Feasibility Study on the Design and Synthesis of Functional Porous Organic Polymers with Tunable Pore Structure as Metallocene Catalyst Supports.

Xiong Wang,Pingsheng Zhang,Cuiling Zhang,Wenxia Liu

doi:10.3390/polym10090944

Abstract

Porous organic polymers (POPs) are highly versatile materials that find applications in adsorption, separation, and catalysis. Herein, a feasibility study on the design and synthesis of POP supports with a tunable pore structure and high ethylene-polymerization activity was conducted by the selection of functional comonomers and template agents, and control of cross-linking degree of their frameworks. Functionalized POPs with a tunable pore structure were designed and synthesized by a dispersion polymerization strategy. The functional comonomers incorporated in the poly(divinylbenzene) (PDVB)-based matrix played a significant role in the porous structure and particle morphology of the prepared polymers, and a specific surface area (SSA) of 10–450 m2/g, pore volume (PV) of 0.05–0.5 cm3/g, bulk density with a range of 0.02–0.40 g/cm3 were obtained by the varied functional comonomers. Besides the important factors of thermodynamic compatibility of the selected solvent system, other factors that could be used to tune the pore structure and morphology of the POP particles have been also investigated. The Fe3O4 nanoaggregates as a template agent could help improve the porous structure and bulk density of the prepared POPs, and the highly cross-linking networks can dramatically increase the porous fabric of the prepared POPs. As for the immobilized metallocene catalysts, the pore structure of the prepared POPs had a significant influence on the loading amount of the Zr and Al of the active sites, and the typically highly porous structure of the POPs would contribute the immobilization of the active species. High ethylene-polymerization activity of 8033 kg PE/mol Zr h bar was achieved on the POPs-supported catalysts, especially when high Al/Zr ratios on the catalysts were obtained. The performance of the immobilized metallocene catalysts was highly related to the pore structure and functional group on the POP frameworks.

Highlights

Porous organic polymers (POPs) have received a staggering degree of attention in various research areas, including adsorption, separation, and heterogeneous catalysis, owing to their huge surface area, tunable pore size, flexible synthetic strategy, and readily modifiable functionality [1,2,3,4,5,6,7,8,9]
A feasibility study on the design and synthesis of POP supports with a tunable pore structure and high performance of ethylene polymerization was conducted by the selection of functional comonomers, template agent, and control of the cross-linking degree of their frameworks
Functional porous organic polymers with a tunable pore structure and varied particle morphology were designed and synthesized, and the pore-size distributions of POPs are generally wider than the crystalline polymers, and the micropores and the mesopores could be tuned at the same time by the dispersion polymerization method

Summary

Introduction

Porous organic polymers (POPs) have received a staggering degree of attention in various research areas, including adsorption, separation, and heterogeneous catalysis, owing to their huge surface area, tunable pore size, flexible synthetic strategy, and readily modifiable functionality [1,2,3,4,5,6,7,8,9] Numerous studies on these porous organic materials, including covalent organic frameworks (COFs) and porous coordination polymers (PCPs) or metal-organic frameworks (MOFs), as olefin polymerization-catalyst supports and mobilization procedures have been investigated [10,11,12]. The incorporation of functional groups and active sites, in turn, would cause defects on the frameworks broadening the pore-size distribution of the pore structure [21,31]

Methods

Results

Conclusion