All issues
Predecessor
Volume 39, Issue 5
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
Masaharu ASANO, Masaru YOSHIDA, Isao KAETSU1982 Volume 39 Issue 5 Pages 327-332
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSTo obtain protein-anticancer composites, proteins mixed with aqueous solutions of anticancers, were shaped, and then denaturated by thermal treatment. The release behaviors of anticancers from the composites in buffer solutions containing proteases as release media were investigated. The measure (Q/t1/2) of anticancer release depended on the kind of the proteins and on denaturation conditions such as temperature, time, water content of anticancer-protein mixtures, and molding pressure. The Q/t1/2 value was the smallest when the crystallized albumin from Bovine was used as a carrier. With the elapse of release time, the pore structure was formed on the surface of some composites. This structure is related to the heterogeneity of the degree of denaturation of proteins, indicating that the digestion occurs at the segments of low denaturation. In such cases, Q/t1/2 values were markedly accelerated by digestion.View full abstractDownload PDF (1665K) -
Masaharu ASANO, Masaru YOSHIDA, Isao KAETSU1982 Volume 39 Issue 5 Pages 333-338
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe release behavior has been studied for bleomycin hyrdochloride (BLM), an anticancer drug, from carrier composites prepared from mixtures of proteins and hydrophilic vinyl monomers by combined procedures of radiation polymerization and thermal denaturation. The magnitude, Q/t1/2, for BLM release was the smallest when albumin was denatured by thermal treatment after the polymerization of albumin-2-hydroxyethyl methacrylate (HEMA) by radiation at -78°C. This retardation was further enhanced by the use of cross-linked polymers. On the other hand, the digestion of the albumin-HEMA composite, during the release test carried out in the saline containing some proteases, was markedly suppressed with increasing the HEMA content in the composite. The digestion was lowered more than expected from the albumin content in the composite. In summary of the release tests and the scanning electron microscopic observations, it was concluded that the release of BLM and the digestion of albumin component contained in the composites can be markedly suppressed by the incorporation of the polymeric component.View full abstractDownload PDF (1716K) -
Sadaatsu YAMAGUCHI, Tetsuo SHIMIZU1982 Volume 39 Issue 5 Pages 339-344
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe morphological change by an electron irradiation in a microspope has been studied for as-polymerized, granular and rod-like polytetrafluoroethylene particles. At a total dose of electron irradiation above ca. 2.5×10-3c/cm2, banded structures appeared, in all the particles, parallel to their longitudinal axes, accompanying a 40-60% decrease in the particle thickness. More than one step-like bands formed in wide rod-like particles, the band width being comparable to that for the granular particles. It is also noted that central protrusions along the longitudinal axes, which had been in the rod-like particles, were greatly depressed by electron irradiation. The formation of the banded structure seems to be closely related to the depression of the rod-like particles.View full abstractDownload PDF (3046K) -
Masayoshi OKUBO, Yoshinobu NAKAMURA, Mitsuhiko ASAKURA, Toyokichi TANG ...1982 Volume 39 Issue 5 Pages 345-350
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn order to prepare an alkali thickened emulsion composed of carboxylated polymer particles at an high solid content, a study was made for the effect of the crosslinking points in the polymer particles on its alkali thickening and film forming abilities. For this purpose, polymer emulsions consisting of methacrylic acid (A), methyl methacrylate (B), ethyl acrylate (C), and divinylbenzene (D) were prepared by different monomer addition methods. When mixtures of A, B, C, and D were polymerized, film forming ability of the produced emulsion decreased with an increase on the amount of D. The emulsion prepared by two-stage emulsion polymerization, in which D was added in 2nd-stage, possessed low alkali thickening and high film forming abilities. It was found to be effective that the mixtures of the monomers were portionwisely added at regular intervals so as to increase the concentration of D gradually.View full abstractDownload PDF (984K) -
Masaki YOSHII, Masayoshi AOKI, Hidemi SATO, Aizo KANEDA1982 Volume 39 Issue 5 Pages 351-358
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSWith the aim to reduce the dimensional variation of the injection molded part in precision molding, relations between the dimensional variation and the molding factors have been studied.
Three factors for the dimensional variation were deduced: packing (filling into the cavity and compression), thermal expansion (or shrinkage) and crystallization factor).
A new concept, the integration of the cavity pressure against time lapse, was introduced to elucidate the relationship between the packing state and the dimension of the molded part.
For the cylinderical part molded with polyacetal, relations between the dimensional variation and the molding conditions (injection pressure, holding pressure, mold temperature, material temperature) were obtained experimentally. These relations were explained in terms of the three factors.
The results show that the relations can be utilized for the quantitative molding control of the dimensional variation of the injection molded parts.View full abstractDownload PDF (1219K) -
Yasuo FUJIMURA, Shu UEHARA, Isoji SAKAI, Katsuhiko NAKAMAE, Tsunetaka ...1982 Volume 39 Issue 5 Pages 359-364
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSFoamability of nonionic surfactant and chemical stability of polymer emulsion were studied in order to clarify the making Process of polymer-cement foam. Foamability of nonionic surfactant was maximum at the following condition; HLB>10, concentration of surfactant>ten times CMC, foaming temperature<cloud Point-20°C. The kind of electric charge on the emulsion particle surface had a great influence on the stability of the emulsion in cement-emulsion system.
It was concluded that polymer-cement foam was made by using the polymer emulsion with cationic initiator as positive charge introducer on the emulsion particle surface and also by using low cloud point nonionic surfactant as a foaming agent.View full abstractDownload PDF (1155K) -
Shinichi SUTO, Toshikazu FUJIMURA1982 Volume 39 Issue 5 Pages 365-371
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSTo predict the static solidification of melt in non-isothermal calendering, the difference equation of heat conduction was derived. Temperatures in molten high density polyethylene as a function of time were determined by means of infrared thermister, and experimental data and calculated ones were compared. The applicability of the derived equation to calendering and effects of operating parameters on static solidification were discussed.
1) Solid layer thickness was proportional to the square root of time, and the mechanism of static solidification in its early stages was similar to the one obtained by Stefan for a semi-infinite medium. The derived equation could predict approximately the solidification of molten high density polyethylene, and be applied to the calendering.
2) Roll surface temperature affected solidification more than initial melt temperature did, and suitable processing conditions could be estimated.View full abstractDownload PDF (998K) -
Katsuo ORIHARA, Tsuneyoshi ONODERA, Masakazu MATSUMOTO1982 Volume 39 Issue 5 Pages 373-377
Published: May 25, 1982
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThis report describes the effects of poly (vinylpyrrolidone) (PVP) on the reactions of substrates (A), 2, 4- dinitrofluorobenzene (DNFB) and 2, 4-dinitrochlorobenzene (DNCB) with nucleophiles (B), ammonia or various amino compounds in aqueous solution. These effects are divided into those for the reactions (I) of A with undissociated B and the other ones for the reactions (II) with OH- produced by dissociation of B. In both the effects thus divided, the effects for reaction (II) are much larger than for reaction (I). The order of the effects is as follows; OH->>ammonia>cyclohexylamine 3-amino-1-propanol n-propyl amine n-pentyl amine. This order suggests that the acceleration becomes much less if A and B compete and interfere much more in occupying the binding sites on the PVP coils.View full abstractDownload PDF (861K)
- |<
- <
- 1
- >
- >|