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Critical content of ultrahigh-molecular-weight polyethylene to induce the highest nucleation rate for isotactic polypropylene in blends / Wei Shao in Industrial & engineering chemistry research, Vol. 51 N° 49 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 15953–15961 Titre : Critical content of ultrahigh-molecular-weight polyethylene to induce the highest nucleation rate for isotactic polypropylene in blends Type de document : texte imprimé Auteurs : Wei Shao, Auteur ; Yaqiong Zhang, Auteur ; Zhigang Wang, Auteur Année de publication : 2013 Article en page(s) : pp. 15953–15961 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crystallization  kinetics  isotactic Résumé : The influence of the addition of low amounts of ultrahigh-molecular-weight polyethylene (UHMWPE) on the crystallization kinetics of isotactic polypropylene (iPP) in iPP/UHMWPE blends has been investigated by means of differential scanning calorimetry (DSC) and polarized optical microscopy. During the nonisothermal crystallization process, the primarily formed UHMWPE crystals serve as heterogeneous nucleating agents for iPP nucleation, whereas during the isothermal crystallization process, UHMWPE is in the molten state, iPP nucleation preferentially occurs at the UHMWPE and iPP phase interfaces, and the spherulitic growth rates are not obviously affected. It is particularly interesting to find a critical UHMWPE content (2.5 wt %) in the blends to induce the highest iPP nucleation rate; however, above the critical UHMWPE content, the iPP nucleation rate slows because of aggregation of the UHMWPE component. A delicately designed DSC measurement provides insight into the nucleation mechanism of iPP at the interfaces between the UHMWPE and iPP phase domains. It is proposed that the concentration fluctuations generated from the unstable inhomogeneous phase interfaces in the iPP/UHMWPE blends promote the formation of nuclei, which eventually enhances the nucleation and overall crystallization rates of the iPP component. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302542x [article] Critical content of ultrahigh-molecular-weight polyethylene to induce the highest nucleation rate for isotactic polypropylene in blends [texte imprimé] / Wei Shao, Auteur ; Yaqiong Zhang, Auteur ; Zhigang Wang, Auteur . - 2013 . - pp. 15953–15961. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 15953–15961 Mots-clés : Crystallization  kinetics  isotactic Résumé : The influence of the addition of low amounts of ultrahigh-molecular-weight polyethylene (UHMWPE) on the crystallization kinetics of isotactic polypropylene (iPP) in iPP/UHMWPE blends has been investigated by means of differential scanning calorimetry (DSC) and polarized optical microscopy. During the nonisothermal crystallization process, the primarily formed UHMWPE crystals serve as heterogeneous nucleating agents for iPP nucleation, whereas during the isothermal crystallization process, UHMWPE is in the molten state, iPP nucleation preferentially occurs at the UHMWPE and iPP phase interfaces, and the spherulitic growth rates are not obviously affected. It is particularly interesting to find a critical UHMWPE content (2.5 wt %) in the blends to induce the highest iPP nucleation rate; however, above the critical UHMWPE content, the iPP nucleation rate slows because of aggregation of the UHMWPE component. A delicately designed DSC measurement provides insight into the nucleation mechanism of iPP at the interfaces between the UHMWPE and iPP phase domains. It is proposed that the concentration fluctuations generated from the unstable inhomogeneous phase interfaces in the iPP/UHMWPE blends promote the formation of nuclei, which eventually enhances the nucleation and overall crystallization rates of the iPP component. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302542x