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Influence of eucalyptus globulus kraft pulping severity on the rheological properties of gel - like cellulose pulp dispersions in castor oil / N. Nunez in Industrial & engineering chemistry research, Vol. 51 N° 29 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 29 (Juillet 2012) . - pp. 9777–9782 Titre : Influence of eucalyptus globulus kraft pulping severity on the rheological properties of gel - like cellulose pulp dispersions in castor oil Type de document : texte imprimé Auteurs : N. Nunez, Auteur ; J. E. Martin-Alfonso, Auteur ; M. E. Eugenio, Auteur Année de publication : 2012 Article en page(s) : pp. 9777–9782 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dispersion  Rheological  properties  Paper  industry  Pulping Résumé : The development of some cellulose pulp gel-like dispersions in castor oil with application as biodegradable lubricants was explored in this work by analyzing the effect that Kraft cellulosic pulp cooking conditions exerts on the rheological properties and mechanical stability of these formulations. With this aim, Eucalyptus globulus cellulosic pulps were obtained by increasing the pulping time at the maximum temperature, yielding H factors ranging from 150 to 500. Gel-like dispersions of cellulosic pulps in castor oil were prepared and characterized from a rheological point of view. Small-amplitude oscillatory shear (SAOS) measurements and some standard mechanical tests, usually performed on commercial lubricating greases, were carried out in order to evaluate the lubricant performance of these dispersions. In general, the values of linear viscoelastic functions increase with the H factor. Cellulose pulps submitted to lower H factors provides gel-like dispersions with SAOS functions values more similar to those found in traditional lubricating greases. Results were explained attending to a balance between the cellulose polymerization degree and lignin and α-cellulose contents, all of them affected by the H factor applied. An empirical correlation between these variables and both the plateau modulus and the loss of consistency has been proposed to predict the rheological behavior and mechanical stability of gel-like cellulose pulp dispersions in castor oil. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26184956 [article] Influence of eucalyptus globulus kraft pulping severity on the rheological properties of gel - like cellulose pulp dispersions in castor oil [texte imprimé] / N. Nunez, Auteur ; J. E. Martin-Alfonso, Auteur ; M. E. Eugenio, Auteur . - 2012 . - pp. 9777–9782. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 29 (Juillet 2012) . - pp. 9777–9782 Mots-clés : Dispersion  Rheological  properties  Paper  industry  Pulping Résumé : The development of some cellulose pulp gel-like dispersions in castor oil with application as biodegradable lubricants was explored in this work by analyzing the effect that Kraft cellulosic pulp cooking conditions exerts on the rheological properties and mechanical stability of these formulations. With this aim, Eucalyptus globulus cellulosic pulps were obtained by increasing the pulping time at the maximum temperature, yielding H factors ranging from 150 to 500. Gel-like dispersions of cellulosic pulps in castor oil were prepared and characterized from a rheological point of view. Small-amplitude oscillatory shear (SAOS) measurements and some standard mechanical tests, usually performed on commercial lubricating greases, were carried out in order to evaluate the lubricant performance of these dispersions. In general, the values of linear viscoelastic functions increase with the H factor. Cellulose pulps submitted to lower H factors provides gel-like dispersions with SAOS functions values more similar to those found in traditional lubricating greases. Results were explained attending to a balance between the cellulose polymerization degree and lignin and α-cellulose contents, all of them affected by the H factor applied. An empirical correlation between these variables and both the plateau modulus and the loss of consistency has been proposed to predict the rheological behavior and mechanical stability of gel-like cellulose pulp dispersions in castor oil. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26184956

Optimization of the methylation conditions of kraft cellulose pulp for its use as a thickener agent in biodegradable lubricating greases / J. E. Martin-Alfonso in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6765–6771 Titre : Optimization of the methylation conditions of kraft cellulose pulp for its use as a thickener agent in biodegradable lubricating greases Type de document : texte imprimé Auteurs : J. E. Martin-Alfonso, Auteur ; R. Yañez, Auteur ; C. Valencia, Auteur Année de publication : 2009 Article en page(s) : pp. 6765–6771 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Kraft  cellulose  pulp  Methylation  conditions  Thickener  agent Résumé : This work evaluates the influence of the operating conditions used in the derivatization of commercial Kraft cellulose pulp (mercerization time (1−3 h) methylation process temperature (30−60 °C), methylation process time (1−4 h), (initial pulp)/(final wet alkali pulp) ratio (S/S) (1/7−1/12), and pulp/acetone ratio (S/L) concentration (1/3−1/12)) on the obtained methylcellulose pulp characteristics such as degree of polymerization of cellulose, substitution degree, water solubility, and viscosity of the resulting pulps in order to determine the best process conditions of this pulp for its use as a thickener agent in biodegradable lubricating grease formulations. Efficient use of the raw material (i.e., obtaining a degree of polymerization with suitable substitution degree) entailed using a 2.5 h methylation time and a 45 °C methylation temperature. The substitution degree (DS) and consistency index thus obtained are only 14.5% and 36.3% respectively lower than the optimum value, and an increment of 28.6% could be obtained for the degree of polymerization. Some methylcellulose-based oleogels display rheological properties very similar to those found in traditional lubricating greases. Methylcellulose with DS values of around 0.4 produces oleogels with better mechanical properties than highly derivatized cellulose and much better than the original Kraft cellulose pulp. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002766 [article] Optimization of the methylation conditions of kraft cellulose pulp for its use as a thickener agent in biodegradable lubricating greases [texte imprimé] / J. E. Martin-Alfonso, Auteur ; R. Yañez, Auteur ; C. Valencia, Auteur . - 2009 . - pp. 6765–6771. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6765–6771 Mots-clés : Kraft  cellulose  pulp  Methylation  conditions  Thickener  agent Résumé : This work evaluates the influence of the operating conditions used in the derivatization of commercial Kraft cellulose pulp (mercerization time (1−3 h) methylation process temperature (30−60 °C), methylation process time (1−4 h), (initial pulp)/(final wet alkali pulp) ratio (S/S) (1/7−1/12), and pulp/acetone ratio (S/L) concentration (1/3−1/12)) on the obtained methylcellulose pulp characteristics such as degree of polymerization of cellulose, substitution degree, water solubility, and viscosity of the resulting pulps in order to determine the best process conditions of this pulp for its use as a thickener agent in biodegradable lubricating grease formulations. Efficient use of the raw material (i.e., obtaining a degree of polymerization with suitable substitution degree) entailed using a 2.5 h methylation time and a 45 °C methylation temperature. The substitution degree (DS) and consistency index thus obtained are only 14.5% and 36.3% respectively lower than the optimum value, and an increment of 28.6% could be obtained for the degree of polymerization. Some methylcellulose-based oleogels display rheological properties very similar to those found in traditional lubricating greases. Methylcellulose with DS values of around 0.4 produces oleogels with better mechanical properties than highly derivatized cellulose and much better than the original Kraft cellulose pulp. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002766

Preparation and characterization of gel-like dispersions based on cellulosic pulps and castor oil for lubricant applications / N. Nunez in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5618-5627 Titre : Preparation and characterization of gel-like dispersions based on cellulosic pulps and castor oil for lubricant applications Type de document : texte imprimé Auteurs : N. Nunez, Auteur ; J. E. Martin-Alfonso, Auteur ; M. E. Eugenio, Auteur Année de publication : 2011 Article en page(s) : pp. 5618-5627 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Lubricant  Dispersion  Preparation Résumé : In this work, the use of different cellulosic pulp samples to prepare new formulations potentially applicable as biodegradable lubricating greases is explored. Cellulosic pulps from different raw materials and submitted to different pulping process and/or several acidic treatments were characterized and used as biothickener agents to formulate gel-like dispersions. Cellulose pulp samples mainly differed in polymerization degree (160―893 cm3/g) and lignin (0.3―27.1% w/w) and α-cellulose (46.0―85.1% w/w) contents. Rheological measurements and some standard mechanical tests usually performed with lubricants were carried out. The rheological response of cellulosic pulp-based gel-like dispersions is mainly a consequence of the balance between the cellulose polymerization degree and lignin and α-cellulose contents, independently on the origin of cellulose samples and pulping treatment. An empirical correlation between a power function of these variables and the plateau modulus has been proposed to predict the rheological behavior of resulting formulations. However, cellulosic pulp-based dispersions studied generally present either poor mechanical stability or low consistency indexes than expected for lubricating greases. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128686 [article] Preparation and characterization of gel-like dispersions based on cellulosic pulps and castor oil for lubricant applications [texte imprimé] / N. Nunez, Auteur ; J. E. Martin-Alfonso, Auteur ; M. E. Eugenio, Auteur . - 2011 . - pp. 5618-5627. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5618-5627 Mots-clés : Lubricant  Dispersion  Preparation Résumé : In this work, the use of different cellulosic pulp samples to prepare new formulations potentially applicable as biodegradable lubricating greases is explored. Cellulosic pulps from different raw materials and submitted to different pulping process and/or several acidic treatments were characterized and used as biothickener agents to formulate gel-like dispersions. Cellulose pulp samples mainly differed in polymerization degree (160―893 cm3/g) and lignin (0.3―27.1% w/w) and α-cellulose (46.0―85.1% w/w) contents. Rheological measurements and some standard mechanical tests usually performed with lubricants were carried out. The rheological response of cellulosic pulp-based gel-like dispersions is mainly a consequence of the balance between the cellulose polymerization degree and lignin and α-cellulose contents, independently on the origin of cellulose samples and pulping treatment. An empirical correlation between a power function of these variables and the plateau modulus has been proposed to predict the rheological behavior of resulting formulations. However, cellulosic pulp-based dispersions studied generally present either poor mechanical stability or low consistency indexes than expected for lubricating greases. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128686

Rheological modification of lubricating greases with pecycled polymers from different plastics waste / J. E. Martin-Alfonso in Industrial & engineering chemistry research, Vol. 48 N° 8 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 4136–4144 Titre : Rheological modification of lubricating greases with pecycled polymers from different plastics waste Type de document : texte imprimé Auteurs : J. E. Martin-Alfonso, Auteur ; C. Valencia, Auteur ; M. C. Sánchez, Auteur Année de publication : 2009 Article en page(s) : pp. 4136–4144 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Lubricating  greases  Recycled  polymers  Plastics  waste  Small-amplitude  oscillatory  shear  Viscous  flow  measurements Résumé : There is a growing interest on the development of new materials based on recycled polymers from plastics waste, since the use of such plastics represents a low-cost source of raw material. The purpose of the present work is to evaluate, from a comparative point of view, the effect that different waste and virgin polymers, used as viscosity modifier additives, exert on the rheological properties of standard lithium lubricating greases. Grease formulations containing diverse polymers, differing in nature and/or origin, were manufactured and rheologically characterized. Particularly, the influences of the type of polymer, the molecular weight and the presence of carbon black, used as filler in recycled polymers, have been evaluated. Small-amplitude oscillatory shear (SAOS) and viscous flow measurements were carried out, as well as calorimetric and thermogravimetric analysis. In general, recycled polymers induce a more important rheological modification than virgin polymers of the same nature. Thus, the addition of some recycled polymers such as HDPE, LDPE, PP, and EVA copolymer to lithium lubricating grease significantly increases the values of the rheological parameters analyzed. The crystallinity degree, mainly dependent on the nature of the polymer, and the carbon black content of recycled polymers have been pointed out as the most highly influencing parameters on the rheology of the lubricating greases studied. However, an apparent loss in mechanical stability for lubricating greases containing recycled polymers has been found when they were submitted to a severe mechanical treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801359g [article] Rheological modification of lubricating greases with pecycled polymers from different plastics waste [texte imprimé] / J. E. Martin-Alfonso, Auteur ; C. Valencia, Auteur ; M. C. Sánchez, Auteur . - 2009 . - pp. 4136–4144. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 4136–4144 Mots-clés : Lubricating  greases  Recycled  polymers  Plastics  waste  Small-amplitude  oscillatory  shear  Viscous  flow  measurements Résumé : There is a growing interest on the development of new materials based on recycled polymers from plastics waste, since the use of such plastics represents a low-cost source of raw material. The purpose of the present work is to evaluate, from a comparative point of view, the effect that different waste and virgin polymers, used as viscosity modifier additives, exert on the rheological properties of standard lithium lubricating greases. Grease formulations containing diverse polymers, differing in nature and/or origin, were manufactured and rheologically characterized. Particularly, the influences of the type of polymer, the molecular weight and the presence of carbon black, used as filler in recycled polymers, have been evaluated. Small-amplitude oscillatory shear (SAOS) and viscous flow measurements were carried out, as well as calorimetric and thermogravimetric analysis. In general, recycled polymers induce a more important rheological modification than virgin polymers of the same nature. Thus, the addition of some recycled polymers such as HDPE, LDPE, PP, and EVA copolymer to lithium lubricating grease significantly increases the values of the rheological parameters analyzed. The crystallinity degree, mainly dependent on the nature of the polymer, and the carbon black content of recycled polymers have been pointed out as the most highly influencing parameters on the rheology of the lubricating greases studied. However, an apparent loss in mechanical stability for lubricating greases containing recycled polymers has been found when they were submitted to a severe mechanical treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801359g