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Volume 35, Issue 4
Displaying 1-9 of 9 articles from this issue
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Isoji SAKAI, Katsuhiko NAKAMAE, Keizo NONAKA, Tsunetaka MATSUMOTO1978 Volume 35 Issue 4 Pages 209-214
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDegree of interfacial occupation (I) of polymer was estimated from γW/O (interfacial tension at toluene solution of polymer-water interface) and γW/P (interfacial tension at water-polymer interface) to clarify the solvation state of polymer adsorbed at the water/oil interface (II). γW/O and γW/P were measured by du Noüy ring and contact angle respectively and were calculated from modified Fowkes' equation. I of poly (vinyl acetate) and ethylene-vinyl acetate copolymer (EVAc) adsorbed at II increased with the decrease in the solvent power of oil. I of EVAc increased with the increase in VAc content in EVAc. I of polymer at II was proportional to the saturated amount of polymer adsorbed onto α-Fe2O3. The above results help to elucidate that the solvation state of polymer adsorbed at II directly reflects the state of polymer in the solution and is similar to the solvation state between polymer of polymer adsorbed at α-Fe2O3/oil interface.View full abstractDownload PDF (1039K) -
Tomoyuki KASEMURA, Norio YAMASHITA, Katsumi Suzuki, Takashi KONDO, Tos ...1978 Volume 35 Issue 4 Pages 215-222
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSSurface tension (γ) of alkanediols, HO- (CH2) m-OH, (I) and poly (alkylene glycol) s, HO- [(CH2) m-O] n-H, (II) and their interfacial tension (γ12) against eicosane were measured with the sessile bubble method at various temperatures. The relationships of γ and γ12 to the number of methylene groups (m) in I and in the repeating unit of II are discussed. γ of I series increases proportionally with 1/ (m+2) according to Hata's equation, and extrapolated value of γ to m→ ∞ is in accordance with that of polyethylene. For γ of II series, we derived an equation which show the linear relationship of γ to 1/ (m+1), based on the additivity of parachor and molecular volume. The measured values of γ for II series, however, deviate from the straight line predicted by the equation. γ12 of both series of samples against eicosane decrease rapidly with the increase of m. The component of γdue to the dispersion force (γd) and the polar force (γp) were caluculated by Fowkes equation from γ12 data.View full abstractDownload PDF (1333K) -
Teruo TSUNODA, Katsuyoshi CHIBA, Masuo FUKUMURA1978 Volume 35 Issue 4 Pages 223-228
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe change in contact angle of nitrobenzene on the surface of polyethylene which was pretreated either by immersion into an aqueous sulfuric-chromic acid solution, by irradiation of ultraviolet light, or by bombardment with electron under a reduced pressure, has been measured in water. The increase of the contact angle depended on the pretreatment method. Pretreatment of polyethylene by immersion into an sulfuric-chromic acid aqueous solution at room temperature made the contact angle nearly constant within 10 min of treatment. UV irradiation increased the contact angle slowly, but continuously. In the case of pretreatment by electron bombardment under about a pressure of 0.1 mmHg, the maximum contact angle was obtained. Adhesion tensions of water in air and of nitrobenzene in water on pretreated polyethylene were calculated from observed contact angle data. Formation of hydrophilic functional groups on pretreated surfaces was inferred as the reason of increase in contact angle of nitrobenzene in water. The difference between the calculated and observed adhesion tensions of nitrobenzene in water was discussed.View full abstractDownload PDF (981K) -
Teruo TSUNODA, Yoichi OBA, Masuo FUKUMURA1978 Volume 35 Issue 4 Pages 229-235
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe change in the surface properties due to UV irradiation has been discussed from the data of contact angles, IR spectroscopy, surface roughness by Talysurf, the results of surface observation using a usual and a scanning electron microscopes, and peel strength. Contact angles of liquids on a poly (ethylene terephthalate) in air decreased, but critical surface tension increased by pretreating the polymer surface. In water, on the other hand, contact angle of nitrobenzene increased by the pretreatment. From these wettability experiments, formation of hydrophilic polar groups on pretreated samples was inferred. About fourfold peel strength as compared with one of the untreated samples was observed for UV treated samples. The increases in adhesion tensions of water and glycerin and in peel strength agreed each other.View full abstractDownload PDF (1156K) -
Takeshi SUWA, Terutaka WATANABE, Jiro OKAMOTO, Sueo MACHI1978 Volume 35 Issue 4 Pages 237-243
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe stabilization mechanism and stability of poly (tetrafluoroethylene) (PTFE) latex prepared in the absence of emulsifier by radiation polymerization were investigated by the measurements of ζ-potential, conductometric titration and coagulation rate. The surface charge of PTFE particles is negative. It is suggested from the dependence of ζ-potential on pH and conductometric titration that some acids are formed on the particle surfaces. The polymerization mechanism suggests that the acids are carboxyl end groups of polymer chain and HF adsorbed on the surface. PTFE particles are stabilized mainly by these acids and OH- groups formed from radiolysis of water. On the basis of the potential energy curve calculated from the DLVO theory, the stability of PTFE latex was discussed. The maximum in the potential energy curve is more than 50kT at a KCl concentration below 1mmol/l. In fact, the latex is very stable and does not coagulate even at the polymer concentration of 60wt%. This is in accordance with the result of potential energy curve.View full abstractDownload PDF (1206K) -
Isoji SAKAI, Tetsuo EGAWA, Yasuo FUJIMURA, Tsunetaka MATSUMOTO1978 Volume 35 Issue 4 Pages 245-252
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMechanism of interaction between poly (ethyl acrylate) (I) and cement in the composite was studied. Adsorbance of I and poly (ethyl acrylate-acrylic acid) copolymer (II) as the model polymer of saponfied I onto the hydrated cement and the interfacial tension (γW/T) between toluene and the supernatant liquid of hydrated cement suspension were measured. Adsorbance of II onto the hydrated cement was 5.7 times as large as that of I. γW/T between water and toluene solution of II decreased with increasing concentration of Ca (OH) 2 in aqueous phase. Amount of Ca which was bound to II adsorbed at the interface between toluene and the supernatant liquid of hydrated cement suspension was 30 times as large as Ca bound to I. Interaction between PEA and cement was remarkably increased by the ionic bond between carboxyl group formed by the saponification of I and Ca (OH) 2 produced by the hydration of cement.View full abstractDownload PDF (2091K) -
Takashi NOHMI, Hiroyuki MAKINO, Sei-ichi MANABE, Kenji KAMIDE, Toru KA ...1978 Volume 35 Issue 4 Pages 253-261
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSFor the purpose of disclosing the mechanism of gas permeation through porous polymeric membrane, the effects of the pore size distribution N (r) and the chemical nature of permeating gas on the gas permeability coefficient P (P1, P2) (P1 and P2 are pressure of both sides of the membrane, P1≥P2) of cylindrically straight through porous membrane having average pore size (2r1) of 0.75-0.035μm were studied. Gas flow through a capillary (radius r) consists of the free molecular (F) flow only in the case of 2r≤λ (λ: mean free path of the gas) and can be approximated with a mixed flow of viscous and slip flow (V flow) for 2r>λ. The experimental P (P1, P2) value is in excellent agreement with the theoretical one calculated by assuming that, in the range P2≤P0<P1 (P0, pressure at which 2r=λ is realized), V flow occurs at the inlet and F flow dominates near the outlet of the capillary. The dependence of P (P1, P2) of inorganic gases on P1, P2, N (r) and λ can be expressed by a theoretical equation proposed in this Journal, 34, 729 (1977). The experimental P (P1, P2) values of membrane (2r1=0.035μm) for organic gases under the conditions that F flow occurs exclusively, are much larger than the theoretical value. The difference increases with an increase in boiling temperature of the gas, suggesting strongly that the gas flow relating to interaction between membrane and gas (for example, surface diffusion) contributes to P (P1, P2) significantly.View full abstractDownload PDF (1588K) -
Tomoyuki KASEMURA, Norio YAMASHITA, Katsumi SUZUKI, Takashi KONDO, Tos ...1978 Volume 35 Issue 4 Pages 263-268
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSSurface tensions (γ) of ethylene-propylene copolymers and tetrahydrofran-propylene oxide copolymers of various compositions were measured by the sessile bubble method at various temperaturers. An equation which relates the surface tension of copolymers to their composition was derived by assuming the additivity of parachor and molecular volume of each component. In the range of x2 (mole fraction of lower surface tension component) <0.4, the measured values of γ of both copolymer series show good agreement with the value predicted by the equation, which the values for x2>0.4 are lower than it. This behavior may be explained by the formation of relatively long sequence of lower surface tension component and its selective adsorption on the surface. Surface energy decreases with x2, and surface entropy and MacLeord's exponent (β) do not largely depend on the composition of copolymers.View full abstractDownload PDF (977K) -
Akira TAKAHASHI, Hiroshi WAKABAYASHI, Kazuhiko HONDA, Tadaya KATO1978 Volume 35 Issue 4 Pages 269-274
Published: April 25, 1978
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe wettability and surface morphology of cast films of styrene-tetrahydrofuran block (AB and ABA type) copolymers were studied. Contact angles (θ) of water droplets against films cast from cyclohexane solutions were measured and surface morphology of the films was also examined by OSO4 stainning electronmicroscopy. Cos θ was not a unique function of copolymer composition. The wettability of tetrahydrofuran-rich copolymers was almost equal to that of homopolystyrene, whereas styrene-rich copolymers exhibited reverse wettability. Surface composition or fraction of styrene portion was evaluated from the electron micrographs. The accumulation of styrene or tetrahydrofuran block at the surface of films was indicated, which depends upon the crystallization segregation or the surface activity caused by tetrahydrofuran block. It was found that cos θ is a function of surface composition and this shows that the wettability is the reflection of the, surface composition of the copolymers irrespective of morphologies.View full abstractDownload PDF (1600K)
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