Lezenje polifenilsulfona pri veliki strižni napetosti

Bukovnik, Gašper (author), Nagode, Aleš (mentor), Šturm, Roman (co-mentor)

Namen diplomske naloge je bil preveriti linearno področje polimernega materiala polifenilsulfona (PPSU) pri veliki strižni napetosti in na podlagi tega napovedati življenjsko dobo materiala pri nazivni napetosti 8,4 MPa, kateri naj bi bil material izpostavljen. Pri napetosti 0,1 MPa so bile lastnosti materiala že pomerjene in so potrdile linearno področje. Področje linearnosti pri veliki strižni napetosti je bilo preverjeno z opravljenimi meritvami lezenja in kasneje analizo krivulj lezenja. Meritve lezenja so bile izvedene pri več različnih temperaturah in sicer od 90 °C do 210 °C, z dvigom temperature za 10 °C pri vsaki novi meritvi. S pomočjo časovno-temperaturne superpozicije so bile sestavljene sumarne krivulje lezenja pri referenčni temperaturi 90 °C in 190 °C, prav tako pa so bile narejene izohrone krivulje. Rezultati raziskav so pokazali, da omenjeni material pri nazivni napetosti 8,4 MPa ohranja linearno področje do časa 30 let, od koder naprej nastopi trenutna nelinearnost, ki se s časoma prevesi v časovno-odvisno nelinearnost. Napoved življenjske dobe materiala je tako mogoča do 30 let.

• Language: Slovenian
• Keywords: polifenilsulfon, strižno lezenje, linearna teorija viskoelastičnosti, časovno-temperaturna superpozicija, življenjska doba
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-96281
• Publication date in RUL: 28.09.2017

Secondary language

• Language: English
• Title: Creep of polyphenylsulfone at high shear stress

Abstract

The purpose of diploma thesis was to find out linear behaviour of polyphenylsulfone (PPSU) at high shear stress 8,4 MPa and thus predict the lifetime of material. Linearity at lower shear stress 0,1 MPa has already been determined and has confirmed the linearity of material. Determination of linear behaviour at high shear stress has been done with shear creep compliance test and analyzing shear creep curves. Measurements have been done at several different temperatures going from 90 °C to 210 °C and increasing temperature by 10 °C for each new measurement. With a help of time-temperature superposition master and isochronal curves have been made. The results have shown that material has linear behaviour up to 30 years. From there on the effects of current nonlinearity are observed. Current nonlinearity slowly transforms into time-dependent nonlinearity with passing time. The conclusion is that behaviour of polyphenylsulfone can be predicted up to 30 years lifetime.

• Keywords: polyphenylsulfone, shear creep, linear theory of viscoelasticity, time-temperature superposition, lifetime