical properties significantly. The impact fracture behavior of HDPE depends on the diameter of the CaCO3 particles. When investigating HDPE showed ductile fracture in impact testing, CaCO3 inclusion increased tensile yield stress and impact strength. Especially, the CaCO3 having 1.4 µm of diameter improved significantly the impact strength. On the other hand, when the HDPE showing brittle fracture at impact test was used, CaCO3 inclusion decreased tensile yield stress and impact strength. Thus, during impact testing, CaCO3 inclusion varied ductile HDPE to be more ductile, while, in contrast, brittle HDPE became more brittle.View full abstractDownload PDF (1511K)
Short Communications
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Katsuhiko HIROTA, Haruo SASAKI, Fumio KEITOKU, Yoichiro MIYAKE2017 Volume 74 Issue 6 Pages 631-634
Published: November 25, 2017
Released on J-STAGE: November 24, 2017
Advance online publication: September 06, 2017JOURNAL FREE ACCESSThe first step for bacteria to cause infection is the attachment to the host. As almost all of the bacteria in the natural world adhere to some solid surface and proliferate, they can become the source for an infection. Therefore, the development of materials that are less prone to bacterial adhesion seems to be useful for the prevention of infectious diseases. Since we found that some isosorbide polycarbonates repell bacteria, we investigated the influence of isosorbide concentration on the repellent effect. The number of attached bacteria, Staphylococcus aureus 209P and Escherichia coli K12, per per surface area decreased significantly (p < 0.01) with increasing isosorbide polycarbonate mole fraction. It seems that the molar fraction of isosorbide polycarbonate changes the surface hydrophilicity and this, greatly influenced the first stage of biofilm formation of S. aureus 209P and E. coli K12.View full abstractDownload PDF (590K)
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