Documents disponibles écrits par cet auteur

Hydrophobic thermoplastic starches modified with polyester - based polyurethane microparticles / Yamei Leng in Industrial & engineering chemistry research, Vol. 50 N° 19 (Octobre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 19 (Octobre 2011) . - pp. 11130-11135 Titre : Hydrophobic thermoplastic starches modified with polyester - based polyurethane microparticles : effects of various diisocyanates Type de document : texte imprimé Auteurs : Yamei Leng, Auteur ; Yu Zhang, Auteur ; Xiaoxia Chen, Auteur Année de publication : 2011 Article en page(s) : pp. 11130-11135 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microparticle Résumé : It is critical to prepare ductile and hydrophobic modified starch material in an effective and environmentally friendly way. In this work, polyurethane prepolymers (PUPs) with various isocyanates were synthesized and mixed reactively with thermoplastic starches (TPS) in an intensive mixer to prepare modified TPS. The effects of the isocyanates on the structure and properties of the modified TPS were then investigated by using scanning electron microscope (ESEM), tensile tester, and contact angle meter. Results showed that mechanical properties ofthe modified TPS were improved with the increase in hydrophobicity of the isocyanate. 4,4'-Methylenedi-p-phenyl diisocyanate (MDI) was hydrophobic, the NCO groups in PUPs were not easily consumed by water when modified starch was prepared, leading to a significantly increased reaction of the NCO groups with starch. As the amount of urethane bonds between starch and PUP increased, the compatibility between the two polymers was also improved, resulting in the improvement of tensile properties. Isocyanates played an important role in improving the compatibility between the starch and PUP and the properties of the modified TPS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24573311 [article] Hydrophobic thermoplastic starches modified with polyester - based polyurethane microparticles : effects of various diisocyanates [texte imprimé] / Yamei Leng, Auteur ; Yu Zhang, Auteur ; Xiaoxia Chen, Auteur . - 2011 . - pp. 11130-11135. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 19 (Octobre 2011) . - pp. 11130-11135 Mots-clés : Microparticle Résumé : It is critical to prepare ductile and hydrophobic modified starch material in an effective and environmentally friendly way. In this work, polyurethane prepolymers (PUPs) with various isocyanates were synthesized and mixed reactively with thermoplastic starches (TPS) in an intensive mixer to prepare modified TPS. The effects of the isocyanates on the structure and properties of the modified TPS were then investigated by using scanning electron microscope (ESEM), tensile tester, and contact angle meter. Results showed that mechanical properties ofthe modified TPS were improved with the increase in hydrophobicity of the isocyanate. 4,4'-Methylenedi-p-phenyl diisocyanate (MDI) was hydrophobic, the NCO groups in PUPs were not easily consumed by water when modified starch was prepared, leading to a significantly increased reaction of the NCO groups with starch. As the amount of urethane bonds between starch and PUP increased, the compatibility between the two polymers was also improved, resulting in the improvement of tensile properties. Isocyanates played an important role in improving the compatibility between the starch and PUP and the properties of the modified TPS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24573311

Novel method for production of phenolics by combining lignin extraction with lignin depolymerization in aqueous ethanol / Yueyuan Ye in Industrial & engineering chemistry research, Vol. 51 N° 1 (Janvier 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 1 (Janvier 2012) . - pp. 103–110 Titre : Novel method for production of phenolics by combining lignin extraction with lignin depolymerization in aqueous ethanol Type de document : texte imprimé Auteurs : Yueyuan Ye, Auteur ; Yu Zhang, Auteur ; Juan Fan, Auteur Année de publication : 2012 Article en page(s) : pp. 103–110 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phenolics  Aqueous  ethanol Résumé : A method for production of high-value-added phenolics by combining organosolv lignin extraction with lignin hydrothermal depolymerization without catalysts under mild conditions was successfully developed. During lignin extraction, the optimal ethanol concentration in mixed solvent is 65 vol %, with which 78% purity (based on Klason lignin) of crude lignin was obtained. High yield of liquid products up to 65.5% was recovered from lignin depolymerization under conditions of 523 K, 90 min, 65 vol % ethanol, and 3% lignin; meanwhile, only 17% solid residue was obtained. The gas chromatography–mass spectrometry (GC–MS) analyses of the obtained liquid products confirmed the presence of value-added phenolics, among which the yields of 4-ethylphenol, 4-vinylphenol, guaiacol, 4-ethylguaiacol, and 4-vinylguaiacol were very high (30% of the identified compounds). Gel permeation chromatography (GPC) and Fourier transform infrared (FT-IR) spectroscopy of these liquid products indicated that lignin was really depolymerized to low molecular weight compounds and that the cleavage of ether bonds and decarbonylation were the major reactions during lignin depolymerization. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202118d [article] Novel method for production of phenolics by combining lignin extraction with lignin depolymerization in aqueous ethanol [texte imprimé] / Yueyuan Ye, Auteur ; Yu Zhang, Auteur ; Juan Fan, Auteur . - 2012 . - pp. 103–110. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 1 (Janvier 2012) . - pp. 103–110 Mots-clés : Phenolics  Aqueous  ethanol Résumé : A method for production of high-value-added phenolics by combining organosolv lignin extraction with lignin hydrothermal depolymerization without catalysts under mild conditions was successfully developed. During lignin extraction, the optimal ethanol concentration in mixed solvent is 65 vol %, with which 78% purity (based on Klason lignin) of crude lignin was obtained. High yield of liquid products up to 65.5% was recovered from lignin depolymerization under conditions of 523 K, 90 min, 65 vol % ethanol, and 3% lignin; meanwhile, only 17% solid residue was obtained. The gas chromatography–mass spectrometry (GC–MS) analyses of the obtained liquid products confirmed the presence of value-added phenolics, among which the yields of 4-ethylphenol, 4-vinylphenol, guaiacol, 4-ethylguaiacol, and 4-vinylguaiacol were very high (30% of the identified compounds). Gel permeation chromatography (GPC) and Fourier transform infrared (FT-IR) spectroscopy of these liquid products indicated that lignin was really depolymerized to low molecular weight compounds and that the cleavage of ether bonds and decarbonylation were the major reactions during lignin depolymerization. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202118d

Study on dissociation behaviors of methane hydrate in porous media based on experiments and fractional dimension shrinking-core model / Xiao-Sen Li in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 808-812 Titre : Study on dissociation behaviors of methane hydrate in porous media based on experiments and fractional dimension shrinking-core model Type de document : texte imprimé Auteurs : Xiao-Sen Li, Auteur ; Yu Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 808-812 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : hydrate  fractal  theory  porous  media  dissociation Résumé : The dissociation process of gas hydrate was regarded as a gas-solid reaction without solid production layer when the temperature was above the zero centigrade. Based on the shrinking core model and the fractal theory, a fractional dimension dynamical model for gas hydrate dissociation in porous sediment was established. The new approach of evaluating the fractal dimension of the porous media was also presented. The fractional dimension dynamical model for gas hydrate dissociation was examined with the previous experimental data of methane hydrate and carbon dioxide hydrate dissociations, respectively. The calculated results indicate that the fractal dimensions of porous media acquired with this method agree well with the previous study. With the absolute average deviation (AAD) below 10%, the present model provided satisfactory predictions for the dissociation process of methane hydrate and carbon dioxide hydrate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=21773523 [article] Study on dissociation behaviors of methane hydrate in porous media based on experiments and fractional dimension shrinking-core model [texte imprimé] / Xiao-Sen Li, Auteur ; Yu Zhang, Auteur . - 2011 . - pp. 808-812. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 808-812 Mots-clés : hydrate  fractal  theory  porous  media  dissociation Résumé : The dissociation process of gas hydrate was regarded as a gas-solid reaction without solid production layer when the temperature was above the zero centigrade. Based on the shrinking core model and the fractal theory, a fractional dimension dynamical model for gas hydrate dissociation in porous sediment was established. The new approach of evaluating the fractal dimension of the porous media was also presented. The fractional dimension dynamical model for gas hydrate dissociation was examined with the previous experimental data of methane hydrate and carbon dioxide hydrate dissociations, respectively. The calculated results indicate that the fractal dimensions of porous media acquired with this method agree well with the previous study. With the absolute average deviation (AAD) below 10%, the present model provided satisfactory predictions for the dissociation process of methane hydrate and carbon dioxide hydrate. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=21773523

Tough thermoplastic starch modified with polyurethane microparticles / Yu Zhang in Industrial & engineering chemistry research, Vol. 50 N° 21 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 11906-11911 Titre : Tough thermoplastic starch modified with polyurethane microparticles : the effects of NCO content in prepolymers Type de document : texte imprimé Auteurs : Yu Zhang, Auteur ; Yan Huang, Auteur ; Xiaoxia Chen, Auteur Année de publication : 2011 Article en page(s) : pp. 11906-11911 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microparticle Résumé : In this work, polyurethane prepolymers (PUPs) with various NCO content proportions were synthesized and mixed reactively with a starch-water mixture to prepare modified thermoplastic starch (TPS) in an environmentally friendly way. The effects of polyurethane NCO content on the structure and/or properties of the modified TPS sheets were investigated. Results revealed that the reaction ratio of PUPs used for preparing the modified TPS was 99.8%, indicating that the PUPs were almost cross-linked to the starch matrix. With an increase of NCO content in PUP, the tensile strength of the modified TPS increased from 19.3 to 37.4 MPa, and the elongation from 1.7% to 17.2%. As the PUP's NCO content increased, the amount of urethane linkage between PU microparticles and the starch matrix would increase. In addition, the compatibility of the two polymers was also improved resulting in the improvement of tensile properties. The urethane linkage between PU and starch therefore played an important role in improving the toughness of the modified TPS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697507 [article] Tough thermoplastic starch modified with polyurethane microparticles : the effects of NCO content in prepolymers [texte imprimé] / Yu Zhang, Auteur ; Yan Huang, Auteur ; Xiaoxia Chen, Auteur . - 2011 . - pp. 11906-11911. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 11906-11911 Mots-clés : Microparticle Résumé : In this work, polyurethane prepolymers (PUPs) with various NCO content proportions were synthesized and mixed reactively with a starch-water mixture to prepare modified thermoplastic starch (TPS) in an environmentally friendly way. The effects of polyurethane NCO content on the structure and/or properties of the modified TPS sheets were investigated. Results revealed that the reaction ratio of PUPs used for preparing the modified TPS was 99.8%, indicating that the PUPs were almost cross-linked to the starch matrix. With an increase of NCO content in PUP, the tensile strength of the modified TPS increased from 19.3 to 37.4 MPa, and the elongation from 1.7% to 17.2%. As the PUP's NCO content increased, the amount of urethane linkage between PU microparticles and the starch matrix would increase. In addition, the compatibility of the two polymers was also improved resulting in the improvement of tensile properties. The urethane linkage between PU and starch therefore played an important role in improving the toughness of the modified TPS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24697507