doktorska disertacija
Daša Krapež (Author), Mirko Kariž (Mentor)

Abstract

V disertaciji so predstavljeni vplivi delcev termično modificiranega lesa v lesno-plastičnih kompozitih za 3D tiskanje na lastnosti filamentov in 3D natisnjenih izdelkov ter ugotovitve, kako pogoji uporabe (npr. temperatura, relativna zračna vlažnost) vplivajo na dimenzijsko stabilnost in mehanske ter fizikalne lastnosti 3D natisnjenih delov. Vključena je izdelava lesno-plastičnih kompozitnih filamentov, 3D tiskanje vzorcev iz lesno-plastičnih ekstrudiranih filamentov ter pregled reoloških in mehanskih lastnosti 3D natisnjenih lesno-plastičnih kompozitov. Dodatek termično modificiranega lesa povzroči izboljšanje kakovosti površine (manjša hrapavost, večja hidrofobnost), višji modul akumulacije energije, manjšo gostoto filamenta, nižjo temperaturo steklastega prehoda, višji modul elastičnosti in trdoto. Natezna trdnost se z naraščajočo vsebnostjo lesnih delcev zmanjšuje. Z mikroskopskimi tehnikami smo potrdili, da termična modifikacija lesa izboljša medfazni oprijem med lesnimi delci in polimerom, poroznost filamentov se zmanjša in delci so bolj homogeno razporejeni. Najboljše lastnosti 3D natisnjenih delov so bile izmerjene pri 30 % dodatku termično modificiranega lesa v osnovno matrico polimera. Uporaba mikroceluloze v filamentu izboljša obdanost lesnih delcev s polimerom in s tem tudi mehanske lastnosti 3D tiskanih predmetov. Dodatek lesnih delcev v PLA ustvari higroskopsko aktiven kompozit, ki lahko v spremenljivih klimatskih pogojih povzroči dimenzijske spremembe in s tem spremembo oblike načrtovanih aktuatorjev, zato je tak material primeren za 4D tisk.

Keywords

lesno-plastični kompoziti;filamenti;3D tisk;termično modificiran les;4D tisk;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UL BF - Biotechnical Faculty
Publisher: [D. Krapež]
UDC: 630*862: 004.356.2(043.3)
COBISS: 206750723 Link will open in a new window
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Downloads: 44
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Other data

Secondary language: English
Secondary title: Influence of the addition of wood particles to the polylactic acid polymer on the properties of 3D-printed composites
Secondary abstract: The dissertation presents the effects of thermally modified wood in wood-plastic composites for 3D printing on the properties of filaments and 3D-printed products, as well as the findings on how the conditions of use (e.g. temperature, relative humidity) affect the dimensional stability and mechanical and physical properties of 3D-printed parts. This includes the production of filaments from wood-plastic composites, the 3D printing of samples from extruded wood-plastic filaments and the investigation of the rheological and mechanical properties of 3D-printed wood-plastic composites. The addition of thermally modified wood leads to an improved surface quality (lower roughness, higher hydrophobicity), a higher maximum storage modulus, a lower filament density, a lower glass transition temperature, a higher modulus of elasticity and a higher hardness. The tensile strength decreases with increasing wood particle content. Using microscopic techniques, we have confirmed that thermally modified wood improves the interfacial adhesion between wood particles and the polymer, the porosity is lower, and the particles are more homogeneously distributed. The best properties of 3D-printed products were measured with a 30% addition of thermally modified wood to the base polymer matrix. The mechanical properties of 3D-printed products are improved by incorporating microcellulose into the filament, mainly due to better encapsulation of the wood particles with the polymer. The addition of wood particles to PLA creates a hygroscopically active composite material that can lead to dimensional changes under variable climatic conditions and thus to a change in the shape of the designed actuators, making this material suitable for use in 4D printing.
Secondary keywords: wood-plastic composites;filaments;3D printing;thermally modified wood;4D printing;
Type (COBISS): Doctoral dissertation
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak.
Pages: 1 spletni vir (1 datoteka PDF (IX, 156 f., [6] f. pril.))
ID: 24956254