Synthesis of Nanosized Polymer Particles in Nonaqueous Emulsion

2013 ◽  
Vol 1546 ◽  
Author(s):  
Robert Dorresteijn ◽  
Robert Haschick ◽  
Kevin Müller ◽  
Markus Klapper ◽  
Klaus Müllen
Keyword(s):  
Ring Opening ◽  
Continuous Phase ◽  
Size Distributions ◽  
Aqueous Emulsion ◽  
Long Term Stability ◽  
Dispersed Particles ◽  
One Step ◽  
Moisture Sensitive ◽  
The One

ABSTRACTIn nonaqueous emulsion, moisture-sensitive polymerizations are performed in order to generate nanoparticles, which are not accessible by common aqueous emulsion polymerization. A nonaqueous emulsion, consisting of two immiscible aprotic organic solvents, is stabilized by amphiphilic block copolymers, such as PIb-PEO or PIb-PMMA copolymer, and lead to formation of nanosized dispersed droplets. They act as dispersed “nanoreactors” for the one-step synthesis of poly(urethane) nanoparticles in a polyadditon reaction as well as poly(L-lactide) nanoparticles through ring-opening polymerization, catalyzed by a moisture-sensitive catalyst. The well-dispersed particles possess average diameters below 100 nm and have narrow size distributions owing to the long-term stability of the dispersed droplets in the continuous phase.

scholarly journals Efficient Cryopreservation of Populus tremula by In Vitro-Grown Axillary Buds and Genetic Stability of Recovered Plants

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 77
Author(s):  
Elena O. Vidyagina ◽  
Nikolay N. Kharchenko ◽  
Konstantin A. Shestibratov
Keyword(s):  
Survival Rate ◽  
Axillary Buds ◽  
Long Term Storage ◽  
Average Survival ◽  
Transgenic Lines ◽  
Ssr Loci ◽  
One Step ◽  
The One

Axillary buds of in vitro microshoots were successfully frozen at –196 °C by the one-step freezing method using the protective vitrification solution 2 (PVS2). Microshoots were taken from 11 transgenic lines and three wild type lines. Influence of different explant pretreatments were analyzed from the point of their influence towards recovery after cryopreservation. It was found out that the use of axillary buds as explants after removal of the apical one increases recovery on average by 8%. The cultivation on growth medium of higher density insignificantly raises the regenerants survival rate. Pretreatment of the osmotic fluid (OF) shows the greatest influence on the survival rate. It leads to the increase in survival rate by 20%. The cryopreservation technology providing regenerants average survival rate of 83% was developed. It was based on the experimental results obtained with explant pretreatment. Incubation time in liquid nitrogen did not affect the explants survival rate after thawing. After six months cryostorage of samples their genetic variability was analyzed. Six variable simple sequence repeat (SSR) loci were used to analyze genotype variability after the freezing-thawing procedure. The microsatellite analysis showed the genetic status identity of plants after cryopreservation and of the original genotypes. The presence of the recombinant gene in the transgenic lines after cryostorage were confirmed so as the interclonal variation in the growth rate under greenhouse conditions. The developed technique is recommended for long-term storage of various breeding and genetically modified lines of aspen plants, as it provides a high percentage of explants survival with no changes in genotype.

scholarly journals Electret Filters—From the Influence of Discharging Methods to Optimization Potential

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 65
Author(s):  
Maximilian Kerner ◽  
Kilian Schmidt ◽  
Stefan Schumacher ◽  
Christof Asbach ◽  
Sergiy Antonyuk
Keyword(s):  
Fine Particles ◽  
Operating Time ◽  
Filtration Efficiency ◽  
Long Term Stability ◽  
Aerosol Filtration ◽  
Charge Decay ◽  
The One ◽  
Testing Standards ◽  
Discharge Efficiency

Electret filters are electrostatically charged nonwovens which are commonly used in aerosol filtration to remove fine particles from gases. It is known that the charge and thus also the filtration efficiency can degrade over time. Thus, many testing standards require to remove the charge by treatment with liquid isopropanol (IPA) or IPA-saturated air. However, the parameters influencing this discharge have not been completely clarified yet. The aim of this work was, on the one hand, to experimentally investigate the influence of the IPA treatment on different electret filters and, on the other hand, to show the optimization potential of electret filters with respect to efficiency and long-term stability by numerical simulations. The experiments revealed that the air permeability is a central influencing parameter. Small pores lead to a reduced discharge efficiency using liquid IPA, while both treatment methods are suitable for larger pores. The simulations showed that a homogeneous charge distribution within the filter depth is advantageous for the initial performance. In contrast, charge penetrating deeper in the filter medium delays the charge decay and thus increases the operating time, with the trade-off of a lower initial performance.

scholarly journals One-step synthesis of carbon-supported electrocatalysts

2020 ◽  
Vol 11 ◽  
pp. 1419-1431
Author(s):  
Sebastian Tigges ◽  
Nicolas Wöhrl ◽  
Ivan Radev ◽  
Ulrich Hagemann ◽  
Markus Heidelmann ◽  
...  
Keyword(s):  
Hybrid Material ◽  
Chemical Vapor ◽  
Narrow Particle Size Distribution ◽  
Long Term Stability ◽  
Operational Lifetime ◽  
Metal Acetylacetonate ◽  
One Step ◽  
Supported Electrocatalysts ◽  
Platinum Loading

Cost-efficiency, durability, and reliability of catalysts, as well as their operational lifetime, are the main challenges in chemical energy conversion. Here, we present a novel, one-step approach for the synthesis of Pt/C hybrid material by plasma-enhanced chemical vapor deposition (PE-CVD). The platinum loading, degree of oxidation, and the very narrow particle size distribution are precisely adjusted in the Pt/C hybrid material due to the simultaneous deposition of platinum and carbon during the process. The as-synthesized Pt/C hybrid materials are promising electrocatalysts for use in fuel cell applications as they show significantly improved electrochemical long-term stability compared to the industrial standard HiSPEC 4000. The PE-CVD process is furthermore expected to be extendable to the general deposition of metal-containing carbon materials from other commercially available metal acetylacetonate precursors.

Bread-inspired foaming strategy to fabricate a wine lees-based porous carbon framework for high specific energy supercapacitors

2021 ◽  
Vol 5 (19) ◽  
pp. 4965-4972
Author(s):  
Hui Peng ◽  
Yipu Xu ◽  
Yaping Jiang ◽  
Xin Wang ◽  
Rui Zhao ◽  
...  
Keyword(s):  
Energy Density ◽  
Porous Carbon ◽  
Fermentation Process ◽  
High Energy ◽  
High Energy Density ◽  
Long Term Stability ◽  
Carbon Framework ◽  
One Step ◽  
High Specific Energy

Inspired by the fermentation process of bread, a novel wine lees-based porous carbon framework (WLCF) having high energy density and excellent long-term stability is prepared via one-step sodium bicarbonate foaming and activation strategy.

One-step solid-phase boronation to fabricate self-supported porous FeNiB/FeNi foam for efficient electrocatalytic oxygen evolution and overall water splitting

2019 ◽  
Vol 7 (33) ◽  
pp. 19554-19564 ◽  
Author(s):  
Hefeng Yuan ◽  
Shumin Wang ◽  
Xundi Gu ◽  
Bin Tang ◽  
Jinping Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Alkaline Medium ◽  
Solid Phase ◽  
Core Shell ◽  
Environment Friendly ◽  
Long Term Stability ◽  
One Step

A 3D core–shell-type FeNi@FeNiB electrocatalyst fabricated by environment-friendly solid-phase boronation exhibits remarkable catalytic activity and long-term stability for the OER in alkaline medium.

Nitrogen-doped graphene/carbon nanotube/Co3O4 hybrids: one-step synthesis and superior electrocatalytic activity for the oxygen reduction reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (115) ◽  
pp. 94615-94622 ◽  
Author(s):  
Hengyi Lu ◽  
Yunpeng Huang ◽  
Jiajie Yan ◽  
Wei Fan ◽  
Tianxi Liu
Keyword(s):  
Carbon Nanotube ◽  
Reduction Reaction ◽  
Nitrogen Doped ◽  
Long Term Stability ◽  
Crossover Effects ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
One Step ◽  
Orr Activity

N-rGO/CNTs/Co3O4 hybrids were prepared through a simple one-step hydrothermal method, and exhibited comparable electrocatalytic ORR activity to Pt/C catalysts, excellent tolerance to methanol crossover effects, and even better long-term stability.

One-Step Surgical Correction of Transverse and Anteroposterior Maxillary Deficiencies Using Wire Fixation. A New Approach and Long-Term Stability

2017 ◽  
Vol 75 (7) ◽  
pp. 1498-1513
Author(s):  
Max Domingues Pereira ◽  
Vivian Farfel ◽  
Gabriela Pereira Ribeiro Prado ◽  
Lydia Masako Ferreira
Keyword(s):  
Surgical Correction ◽  
New Approach ◽  
Term Stability ◽  
Long Term Stability ◽  
Wire Fixation ◽  
One Step
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