Role of water as a coporogen in the synthesis of mesoporous poly(divinylbenzenes)

Hanková, Libuše; Holub, Ladislav; Meng, Xiangju; Xiao, Feng‐Shou; Jeřábek, Karel

doi:10.1002/app.41198

Cited by 7 publications

(10 citation statements)

References 22 publications

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“…This technique is performed at relatively high temperature (100 °C) in an autoclave under pressure in which the volume of porogenic solvents is 10 times that of the monomers. An investigation of the morphology of the “solvothermally” prepared polymers, especially in their swollen state, by inverse steric exclusion chromatography (ISEC) showed that the “solvothermally” prepared polymers exhibited exceptionally high pore volumes surviving volume changes from collapse during drying followed by re‐swelling …”

Section: Introductionmentioning

confidence: 99%

“…The microsyneresis mechanism of phase separation in polymer gels has so far been considered as possible only in polymer materials with a very low degree of crosslinking . In the synthesis of highly crosslinked polymers it has not been observed yet, except the “solvothermal” synthesis of mesoporous poly(DVB), which is performed under rather unusual conditions (typically at 100 °C, a pressure about 4 bars, and a monomer diluted in 10 times its volume of tetrahydrofuran), originally devised as an analogy to the conditions known to be useful for the template‐less synthesis of zeolites…”

Section: Introductionmentioning

confidence: 99%

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Formation of porous polymer morphology by microsyneresis during divinylbenzene polymerization

Hanková

Holub

Jeřábek

2015

J. Polym. Sci. Part B: Polym. Phys.

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This article describes the investigation of the importance of various reaction conditions on microsyneretic pore formation during polymerization of divinylbenzene (DVB) under so-called "solvothermal" conditions. To induce microsyneretic pore formation, the most important parameter is an unusually high dilution of monomers with a "good" porogen solvating the polymer chains. High dilution and solvation of the growing poly(DVB) chains promote the prolongation of the polymer chains rather than their interconnection by crosslinking. Consequently, when the polymer gel density reaches the point where syneresis starts, the polymer network is geometrically too extensive to be broken up into precipitating entities and, instead, porogen droplets are formed within the continuous polymer gel. The pore geometry created by microsyneresis offers high surface area in wide mesopores and hence, high capacity for supporting functional groups or reactions with much better accessibility than narrow pores between polymer microspheres produced by macrosyneresis in conventional styrenic polymer supports. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 774-781 KEYWORDS: crosslinking; macroporous polymers; mesopores; morphology; phase separation; porosity; porous polymer; syneresis INTRODUCTION The standard technique for creating a porous morphology of crosslinked polymers such as poly(styrene-codivinylbenzene) is through dilution of monomers before polymerization with a solvent in which they are miscible. The porosity of the polymer is generated via syneresis mechanism that is phase separation between the solvent and the polymer gel when with increasing conversion of monomers by diminishes the ability of crosslinked polymer network to absorb the inert solvent. In a two-phase system, one of the phases is predominantly continuous and surrounds the domains of the second discontinuous phase. The situation in which the discontinuous phase is the polymer precipitating from the surrounding solution is known as macrosyneresis and leads to a morphology in which the pores constitute spaces between polymer micro-or nano-particles. This is the most common type of the morphology of macroreticular (or macroporous) polymer materials, 1,2 but such a geometry limits the extent of the porosity to at most 50 or 60%, as greater volumes of the interparticle spaces cause the whole structure to become unstable.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Formation of porous polymer morphology by microsyneresis during divinylbenzene polymerization

Hanková

Holub

Jeřábek

2015

J. Polym. Sci. Part B: Polym. Phys.

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“…Amberlite gel-type ion-exchange resins are based on a styrene divinylbenzene copolymer backbone. With this in mind, two mesoporous poly(divinylbenzenes) were adapted from the literature [ 30 ] and sulfonated for comparison to the silicate based materials ( Section 3.5 ; Figure 8 ). Fitting of the glycerol binding result for these PDVB resins resulted in saturation capacities of 4.7 and 11.2 mg/g for PDVB-2 and PDVB-3, respectively ( Table 2 ).…”

Section: Resultsmentioning

confidence: 99%

“…Divinylbenzene (DVB) resins were synthesized in a Teflon-lined autoclave reactor (23 mL capacity) [ 30 ]. For PDVB-2, DVB (1.5 g; Aldrich technical grade, 80%) was added to tetrahydrofuran (15 mL) with water (0.75 mL) and 2,-2′-azobis(2-methylpropionitrile) (0.0375 g; Aldrich, 98%).…”

Section: Methodsmentioning

confidence: 99%

Improving Sorbents for Glycerol Capture in Biodiesel Refinement

et al. 2017

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Biodiesel is produced by transesterification of animal fat, vegetable oil, or waste cooking oil with alcohol. After production costs, the economic viability of biodiesel is dependent on what steps are necessary to remove impurities following synthesis and the effectiveness of quality control analysis. Solid-phase extraction offers a potentially advantageous approach in biodiesel processing applications. Nanoporous scaffolds were investigated for adsorption of glycerol, a side product of biodiesel synthesis that is detrimental to engine combustion when present. Materials were synthesized with varying pore wall composition, including ethane and diethylbenzene bridging groups, and sulfonated to promote hydrogen bonding interactions with glycerol. Materials bearing sulfonate groups throughout the scaffold walls as well as those post-synthetically grafted onto the surfaces show notably superior performance for uptake of glycerol. The sorbents are effective when used in biodiesel mixtures, removing greater than 90% of glycerol from a biodiesel preparation.

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“…In addition to this it absorbs a volume of liquids much higher than its pore volume, which further increase its specific surface area to almost 1000 m 2 •g −1 [40]. These features apparently arise from the high nominal cross-linking degree and the high dilution of the monomer in the polymerization mixture [41], which favors the chain growth with respect to cross-linking and the switch from macroto microsyneresis as the mechanism of phase separation [42]. As the result the pore system of this kind of pDVB, which will be hereafter referred to as mesoporous (µ-pDVB), can be described as interconnected cavities crossing a continuous polymer framework rather than void spaces between partially aggregated polymer lumps ( Figure 2), as in conventional macroreticular resins [39,40,42].…”

Section: Introductionmentioning

confidence: 99%

Direct Synthesis of Hydrogen Peroxide under Semi-Batch Conditions over Un-Promoted Palladium Catalysts Supported by Ion-Exchange Sulfonated Resins: Effects of the Support Morphology

et al. 2019

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Palladium catalysts supported by a mesoporous form of sulfonated poly-divinylbenzene, Pd/µS-pDVB10 (1%, w/w) and Pd/µS-pDVB35 (3.6% w/w), were applied to the direct synthesis of hydrogen peroxide from dihydrogen and dioxygen. The reaction was carried for 4 h out in a semibatch reactor with continuous feed of the gas mixture (H2/O2 = 1/24, v/v; total flow rate 25 mL·min−1), at 25 °C and 101 kPa. The catalytic performances were compared with those of a commercial egg-shell Pd/C catalyst (1%, w/w) and of a palladium catalyst supported by a macroreticular sulfonated ion-exchange resin, Pd/mS-pSDVB10 (1%, w/w). Pd/µS-pDVB10 and Pd/C showed the highest specific activity (H2 consumption rate of about 75–80 h−1), but the resin supported catalyst was much more selective (ca 50% with no promoters). The nanoparticles (NP) size was somewhat larger in Pd/µS-pDVB10, showing that either the reaction was structure insensitive or diffusion limited to some extent over Pd/C, in which the support is microporous. The open pore structure of Pd/µS-pDVB10, possibly ensuring the fast removal of H2O2 from the catalyst, could also be the cause of the relatively high selectivity of this catalyst. In summary, Pd/µS-pDVB10 was the most productive catalyst, forming ca 375 molH2O2·kgPd−1·h−1, also because it retained a constant selectivity, while the other ones underwent a more or less pronounced loss of selectivity after 80–90 min. Ageing experiments showed that for a palladium catalyst supported on sulfonated mesoporous poly-divinylbenzene storage under oxidative conditions implied some deactivation, but a lower drop in the selectivity; regeneration upon a reductive treatment or storage under strictly anaerobic conditions (dry-box) lead to an increase of the activity but to both a lower initial selectivity and a higher drop of selectivity with time.

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Role of water as a coporogen in the synthesis of mesoporous poly(divinylbenzenes)

Cited by 7 publications

References 22 publications

Formation of porous polymer morphology by microsyneresis during divinylbenzene polymerization

Formation of porous polymer morphology by microsyneresis during divinylbenzene polymerization

Improving Sorbents for Glycerol Capture in Biodiesel Refinement

Direct Synthesis of Hydrogen Peroxide under Semi-Batch Conditions over Un-Promoted Palladium Catalysts Supported by Ion-Exchange Sulfonated Resins: Effects of the Support Morphology

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