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Volume 9 (1981)
- Issue 4 Pages 139-
- Issue 3 Pages 99-
- Issue 2 Pages 55-
- Issue 1 Pages 3-
Volume 9, Issue 2
Displaying 1-7 of 7 articles from this issue
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[in Japanese]1981 Volume 9 Issue 2 Pages 55-58
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDownload PDF (557K) -
Zhunwen WU, Rikio YOKOTA, Masakatsu KOCHI, Hirotaro KAMBE1981 Volume 9 Issue 2 Pages 59-64
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThermal stress analyzer (TSA) was used to study the molecular aggregation of aromatic polymers: copoly (ether-sulfone) (CPES), polycarbonate (PC), poly (aryl sulfone) (PASF), aromatic polyamide (PA), poly (amide imide) (PAI) and polyimide (PI). A state of thermodynamic equilibrium was attained by annealing at temperatures lower by 10°C than the glass transition temperature (Tg). After annealing, an increase of elastic recovery was observed in their rubbery state. It means that some crosslinking has been formed. Increase in Tg and thermal distortion temperature were also observed. All these results are interpreted in terms of the appearance of “ordered regions”, in which main chains of the polymers are densely packed. Though the annealing effect on molecular aggregation was investigated for some vinyl polymers such as poly (ethyl methacrylate) (PEMA), poly(methyl methacrylate) (PMMA) and polystyrene (PS), it was found negligible. The formation of ordered regions seems to be enhanced by the planar structure involving phenyl or heterocyclic rings and the strong intermolecular interactions of those rings in the aromatic polymers.View full abstractDownload PDF (681K) -
Hiroaki GOTO, Mamoru SENNA, Hiroshi KUNO1981 Volume 9 Issue 2 Pages 65-69
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSRelative viscosities, ηr, of neutrally buoyant model suspension of polystyrene spheres in a mixture of ethylene glycol and propylene glycol or ethylene glycol and ethanol were measured with an efflux-type vertical-capillary viscometer for various particle-to-tube diameter ratio, λ (0.040 to 0.32), solid volume fraction, C (0.05 to 0.22), and wall shear rate, γω(102 to 104 sec-1).
The relative viscosity in the Newtonian flow regime,ηN, decreased with the increase in,λ(Sigma effect), which is less than 0.1, and the values ofηN agreed with the values, ηM, predicted from Maude's two-phase model. However, ηN increased with λ in the region where λ is larger than 0.1. In the latter case the discrepancy between ηN and ηM became larger with the increase in C. This disagreement may be attributed to the formation of large aggregates of particles in the capillary tube.View full abstractDownload PDF (918K) -
Mitsunobu KITAMURA, Mamoru ISHIDA, Toshiro MASUDA, Shigeharu ONOGI1981 Volume 9 Issue 2 Pages 70-76
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDynamic viscoelastic properties of styrene-butadiene block copolymers having different molecular weights and compositions were measured at elevated temperatures. The Phase structure formed in the copolymers is broken by shear flow at high rates. For the samples having molecular weights lower than 105, the broken phase structure recovers completely after heat treatment at 160°C for 1 hr, while for the samples having molecular weights higher than 2.5×105, the recovery of the broken structure is very difficult. Frequency dependence curves of the storage shear modulus, relaxation spectrum, entanglement modulus, and characteristic time for entanglement relaxation are discussed in relation to molecular factors such as the molecular weight and composition of the component blocks in the copolymers. The experimental results are also compared with theological properties of styrene and butadiene homopolymers. It is suggested that the dynamic measurement is very useful for the investigation of phase structure formed in block copolymers.View full abstractDownload PDF (1313K) -
Toshiro MASUDA, Keiji TOEI, Mitsunobu KITAMURA, Shigeharu ONOGI1981 Volume 9 Issue 2 Pages 77-82
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSExtensional properties at constant rates were measured for styrene-butadiene copolymers having various molecular weights and compositions. The result shows that the extensional behavior of block copolymers is affected strongly by the phase structure. Samples of intermediate compositions form two-phase structure composed of polybutadiene (PB) and polystyrene (PS) phases. Both the initial modulus of extension and failure behavior are mainly dominated by the deformation of the PB phase. The flow of PB chains at and beyond the failure point is obstructed by the PS phase. Deformation and flow of PS chains are dominant in the extensional behavior of the samples having low butadiene contents, in which the PS phase is plasticized by short PB chains. Time-temperature superposition can be applied to strain-rate dependence curves of failure stress and strain measured at different temperatures. The temperature dependence of shift factor aT obtained for the samples, which form two-phase structure, agree well with that for homo-polybutadiene, reflecting that the onset of flow of PB chains is the dominant factor governing the failure phenomenon. However, aT for the samples having low butadiene content is higher than that for other samples.View full abstractDownload PDF (749K) -
Yoshio SHIRASAKI, Tetsuya TATEISHI, Toru FUKUBAYASHI1981 Volume 9 Issue 2 Pages 83-90
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSIn order to disclose the mechanical characteristics of human cancellous bones, viscoelasticity, compressive strength and regional difference have been investigated in normal human knee joint by a visco-elastic spectrometer and a testing machine of Instron type. At the upper tibia in cancellous bone, the averaged dynamic compressive elastic modulus of medial part was 427.5 MPa and that of lateral part 202.5 MPa. At the patella, this modulus was 627.1 MPa at the lateral part and 245.8 MPa at the medial part.
The stereological pattern analysis indicated that the internal structures of cancellous bone at the upper tibia and the patella were highly load-adapted. These facts imply that the medial part of the upper tibia and the lateral part of the patella are stiffened as the result of functional adaptation.View full abstractDownload PDF (1588K) -
Masahiko NAKAMURA, Kenji KOMATSU, Eiji FURUI, Keikichi INOUE, Susumu O ...1981 Volume 9 Issue 2 Pages 91-93
Published: June 30, 1981
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSIn order to elucidate the mechanism of memory phenomena of a ceramic mass of water medium, preliminary experiments have been carried out using the Moiré topography technique which gives topographic information to analyse a strain distribution on the surface. A gentle and continuous deformation toward the direction opposite to the preceding one during the drying period of constant rate has clearly been detected for an earthenware plastic body. The deformation due to the memory increases with increasing the previous deformation. The technique used here has been found to be very useful to detect the memory phenomena on a pottery green mass.View full abstractDownload PDF (541K)
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