جداسازي دي اكسيد كربن از متان توسط غشاي پلي يورتاني و نانو كامپوزيت پلي يورتان/سيليكا

چكيده انگليسي :

CO2 CH4 Separation by Polyurethane and Polyurethane Silica Nanocomposite Membranes Mohammad Mehdi Talakesh m talakesh@ce iut ac ir Date of Submission 20 04 2011 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Morteza Sadeghi m sadeghi@cc iut ac irAbstract In this research correlations between gas permeation and structure of polyether based polyurethanemembranes and also effect of silica nanoparticles on the gas permeation properties of them has beeninvestigated A series of polyurethane based on hard segments consisting of hexamethylene diisocyanate HDI and 1 4 butanediol and different soft segments consisting of poly tetramethylene glycol PTMG 2000g mol poly ethylene glycol PEG 2000 g mol and mixed PTMG PEG were synthesized The polymerswere synthesized in mole ratios of 3 2 1 of diisocyanate chain extender polyol by bulk two steppolymerization PU membranes were prepared by thermal phase inversion method Physical properties ofsynthesized polyurethanes were investigated by FT IR XRD and DSC Results obtained by FT IR and DSCindicate that phase separation of hard and soft segments decreased and chain mobility has been restricted resulting in the increase in glass transition temperature of the soft segment by content of the PEG inpolyurethane structure It is due to the more population of ether group in PEG in comparison to PTMG toconnect to N H groups in hard segments via hydrogen bonding The permeability of N2 O2 CH4 and CO2were determined using constant pressure method at the different pressure and temperature The results of gaspermeation experiments represented that by increasing the ether group content in polymer structure permeability of the pure gases decreased and selectivity increased The glassy behaviour was observed withincreasing pressure and the content of ether groups in polymer structure For example at PU100 containing100 wt of PEG in soft segment by increasing pressure permeability of pure gases decrease but theselectivities increase The results indicated that the permeability of CO2 and CH4 in PU0 containing 100 wt of PTMG in soft segment is 132 52 and 16 24 barrer that decrease to 20 26 and 0 64 barrer in PU100 respectively Polyurethane silica nanocomposite membranes were prepared by thermal phase inversionmethod The prepared polyurethane silica membranes were characterized by using FT IR and SEM Theobtained SEM micrographs and FT IR spectras confirmed that the silica nanoparticles distributed in polymermatrix homogenously Gas permeation properties of polyurethane silica nanocomposite membranes withsilica content of 5 10 and 30 wt was studied for pure gases at 10 bar pressure and at 25 C The obtainedresults showed the reduction in permeability of all gases in PU0 and PU75 containing PEG PTMG ratio of 3in soft segment based nanocomposite membranes but the increment in CO2 N2 CO2 CH4 and O2 N2selectivities by increasing the content of silica nanoparticles in them In PU100 based nanocompositemembrane permeability of all gases increased but the selectivity decreased The reduction of selectivity isdue to increasing nano gaps around the silica nanoparticles On the other hand pure polymer was saturatedby ether groups that even the presence of ether groups of the silica nanoparticles no effect on the increasingselectivity and thus the selectivity decreases The permeability of condensable gases in comparison to non condensable ones more increase by increasing the silica content in polymer structure Hence the selectivityof condensable gases in polyurethane considerably decreased In PU100 based nanocomposite membrane permeability of CO2 and N2 was increased from 20 26 and 0 22 barrer to 50 10 and 0 72 barrer respectively by increasing of the silica nanoparticles from 0 to 30 wt Keywords Membrane polyurethane silica nanocomposite gas permeation structureproperty ether group

طلاكش، محمد مهدي

جداسازي دي اكسيد كربن از متان توسط غشاي پلي يورتاني و نانو كامپوزيت پلي يورتان/سيليكا

غشاي چگال , نانو سيليكا , جداسازي گاز