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4 results on '"Yingjuan Huang"'

1. Polypropylene/Graphene Oxide Nanocomposites Prepared by In Situ Ziegler−Natta Polymerization

Author

Yong Zhou, Yingjuan Huang, Hui Niu, Jin-Yong Dong, Yawei Qin, and Zhong-Zhen Yu

Subjects
Polypropylene, Nanocomposite, Materials science, Graphene, General Chemical Engineering, Oxide, General Chemistry, Exfoliation joint, Catalysis, law.invention, chemistry.chemical_compound, Polymerization, chemistry, law, Materials Chemistry, Composite material, Dispersion (chemistry)
Abstract

This paper reports the first example of preparation of polypropylene/graphene oxide (PP/GO) nanocomposites via in situ Ziegler−Natta polymerization. A Mg/Ti catalyst species was incorporated into GO via surface functional groups including −OH and −COOH, giving a supported catalyst system primarily structured by nanoscale, predominantly single GO sheet. Subsequent propylene polymerization led to the in situ formation of PP matrix, which was accompanied by the nanoscale exfoliation of GO, as well as its gradual dispersion. Morphological examination of the ultimate PP/GO nanocomposites by TEM and SEM techniques revealed effective dispersion in nanoscale of GO in PP matrix. High electrical conductivity was discovered with thus prepared PP/GO nanocomposites; for example, at a GO loading of 4.9 wt %, σc was measured at 0.3 S·m−1.

Published
2010

2. Preparation of polypropylene/montmorillonite nanocomposites by intercalative polymerization: Effect of in situ polymer matrix functionalization on the stability of the nanocomposite structure

Author

Jin-Yong Dong, Yingjuan Huang, and Kefang Yang

Subjects
chemistry.chemical_classification, Polypropylene, Multidisciplinary, Nanocomposite, Materials science, Polymer, Borane, Exfoliation joint, chemistry.chemical_compound, Montmorillonite, chemistry, Polymerization, Polymer chemistry, Copolymer
Abstract

The copolymerization of propylene and 5-hexenyl-9-borabicyclo[3.3.1]nonane (5-hexenyl-9-BBN) has been conducted with an MgCl2/TiCl4 catalyst intercalated in an organically modified montmorillonite (OMMT) with triethylaluminum (AlEt3) cocatalyst and diphenyldimethoxysilane (DDS) external donor. This polymerization process simultaneously results in both the exfoliation of MMT layers to realize the preparation of polypropylene (PP)/MMT nanocomposites and the implantation of reactive borane groups in the formed PP matrix. The polymer-borne borane groups have been able to undergo an efficient hydrolysis process under very mild reaction conditions (40°C, 3 h, in THF), introducing hydroxy groups into PP without sacrificing the polymerization-formed nanocomposite structure (the exfoliation of MMT). The resultant hydroxyl-functionalized PP/MMT nanocomposites exhibit enhanced structural stability against processing compared with those based on unfunctionalized PP matrix.

Published
2007

3. Polypropylene/Graphene Oxide Nanocomposites Prepared by In Situ Ziegler−Natta Polymerization.

Author

Yingjuan Huang, Yawei Qin, Yong Zhou, Hui Niu, Zhong-Zhen Yu, and Jin-Yong Dong

Subjects
*POLYPROPYLENE, *OXIDES, *NANOCOMPOSITE materials, *ZIEGLER-Natta catalysts, *POLYMERIZATION, *SURFACE chemistry, *FUNCTIONAL groups, *TRANSMISSION electron microscopy, *ELECTRIC conductivity
Abstract

This paper reports the first example of preparation of polypropylene/graphene oxide (PP/GO) nanocomposites via in situ Ziegler−Natta polymerization. A Mg/Ti catalyst species was incorporated into GO via surface functional groups including −OH and −COOH, giving a supported catalyst system primarily structured by nanoscale, predominantly single GO sheet. Subsequent propylene polymerization led to the in situ formation of PP matrix, which was accompanied by the nanoscale exfoliation of GO, as well as its gradual dispersion. Morphological examination of the ultimate PP/GO nanocomposites by TEM and SEM techniques revealed effective dispersion in nanoscale of GO in PP matrix. High electrical conductivity was discovered with thus prepared PP/GO nanocomposites; for example, at a GO loading of 4.9 wt %, σcwas measured at 0.3 S·m−1. [ABSTRACT FROM AUTHOR]

Published
2010
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4. Crystallization behaviors in the isotactic polypropylene/graphene composites.

Author

Songmei Zhao, Fenghua Chen, Yingjuan Huang, Jin-Yong Dong, and Han, Charles C.

Subjects
*CRYSTALLIZATION, *NUCLEATION, *THERMAL stability, *GRAPHENE, *FILLER materials, *POLYPROPYLENE, *COMPOSITE materials, *ISOTACTIC polymers
Abstract

Crystallization behaviors and kinetics of iPP in an in-situ prepared isotactic polypropylene/graphene (iPP/G) composites were studied in this paper. In samples used in this study, the graphene fillers were well dispersed, and the interfacial adhesion exhibited enhanced features between graphene and iPP components. The thermal stability of the composites was improved by about 100 °C compared to the pristine iPP. It was found that the crystallization morphology, crystallization rate and kinetics of the iPP/G composites were significantly influenced by the presence of graphene. The nucleation and epitaxial growth of iPP on the graphene surface were observed and studied in detail. It was observed that the nucleation of iPP favored to occur at the wrinkles and edges due to the good match of the lattice parameters and the weak spatial hindrance compared to the smooth surface. Numerous nuclei epitaxially formed and the size of the crystals was very small. The schematic diagram was also proposed for the nucleation and growth process of iPP on the graphene surface in the iPP/G composites. Meanwhile, the overall crystallization kinetics and crystals growth were analyzed through Avrami equation. The obtained Avrami index n decreased with the graphene loadings and was close to 2 for the iPP/G composites, which implied that the growth of iPP in the composites was in two-dimension. And this was caused by the structure of graphene and the spatial confinement effect of graphene platelets in the iPP/G composites. [ABSTRACT FROM AUTHOR]

Published
2014
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