Structure-Property Relationships in Polymers for Dielectric Capacitors
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University of Akron / OhioLINK
2014
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ndltd-OhioLink-oai-etd.ohiolink.edu-akron13956823932021-08-03T06:22:50Z Structure-Property Relationships in Polymers for Dielectric Capacitors Gupta, Sahil Polymer Chemistry Polymers Plastics Materials Science Energy Engineering Morphology hydroxyl-functionalization polypropylene sulfonation polystyrene polyether ether ketone poly 4-methyl-1-pentene crystal structure crystallization kinetics rheology H-bonding surface topology dielectric spectroscopy breakdown Effective energy storage is a key challenge of the 21st century that has fueled research in the area of energy storage devices. In this dissertation, structure-property relationships have been evaluated for polymers that might be suitable for storing energy in high-energy density, high-temperature capacitors.Firstly, hydroxyl-modified polypropylenes (PPOH) were synthesized by copolymerization of the propylene and undecenyloxytrimethylsilane monomers. The presence of H-bonding in PPOH copolymers increased their glass-transition temperature. Steric hindrance by the comonomer reduced the PP crystal growth rate and crystal size, resulting in a melting point depression. The comonomer was restricted outside the crystalline domains leaving the α-monoclinic crystal structure of PP unaffected, but increasing the fold-surface free energy. Crystallization was slower for PPOH copolymers than PP, but exhibited a skewed bell curve as a function of hydroxyl concentration. H-bonding persisted even at melt temperatures up to 250°C resulting in a higher elasticity and viscosity for PPOH copolymers.Secondly, sulfonated poly(ether ether ketone) (HSPEEK) was synthesized by sulfonating PEEK with sulfuric acid, and further neutralized with Zn to obtain ZnSPEEK. The thermal and dielectric properties of SPEEK were compared with PEEK. The glass-transition increased and melting point were high enough to enable the use of polymer at 180°C. The incorporation of sulfonic groups in PEEK increased the dielectric constant. HSPEEK had a higher dielectric constant than ZnSPEEK due to higher dipolar mobility, but the dielectric loss was also higher for HSPEEK due to electrode polarization and DC conduction. These results were consistent with our observations from sulfonated polystyrene (HSPS), which was used as a 〉model&lang' polymer.Lastly, commercial poly(4-methyl-1-pentene) (P4MP) was characterized to check its viability as a high-temperature polymer dielectric. Thermal stability up to 200°C, high melting point (> 225°C) and melting onset at 160 - 190°C indicated that P4MP could be used at 180 - 200°C. Thin free-standing films (~10 μm) with controlled crystal structure and surface morphology were prepared using blade coating and their drying dynamics were measured using a custom-designed solvent-casting platform. These films were further stretched uniaxially or biaxially, and their effect on the dielectric properties of P4MP was studied. 2014-05-16 English text University of Akron / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=akron1395682393 http://rave.ohiolink.edu/etdc/view?acc_num=akron1395682393 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Polymer Chemistry Polymers Plastics Materials Science Energy Engineering Morphology hydroxyl-functionalization polypropylene sulfonation polystyrene polyether ether ketone poly 4-methyl-1-pentene crystal structure crystallization kinetics rheology H-bonding surface topology dielectric spectroscopy breakdown |
| spellingShingle |
Polymer Chemistry Polymers Plastics Materials Science Energy Engineering Morphology hydroxyl-functionalization polypropylene sulfonation polystyrene polyether ether ketone poly 4-methyl-1-pentene crystal structure crystallization kinetics rheology H-bonding surface topology dielectric spectroscopy breakdown Gupta, Sahil Structure-Property Relationships in Polymers for Dielectric Capacitors |
| author |
Gupta, Sahil |
| author_facet |
Gupta, Sahil |
| author_sort |
Gupta, Sahil |
| title |
Structure-Property Relationships in Polymers for Dielectric Capacitors |
| title_short |
Structure-Property Relationships in Polymers for Dielectric Capacitors |
| title_full |
Structure-Property Relationships in Polymers for Dielectric Capacitors |
| title_fullStr |
Structure-Property Relationships in Polymers for Dielectric Capacitors |
| title_full_unstemmed |
Structure-Property Relationships in Polymers for Dielectric Capacitors |
| title_sort |
structure-property relationships in polymers for dielectric capacitors |
| publisher |
University of Akron / OhioLINK |
| publishDate |
2014 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=akron1395682393 |
| work_keys_str_mv |
AT guptasahil structurepropertyrelationshipsinpolymersfordielectriccapacitors |
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1719435697043013632 |