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Seeded emulsion polymerization of butyl acrylate using a redox initiator system / Zhen-guo Liu in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7152–7158 Titre : Seeded emulsion polymerization of butyl acrylate using a redox initiator system : kinetics and mechanism Type de document : texte imprimé Auteurs : Zhen-guo Liu, Auteur ; Ye Han, Auteur ; Chao Zhou, Auteur Année de publication : 2010 Article en page(s) : pp. 7152–7158 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics  Mechanism Résumé : Seeded emulsion polymerization of n-butyl acrylate (n-BA) was initiated by a redox initiator system: cumene hydroperoxide/ferrous sulfate hexahydrate/ethylene-diaminetetraacetic acid monosodium salt/sodium formaldehyde sulfoxylate (CHP−Fe2+−EDTA−SFS). Final poly(n-butylacrylate) (PBA) particles with narrow size distribution were obtained. The kinetics and mechanism of seeded emulsion polymerization initiated by the redox initiator system were investigated. Special care was focused on effects of component concentration of the redox initiator system on the seeded emulsion polymerization kinetics. Particle growth and pH variation during the polymerization were also studied. It was found that the polymerization rate and the overall conversion increased with increasing CHP and SFS concentration. Interestingly, the optimal molar ratio of CHP/SFS was 1.10/3.81 rather than being equimolar in our work. In addition, an optimal molar ratio of EDTA to ferrous ions (2.19 × 10−5 mol/7.12 × 10−6 mol) was found. The polymerization rate increased first and then decreased with increases in ferrous ion concentration. The pH value in the system decreased as the polymerization proceeded. A limiting conversion phenomenon of conversion not being able to exceed 20% was found, and an explanation to the limiting conversion was proposed on the basis of the views of the practical cumulative formation constant log KMY and reaction rate comparison. When another activator solution (EDTA/FES/SFS (mol) 2.19 × 10−5/7.12 × 10−6/1.91 × 10−3) was added, the limiting conversion was removed and the final conversion reached 97%. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901359z [article] Seeded emulsion polymerization of butyl acrylate using a redox initiator system : kinetics and mechanism [texte imprimé] / Zhen-guo Liu, Auteur ; Ye Han, Auteur ; Chao Zhou, Auteur . - 2010 . - pp. 7152–7158. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7152–7158 Mots-clés : Kinetics  Mechanism Résumé : Seeded emulsion polymerization of n-butyl acrylate (n-BA) was initiated by a redox initiator system: cumene hydroperoxide/ferrous sulfate hexahydrate/ethylene-diaminetetraacetic acid monosodium salt/sodium formaldehyde sulfoxylate (CHP−Fe2+−EDTA−SFS). Final poly(n-butylacrylate) (PBA) particles with narrow size distribution were obtained. The kinetics and mechanism of seeded emulsion polymerization initiated by the redox initiator system were investigated. Special care was focused on effects of component concentration of the redox initiator system on the seeded emulsion polymerization kinetics. Particle growth and pH variation during the polymerization were also studied. It was found that the polymerization rate and the overall conversion increased with increasing CHP and SFS concentration. Interestingly, the optimal molar ratio of CHP/SFS was 1.10/3.81 rather than being equimolar in our work. In addition, an optimal molar ratio of EDTA to ferrous ions (2.19 × 10−5 mol/7.12 × 10−6 mol) was found. The polymerization rate increased first and then decreased with increases in ferrous ion concentration. The pH value in the system decreased as the polymerization proceeded. A limiting conversion phenomenon of conversion not being able to exceed 20% was found, and an explanation to the limiting conversion was proposed on the basis of the views of the practical cumulative formation constant log KMY and reaction rate comparison. When another activator solution (EDTA/FES/SFS (mol) 2.19 × 10−5/7.12 × 10−6/1.91 × 10−3) was added, the limiting conversion was removed and the final conversion reached 97%. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901359z

Toughening of polyamide - 6 with a maleic anhydride functionalized acrylonitrile - styrene - butyl acrylate copolymer / Zhenguo Liu in Industrial & engineering chemistry research, Vol. 51 N° 27 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9235-9240 Titre : Toughening of polyamide - 6 with a maleic anhydride functionalized acrylonitrile - styrene - butyl acrylate copolymer Type de document : texte imprimé Auteurs : Zhenguo Liu, Auteur ; Yunjiao Deng, Auteur ; Ye Han, Auteur Année de publication : 2012 Article en page(s) : pp. 9235-9240 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Polyamide Résumé : Maleic anhydride (MAH) functionalized acrylate-styrene-acrylonitrile (ASA) copolymers (F-ASA) were prepared via an emulsion polymerization process. The F-ASA particles were used to toughen Polyamide-6 (PA-6). Molau tests showed the compatibilization reactions between PA-6 and F-ASA. The notched impact strength of PA-6 was effectively improved by the use of F-ASA. At a rubber content of 20% by weight in PA-6/F-ASA blends, it was found that the impact strength increased with the MAH content. When the MAH content was 8% in F-ASA, the impact strength was 1008 J/m. The influence of rubber content on the properties of PA-6/F-ASA8 blends was investigated. The results showed that brittle-ductile transition took place when the rubber content was 20%. Moreover, increasing the MAH content of the blends reduced the brittle-ductile temperature of the F-ASA/PA-6 blends from 50 °C to about 0 °C. Scanning electron microscopy (SEM) results showed that cavitation of rubber particles and shear yielding of the PA-6 matrix were the major toughening mechanisms. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202960q [article] Toughening of polyamide - 6 with a maleic anhydride functionalized acrylonitrile - styrene - butyl acrylate copolymer [texte imprimé] / Zhenguo Liu, Auteur ; Yunjiao Deng, Auteur ; Ye Han, Auteur . - 2012 . - pp. 9235-9240. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9235-9240 Mots-clés : Polyamide Résumé : Maleic anhydride (MAH) functionalized acrylate-styrene-acrylonitrile (ASA) copolymers (F-ASA) were prepared via an emulsion polymerization process. The F-ASA particles were used to toughen Polyamide-6 (PA-6). Molau tests showed the compatibilization reactions between PA-6 and F-ASA. The notched impact strength of PA-6 was effectively improved by the use of F-ASA. At a rubber content of 20% by weight in PA-6/F-ASA blends, it was found that the impact strength increased with the MAH content. When the MAH content was 8% in F-ASA, the impact strength was 1008 J/m. The influence of rubber content on the properties of PA-6/F-ASA8 blends was investigated. The results showed that brittle-ductile transition took place when the rubber content was 20%. Moreover, increasing the MAH content of the blends reduced the brittle-ductile temperature of the F-ASA/PA-6 blends from 50 °C to about 0 °C. Scanning electron microscopy (SEM) results showed that cavitation of rubber particles and shear yielding of the PA-6 matrix were the major toughening mechanisms. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202960q