Yanfeng Li

Functional porous organic polymers (POPs) {poly(2-hydroxyethylmethylacrylate-co-divinylbenzene) [P(HEMA-co-DVB)]} with different pore structures and morphology were prepared via a dispersion polymerization strategy. The effect of different solvent types, different ethanol/H₂O volume ratios in the mixture solvent, and the (HEMA)/DVB molar ratio on the specific surface area and porosity was investigated. Non-local density functional theory (NLDFT) simulation based on nitrogen sorption porosimetry and scanning electron microscopy (SEM) were used to study the pore structure and morphology of the prepared P(HEMA-co-DVB) particles. The results showed a trend that P(HEMA-co-DVB) particles with a higher specific surface area and a lower average pore diameter were obtained in ethanol/deionized water mixture solvents with better thermodynamic compatibility; however, when different types of solvents were used, a higher average pore diameter (14.5 nm) and total pore volume (0.923 cm³ g⁻¹) were achieved in a good thermodynamically compatible solvent–ethyl acetate. The HEMA functional comonomer could also be a good pore-adjuster that provides a feasible route to prepare functionalized PDVB particles with controllable pore structure and particle morphology. In the ethylene homopolymerization evaluation of supported metallocene catalysts, these nanoporous polymer supports reveal better catalytic activity compared with silica used as the metallocene support, exhibiting great potential for future applications in the polyolefin catalysis industry.

Porous organic polymers (POPs) are a kind of carrier and support material which could be used in the fields of absorption, separation and catalysis. In this paper, poly(2-hydroxyethylmethylacrylate-co-divinylbenzene) [P(HEMA-co-DVB)] particles were prepared by using metal oxide as a particle-forming template. The effects of Fe₃O₄/monomer mass ratio, sonification of Fe₃O₄ nano-bead aggregates, and other types of metal oxide template were investigated. The results showed that the metal oxide could be a good particle-forming template for obtaining a suitable particle morphology and pore structure of the P(HEMA-co-DVB). A shift of pore size distribution to the right or increase of pore size abundance of the prepared P(HEMA-co-DVB) particles was observed when increasing the Fe₃O₄/monomer ratio from 0 to 7%, and the specific surface area (SSA) and the total pore volume (PV) of the prepared P(HEMA-co-DVB) particles increased dramatically with 248 g m⁻² of SSA and 0.394 g ml⁻¹ of PV, when 1.5 wt% Fe₃O₄/monomer was added. The SSA and PV of the final P(HEMA-co-DVB) also increased dramatically after sonification of the Fe₃O₄ nano-bead aggregates, however, the bulk density of the support decreased. Larger PV (0.488 cm³ g⁻¹) and average pore diameter (12.1 nm) of the prepared P(HEMA-co-DVB) particles were obtained with a relatively high HEMA content. This provides a feasible route to prepare functional PDVB particles with controllable pore structure and particle morphology. In the ethylene homopolymerization evaluation of supported metallocene catalysts, these nanoporous polymeric supports show better catalytic activity compared to the conventional silica support. The availability of such porous polymer supports is expected to stimulate further studies of these materials in polymer synthesis technologies and polyolefin catalysis applications.

A novel magnetic WPU/Fe₃O₄ nanocomposite has been successfully synthesized by in situ polymerization method. The nanocomposite films present excellent magnetic properties, which would have a promising application in microwave-absorption field.

Polycationic vectors have been used to deliver short hairpin RNAs (shRNAs) to knock-down genes for cancer therapies, but their inefficiency in lysosomal escape and shRNA release causes their low gene transcription efficiency. Herein, a three-layered polyethyleneimine (PEI)-coated gold nanocomplex interlaid with a pH-responsive charge-reversible chitosan-aconitic anhydride (CS-Aco) is constructed: a Au-PEI/CS-Aco/PEI/shRNA nanoparticle. The negatively charged CS-Aco hydrolyzes into positively charged CS in lysosomes, causing the nanocomposite to disassemble. The released Au-PEI nanoparticles efficiently rupture the lysosomes and thus release the PEI/shRNA polyplexes into cytoplasm, where they quickly disassociate because the PEI chains are short (1.2 kDa). As a consequence, the nanocomplexes display higher shRNA delivery efficiency than the 25 kDa PEI, and efficiently deliver shABCG2 to tumors and markedly silence ABCG2 expression, which sensitizes HepG2 cells to the drugs with minimal toxicity.

This study involved the adsorption removal of Cd (II) by “green” chelating PS-DETA resins and its application in a column mode for industrial wastewater treatment. An initial factorial design of experiments showed that factors such as pH of the solution, agitation speed, and contact time were important. Competing adsorption of Cd (Ⅱ) and Zn (Ⅱ) onto the PS-DETA resins in binary system showed that the adsorption affinity may be in the following order: Cd (Ⅱ)>> Zn (Ⅱ). The adsorption kinetics for Cd (II) was found to follow pseudo-second-order reaction. Isotherm studies conducted at 5–500 mg/g of initial Cd (II) concentrations provided the maximum adsorption capacities of 92.1 mg/g for the PS-DETA resins. The Langmuir isotherm model was found to describe adsorption well indicating the monolayer adsorption process. It was evident from results of the desorption studies that desorption efficiency larger than 99.6% could be obtained for Zn (Ⅱ) and Cd (Ⅱ) with 0.1 M HCl or HNO₃. Data from a column study using PS-DETA resins for Cd (II) and Zn (II) from industrial wastewater showed that after approximately 760 BV, removal of Cd (II) achieved 50%. Hence, it was concluded that it was effective to remove Cd (II) from industrial wastewater with the column operation although the adsorption capacity of the PS-DETA resins for Cd (II) and Zn (II) was found to be less than the adsorption capacity obtained in the batch study.