پيوندزني استايرين بر روي نشاسته اصلاح شده جهت تهيه بيوپلاستيك با روش اختلاط گرم

چكيده انگليسي :

Grafting of styrene on modified starch for preparation of bioplastic by hot mixing method Monireh shekari m shekari@ce iut ac ir Date of Submission Department of Chemical Enginee Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor N Etesami and R BagheriAbstract Because of poor mechanical properties and hydrophilicity of starch for using of this natural polymer asbiocompatible polymer many researchers have investigated to starch composite with different polymers such asstyrene But significant differences between structure of starch and synthetic polymers are factors forincompatibility Therefore many researchers have investigated on chemical modification of starch and styrenestructures and or adding a compatibilizer to the compound for more compatibility In this work graft copolymer ofstarch polystyrene PS g starch by using benzoyl peroxide as thermal initiator was prepared in an internal mixer asreactor In order to increase the percentage of grafting maleic anhydride MA was used as dry compatibilizer byone or two stages mechanism in the same internal mixer To evaluate grafting and homopolymerization percentage extraction analysis carried out in soxhlet apparatusand toluene as solvent for isolating homopolymer part Then acidleaching method with acetic acid and perchloric acid was used for isolating grafting part Grafting andhomopolymerizationpercent and yield werecalculated by gravimetry method The highest percentage of graftedpolymer in one and two steps methods was 36 152 and 57 25 respectively in 10 composition of MA Toconfirm the grafting reaction and kinds of new functional groups Transfer Infrared Spectroscopy FTIR of samplesafter grafting extraction was used that showed new peaks in 1720 cm 1 for C O band of grafted MA in soxhletedsamples and in 1460 1553 and 3058 cm 1 for C H groups and 1600 for C C group of aromatic rings of polystyrene Because of extraction of samples these results are reason for successful substitution of MA s carboxilic groups andgrafting of polystyrene on starch chains To confirm the quality of esterification and grafting reactions ScanningElectronic Microscope SEM was used this analyse before and after of soxhlet extraction showed the covering andgrafting of polystyrene on starch respectively and after alloying of samples with High impact polystyrene HIPS showed the hemogen samples and no phase separation was observed To investigate of thermal stability of samples thermal gravimetric analyses TGA was used Their thermal stability of the product were obtained from thetemperature test TGA was used Result indicated that the samples showed two steps thermal degradation The firststep occurred in 320 410 C indicates modificated starchpart degridation that was incresed than native starch and thesecond step occurred in 410 560 C representing the polystyrene degradation To evaluate the process ability ofcompounds the melt flow index was determined and sheats with hot press at 180 C was prepared Above resultsindicated that synthesized samples have prossesability and thermoplasticcharacter In order to increasing MFI ofsamples the moderate amonght of HIPS was added to samples and MFI was measured that shows MFI wasincreased by increasing HIPS highest MFI was 0 33 g min at 10 HIPS composition Also for determination ofhardness physical properties Hardness shore D was used that shows Hardness was decreased by increasing HIPS and for evaluation of Impact strength of samples Impact test was used and results shows increasing in breakageenergy by increasing HIPS highest breakage energy was 0 2 J at 10 HIPS composition Keywords Starch styrene maleic anhydride esterification graft copolymer internal mixer

شكاري، منيره

پيوندزني استايرين بر روي نشاسته اصلاح شده جهت تهيه بيوپلاستيك با روش اختلاط گرم

مالئيك انيدريد , كوپليمر پيوندي , مخلوط كن داخلي