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Results for “Porous Polymer”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Solvent-Induced Self-Assembly Strategy to Synthesize Well-Defined Hierarchically Porous Polymers

Porous polymers with well-orchestrated nanomorphologies are useful in many fields, but high surface area, hierarchical structure, and ordered pores are difficult to be satisfied in one polymer simultaneously. A solvent-induced self-assembly strategy to synthesize hierarchical porous polymers with tunable morphology, mesoporous structure, and microporous pore wall is reported. The poly(ethylene oxide)-b-polystyrene (PEO-b-PS) diblock copolymer micelles are cross-linked via Friedel–Crafts reaction, which is a new way to anchor micelles into porous polymers with well-defined structure. Varying the polarity of the solvent has a dramatic effect upon the oleophobic/oleophylic interaction, and the self-assembly structure of PEO-b-PS can be tailored from aggregated nanoparticles to hollow spheres even mesoporous bulk. A morphological phase diagram is accomplished to systematically evaluate the influence of the composition of PEO-b-PS and the mixed solvent component on the pore structure and morphology of products. The hypercrosslinked hollow polymer spheres provide a confined microenvironment for the in situ reduction of K 2 PdCl 4 to ultrasmall Pd nanoparticles, which exhibit excellent catalytic performance in solvent-free catalytic oxidation of hydrocarbons and alcohols.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Charged Porous Polymers using a Solid C-O Cross-Coupling Reaction

We report a green, fast, efficient mechanochemical strategy for charged porous polymers (CPPs). A cationic CPP with basic anions and an anionic CPP with Li + cations were fabricated by solid grinding under solvent- free conditions. Compared with solution-based synthesis, mechanochemical grinding can shorten the reaction time from dozens of hours to several minutes (60– 90 min) to form polymers possessing a high molecular mass and low polydispersity. During the construction of CPPs, a Pd-catalyzed solid polycondensation based on unactivated organic linkers was introduced. In particular, CPPs with basic phenolic or proline anions showed good activity and stability in SO 2 capture, and Li + -functionalized CPPs can be post-modified to CPPs with other metal ions by ion exchange, highlighting the tailorable feature of ionic-modified CPPs.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Open‐Pore Two‐Dimensional MFI Zeolite Nanosheets for the Fabrication of Hydrocarbon‐Isomer‐Selective Membranes on Porous Polymer Supports

Abstract Two‐dimensional zeolite nanosheets that do not contain any organic structure‐directing agents were prepared from a multilamellar MFI (ML‐MFI) zeolite. ML‐MFI was first exfoliated by melt compounding and then detemplated by treatment with a mixture of H 2 SO 4 and H 2 O 2 (piranha solution). The obtained OSDA‐free MFI nanosheets disperse well in water and can be used for coating applications. Deposits made on porous polybenzimidazole (PBI) supports by simple filtration of these suspensions exhibit an n ‐butane/isobutane selectivity of 5.4, with an n ‐butane permeance of 3.5×10 −7 mol m −2 s −1 Pa −1 (ca. 1000 GPU).

Zhang, Han↗
DOE OSTI2023

Effect of Silica and Mixing Time on Microstructures of Porous Polymer Composite by Emulsion Templating

Porous polymer composite with tailored porosity is applied in the myriads of areas such as energy storage, oil/water absorption, bioengineering, and advanced areas of material science. The emulsion templating technology is one of the most popular methods for synthesizing porous polymer composite. It involves solidifying a two-phase mixture of porogen and polymer, then removing porogen to create pores within the continuous emulsion phase by polymerization or curing. The surfactant plays a pivotal role in accomplishing a stable emulsion, a key factor in designing the internal porous structure. This study highlights the effect of silica filler and mixing time on pore morphology, i.e., shape, size, and distribution. on polydimethylsiloxane (PDMS) porous structure utilizing the water-in-oil emulsion templating method. Span® 80 is used as a surfactant to reduce the surface tension between water, silica, and PDMS and simultaneously create a strong foaming effect. Different weight concentrations of silica (1-10 wt%) were chosen while keeping the internal phase, i.e., water (50 wt%) constant. The designed porous structures were further characterized through scanning electron microscopy (SEM). Porous composite specimens fabricated with higher silica content and mixing time consistently exhibit smaller pore sizes than specimens fabricated with lower mixing time and silica content. A breakthrough of pore morphology is seen at silica content higher than 5wt% at 1 min mixing, however, pore morphology drastically changes when mixing time increases from 1 min to 6 min. Variation of finer mixing time beyond 1 min shows stepwise changes in pore morphology from a large single-phase porous structure to a bi-modal porous structure which eventually become a smaller single-mode porous structure. Thus, the emulsion templating technique, in combination with different filler content and mixing time, will effectively aid in designing engineered porous polymer composite with varying stiffness and pore morphology.

Porous polymer, Emulsion templating, Surfactant, P↗
DOE OSTI2016

Porous polymer network materials

Functionalized Porous Polymer Networks (PPNs) exhibiting favourable characteristics such as high surface area′ and gas uptake properties are disclosed, including methods of making such networks. A method of preparing a porous polymer network, comprising: (a) a step of homo-coupling a monomer in the presence of 2,2′-bipyridyl, 1,5-cycloocta-1,5-diene, a mixed solvent of DMF/THF and a compound or mixture selected from the group consisting of bis(1,5-cydoocta-1,5-diene)nickel(0), Ni(PPH3) 4, and Zn/NiCI2/NaBr/PPH3 at a temperature in the range of 20 to 40° C. These stable PPNs may be useful in the context of carbon capture, gas storage and separation, and as supports for catalysts.

Zhou, Hong -Cai↗
DOE OSTI2015

Microfluidic devices and methods including porous polymer monoliths

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Atomic layer deposition of nanofilms on porous polymer substrates: Strategies for success

Atomic layer deposition (ALD) is a versatile technique for engineering the surfaces of porous polymers, imbuing the flexible, high-surface-area substrates with inorganic and hybrid material properties. Previously reported enhancements include fouling resistance, electrical conductance, thermal stability, photocatalytic activity, hydrophilicity, and oleophilicity. However, there are many poorly understood phenomena that introduce challenges in applying ALD to porous polymers. In this paper, we address five common challenges and ways to overcome them: (1) entrapped precursor, (2) embrittlement, (3) film fracture, (4) deformation, and (5) pore collapse. These challenges are often interrelated and can exacerbate one another. To investigate these phenomena, we applied various ALD chemistries to porous polymers including polyethersulfone, polysulfone, polyvinylidene fluoride, and polycarbonate track-etched membranes. Reaction-diffusion modeling revealed why certain precursors and processing conditions result in embrittling subsurface material growth, entrapment of unreacted precursors, and nongrowth. We quantify the limits of ALD processing temperatures that are dictated by thermal expansion mismatch and can lead to fractured ALD films. The results herein allow us to make recommendations to avoid, mitigate, or overcome the difficulties encountered when performing ALD and plasma-enhanced ALD on porous polymers. We intend this article to serve as a “lessons learned” guide informed by previous experience to provide a better understanding of the difficulties and limitations of ALD on porous polymers and knowledge-based guidelines for successful depositions. This knowledge can accelerate future research and help experimentalists navigate and troubleshoot as they expose porous polymers to reactive precursor vapors.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Electrocatalysts using porous polymers and method of preparation

A method of producing an electrocatalyst article using porous polymers. The method creates a porous polymer designed to receive transition metal groups disposed at ligation sites and activating the transition metals to form an electrocatalyst which can be used in a fuel cell. Electrocatalysts prepared by this method are also provided. A fuel cell which includes the electrocatalyst is also provided.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2015

Electrocatalysts using porous polymers and method of preparation

A method of producing an electrocatalyst article using porous polymers. The method creates a porous polymer designed to receive transition metal groups disposed at ligation sites and activating the transition metals to form an electrocatalyst which can be used in a fuel cell. Electrocatalysts prepared by this method are also provided. A fuel cell which includes the electrocatalyst is also provided.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2019

Photolytic synthesis and hydrophobization of plates of porous polymer material based on dimethacrylate oligomer MDP-2

Plates of poly-MDP-2 porous material with a characteristic size of inhomogeneities of 0.3, 0.7, 2.5, 10, and 20 µm were synthesized by the photopolymerization technique. The conditions for the photolytic modification of the hydrophilic/hydrophobic properties of poly-MDP-2 by the graft copolymerization method under visible light irradiation were selected using 9,10-phenanthrenequinone as a photoinitiator and isodecyl methacrylate as a modifying monomer. It is shown on the samples with an inhomogeneity size of 10 µm that the stable hydrophobization effect (contact angle of water droplet θ = 135°) is achieved at a photoinitiator concentration of 2.4 · 10{sup −3} mol L{sup −1} and an irradiation time of the sample in the modifying solution of 1 h. The effect of photolytic hydrophobization increases with an increase in the size of inhomogeneities in the porous polymer material and reaches θ = 140° for inhomogeneities ∼20 µm in size.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Evaluation of amine-incorporated porous polymer networks (aPPNs) as sorbents for post­combustion CO 2 capture

This is the final report for the TAMU project “Evaluation of amine-incorporated porous polymer networks (aPPNs) as sorbents for post­combustion CO 2 capture.” During this project, a team consisting of the Zhou group at Texas A&M University and framergy Inc. were tasked with developing a porous polymer network (PPN) based sorbent system for CO 2 capture applications. The three year project was divided up into 3 individual budget periods. During budget period 1 the team develop multiple novel PPN based sorbents and began initial CO 2 capture experiments. During the course of this research the team determined that two sorbents were the standout targets, PPN-150-DETA and PPN-151-DETA. During budget period 2 the team further developed these two materials, gathering data to determine their performance under both wet and dry conditions, determine their CO 2 adsorption capacities, heats of adsorption, regenerative energy demands, and mechanical attrition. In addition, budget period 2 saw the development of 50 g and 250 g batches of both sorbents, while still maintaining >0.10 g/g uptake capacity under wet gas conditions. Following budget period 2 testing, the team opted to continue on with PPN-151-DETA due to its superior CO 2 cycling capabilities, with a consistent uptake capacity observed over 30 cycles at the lab scale. During budget period 3 the team further developed the material at scale, producing a 1 kg batch of material. Following this, the team performed multiple long-term cycling tests in the presence and absence of SO 2 using a 100 mL column. During this testing the team observed that the material loses significant uptake capacity due to SO 2 , as well as shows some level of DETA loss, which resulted in instrument breakdown and a request for a no-cost extension. The team was able to finalize the experiment with a test using a 1.5 L column in the absence of SO 2 , with the final cycle uptakes being around 0.035 g/g due to the need to harshly activate the material to prevent DETA desorption.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2015

Facile one-pot synthesis of porphyrin based porous polymer networks (PPNs) as biomimetic catalysts

Stable porphyrin based porous polymer networks, PPN-23 and PPN-24, have been synthesized through a facile one-pot approach by the aromatic substitution reactions of pyrrole and aldehydes. We report PPN-24(Fe) shows high catalytic efficiency as a biomimetic catalyst in the oxidation reaction of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) in the presence of H 2 O 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Cation-Dependent Stabilization of Electrogenerated Naphthalene Diimide Dianions in Porous Polymer Thin Films and Their Application to Electrical Energy Storage

Porous polymer networks (PPNs) are attractive materials for capacitive energy storage because they offer high surface areas for increased double-layer capacitance, open structures for rapid ion transport, and redox-active moieties that enable faradaic (pseudocapacitive) energy storage. Here we demonstrate a new attractive feature of PPNs—the ability of their reduced forms (radical anions and dianions) to interact with small radii cations through synergistic interactions arising from densely packed redox-active groups, only when prepared as thin films. When naphthalene diimides (NDIs) are incorporated into PPN films, the carbonyl groups of adjacent, electrochemically generated, NDI radical anions and dianions bind strongly to K+, Li+, and Mg2+, shifting the formal potentials of NDI’s second reduction by 120 and 460 mV for K+ and Li+-based electrolytes, respectively. In the case of Mg2+, NDI’s two redox waves coalesce into a single two-electron process with shifts of 240 and 710 mV, for the first and second reductions, respectively, increasing the energy density by over 20 % without changing the polymer backbone. In contrast, the formal reduction potentials of NDI derivatives in solution are identical for each electrolyte, and this effect has not been reported for NDI previously. This study illustrates the profound influence of the solid-state structure of a polymer on its electrochemical response, which does not simply reflect the solution-phase redox behavior of its monomers.

36 MATERIALS SCIENCE↗