Utjecaj vremena tretiranja lanenih vlakana morskom vodom na mehanička svojstva kompozita s epoksidnom matricom

master's thesis

• Title (english): Effect of duration of seawater treatment of flax fibers on mechanical properties of epoxy based composites
• Author: Janko Zechner
• Mentor: Tatjana Haramina (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Zahvaljujući povećanoj osviještenosti o nužnosti zaštite okoliša, sve više se koriste lignocelulozna vlakna iz obnovljivih izvora kao zamjena za tradicionalno korištena sintetska vlakna. Sa ciljem ostvarivanja bolje povezanosti vlakana i matrice, vlakna se mogu tretirati lužinama. Morska voda ima blago lužnati karakter, ekološki je prihvativ i široko dostupan medij. Rad je podijeljen na teorijski i eksperimentalni dio. U teorijskom dijelu dân je uvod u kompozitne materijale, biološka, odnosno vlakna iz obnovljivih izvora kao i pregled njihove strukture i svojstava. Pronađena su srodna istraživanja u kojima se radi o biljnim vlaknima i njihovoj alkalnoj obradi koja, u pravilu, poboljšava svojstva konačnog proizvoda – kompozitnoga materijala ojačanog biljnim vlaknima s polimernom matricom. U radu je provedeno ispitivanje i analiza mehaničkih svojstava kompozita s epoksidnom matricom ojačanom lanenim vlaknima prethodno tretiranima morskom vodom 4, 10, 21 i 30 dana. Provedena su ispitivanja pri savojnom i rasteznom opterećenju, te ispitivanje prividne međuslojne smične čvrstoće. Rezultati su uspoređeni s referentnom pločom izrađenom s netretiranim vlaknima, kao i sa zahtjevima propisanim od Hrvatskog registra brodova (HRB) sa ciljem eventualne primjene u maloj brodogradnji. Nakon provedenog istraživanja, utvrđeno je da su mehanička svojstva kompozita s tretiranim vlaknima lošija od referentne ploče.

Abstract (english)

Due to the increased recent environmental awareness, lignocellulosic fibres from renewable sources are used more and more often as a substitute to the traditionally used synthetic fibres. One of the possible options to increase the adhesive connection between the fibres and the matrix of composite material is to apply the alkaline treatment to the fibres. Seawater has a mildly alkaline character; thus, it is an ecologically acceptable and widely available medium suitable for such a purpose. This thesis is divided into a theoretical and experimental parts. The theoretical part consists of the introduction to composite materials as well as biofibres with their respective structure and properties. Similar research papers dealing with the alkaline treatment of plant–based fibres have been reviewed. In the experimental part, the seawater alkaline treatment of flax fibre/epoxy resin composites is described. The composites were subject to the effects of seawater for 4, 10, 21, and 30 days. After that, the analysis of the achieved mechanical properties is provided. The studied mechanical properties were the following: tensile modulus and strength, flexural modulus, and strength, and interlaminar shear strength. The results were compared to the composite with untreated fibre used as a reference as well as the requirements prescribed by the Croatian Ship Registry (CSR). After the study was conducted, it is concluded that the mechanical properties of composites with treated fibres are worse than the ones of the referent composite.

• Keywords: lanena vlakna; kompoziti; alkalna obrada; mala brodogradnja; mehanička svojstva
• Keywords (english): flax fibers; composites; alkaline treatment; marine application; mechanical properties
• Language: croatian
• URN:NBN: urn:nbn:hr:235:649176
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-07-08 07:44:21