توليد نانوكامپوزيت هاي مقاوم در برابر اشتغال و حرارت بر پايه كوپليمراتيلن وينيل استات ﴿EVA)

چكيده انگليسي :

Preparation of Flame Retardant and Thermal Resistant anocomposites based on Ethylene Vinyl acetate copolymer EVA Leila Ahmadkhanbeigi L Khanbeigi@ce iut ac ir 6 5 2009 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Roohollah Baghri supervisor bagheri@cc iut ac ir Mahmood Masoomi supervisor mmasoomi@cc iut ac ir Abstract Flammability of poly ethylene co vinyl acetate EVA low density polyethylene LDPE and their blends represents a great drawback that restricts their applications in wire and cable industry as insulating materials Magnesium hydroxide MDH is a non toxic flame retardant that its high loading level causes mechanical and processing properties of final composite to become deterirate In this study in order to imrove flame retardancy and thermal stability of EVA LDPE MDH composite while keeping its mechanical properties two organo modified montmorillonites OMMT with different surface polarity and basal spacing were used The Samples were prepared via twin screw extruder and with total loading MDH OMMT of 55 and 60 w w Results VKRZHG WKDW LQFUHDVLQJ 0 FRQWHQW IURP WR QRW RQO GLGQ W HQKDQFH IODPH UHWDUGDQF EXW DOVR resulted in about 30 reduction in elongation at break while substituting even 2 of magnesium hydroxide with OMMT significantly improved the thermal stability flame retardancy and tensile strength of the composite As in comparison with OMMT free sample limiting oxygen index LOI increased about 16 and in vertical burning test UL 94V dripping was suppressed furthermore degradation peak in derivative thermogravimetry DTG curve 50 C shifted to higher temperatures and tensile strength increased about 30 Moreover in differential scanning calorimetry DSC test oxidative induction time OIT of OMMT free sample was evaluated about 20 minutes while for the nanocomposites this quantity was more than 140 minutes According to the LOI and UL 94 tests synergistic effect was observed between MDH and OMMT on flame retatdant properties this behaviour could be relared to more char production in the presence of OMMT In addition SEM micrographs showed that nanocomposite based on non polar nanoclay has better distribution than the polar one with higher elongation at break and thermal stability and lower tensile strength and viscosity This behavior could be related to more gallery distance in non polar nanoclay Surprisingly the combination of two organoclays approximately with the same ratio of EVA LDPE brought interesting properties to the nanocomposite Whereas each of organoclays resulted in intercalated structure by combination of them semi intercalated semi exfoliated nanocomposite was obtained with mechanical and thermal properties DQG YLVFRVLW LQ EHWZHHQ LQGLYLGXDO QDQRFRPSRVLWHV KDQJLQJ W SH RI 2007 GLGQ W FKDQJH 2 DQG 8 9 WHVWV UHVXOWV 7KH EHVW IODPH UHWDUGDQF WKHUPDO VWDELOLW DQG PHFKDQLFDO SURSHUWLHV ZDV REWDLQHG LQ VDPSOH with EVA as matrix 53 magnesium hydroxide and 2 polar montmorillonite In addition X ray diffraction analysis showed semi intercalated semi exfoliated structure in the nanocomposite Unexpectedly increasing 2007 WR QRW RQO GLGQ W LQFUHDVH IODPH UHWDUGDQF EXW DOVR UHVXOWHG LQ VLJQLILFDQW GHFUHDVH LQ HORQJDWLRQ DW break this could be related to poorer dispersion of nanolay and lower content of MDH that is the main flame retardant in this samples Substituting 5 and 10 of LDPE with polyethylene polypropylene grafted maleic anhydride PEgMA and PPgMA resulted in significant increase in tensile strength and significant decrese in pdfMachine Is a pdf writer that produces quality PDF files with ease Produce quality PDF files in seconds and preserve the integrity of your original documents Compatible across nearly all Windows platforms if you can print from a windows application you can use pdfMachine Get yours now

احمد خان بيگي، ليلا

توليد نانوكامپوزيت هاي مقاوم در برابر اشتغال و حرارت بر پايه كوپليمراتيلن وينيل استات ﴿EVA)

پلي ﴿اتيلن-كو-وينيل استات﴾ , كندسوزكنندگي , پايداري حرارتي , صنايع كابل سازي , OMMT