Vpliv celuloznih vlaken na mehanske lastnosti 3D-tiskanega termoplastičnega poliuretana : diplomsko delo

Pavlinič, Neža (author), Sever Škapin, Andrijana (mentor), Vaupot, Jaka (comentor), Trebše, Polonca (reviewer)

Uvod: Aditivna tehnologija omogoča hitro in cenovno ugodno izdelavo prototipov in končnih izdelkov. Ključne prednosti te tehnologije so krajši razvojni čas, enostavno preverjanje idej, zmanjšanje odpadnega materiala ter možnost izdelave kompleksnih struktur. Uporablja se v številnih panogah, med drugim tudi v zdravstvu in rehabilitaciji. Kljub številnim prednostim ima tehnologija nekatere omejitve, kot so omejene dimenzije končnih izdelkov, nižja produktivnost pri serijski proizvodnji ter negotovost mehanskih lastnosti. Izbira primernih materialov še vedno predstavlja izziv. Najpogosteje uporabljeni materiali so polimlečna kislina (PLA), akrilonitril-butadien-stiren (ABS) in termoplastični poliuretan (TPU). Vse pogosteje se tem materialom dodajajo ojačitve za izboljšanje njihovih mehanskih lastnosti. V raziskavi smo preučevali biokompozit, katerega osnova je TPU in je ojačan s celuloznimi vlakni. Namen: Namen diplomskega dela je analizirati mehanske lastnosti 3D-tiskanega TPU biokompozita z različnimi masnimi deleži celuloznih vlaken (10 mas. %, 15 mas. % in 20 mas. %). Rezultate smo primerjali s TPU kompozitom, ojačanim z ogljikovimi vlakni, ter ocenili njihov potencial za uporabo v ortotiki in protetiki. Metode dela: Pripravili smo filamente iz čistega TPU in mešanic TPU s celuloznimi vlakni ter nato s 3D-tiskalnikom natisnili preizkušance. Opravili smo meritve trdote po Shoru A in D ter izvedli natezni test za določitev modula elastičnosti, natezne trdnosti in raztezka pri pretrgu. Rezultati: Z dodajanjem celuloznih vlaken se trdota povečuje. Največja izmerjena trdota je bila pri vzorcu TPU + 20 mas. % celuloznih vlaken (Shore A = 87). Modul elastičnosti se je pri tem vzorcu v primerjavi s čistim TPU povečal s 30 MPa na 108 MPa, medtem ko sta se natezna trdnost (z 21 MPa na 11 MPa) in raztezek pri pretrgu zmanjšala (s 475 % na 70 %). Razprava in zaključek: Glede na dobljene rezultate smo ugotovili, da vsebnost celuloznih vlaken vpliva na mehanske lastnosti TPU. Celulozna vlakna učinkovito povečujejo trdoto in togost materiala, hkrati pa zmanjšujejo njegovo elastičnost in duktilnost, kar vodi k večji krhkosti biokompozita. TPU z dodatkom celuloznih vlaken ima potencial za izdelavo personaliziranih ortotičnih in protetičnih pripomočkov, pri čemer so ključne nizka masa, biokompatibilnost in prilagodljivost. Za nadaljnje izboljšanje in prilagoditve je priporočljivo raziskati vpliv mehanske obremenitve pri realnih pogojih uporabe.

• Language: Slovenian
• Keywords: diplomska dela, ortotika in protetika, aditivna tehnologija, termoplastičen poliuretan, biokompoziti, celulozna vlakna
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: ZF - Faculty of Health Sciences
• Place of publishing: Ljubljana
• Publisher: [N. Pavlinič]
• Year: 2025
• Number of pages: 37 str., [1] str. pril.
• PID: 20.500.12556/RUL-174497
• UDC: 617.3
• COBISS.SI-ID: 251608835
• Publication date in RUL: 03.10.2025

Secondary language

• Language: English
• Title: The effect of cellulose fibers on the mechanical properties of 3d-printed thermoplastic polyurethane : diploma work

Abstract

Introduction: Additive technology offers fast and affordable production of prototypes and final products. The main advantages are shorter development times, easy testing of ideas, less waste, and the ability to make complex structures. It is used in many industries, including healthcare and rehabilitation. Despite its many advantages, technology has some limitations, such as limited dimensions of final products, lower productivity in mass production, and uncertain mechanical properties. The challenge still exists in selecting suitable materials. The most frequently used materials are polylactic acid (PLA), acrylonitrile-butadiene-styrene (ABS), and thermoplastic polyurethane (TPU). Reinforcing materials are increasingly used to improve the mechanical properties of these materials. In this study, we have analyzed a TPU-based biocomposite reinforced with cellulose fibers. Purpose: The purpose of this thesis is to analyze the mechanical properties of a 3D-printed TPU biocomposite with different weight percentages of cellulose fibers (10 wt. %, 15 wt. %, and 20 wt. %). The results were compared with a carbon fiber-reinforced TPU composite and assessed for their potential use in orthotics and prosthetics. Methods: We prepared filaments from pure TPU and TPU mixtures with cellulose fibers, then printed the test specimens with a 3D printer. Measurements of Shore A and D hardness were made, and a tensile test was done to define the Young's modulus, tensile strength, and rupture elongation. Results: Adding cellulose fibers causes increases in hardness. The highest measured was for the TPU + 20 wt. % cellulose fibers (Shore A = 87). The Young's modulus of this sample increased from 30 MPa to 108 MPa compared to pure TPU, while the tensile strength (from 21 MPa to 11 MPa) and rupture elongation (from 475 % to 70 %) decreased. Discussion and conclusion: Based on the results we concluded that the content of cellulose fibers affects the mechanical properties of TPU. Cellulose fibers effectively increase the hardness and stiffness of the material, while reducing its elasticity and ductility, which leads to greater brittleness of the biocomposite. TPU with cellulose fibers has potential for the design of personalized orthoses and prostheses, where it is important to have low weight, biocompatibility and flexibility. Further investigation of the impact of mechanical stress in real use conditions is recommended for further improvement and adaptation.

• Keywords: diploma theses, orthotics and prosthetics, additive technology, thermoplastic polyurethan, biocomposites, cellulose fibers