Zeolite effect on the mechanical properties of the polyolefins

Poliolefini so vse vrste polimerov, proizvedeni iz preprostega olefina, monomera, imenovanega tudi alken. Primer poliolefina sta polietilen in polipropilen, ki sta proizvedena s polimerizacijo etilena in propilena. Oba imata dobre mehanske lastnosti za širšo komercialno uporabo. Zeoliti so mikroporozni, kristalinični aluminosilikati, ki se najpogosteje uporabljajo kot adsorbenti in katalizatorji, v industriji pralnih praškov pa nadomeščajo fosfate. Zanimiva so novejša področja uporabe zeolitov, ki so povezana z zmanjšanjem porabe energije in še ne tako raziskano področje, to je dodatek zeolita k poliolefinom in vpliv na njihove mehanske lastnosti. Naš namen je bil raziskati vpliv dodatka različnih koncentracij zeolita v HD (visoke gostote, angl. high density) polietilenu in polipropilenu na njune mehanske lastnosti in jih izboljšati. Diplomska naloga obsega dodatek 1 %, 2 %, ter 3 % zeolita, izvedli pa smo natezni poiskus, izmerili smo število MFI (melt flow index) oziroma talilni indeks in skrčke posameznega materiala. Natezni poiskus smo izvedli na trgalnem stroju. Rezultati kažejo, da je optimalni dodatek bližje 1% dodatka zeolita, kot pa 3%. Izmerili smo talilni indeks, ki se pri nobenem materialu ni drastično spremenil. Preizkus za skrčke materiala je pokazal malenkost manjše krčenje materiala pri polipropilenu, in sicer z večanjem dodatka zeolita se zmanjšuje tudi procent krčenja. Ker je to področje še neraziskano in relativno novo, nimamo literature, na katero bi se lahko oprli in primerjali rezultate. Ugotovili smo, da dodatek zeolita ni izboljšal mehanskih lastnosti polietilena in polipropilena kot smo predvidevali, optimalni dodatek pa je najbližje 1% dodatka zeolita. Iz rezultatov sklepamo tudi, da ni prišlo do poslabšanja lastnosti polietilena in polipropilena, kar je pomembno, saj lahko dodamo tudi do 3% zeolita in se pri tem bistveno ne spremenijo lastnosti materiala.A polyolefin is any of a class of polymers produced from a simple olefin, a monomer also called an alkene. Examples of polyolefins include polyethylene and polypropylene, which are produced by polymerising ethylene and propylene, respectively. Both have good mechanical properties for wider commercial use. Zeolites are microporous, crystalline aluminosilicates, which are most commonly used as adsorbents and catalysts, and as a replacement for phosphates in the laundry detergent industry. Of interest are the newer fields of zeolite use, which are associated with a reduction in energy consumption, and a not yet fully researched area – the addition of zeolite to polyolefins and the impact on their mechanical properties. Our aim was to study the impact of the addition of various zeolite concentrations to HD (High Density) polyethylene and polypropylene and their resulting mechanical properties, and to improve them. This diploma thesis covers the addition of 1%, 2% and 3% of zeolite. We also carried out a tensile test and measured the Melt Flow Index (MFI) and each material’s shrinkage. We performed the tensile test using a tensile-testing machine. The results show that the optimum addition of zeolite is closer to 1% than to 3%. We measured the MFI, which did not drastically change in any of the materials. The material shrinkage test showed a slightly lower shrinkage in the case of polypropylene, i.e. adding more zeolite lowers the percentage of shrinkage. As this field is still unexplored and relatively new, there is no literature that we could use to compare our results. We established that the addition of zeolite did not improve the mechanical properties of polyethylene and polypropylene as we had expected, and that the optimum addition of zeolite is closest to 1%. Based on the results, we conclude that no deterioration of the properties of polyethylene and polypropylene occurred, which is important, because it means that up to 3% of zeolite can be added without substantially changing the properties of the material