Confined polymerization: catalyzed synthesis of high T<sub>m</sub>, nanofibrous polyethylene within porous polymer microspheres

Wang, Kui; Lei, Jian; Zhou, Guangyuan

doi:10.1039/c5ra13945g

Cited by 6 publications

(4 citation statements)

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“…In the process of heating, a large number of entangled chains and fewer chain ends can reduce the value of σ e , resulting in high T m2. [14] Results showed that the high T m2 is the inherent property of polyethylene prepared by PPM‐supported Ziegler‐Natta catalyst, which is attributed to the unique interconnected multi‐modal pore structure of the PPMs supports [10,15] …”

Section: Resultsmentioning

confidence: 99%

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High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst

et al. 2020

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In this work, different types of polyethylene (linear, spiral nanofibers and microspheres) were obtained via confined polymerization by a PPM-supported Ziegler-Natta catalyst. Firstly, the Ziegler-Natta catalyst was chemical bonded inside the porous polymer microspheres (PPMs) supports with different pore diameter and supports size through chemical reaction. Then slightly and highly confined polymerization occurred in the PPM-supported Ziegler-Natta catalysts. SEM results illustrated that the slightly confined polymerization was easy to obtain linear and spiral nanofibers, and the nanofibers were observed in polyethylene catalyzed by PPMs-1#/cat and PPMs-2#/cat with low pore diameter (about 23 nm). Furthermore, the highly confined polymerization produced polyethylene microspheres, which obtained through other PPM-supported Ziegler-Natta catalysts with high pore diameter. In addition, high second melting point (T m2 : up to 143.3°C) is a unique property of the polyethylene obtained by the PPM-supported Ziegler-Natta catalyst after removing the residue through physical treatment. The high T m2 was ascribed to low surface free energy (σ e), which was owing to the entanglement of polyethylene polymerized in the PPMs supports with interconnected multimodal pore structure.

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Section: Resultsmentioning

confidence: 99%

“…[14] Results showed that the high T m2 is the inherent property of polyethylene prepared by PPM-supported Ziegler-Natta catalyst, which is attributed to the unique interconnected multi-modal pore structure of the PPMs supports. [10,15]…”

Section: Further Analysis Of Polyethylene With High T M2 After Physic...mentioning

confidence: 99%

High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst

et al. 2020

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“…The pore of silica with a size ranging from 10 to 180 nm is able to provide spaces for accommodating the POSSs. This means that the POSS molecules can diffuse into the pores with a large size but are hard to accommodate into the small pores because of the confined structures. ,, Thus, it is shown that the large pores (i.e., 130–180 nm) are blocked. The pore size of the POSS-modified catalyst is mainly around 10–50 nm owing to the incorporation of POSS (see Figure c).…”

Section: Resultsmentioning

confidence: 99%

Influence of the Fragmentation of POSS-Modified Heterogeneous Catalyst on the Formation of Chain Entanglements

Liu

Yue

Yang

et al. 2018

Ind. Eng. Chem. Res.

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The fluorinated bis(phenoxyimine)Ti complexes (FI catalyst) are immobilized onto the polyhedral oligomeric silsesquioxane (POSS)-modified silica for the preparation of ultrahigh molecular weight polyethylene (UHMWPE) with a weakly entangled state. The POSSs can assemble to spherical nanoaggregates with an average size of 60 nm, which can serve as isolators to separate the active species and growing chains. The weakly entangled UHMWPE is prepared with an exceptional activity owing to this isolation. The evolution of entanglements for polymer chains is studied based on the fragmentation of catalytic particles. It is evidenced by the results of polymerization and characterization that 30 min of polymerization is the critical time for the entire fragmentation of catalytic particles. Importantly, this fragmentation leads to a rupture of the reacted environment which is established by the POSS nanoaggregates. Further polymerization will synthesize the UHMWPE with more entangled density.

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“…In general, while designing new self-assembling structures, porous materials can be used as a smart media which allows to stabilize mechanically the desired properties [57][58][59][60][61][62]. Specifically, porous macromolecular materials have attracted durable attention of the scientific community [58,[63][64][65][66] due to their functionality and possibility of mechanical control.…”

Section: Introductionmentioning

confidence: 99%

Self-Assembling Behavior of Smart Nanocomposite System: Ferroelectric Liquid Crystal Confined by Stretched Porous Polyethylene Film

et al. 2020

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The control and prediction of soft systems exhibiting self-organization behavior can be realized by different means but still remains a highlighted task. Novel advanced nanocomposite system has been designed by filling of a stretched porous polyethylene (PE) film with pore dimensions of hundreds of nanometers by chiral ferroelectric liquid crystalline (LC) compound possessing polar self-assembling behavior. Lactic acid derivative exhibiting the paraelectric orthogonal smectic A* and the ferroelectric tilted smectic C* phases over a broad temperature range is used as a self-assembling compound. The morphology of nanocomposite film has been checked by Atomic Force Microscopy (AFM). The designed nanocomposite has been studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), small and wide-angle X-ray scattering and broadband dielectric spectroscopy. The effect of a porous PE confinement on self-assembling, structural, and dielectric behavior of the chiral LC compound has been established and discussed. While the mesomorphic and structural properties of the nanocomposite are found not to be much influenced in comparison to that of a pure LC compound, the polar properties have been toughly suppressed by the specific confinement. Nevertheless, the electro-optic switching was clearly observed under applied electric field of low frequency (210 V, 19 Hz). The dielectric spectroscopy and X-ray results reveal that the helical structure of the ferroelectric liquid crystal inside the PE matrix is completely unwound, and the molecules are aligned along stretching direction. Obtained results demonstrate possibilities of using stretched porous polyolefins as promising matrices for the design of new nanocomposites.

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Confined polymerization: catalyzed synthesis of high T_m, nanofibrous polyethylene within porous polymer microspheres

Cited by 6 publications

References 33 publications

High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst

High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst

Influence of the Fragmentation of POSS-Modified Heterogeneous Catalyst on the Formation of Chain Entanglements

Self-Assembling Behavior of Smart Nanocomposite System: Ferroelectric Liquid Crystal Confined by Stretched Porous Polyethylene Film

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Confined polymerization: catalyzed synthesis of high Tm, nanofibrous polyethylene within porous polymer microspheres

Cited by 6 publications

References 33 publications

High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst

High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst

Influence of the Fragmentation of POSS-Modified Heterogeneous Catalyst on the Formation of Chain Entanglements

Self-Assembling Behavior of Smart Nanocomposite System: Ferroelectric Liquid Crystal Confined by Stretched Porous Polyethylene Film

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Confined polymerization: catalyzed synthesis of high T_m, nanofibrous polyethylene within porous polymer microspheres