{"title":"Flow-Induced Structure Change and Flow-Instability of CTAB/NaSal Aqueous Solution in a Two-Dimensional Abrupt Contraction Channel","authors":"M. Ouchi, Tsutomu Takahashi, M. Shirakashi","doi":"10.1678/RHEOLOGY.34.229","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.229","url":null,"abstract":"It is known that the CTAB/NaSal aqueous solution forms wormlike micelles when the concentration is higher than a certain value and shows the flow-induced structure change when both the shear rate and shear strain exceed respective critical values. In the present work, the start-up behavior of this surfactant solution in a two-dimensional abrupt contraction channel driven by a constant pressure was investigated. At a low driving pressure, the flow rate increases gradually and reaches an equilibrium state. When the driving pressure is higher than a certain value, the flow rate rises at a certain elapsed time. The elapsed time showing increase in flow rate shortens with increasing driving pressure. In the entry area of the narrow channel, a pair of wedge shape opaque regions appears. From the comparison with the observation in Couette flow of the same solution, it is found the opaque regions are caused by shear induced structure and the viscosity of the regions is higher than the other region. The regions grow up and make the other region with low viscosity narrower. The opaque regions suddenly break and disappear when the flow rate changes. Flow instability is induced by a sudden change of flow states. These phenomena are characteristic of the fluid showing the flow-induced structure change, whereas ordinary polymer solution do not exhibit such behavior.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"1 1","pages":"229-234"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84152016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Akiyama, Y. Tsuruda, S. Takeda, Y. Izumi, S. Nishijima
{"title":"Application Feelings of Skin Care Products and Their Rheological Properties","authors":"Y. Akiyama, Y. Tsuruda, S. Takeda, Y. Izumi, S. Nishijima","doi":"10.1678/RHEOLOGY.34.171","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.171","url":null,"abstract":"To establish the design methodology of skin care products with good application feeling based on physical evidence, the correlation between rheological and sensory properties of skin care products was examined. To clarify the effect of surface properties of skin, fluidity tests were performed using glass plate and artificial leather other than skin. The results of fluidity test showed a strong correlation with the results of sensory evaluation for each substrate. To evaluate the surface free energy of skin care properties and substrates, contact angles were measured. Application feeling was excellent when hydrophilic-oleophilic property of skin care product was similar to that of substrate. It was found that the application feeling of skin care product depends not only on the viscoelasticity of itself, but also on the surface free energy of substrate and skin care product.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"26 1","pages":"171-175"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81576180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rheological Measurements of Solder Pastes in Heating Processes","authors":"Toshiaki Yazaki, Y. Otsubo","doi":"10.1678/RHEOLOGY.34.301","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.301","url":null,"abstract":"In production of printed circuit boards, the solder pastes are deposited on the boards by screen printing and the conductive lines are formed by melting the solder particles at high temperatures. For formation of precise patterns and sufficient adhesion, the solder pastes are required to hold their shapes until the solder particles begin to melt. An evaluation method of practical processability of solder pastes is examined through dynamic viscoelastic measurements in heating process. However, the difficulties arise in cleaning the sensors (parallel-plate geometry in the present study) because the sensor surfaces are covered with the solidified solder after the measurements. By the use of disposable aluminum sensors, the measuring procedure is established at temperatures above the melting points of solder. The temperature dependence of dynamic viscoelasticity would be useful to design the binder resins and to control of reflow processes.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"2006 1","pages":"301-302"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83036166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Harada, K. Tachi, Yasuhiko Suzuki, J. Ikeno, S. Umemura
{"title":"Development of a Rheometer Using Laser Trapping Method and Measurements of Viscosity in Multilayer Coatings","authors":"M. Harada, K. Tachi, Yasuhiko Suzuki, J. Ikeno, S. Umemura","doi":"10.1678/RHEOLOGY.34.71","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.71","url":null,"abstract":"Viscosity is a key property controlling the appearance of automotive coatings. However, the direct measurements of the viscosity in automotive coatings have not been achieved, since the automotive coating is a complex system consisting of a multilayer where mass transfer occurs between each thin layers. Using the laser trapping method, we have developed a rheometer to realize non-destructive viscosity measurements of the multilayers. Applying the new rheometer to automotive coatings, the viscosity has been estimated for (A) a clearcoat itself, (B) a clearcoat on a basecoat, and (C) a clearcoat on a basecoat and a surfacer. The results demonstrate an increase of viscosity in the order of (A) < (B) < (C), depending on the thickness of the lower layers. The viscosity increase suggests that the concentration of the clearcoat is likely to increase due to the diffusion of the solvent into the lower layers.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"80 1","pages":"71-75"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80959642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Study on Polymer Melt Rheology Control and Polymer Processability","authors":"K. Koyama","doi":"10.1678/RHEOLOGY.34.267","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.267","url":null,"abstract":"Various polymer materials have been developed in accordance with requirements for high functional and high performance products in recent years. These polymer materials become useful end products through polymer processing. Linear viscoelastic rheology and non-linear rheology are dominant factors for good polymer processing. Non-linear rheology is mainly studied on several polymer melt systems by newly developed rheometers and new characterization methods in the present study. The newly developed rheometers are applied to the flow induced crystallization study and flow induced structural formation experiments in elongational flow as well as shear flow. The control methods of the non-linear rheology are proposed by molecular structure design, meso-structure design, and external field control. The degree of non-linearity, or the degree of strain hardening, of elongational viscosity can be controlled by a small amount of high molecular weight polymer, by an introduction of long chain branching, and by an addition of small particles or small solid fibers. Rheology control methods are applied to the processability of polymer processing such as high speed fiber spinning, foam processing of PP, poly(L-lactic acid) and rice, and blow molding. The new polymer processing CAE system is developed by the use of flow induced crystallization and non-linear rheology of elongational viscosity.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"135 1","pages":"267-274"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77983439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Molecular Simulations for Entangled Polymer Dynamics","authors":"Y. Masubuchi","doi":"10.1678/RHEOLOGY.34.275","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.275","url":null,"abstract":"A novel method for multi-body molecular simulations for entangled polymers including branch polymers, polymer blends and copolymers is developed in this study. Entangled polymer dynamics is important in industry and still challengeable in polymer science due to complicated rheology caused by a broad variety of controllable polymer architectures such as molecular weight, molecular weight distribution, long chain branching, copolymerization, etc. and freedom of their blends. Conventional molecular simulations are inadequate to the polymer dynamics in long time range because of huge calculation cost. Theoretical approaches based on reptation theories are essentially difficult for multi-component situations due to the self-consistent treatment of entanglement among many chains. In this study a new method of molecular simulations for entangled polymer dynamics is developed based on the primitive chain network model where polymers are considered as primitive chains forming real network in 3D space similarly to the conventional molecular simulations and distinguishably from other entanglement based models. Reasonable consistency on established scaling behaviors for static and dynamic properties and quantitative agreement with experiments for linear and nonlinear rheology have been confirmed for linear and branched polymers. For copolymers and blends reasonable results have been obtained on phase behaviors.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"50 1","pages":"275-282"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82285207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Prediction of Flow Distribution for Bingham Fluid in a Slot Die","authors":"Masayuki Nagashima, T. Hasegawa, T. Narumi","doi":"10.1678/RHEOLOGY.34.205","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.205","url":null,"abstract":"Designs of flow channel in a slot die are often required to achieve the uniform thickness of coated films for nonNewtonian fluids having nonnegligible yield stress. In previous studies we have proposed a designing method for deriving the optimum geometries of flow channel from a flow distribution model for Bingham fluid. However, it is hard to provide the optimum geometries precisely without manufacturing burden. Therefore, it is useful to substitute simplified asymptotic curves for complex optimum geometries in designing flow channel. But in that case the deviation of outflow from uniformity due to such approximations needs to be checked whether it is within an allowable range or not. In this work we propose a method for predicting the outflow deviation in given geometories of flow channel using Bingham fluid. The usefulness of the method is confirmed by an experiment conducted using a corresponding fluid.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"18 1","pages":"205-212"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76476606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rheology in Film Processing (2)-Flow Instabilities in Film Casting Process-","authors":"H. Ishihara, M. Shibaya, Kosuke Ikeda","doi":"10.1678/RHEOLOGY.34.3","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.3","url":null,"abstract":"Film casting is one of the important processes for obtaining the plastic film products. Molten polymer casting is conducted by cooling the extruded melts at the surface of chill roller laid below the extrusion dies. Flow instabilities in the film casting are divided into two categories. One is the shear flow instability and the other is the extensional flow instability. These instabilities are similar to those appearing in the melt spinning process. Among many parameters governing shear flow instability, shear rate and Deborah number defined as the ratio of polymer relaxation time to retention time in the land of dies or spinneret orifice are likely to be most important. The small value of Deborah number is found to be effective for depressing the shear flow instability. Regarding the extensional flow instability, draw resonance phenomena were summarized and discussed. Polymer parameters such as power low index in the power low fluid model and relaxation time in Maxwell fluid model were found to be important for onset of draw resonance instability. As process parameters, cooling effect of extruded melts, draft ratio defined as elongation ratio of melts and air gap length corresponding the distance from dies exit to chill roller were also important. Further study on transient response of disturbances having various frequencies was done. It was found that film thickness uniformity changed depending on disturbance frequency.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"16 6 1","pages":"3-8"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89167882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Flow Behavior of Bingham Fluid in a Slot Die","authors":"Masayuki Nagashima, T. Hasegawa, T. Narumi","doi":"10.1678/RHEOLOGY.34.91","DOIUrl":"https://doi.org/10.1678/RHEOLOGY.34.91","url":null,"abstract":"It is necessary to provide well-designed geometries of flow channel in a slot die in order to achieve the uniform thickness of coated films for non-Newtonian fluids, especially for the fluids having nonnegligible yield stress. In this work we have studied the flow in the slot die using Bingham fluid. The present paper derives a model equation for the outflow distribution as functions of the yield stress and the geometries inside the die. Furthermore, we suggest a useful design method to predict an optimum geometry to guarantee the uniformity of outflow from die slot in Bingham fluid. The usefulness of the method is confirmed by an experiment conducted using a corresponding fluid.","PeriodicalId":17434,"journal":{"name":"Journal of the Society of Rheology, Japan","volume":"25 1","pages":"91-96"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78589021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}