Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles

Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles

Bibliographic Details
Main Author: Zhai, Chunhao
Language:English
Published: University of Akron / OhioLINK 2016
Subjects:
Polymers
Aerogel
Nanoparticle filtration
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=akron1464284202
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-akron14642842022021-08-03T06:36:52Z Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles Zhai, Chunhao Polymers Aerogel Nanoparticle filtration Airborne particles are considered extremely hazardous to human health. The hazard level of these particles have an inverse relationship with the size. PM2.5 particles, particulate matter with diameter less than 2.5 µm, can get into human breathing passages to cause general diseases like cough, while even smaller particles with diameter less than 1 µm may go inside the air sacs which may increase the risk of lung cancer. Removal of airborne nanoparticles has become an urgent task in recent years. In first part of this study, the feasibility of using monolithic polyimide aerogels as filter media for removal of airborne nanoparticles in air flow was investigated. Polyimide gels were synthesized from chemical reactions between pyromellitic dianhydride (PMDA), 2,2'-dimethylbenzidine (DMBZ), and 1, 3, 5-triaminophenoxylbenzene (TAB) dissolved in a good solvent. The gels were dried via supercritical drying in CO2 to obtain the aerogels. The porosity of polyimide aerogels was controlled by changing the initial concentration of solids in the solutions from 2.5 wt% to 10 wt%. The resulting aerogels show high porosity(91%-98%), high surface area (473 m2/g-817 m2/g), and low bulk density (0.025 g/cm3-0.12 g/cm3). High values of nanoparticle filtration efficiency (>99.95%) was obtained for those monoliths with high bulk density (>0.05 g/cm3). The measurements showed that air permeability of these aerogels were of the order of 10-10 m2. Carbon dioxide and nitrogen adsorption isotherms were used to determine the fraction of micropores, mesopores, and macropores in total pore volume of these specimens. A strong proportional relationship between the fraction of macropores and the permeability was observed which indicates that the macropores handled air permeability in these aerogel materials, while the mesopores provided high efficiency in nanoparticle filtration. In second part of this study, polyimide aerogel microparticles were produced by conducting sol-gel reactions in an oil-in-oil emulsion system. This emulsion system was created by dispersing in cyclohexane the droplets of polyimide solutions prepared in dimethylformamide. The resultant PI aerogel microparticles showed mean diameter of 40 µm and surface area of 512 m2/g. 2016-10-06 English text University of Akron / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=akron1464284202 http://rave.ohiolink.edu/etdc/view?acc_num=akron1464284202 unrestricted This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center.
collection NDLTD
language English
sources NDLTD
topic Polymers
Aerogel
Nanoparticle filtration
spellingShingle Polymers
Aerogel
Nanoparticle filtration
Zhai, Chunhao
Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles
author Zhai, Chunhao
author_facet Zhai, Chunhao
author_sort Zhai, Chunhao
title Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles
title_short Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles
title_full Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles
title_fullStr Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles
title_full_unstemmed Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles
title_sort polyimide aerogels and their applications in removal of airborne nanoparticles
publisher University of Akron / OhioLINK
publishDate 2016
url http://rave.ohiolink.edu/etdc/view?acc_num=akron1464284202
work_keys_str_mv AT zhaichunhao polyimideaerogelsandtheirapplicationsinremovalofairbornenanoparticles
_version_ 1719439999546425344

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