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The tensile properties of ferrite single-phase low-carbon steel with different initial microstructures were evaluated. Three types of hot-rolled sheet specimens with different microstructures—specimen P (consisting of ferrite and pearlite), specimen B (consisting of bainitic structures), and specimen M (consisting of fully martensitic structures) were used. After hot rolling, these specimens were cold-rolled, subsequently heated to the finishing temperature of ferrite recrystallization, and then water-quenched to room temperature. The recrystallized ferrite grain size decreased in the specimen order of B > P > M. The distribution of cementite was comparatively homogeneous in specimens B and M, whereas that in specimen P was heterogeneous. The yield and tensile strengths decreased in the specimen order of M > P > B. Calculations using the Hall–Petch equation revealed that the yield strength of each specimen depended mainly on the recrystallized ferrite grain size. The total elongation decreased in the specimen order of B > P > M, whereas the local elongation was approximately the same in all of the specimens. In addition, the number of dimples decreased in the specimen order of M > B > P, whereas the size of dimples decreased in the specimen order of P > B > M. These results suggest that the homogeneous distribution of cementite and the fine recrystallized ferrite grains in specimen M suppress void coalescence, thereby resulting in a good balance between the tensile strength and the local elongation.

The corrosion behavior and mechanical degradation of Ni-Ti superelastic alloy in neutral fluoride solution were investigated with a focus on the effect of temperature during immersion. Corrosion was accelerated by increasing the temperature, and mass loss increased with immersion time. Furthermore, Ti ions (Ni ions) preferentially dissolved in the early (later) stage of immersion. The tensile strength of the immersed specimen decreased when the mass loss was approximately 0.040-0.050 mg/mm3. The fracture mechanisms of specimens immersed in 2.0% NaF solution were active path corrosion at room temperature and presumably hydrogen embrittlement at 80 °C. For long-term (e.g., 180 days) immersions at 80 °C, hydrogen embrittlement did not occur, because the absorbed hydrogen diffused to the center of the immersed specimens, rendering the hydrogen distribution comparatively uniform. These findings suggest that the fracture mechanism of immersed specimens can change as a result of the temperature during immersion.

Research and development of controlling and evaluation on ferroelectric domain structures are described in piezoelectric ceramics composed of lead zirconate titanate, lead titanate, barium titanate, alkali bismuth niobate and alkali bismuth titanate. Ferroelectric domain switching and domain rotation could be explained by DC poling field dependence of dielectric and piezoelectric properties. In addition, Young's modulus and Poisson ratio toward poling field in piezoelectric ceramics were investigated by measuring longitudinal and transverse acoustic wave velocities to clarify the relationships between high piezoelectricity and the values. Increasing domain alignment by applying poling field, basically, the Young's modulus decreased and Poisson ratio increased.

Proton polarization at room temperature, produced in a p-terphenyl crystal by using electron population difference in a photo-excited triplet state of pentacene, was enhanced by utilizing an intense laser with an average power of 1.5 W. It was shown that keeping the sample temperature below 300 K is critically important to prevent the rise of the spin–lattice relaxation rate caused by the laser heating. It is also reported that the magnitude of proton polarization strongly depends on the time structure of the laser pulse such as its width and the time interval between them.

漆はさまざまな優れた物性をもつため，昔から日本各地で使われてきた．しかしながら，漆の硬化は通常酵素に関係しているため長時間を要し，用途が限定されている．そこで，漆の主成分であるウルシオールについて基礎的観点から高温における速い硬化反応を検討した．ウルシオールの硬化反応は 100～200℃ の温度範囲で空気および窒素雰囲気下で行った．次に反応機構を理解するためにスチレンとウルシオールについて高温で粘度の時間依存性を調べた．硬化速度や粘度は温度の上昇とともに増加したが，ウルシオールの粘度上昇は窒素雰囲気よりも空気雰囲気下で著しかった．また，硬化速度も粘度と同様に窒素雰囲気よりも空気雰囲気下において速かった．さらに，膜の酸化も空気雰囲気下での硬化でより著しかった．ところが，スチレンの粘度は雰囲気の影響はなく，ウルシオールはスチレンのような純粋なラジカル重合だけで硬化しているのではないことを示した．

When the depth profile of chemical composition is studied with X-ray photoelectron spectroscopy (XPS), the Ar+ ion sputtering method is generally adopted. However, in the case of polymers, chemical composition is destroyed, and so it is impossible to obtain accurate depth profile on polymers. In this research, the depth profile XPS analysis of aliphatic polymers, aromatic polymers, fluorine containing polymers, and natural polymers were conducted with the sputtering source being C60 + ion, and the degree of damage was examined while comparing the results with the case of conventional Ar+ ion. It was found that Ar+ ion induces significant carbonization in all the polymers above-mentioned. Meanwhile, it turned out that C60 + ion causes little damage to most polymers. However, in the case of the non-aromatic polymers containing halogen, hydroxyl, carboxyl, and ether groups in their backbones, the following three damage modes were found: (1) the functional group ratio changes by over ±10%; (2) new functional groups are formed; (3) the above (1) and (2) phenomena occur simultaneously.

The relationship between hydrogen absorption and the corrosion behavior of Ti-6Al-4V alloy has been examined by immersing the alloy in acidulated phosphate fluoride (APF) solution with various concentrations. Upon immersion in 0.1 mass% APF solution, no hydrogen absorption is observed despite the occurrence of general corrosion. In 0.2% APF solution, slight hydrogen absorption occurs soon after immersion, and then the surface of the specimen becomes uniformly covered with a crystalline corrosion product (Na3AlF6), thereby inhibiting further hydrogen absorption. In APF solutions with concentrations higher than 0.4%, the amount of absorbed hydrogen increases with increasing concentration of APF solution and immersion time. The type and morphology of corrosion products sensitively depend on the concentration of APF solution. Upon immersion in 0.4% APF solution, crystalline and massive Na3AlF6 are observed on the surface of the specimen. In 1.0% and 1.5% APF solutions, Na3AlF6 with a foldlike shape and granular Na3AlF6 and Na3TiF6 are observed. In 2.0% APF solution, only granular Na3TiF6 is observed. The corrosion potentials and anodic polarization curves are analogous in all APF solutions except the 0.2% and 0.4% APF solutions. In contrast, the current density of cathodic polarization curves increases with the concentration of APF solution. The results of the present study suggest that the corrosion products play an important role in the hydrogen absorption behavior of Ti-6Al-4V alloy.

ポリプロピレンシートについて空気雰囲気中および窒素雰囲気中でコロナ放電処理を行って X 線光電子分光法(XPS)により表面状態を評価した．また，表面処理試料についてインクの付着性について調べた．窒素雰囲気の場合，酸素含量は 0.6 atom%であった．空気雰囲気での処理では窒素はシート表面にほとんど結合しないが，窒素雰囲気処理では 4 atom%に達した．また，その場合の水の接触角は空気雰囲気中の処理に比べ 18°低い上，長期間安定であった．官能基については接着に最も関係が深いヒドロキシル基とカルボキシル基の含量と経時変化について化学修飾後の XPS により検討した．その結果，ともに窒素雰囲気中で処理した方が安定であった．さらに，窒素雰囲気中で処理した面ではインクの付着安定性が優れていた．このように，窒素雰囲気中でコロナ放電処理すると，処理効果が持続すると同時にインクの付着性も優れていることが確認された．

This chapter consists of two parts; the first part describes “how can high piezoelectricity be realized from measuring acoustic wave velocities?” That is, the measurement of sound velocities resulted in an effective tool for researching and developing piezoelectric materials, and, furthermore, it was possible to design the material compositions of lead-free piezoelectric ceramics as well as lead-containing ceramics. The second part describes the “effects of firing and DC poling treatments on elastic constants measured from acoustic wave velocities in barium titanate piezoelectric ceramics”. Namely, it could be applied to manufacturing processes such as firing and DC poling treatments in piezoelectric ceramics, which is accompanied with densification of ceramics and ferroelectric domain aligment, respectively. It is clarified through the two parts that the evaluation of elastic constants leads to the origin of piezoelectricity in piezoelectric ceramics.

The effects of moisture (H 2 O concentration) and dissolved oxygen in methanol and ethanol solutions containing 0.1% hydrochloric acid (HCl) on hydrogen absorption and desorption behaviors of the Ni–Ti superelastic alloy have been examined by hydrogen thermal desorption analysis. In the methanol solution, the amount of absorbed hydrogen decreases with increasing H 2 O concentration. For 5% H 2 O, the thermal desorption peak of hydrogen gradually shifts from 400 to 250 °C with immersion time. When the H 2 O concentration is higher than 10%, the hydrogen absorption is not observed. Under a deaerated condition, significant dissolution of the specimen due to corrosion is observed; however, the increment in the amount of desorbed hydrogen is not observed. In the ethanol solution, the critical H 2 O concentration for hydrogen absorption is approximately 0.8%. For 2% H 2 O, the hydrogen absorption is not exhibited, although slight corrosion is observed. The amount of absorbed hydrogen under the deaerated condition is ten times more than that under the aerated condition. The dissolved oxygen varies the hydrogen desorption behavior.

The fracturing of Ti–0.2 mass% Pd (Ti–0.2Pd) alloy in acid and neutral fluoride solutions has been investigated by a sustained tensile-loading test. In 2.0% acidulated phosphate fluoride (APF) and neutral 2.0% NaF solution, the time to fracture of the Ti–0.2Pd alloy is shorter than that of commercial pure titanium for the same applied stress. In 2.0 and 0.2% APF solutions, fractures are characterized by a cup-cone mode irrespective of applied stress. In 2.0 and 0.2% NaF solutions, transitions from cup-cone to shear modes of the fractures are observed with decreasing applied stress. The results of the present study suggest that the susceptibility to fracturing of the Ti–0.2Pd alloy is higher than that of commercial pure titanium.

Aromatic polyimide film composed of biphenyl tetracarboxylic acid dianhydride (BPDA) and p-phenylene diamine (PDA) is a very stable polymer at high temperatures and very useful for the electronics industry. Bonding properties were improved by corona discharge treatment of this film. The chemical modification method was applied for generated functional groups, that is, carboxylic, hydroxyl, and amino groups in the gas phase, and the quantity of these functional groups was determined by X-ray photoelectron spectroscopy. The functional groups increased with corona energy, leveling off at a specific corona energy. The bond strength of the copper foil/adhesive/polyimide film was determined. The relationship between bond strength and functional group content was analyzed by multivariate analysis. Bond strength could be sufficiently correlated with functional group quantity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3403–3408, 2006

Hydrogen absorption of biomedical titanium and Ni-Ti alloys in a neutral fluoride (2.0% NaF) solution for up to 10,000 h at 37 degrees C has been evaluated by means of hydrogen thermal desorption analysis. For alpha titanium (commercial pure titanium), the amount of absorbed hydrogen was, at most, 10-30 mass ppm, and the corrosion product and hydride formation were revealed on the surface of the specimen by X-ray diffraction analysis. Ni-Ti superelastic alloy absorbed approximately 150 mass ppm of hydrogen, which was probably sufficient to result in the pronounced degradation of the mechanical properties, although corrosion was hardly observed. In contrast, hydrogen absorption of alpha-beta titanium (Ti-6Al-4V) and beta titanium (Ti-11.3Mo-6.6Zr-4.3Sn) alloys was negligible, although general corrosion was observed. The results of the present study indicate that the susceptibility of titanium and Ni-Ti alloys to hydrogen absorption in the neutral fluoride solution is different from that in the acidic fluoride solution reported previously.

The hydrogen absorption properties of Ti–0.2 mass% Pd (Ti–0.2Pd) alloy in 2.0% and 0.2% acidulated phosphate fluoride (APF) and neutral 2.0% NaF solutions (25 °C) has been evaluated by hydrogen thermal desorption analysis. During the early stage of immersion (120 h) in the 2.0% APF solution, the amount of absorbed hydrogen was lower than 500 mass ppm. A thermal desorption of hydrogen primary appearing with a peak at 500–600 °C and a broad desorption ranging from 100 to 400 °C were observed. In the 0.2% APF solution, the amount of absorbed hydrogen saturated at 100–200 mass ppm; the thermal desorption of hydrogen appeared with a single peak at 550 °C. In the 2.0% NaF solution, hydrogen absorption was negligible even after 1000 h of immersion, although corrosion pits were observed. The results of the present study suggest that the hydrogen absorption of Ti–0.2Pd alloy, as compared with commercial pure titanium, is suppressed in fluoride solutions.

The susceptibility to delayed fracture of the alpha–beta titanium alloy Ti–6Al–4V has been investigated in acidic and neutral fluoride solutions at room temperature. The time to fracture decreased with increasing applied stress in 2.0% and 0.2% acidulated phosphate fluoride (APF) solutions at pH 5.0. The time to fracture in the 2.0% APF solution was shorter than that in the 0.2% APF solution, although at an applied stress higher than 1000 MPa, the times to fracture were almost the same in both the solutions. For immersion in the 0.2% APF solution, when the applied stress was lower than 700 MPa, delayed fracture did not occur within 1000 h. The fracture surface of specimens immersed in the 2.0% APF solution exhibited brittleness associated with hydrogen absorption, while that in the 0.2% APF solution was ductile and characterized macroscopically as having a cup–cone morphology. The amounts of hydrogen absorbed in 2.0% and 0.2% APF solutions for 24 h were approximately 200 and 30 mass ppm, respectively. As the immersion time increased, the amount of hydrogen absorbed in the 2.0% APF solution increased, whereas that in the 0.2% APF solution hardly increased. In neutral 2.0% and 0.2% NaF solutions, the delayed fracture did not occur within 1000 h, although general corrosion was observed. These results indicate that the susceptibility to delayed fracture of alpha–beta titanium alloy, compared with those of the alpha titanium and beta titanium alloy reported previously, is low in acidic and neutral fluoride solutions.

The distribution and thermal desorption behavior of hydrogen in alpha titanium (commercial pure titanium) and beta titanium alloy (Ti–11.3Mo–6.6Zr–4.3Sn) immersed in acidic fluoride solutions (pH 5.0, 25 ± 2 °C) have been investigated. For alpha titanium, most of the hydrogen absorbed in the fluoride solution existed as titanium hydride within approximately 50 μm from the surface of the specimen. The local hydrogen concentration in the vicinity of the surface was evaluated above 5000 mass ppm. Hydrogen thermal desorption was observed in the temperature range from 200 to 700 °C. It is likely that the desorption at a low temperature resulted from the dissociation of the hydride, whereas that at a high temperature was caused by hydrogen strongly trapped in matrix defects induced by hydride formation. For the beta titanium alloy, the absorbed hydrogen diffused toward the center of the specimen without hydride forming. Hydrogen was almost uniformly distributed over the whole cross-section of the specimen, although hydrogen content was high at the surface layer of the specimen. Hydrogen desorption appeared in the range from 400 to 600 °C, implying that the absorbed hydrogen was mostly hydrogen in solution. The corrosion product (TiF3) on the surface of the specimen caused the desorption temperature to rise more than 100 °C, suggesting the origin of the scatter of desorption behavior.

The hydrogen embrittlement of the Ni–Ti superelastic alloy in ethanol solution containing 0.1 mass% hydrochloric acid (HCl) has been investigated using a tensile test (after immersion) and hydrogen thermal desorption analysis (TDA). Upon immersion, the alloy absorbed substantial amounts of hydrogen associated with localized corrosion. The maximum amounts of absorbed hydrogen after immersion for 120 and 600 h were 260 and 1200 mass ppm, respectively. The hydrogen thermal desorption of the immersed specimens appeared as two peaks at approximately 150 and 350 °C. As immersion time increased, the amount of desorbed hydrogen at the lower temperatures increased markedly. When the amount of absorbed hydrogen exceeded 200–400 mass ppm, a marked reduction in tensile strength occurred. The fracture mode of specimens that absorbed hydrogen changed from ductile behavior to brittle behavior; the peripheral parts of the fracture surface exhibited a quasi-cleavage-like topography. The hydrogen embrittlement characteristic of the Ni–Ti superelastic alloy in ethanol solution containing 0.1% HCl was not always in accordance with those of the same alloy in other solutions such as the methanol solution containing 0.1% HCl reported previously.

Hydrogen embrittlement of work-hardened Ni–Ti alloy has been examined in acidulated phosphate fluoride (APF) solutions. Upon immersion in a 2.0% APF solution with a pH of 5.0, tensile strength decreased markedly with immersion time. Moreover, the fracture mode changed from ductile to brittle due to brittle layer formation at the peripheral part of the cross section of the specimen. The amount of absorbed hydrogen increased linearly with immersion time, and it reached above 5000 mass ppm after 24 h. The hydrogen desorption temperature of the immersed specimens shifted from 450°C to a lower temperature with immersion time. As the amount of absorbed hydrogen was larger than 500 mass ppm, the degradation of mechanical properties was recognized. Although the tensile properties and fracture mode scarcely change in a 0.2% APF solution, the slight reduction in hardness and hydrogen absorption of several hundreds mass ppm were observed. The results of the present study imply that work-hardened Ni–Ti alloy is less sensitive to hydrogen embrittlement compared with Ni–Ti superelastic alloy.

Hydrogen absorption of commercial pure titanium in acidulated phosphate fluoride (APF) solutions of various concentrations has been examined by hydrogen thermal-desorption analysis. In immersion in the 2.0% APF solution of pH 5.0 at 25 °C, the amount of absorbed hydrogen increased with immersion time and then saturated at approximately 800–900 mass ppm. During the early stage of the 24 h immersion, the amount of hydrogen absorbed in the 0.2% APF solution was almost the same as that in the 2.0% APF solution, i.e., 200 mass ppm, whereas it saturated at 300 mass ppm with longer immersion time. For the specimen immersed in the 2.0% APF solution for 24 h, hydrogen desorption was observed with a peak at approximately 550 °C. As the immersion time increased, the second desorption appeared in the range from 150 to 400 °C. In contrast, for the specimens immersed in the 0.2% APF solution, the desorption peak temperature tended to shift from 550 to 450 °C with immersion time. Hydrogen absorption was hardly observed in the specimen immersed in the 0.02% APF solution. The concentration of the APF solutions also affected the type of corrosion product and the surface topography of the immersed specimens. The results of the present study clearly indicate that the degradation of the mechanical properties or fracture of titanium caused by hydrogen absorption occurs in acidic fluoride solutions.

超高分子量ポリエチレン繊維を強化材とし, エポキシ樹脂をマトリックスとした複合材料の力学的性質の改善を目的とした検討を行った. すなわち, ポリエチレン繊維のコロナ放電処理後にシランカップリング剤あるいはイソシアネート化合物による処理を行った. まず, 界面せん断強度を測定した結果, いずれの化合物でもコロナ放電処理だけの場合よりも改善されたが, とくにイソシアネート化合物による表面処理は効果があり, 50MPa以上の値が得られた. この結果を踏まえてエポキシ樹脂と複合化し, 複合材料として評価しても力学的性質は著しく改善された. しかし, 仔細にみると弾性率においては理論値とよく一致したが, 破断強度においては理論値の値には至らなかった. これは超高分子量ポリエチレン繊維の破断伸びが5%以上とかなり大きいために, 破断時点での繊維間での応力伝達が不十分になるためと思われる.

The domain switching and rotation in Bi-layer structured ceramics were evaluated by investigating the poling field and pulse response dependences of the ferroelectric properties. The effect of domain clamping on electromechanical coupling factor and dielectric constant at the coercive field was confirmed in Bi-layer structured ceramics as well as in the cases of soft and hard tetragonal lead zirconate titanate, lead titanate and barium titanate ceramics. The minimum frequency constant due to domain rotations was also observed in Bi-layer structured ceramics. The remanent polarization and coercive field increased linearly with increasing the pulse field. Although relatively high DC fields up to 10.0 kV mm −1 could be applied to the ceramics, the P–E hysteresis loop showed a round figure. Furthermore, the oriented polarization by DC poling was highly stable in the ceramics, even though a high bipolar pulse was applied.

Degradation of tensile strength of a Ni–Ti superelastic alloy due to hydrogen absorption has been studied in methanol solution containing 0.1 mass % hydrochloric acid (HCl). The amount of absorbed hydrogen from the solution was measured by thermal desorption analysis (TDA). Hydrogen desorption of immersed specimens appeared in the temperature range from 100 to 600 °C. The amounts of absorbed hydrogen of immersed specimens were in the range of 50–500 mass ppm when immersed in the solution for 8–120 h. Tensile strength of immersed specimens decreased abruptly up to immersion time of 24 h. In the immersion time range from 24 to 120 h, the tensile strength was coincident with the critical stress for martensite transformation. It was concluded that the degradation of tensile strength of a Ni–Ti superelastic alloy is caused by hydrogen absorption in methanol solution containing HCl.

Temperature and poling field dependences of the properties of large high-quality piezoelectric single crystals of Pb[(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 ]O 3 (PZNT91/09) grown by the Bridgman method were measured. The single crystals poled along [001] of the original cubic direction possess giant electromechanical coupling factor k 31 over 80% and piezoelectric d 31 constant nearly m 1700 pC/N. These giant k 31 and d 31 constants results from the control of ferroelectric domain configuration. PZNT91/09 multi-domain single crystal became single-domain in the directions parallel and perpendicular to the poling field resulting in the appearance of giant k 31 and d 31 .

We used protein hydrolyzate, which was obtained from hydrolyzing albuminoid by enzyme, to improve drying rate for urushi (oriental lacquer) and artificial urushi. Suke-urushi (transparent urushi) which is a kind of the most popular urushi, was prepared by adding the protein hydrolyzate to ki -urush (raw urushi) in order to estimate drying properties of urushi at low temperature under low humidity. This suke-urushi dried at 10°C/50% RH, which meant the drying rate of urushi Was improved greatly. Meanwhile, to develop the paint by enzyme reaction using urushi as a model, that is an artificial urushi, we studied the action of enzyme laccase on synthetic urushiol analog by using the protein hydrolyzate as the third component. The enzyme is produced from culture medium of Pycnoporus Coccineus (Pycnoporus Coccineus laccase ; p-laccase), which is a wood destroying fungi, and we synthesized 4-{9'(z),12'(z)-Octadecadienyl} catechol as an urushiol analog. This artificial urushi dried even under low humidity of 50% RH at 20°C. Further, both the films of the suke-urushi containing the protein hydrolyzate and the artificial urushi gave broad tan δ curve and the high temperature of tan δ m a x in dynamic viscoelasticity, just like conventional urushi. From above results, it forwarded greatly the promotion of utilizing urushi and the practical use of environmental -friendly paint such as urushi model.

The reactions of [60]fullerene with bis-o-quinodimethane precursors 3, 4, and 5 containing a dibenzo-18-crown-6, 24-crown-8 and 30-crown-10 moiety, respectively, were investigated. Both 3 and 4 provided trans-4 bisadducts 6a and 7a, respectively, as major product, though the selectivity in the latter was lower than that in the former. As minor product, 6b (cis-2) was produced from 3, while 7c (e) as well as 7b (cis-2) were produced from 4. Precursor 5 exclusively afforded e bisadduct 8 without any other regioisomers. These bisadducts showed different ionophoric properties from one another; for instance, 6a and 7b exhibited a high complexing ability toward the K+ ion, while 6b hardly showed complexation with any alkali metal ions. The selectivity coefficients (K(Na,K)(pot)) of 6a and 7b toward K+ over Na+ ion, determined with an ion-selective electrode, were much higher than that of dibenzo-18-crown-6.

The photochemical reactions of [60]fullerene with various aromatic aldehydes or ketones 1a-n carrying an alkyl group at the ortho position were examined. Some of them afforded stable o-quinodimethane adducts 2 with a hydroxy group attached to the cyclohexene ring. The adducts 2 were found to adopt one or both of two conformers A and E, which possess pseudoaxial and pseudoequatorial hydroxy groups, respectively. The conformer ratios depended remarkably on the substituents attached to the aromatic nucleus and the cyclohexene ring. The dynamic behavior of 2 was also investigated by the VT-NMR technique.

Domain structures of ferroelectric materials were investigated by measuring the poling field dependence of dielectric and piezoelectric properties. Ferroelectric materials evaluated consist of as follows: soft and hard lead zirconate titanate (PZT) ceramics with tetragonal and rhombohedral phases, lead titanate (PT) ceramics, barium titanate (BT) ceramics and a relaxor based single crystal of Pb(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 O 3 (PZNT). Changing the poling field (E) from 0 M +E M 0 M m E M 0 to +E, the electromechanical coupling factor (k p , k 33 ), dielectric constant ( l r ) and frequency constant (fc) were measured. The minimum k p , k 33 and l r were obtained at the same E because of the 180° domain clamping. Furthermore, the E due to the domain clamping corresponded to the coercive field (Ec) determined by the poling field dependences. At the Ec, maximum fc was confirmed in the cases of soft PZT (tetragonal and rhombohedral) and hard PZT (tetragonal) ceramics, BT ceramics and PZNT single crystal. It ...

ポリ乳酸 (PLA) /デンプンブレンド射出成形物 (デンプン30wt%) を作製し, 土壌温度, 微生物数の異なる3期間で, 分解試験を行い破断強度とPLAの分子量低下に与える影響を調べた. その結果, PLA/デンプンブレンド物の破断強度は土壌温度や, 微生物数にはほとんど影響を受けずに速やかに低下し30日後に破断強度がゼロになる形状崩壊を起こした. 一方, 試験片中のPLAの分子量は土壌温度が高く試験片に繁殖した微生物数の多い期間に速く30日後に初期分子量の半分まで低下したが, 破断強度の低下に比べるとかなり遅かった. また, このような分解速度の速いPLA/デンプンブレンド物にそれよりも分解速度の遅いPLAまたはポリカプロラクトン (PCL) 単体をコーティングすることによって分解が一定期間抑制され, その後コーティングしていない試料と同様に速やかに分解する構造を構築することができた.

We studied the effect of repeated bipolar pulses applied to soft and hard lead zirconate titanate (PZT) ceramics on ferroelectric properties. Almost symmetrical P-E hysteresis loops were observed in the case of soft PZT ceramics. On the other hand, the loops in the case of hard PZT ceramics were asymmetrical and shifted to the positive electric field. It was found that a space charge field was generated while applying pulse and the direction of the field was fixed independently of the pulse cycles. The possibility of bipolar pulse poling was investigated. Furthermore, we discuss the effect of pulses on planar coupling factor when the pulses were applied to poled soft and hard PZT ceramics.

ポリ塩化ビニルフィルムについて屋外暴露試験を行い, 一定期間ごとに採取をして引張破断強度, 引張弾性率および破断伸びを測定した. そして, それらの力学物性値とその暴露試験期間中の気象データ (月平均気温, 月間降水量, 月間日照時間および月間紫外線量) から統計学的手法の1つである多変量解析の重回帰分析法を用いて, 重回帰式を求めた. 得られた重回帰式を異なる気象条件下での実験結果に適用した. その結果, 対応する気象データを用いて得られた予測曲線は実験値と一致した. したがって, 本方法はプラスチックフィルムの耐候性予測に使用できることが明らかとなった.

The reaction of [60]fullerene with bis-o-quinodimethane precursor 3 containing a dibenzo-18-crown-6 moiety provided preferentially trans-4 bisadduct 5a along with a small amount of cis-2 bisadduct 5b. These bisadducts showed different ionophoric properties from each other; 5a exhibited a high complexing ability toward K+ ion, while 5b hardly showed complexation with any alkali metal ions.

The interfacial shear strength of an ultrahigh molecular weight (UHMW) polyethylene (PE) fiber/epoxy-resin system was greatly improved by the corona-discharge treatment of the fiber. The UHMW PE-fiber/epoxy-resin composite was prepared with corona-discharge-treated UHMW PE fiber. The mechanical properties of the composite sheet were determined by tensile testing. The tensile strength of the composite was also very much improved. However, the tensile strength of the composite was about one-half of the theoretical strength. This result was due to the molecular degradation of the PE-fiber surface caused by surface modification. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1162–1168, 2001

Domain switching and rotation in soft lead zirconate titanate (PZT) ceramics were investigated in comparison with those in hard PZT ceramics by measuring the poling field dependence of the dielectric and piezoelectric properties. The minimum dielectric constant (fcp) and maximum frequency constant (fcp) were observed at the coercive fields, which correspond to the poling fields required to obtain the minimum planar coupling factor. These phenomena were due to the 180° domain clamping at these fields. The fields of 90° (71° or 109°) domain rotation were estimated using the relationships between the maximum fcp and minimum fcp. While minimum ϵt and maximum fcp due to domain clamping were observed in the compositions of tetragonal and rhombohedral soft PZT ceramics, domain rotations which caused maximum ϵt and minimum fcp were mainly observed in rhombohedral hard PZT ceramics. It was thought that the reason why domain rotations which caused maximum ϵt and minimum fcp were not obtained in soft PZT wa...

Two steel plates were bonded with oil-accommodating adhesives, the components of which are epoxy resin, NBR (nitrile rubber) modified epoxy resin, CaCO3 and silica powder. The effect of components on the apparent shear strength was studied using the plates, which were covered with rust-preventing oil. The shear strength increased most effectively with the silica powder content, as compared with other components. Further, each component was exposed to the vapour of rust-preventing oil. Silica powder absorbed the largest amount of oil among the components per unit weight. We concluded that the performance of the oil-accommodating adhesive was attained by the strong oil absorption ability of silica powder in the adopted adhesive.

Lead zirconate titanate ceramics were evaluated to examine the relationship between domain structures and ferroelectric properties. Responses to repeated voltage pulses applied to the ceramics were measured by a high voltage test system as a dynamical evaluation. Through the evaluation, it was clarified the domain behavior for the 90° (71° and 109°) domain rotation, 180° domain switching and clamping, and transient phenomena on the domain orientation.

Corona discharge treatment was conducted for ultrahigh molecular weight polyethylene (UHMWPE) fiber. The functional groups and surface roughness of the polyethylene fiber surface were determined by an X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The interfacial shear strength of UHMWPE fiber with HDPE film was determined by microbond pullout method. The interfacial shear strength increased by corona treatment. Then, the effect of the chemical and physical factors on the interfacial shear strength was discussed based on the results of multivariate regression analysis. The results indicated that the contribution of functional groups and surface roughness to the interfacial shear strength was expressed as 50 and 50%, respectively. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 243–249, 1999

Three types of high-strength polyethylene (PE) fiber-reinforced composite sheets were made by compression molding at the vicinity of melting point of the fiber. Sheet I was molded from only PE fibers. Sheets II and III were prepared by the compression molding of PE fiber with conventional high- and low-density polyethylene films, respectively. The mechanical properties, thermal behavior, and morphologies of the sheets have been investigated and compared with each other. The tensile strength and elastic modulus of sheet III are 660 MPa and 14 GPa, respectively, which were 60 and 30 times higher than those of typical low-density PE film. Although the elastic modulus of sheet III is 6 GPa less than that of sheet II, the tensile strength of 660 MPa is highest in the three types of sheets prepared in this study. The mechanical properties of sheets II and III were about half of predicted theoretical ones. It was concluded that the interfacial adhesion between PE fiber and PE matrix was an important factor to improve the mechanical properties of this PE sheet. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1431–1439, 1998

The property–structure–processing relationship on the forging of isotactic polypropylene (iPP) has been investigated by applying multiple regression analysis. The analysis showed that the optical and mechanical properties of forged iPP can be described quantitatively by phase structures and the compression draw ratio (CR). For optical clarity, appropriate variables to explain the property are the smectic fraction (Xs), the amorphous fraction (Xa) and CR−1. The increase in the smectic fraction and CR reduced the turbidity (for example, the increase in optical clarity) of the sample. The contribution of smectic phase estimated by the analysis was about one-third of the compression draw, as revealed by CR−1. For mechanical properties, Xs, Xa, and CR1/2 were the appropriate variables. The existence of the smectic phase reduced the tensile mechanical properties. The effect of Xs is 12 times higher in modulus than that in strength. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1297–1302, 1998

The conditions for molecular orientation of electrochemically synthesized polythiophene have been investigated. The polymer chains are preferentially oriented along the film surface direction, i.e. parallel to the electrode surface, under conditions of (a) polymerization around the freezing point of the solvent used in the electrolyte, and (b) polymerization at low current density (below 1 mA/cm 2 ) around the oxidation potential of the monomer. The polymerizations were also carried out in a magnetic field. Under a magnetic field parallel to the electrode surface, the polythiophene chain oriented itself along the electrode surface even at a higher current density of 2 mA/cm 2 . On the other hand, a magnetic field perpendicular to the electrode surface inhibited the molecular orientation, even under the conditions of (a) and (b).

Various copolymides were prepared from two acid dianhydrides (BPDA, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride; PMDA, pyromelitic dianhydride) and two diamines (PPD, p-phenylene diamine; ODA, 4,4′-oxydianiline). The thermal and mechanical properties of these polyimides were examined in detail. By appropriately selecting the ratios of the acid dianhydride component and the diamine component, polyimide films having desirable mechanical and thermal characteristics can be obtained. Further, it was proved that there is a correlation between the properties and the compositions of the copolyimides and that the properties could be estimated from the compositions by the use of multiple regression analysis. © 1996 John Wiley & Sons, Inc.

PURPOSE: To prepare, with good reproducibility, polyimide powder suitable for heat compression molding, by heating an amide solvent solution of a biphenyltetracarboxylic acid component and an aromatic diamine component to a specified temp. under stirring. CONSTITUTION: Nearly equimolar amounts of a biphenyltetracarboxylic acid component and an aromatic diamine component are dissolved, at a temp. below 155°C, in an amide solvent in which the formed polyimide is soluble in less than 1wt%. The temp. of the resultant homogeneous solution with a low rotational viscosity is raised quickly to 160W300°C under stirring and is kept within the temp. range to form an aromatic polyimide with a logarithmic viscosity number of 0.2W1 (0.5g/100cc p-chlorophenol at 50°C) which is then precipitated as fine particles. The reaction soln. in which the aromatic polyimide has been precipitated may be aged at 160W300°C for 0.2W20hr to increase th logarithmic viscosity of the precipitated polyimide. COPYRIGHT: (C)1982,JPO&Japio

One-pot polymerization of polyimide from 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (BPDA) and 4,4′-oxydianiline (ODA) was examined. The equilibrium in the polyimide with water was examined in detail in p-chlorophenol solution during the polymerization. The equilibrium constant was expressed by log K = 1.50 + 1433 (1/T). The polymerization reaction is exothermic. The molecular weight increased with decrease of temperature. © 1996 John Wiley & Sons, Inc.

The one-pot method polymerization of polyimide was carried out from 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (BPDA) and 4,4′-oxydianiline (ODA) by the use of p-chloro-phenol as the solvent. The behavior of the polymerization was compared with that of the two-step method. The imidization reaction in the one-pot method proceeds completely in this system at even a low temperature such as 100°C. In the course of the film preparation from the solution, the embrittlement occurs when the film is prepared from polyamic acid solution, while it does not occur in the case of that from the solution of the one-pot method. A molecular weight of polyimide film is almost the same as that of precursor polyimide in the solution. In the same way, that of polyimide film is almost the same as that of precursor polyamic acid. The mechanical properties of the polyimide film prepared by the one-pot method are similar to those by the two-step method. © 1996 John Wiley & Sons, Inc.

A carbon fiber reinforced Nylon 66 was molded by a typical injection molding machine. The average fiber length and the breadth distribution of the length were examined in detail as a function of the fiber content or the injection conditions.The fiber length became shorter with an increase of the fiber content. It is considered that the breaking of the fibers is mainly caused by the interference of the fibers, and the increase of viscosity. An increase in the injection speed led to considerably shorter fiber lengths. This is considered to be due to an increase in the shearing force with increasing flow speed of the resin. In these cases, the breadth of distribution of the length decreased slightly with decreasing length. On the contrary, the extent of decrease in fiber length became small with an increase of screw speed, and the breadth of the distribution remained nearly constant.