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Optimization of experimental parameters to suppress nozzle clogging in inkjet printing / Ayoung Lee in Industrial & engineering chemistry research, Vol. 51 N° 40 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13195-13204 Titre : Optimization of experimental parameters to suppress nozzle clogging in inkjet printing Type de document : texte imprimé Auteurs : Ayoung Lee, Auteur ; Kai Sudau, Auteur ; Kyung Hyun Ahn, Auteur Année de publication : 2012 Article en page(s) : pp. 13195-13204 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Optimization Résumé : Stable drop jettability is mandatory for a successful, technical scale inkjet printing, and accordingly, this aspect has attracted much attention in fundamental and applied research. Previous studies were mainly focused on Newtonian fluids or polymer solutions. Here, we have investigated the drop jetting for zinc oxide (ZnO) particulate suspensions. Generally, the inverse Ohnesorge number Z = Oh―1, which relates viscous forces to inertia and surface tension, is sufficient to predict the jettability of single phase fluids. For the inkjet printer setup used here, jetting was possible for Newtonian fluids with 2.5 < Z < 26, but in the identical Z-range, nonjetting and nozzle clogging occurred for certain suspensions. A so-called ring-slit device, which allows for simultaneous formation and detection of aggregates in strongly converging flow fields, and single particle detecting techniques, which allow for an accurate determination of the number and size of micrometer-sized aggregates in suspensions of nanopartides, were used to study this phenomenon. Nozzle dogging is induced by heterocoagulation of micrometer-sized aggregates and ZnO nanopartides in the elongational flow field at the nozzle exit. Clogging may occur even if the size of these aggregates is well below the nozzle diameter and their concentration is on the order of only a few hundred parts per million (ppm). Accordingly, increased colloidal stability of nanoparticles and reduced aggregate concentration result in better drop jettability. Also, a nozzle design resulting in a shorter exposure time of the ink to elongational flow and an increased flow velocity helps to avoid nozzle clogging. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451469 [article] Optimization of experimental parameters to suppress nozzle clogging in inkjet printing [texte imprimé] / Ayoung Lee, Auteur ; Kai Sudau, Auteur ; Kyung Hyun Ahn, Auteur . - 2012 . - pp. 13195-13204. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13195-13204 Mots-clés : Optimization Résumé : Stable drop jettability is mandatory for a successful, technical scale inkjet printing, and accordingly, this aspect has attracted much attention in fundamental and applied research. Previous studies were mainly focused on Newtonian fluids or polymer solutions. Here, we have investigated the drop jetting for zinc oxide (ZnO) particulate suspensions. Generally, the inverse Ohnesorge number Z = Oh―1, which relates viscous forces to inertia and surface tension, is sufficient to predict the jettability of single phase fluids. For the inkjet printer setup used here, jetting was possible for Newtonian fluids with 2.5 < Z < 26, but in the identical Z-range, nonjetting and nozzle clogging occurred for certain suspensions. A so-called ring-slit device, which allows for simultaneous formation and detection of aggregates in strongly converging flow fields, and single particle detecting techniques, which allow for an accurate determination of the number and size of micrometer-sized aggregates in suspensions of nanopartides, were used to study this phenomenon. Nozzle dogging is induced by heterocoagulation of micrometer-sized aggregates and ZnO nanopartides in the elongational flow field at the nozzle exit. Clogging may occur even if the size of these aggregates is well below the nozzle diameter and their concentration is on the order of only a few hundred parts per million (ppm). Accordingly, increased colloidal stability of nanoparticles and reduced aggregate concentration result in better drop jettability. Also, a nozzle design resulting in a shorter exposure time of the ink to elongational flow and an increased flow velocity helps to avoid nozzle clogging. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451469

Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends / Indose Aravind in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9942–9951 Titre : Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends Type de document : texte imprimé Auteurs : Indose Aravind, Auteur ; Kyung Hyun Ahn, Auteur ; C. Ranganathaiah, Auteur Année de publication : 2010 Article en page(s) : pp. 9942–9951 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : poly(trimethylene  terephthalate)/polycarbonate  blends  Rheological  measurements Résumé : The phase morphology, rheology, mechanical properties, and free volume of poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends have been investigated as a function of composition. The morphology indicated a two-phase structure, and the blends showed co continuous phase morphology between 30−60 wt % of poly carbonate. Due to the high viscosity of PC, PTT is more finely dispersed in the PC matrix than PC in the PTT matrix. The rheological measurements of the blends revealed that the complex viscosity increased with increase in PC content. Relatively low interfacial tension values of the blends determined using Palierne and Choi−Schowalter methods indicated that there is considerable interaction between the blend components (PTT and PC) due to the transesterification reactions. A random copolyester formed as a result of the transesterification acted as a compatibilizer in the initial stages of reactions which is the main factor for the change in miscibility. The phase morphology and the interfacial adhesion influence the mechanical properties such that addition of the PC phase decreases the tensile strength and Young’s modulus of the system. The free volume data from PALS results showed a slight positive deviation from the known linear additivity rule with increase in PC content, suggesting the blends are partially miscible. Our results show a good correlation among the phase morphology, rheology, mechanical, and free volume parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007503 [article] Rheology, morphology, mechanical properties and free volume of poly(trimethylene terephthalate)/polycarbonate blends [texte imprimé] / Indose Aravind, Auteur ; Kyung Hyun Ahn, Auteur ; C. Ranganathaiah, Auteur . - 2010 . - pp. 9942–9951. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9942–9951 Mots-clés : poly(trimethylene  terephthalate)/polycarbonate  blends  Rheological  measurements Résumé : The phase morphology, rheology, mechanical properties, and free volume of poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends have been investigated as a function of composition. The morphology indicated a two-phase structure, and the blends showed co continuous phase morphology between 30−60 wt % of poly carbonate. Due to the high viscosity of PC, PTT is more finely dispersed in the PC matrix than PC in the PTT matrix. The rheological measurements of the blends revealed that the complex viscosity increased with increase in PC content. Relatively low interfacial tension values of the blends determined using Palierne and Choi−Schowalter methods indicated that there is considerable interaction between the blend components (PTT and PC) due to the transesterification reactions. A random copolyester formed as a result of the transesterification acted as a compatibilizer in the initial stages of reactions which is the main factor for the change in miscibility. The phase morphology and the interfacial adhesion influence the mechanical properties such that addition of the PC phase decreases the tensile strength and Young’s modulus of the system. The free volume data from PALS results showed a slight positive deviation from the known linear additivity rule with increase in PC content, suggesting the blends are partially miscible. Our results show a good correlation among the phase morphology, rheology, mechanical, and free volume parameters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9007503