Vpliv s srebrom oplaščenih bakrenih lusk na izdelavo in fizikalne lastnosti visokoprevodnih polimernih kompozitov

Gartnar, Peter (author), Slemenik Perše, Lidija (mentor)

Razvoj sodobne tehnologije je vedno hitrejši in dosega meje zmogljivosti obstoječih materialov. Z razvojem se pojavlja nuja po kreaciji novih materialov, ki bi bili sposobni zagotavljati nove in boljše lastnosti. Nove aplikacije je težko izdelati z običajnimi tehnikami in zato postaja vedno bolj zanimivo 3D tiskanje materialov. S pravilno uporabo 3D tiskalnikov in pravimi materiali se odpira možnost za izdelavo najrazličnejših izdelkov. Za izdelavo visokoprevodnih aplikacij se v večji meri uporabljajo kovine, ki pa niso kompatibilne z vsemi 3D tehnikami, zato vedno bolj v ospredje prihajajo visokoprevodni polimerni kompoziti. V le-teh se za polnila uporabljajo kovine ali ogljikovi nanomateriali. Ogljikovi nanomateriali trenutno še ne dosegajo želenih prevodnosti, zato se v večji meri uporabljajo kovinska polnila na osnovi srebra in bakra. V magistrskem delu smo v prvem koraku opravili pregled 3D tehnik tiskanja ter izbiro primernih polimerov in polnil. V teoretičnem delu smo si ogledali različna polnila, ki jih lahko uporabimo za izdelavo visokoprevodnih polimernih kompozitov. Bolj podrobno smo si ogledali izdelavo bakrenih polnil, oplaščenih s srebrom, in njihove prednosti pred ostalimi polnili. V praktičnem delu magistrskega dela smo izdelali visokoprevodni polimerni kompozit. Za izdelavo smo uporabili polietilen nizke gostote (LDPE) kot polimerno matriko in bakrene delce, oplaščene z 10 masnimi % srebra, za polnilo. Pri izdelavi smo uporabili ekstruder, s katerim smo pripravili filamente z različnimi deleži polnila. Med ekstrudiranjem smo spremljali procesne spremenljivke kot so tlak, navor in temperatura, ki dajejo podatek o stopnji in hitrosti mešanja kovinskih delcev polnila v kompozit. V nadaljevanju smo pridobljene materiale analizirali s pomočjo nanoindentacije, termičnih in reoloških testov. Pridobljene fizikalne lastnosti kompozitov smo primerjali in ugotovili, da se spremembe v vedenju kompozitov pojavijo med 10 in 20 % polnila. Pri izdelavi filamentov kompozita se po 20 % polnila začnejo pojavljati napake in luskavost površine. Ocenili smo tudi optimalno količino polnila, ki bi nam ponudila najboljše lastnosti visokoprevodnega polimernega kompozita z dodatkom Cu10Ag. Na osnovi reoloških testov smo tako določili reološki ali geometrijski perkolacijski prag pri 14,8 % vsebnosti polnila, kar nam daje idealno količino polnila v kompozitu in potrjuje opažene spremembe v vedenju kompozita med 10 in 20 % polnjenja.

• Language: Slovenian
• Keywords: Visokoprevodni polimerni kompoziti, izdelava kompozitov, termične lastnosti, nanoindentacija, reologija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-150488
• COBISS.SI-ID: 172467203
• Publication date in RUL: 19.09.2023

Secondary language

• Language: English
• Title: Influence of silver coated copper flakes on the preparation and physical properties of highly conductive polymer composites

Abstract

The pace of development of modern technology is accelerating, reaching the limits of the capacity of existing materials. As development continues, there is a need to create new materials, capable of delivering new and better properties. It is difficult to produce new applications using conventional techniques, which is why 3D printing of materials is becoming more and more interesting. With the correct use of 3D printers and the suitable materials, the possibility of producing a wide variety of products is opening up. Metals are widely used for high-conductivity applications, but they are often not compatible with 3D techniques, therefore high-conductivity polymer composites are becoming increasingly popular. These materials metals or carbon nanomaterials are used as fillers. Since carbon nanomaterials currently do not yet achieve the desired conductivities, metal fillers based on silver and copper are being used more extensively. In the Master thesis, we have first reviewed 3D printing techniques and selected the suitable polymers and fillers. In the theoretical part, we studied different fillers that can be used to produce highly conductive polymer composites. We took a closer look at the manufacture of silver-coated copper fillers and their advantages over other fillers. In the practical part, a highly conductive polymer composite was produced. We used low density polyethylene (LDPE) as the polymer matrix and copper particles, coated with 10% silver, as a filler. The filaments with different ratios of the filler were prepared by using extruder. During the extrusion process, we followed process variables that enabled the control of the manufacturing of the composite. The materials were further analysed by nanoindentation, thermal and rheological tests. The obtained physical properties of the composites were compared and it was found that changes in the behaviour of the composites occur between 10 and 20% of the filler. In the manufacture of composite filaments, defects and surface flaking start to occur after 20% of the filler. We also evaluated the optimum amount of filler that would offer the best properties of a Cu10Ag-added high-conductivity polymer composite. Rheological tests enabled the determination of the rheological or geometric percolation threshold at 14.8% filler content, which gives us the ideal amount of filler in the composite and confirms the observed changes in the behaviour of the composite between 10 and 20% fill.

• Keywords: Highly conductive polymer composites, manufacture of composites, nanoindentation, thermal properties, rheology