تهيه كامپوزيت لاستيك طبيعي (NR) هادي الكتريسيته حاوي نانو ذرات مس و بررسي مقاومت ازوني آن

چكيده انگليسي :

Preparation of Electrical Conductive Natural Rubber Copper Nanoparticle Composites and Investigation of their Ozone Resistance Hadi Najafi h najafi@ce iut ac ir Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Rouhollah Bagheri bagheri@cc iut ac ir AbstractNowadays conductive polymer composites have many applications such as electronic components polymer anodes cablecoverage and etc Compared to metals conductive rubber composites have some advantages such as low density ease ofshaping flexibility wide range of electrical conductivity and corrosion resistance These composites have special applicationslike flexible solar cell biosensors polymer anodes and etc conductive carbon black and metallic particles are commonly usedas Conductive fillers Various rubbers such as NR NBR EPDM and silicone rubber are used for conductive composites Among rubbers NR has been atteracted a lot of attention due to good processability low prices availability and highest elasticproperties However inspite of its high electrical resistance there are some applications that repair electrical conductivity ofNR In this study copper nanoparticles have been used as conductive fillers to increase the conductivity in natural rubber Inorder to increase the compability between Copper particle and natural rubber nanoparticles surfaces were modified withstearic acid and then applied into natural rubber Incorporation of Copper particles into natural rubber was carried out in twoways melt mixing and solvent melt mixing method Vulcanisation of the compounded NR was carried out under the sameconditions The samples containing various amount of nanoparticles were cured with two different curing systems conventional and efficient Electrical resistance of the prepared samples was measured using a four electrode method Threshold percolation and microstructure of samples were analyzed using scanning electron microscopy Mechanicalproperties crosslinking density and ozone resistance of specimens respectively were measured by tensometer swelling andozone resistance tests according to ASTM standard method The results of this study show that the addition 0 5 phr coppernanoparticles there is no significant change in the electrical conductivity The higher value of copper nanoparticles in naturalrubber increases the electrical conductivity In 1 phr copper nanoparticles the threshold percolation occurs and electricalconductivity reaches its highest value But always The electrical conductivity increasing with increasing the copper particlesamount will not happen simultaneously Between copper particles and sulfur always a chemical reaction happens at curingtemperatures Which leads to the production of copper sulfide In addition the formation of copper sulfide particles have resultsin electrical conductivity reduction compared to original copper particles in other hand By taking out the sulfur affectnegatively on crosslinking density of polymer networks and reduce the number of crosslinking per unit volume also Reducingthe amount of crosslinking density electrical conductivity also drops This process normally occurs in both sulfur curingsystems efficient and conventional vulcanization Microscopic images of samples were taken for different percentages and wasdetermined by the method of solvent melt separation is more desirable to achieve maximum dispersion and distribution Similarly samples with different percentages of the composition of the particles were chosen to test the elasticity and hardnessmeasurement Samples of their electrical properties were favorable for ozone resistance test were selected The results of thesetests showed that the presence of copper nanoparticles in natural rubber as a barrier against the penetration and growth ofcracks caused by the ozone destruction Ozonide sample were taken from the ATR IR test The results show that the reactionbetween ozone and unsaturated bonds of polyme

نجفي، هادي

تهيه كامپوزيت لاستيك طبيعي (NR) هادي الكتريسيته حاوي نانو ذرات مس و بررسي مقاومت ازوني آن