Avancerad sökning

Hittade 4 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Towards alkali-stable polymers and hydroxide exchange membranes functionalized with alicyclic quaternary ammonium cations

   Författare :Thanh Huong Pham; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hydroxide exchange membrane; fuel cell; alicyclic quaternary ammonium; alkali-stable; high hydroxide conductivity; structure-property relationship;

   Sammanfattning : In the current work, cationic polymers functionalized with N-alicyclic quaternary ammonium (QA) cations were synthesized and characterized as potential hydroxide exchange membranes (HEMs) for application in fuel cells. Three different polymers, namely poly(arylene ether sulfone), spiro-ionene and poly(arylene alkylene), were explored as polymer backbones for the HEMs. LÄS MER

3. 2. Polyhydroxyalkylations for alkali-stable cationic polymers as hydroxide exchange membranes

   Författare :Dong Pan; Centrum för analys och syntes; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; quaternary ammoniums; aromatic polymers; chemical resistance; ion conductivity;

   Sammanfattning : To alleviate worldwide dependence on fossil fuels for energy production and considerably reduce CO2 emissions, green energy sources and sustainable energy solutions are in high demand. Fuel cells are environmental-friendly electrochemical devices which may use clean fuels, e.g., green hydrogen gas, to generate electricity. LÄS MER

4. 3. Studies on the chemistry of delignification in alkaline media

   Författare :Otto Lindeberg; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Several questions concerning the structure of lignins in pulp (residual lignins) have not been resolved. It is not known whetherit is composed of lignin units originally present in the lignin and stable to the pulping conditions, or ifit contains structures formed by stabilization (side-reactions) of initially labile structures, or ifthere are stable bonds between the carbohydrates and the lignin, initially present and/or formed during the cook, or if4. LÄS MER

5. 4. Development and improvement of methods for characterization of HPLC stationary phases

   Författare :Torgny Undin; Torgny Fornstedt; Jörgen Samuelsson; Anders Törncrona; Johan Ekeroth; Douglas Westerlund; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Adsorption isotherms; Elution by characteristic points; Inflection points; Single component adsorption; Elution by characteristic points method; Slope data; ECP-slope method; Adsorption; Adsorption energy distribution; Adsorption isotherms; AED; Characterization of adsorption processes; Chromatographic analysis; Chromatography; Hydrophobic-subtraction method HSM ; Hydrophobicity; Linear methods; Linear Models; Liquid chromatography; metoprolol; Non-linear methods; Nonlinear methods; phenol; priority journal; propranolol; Retention mechanism; reversed phase liquid chromatography; Solvation; Subtraction method; Thermodynamics; Chemistry with specialization in Surface Biotechnology; Kemi med inriktning mot ytbioteknik;

   Sammanfattning : High Performance Liquid Chromatography (HPLC) is a widely used tech-nique both for detecting and purifying substances in academy and in the industry. In order to facilitate the use of, and knowledge in HPLC, character-ization of stationary phases is of utmost importance. LÄS MER