Demonstracija lezenja polimernih materialov z uporabo preproste naprave

Skalar, Tomaž (author), Slemenik Perše, Lidija (mentor)

Lastnosti polimernih materialov se pri konstantni obremenitvi spreminjajo s časom. Pri konstantni napetosti se deformacija materiala s časom povečuje. Proces povečevanja deformacije s časom pri konstantni napetosti se imenuje lezenje, materialno lastnost materiala, ki iz tega izhaja, pa imenujemo voljnost. V sklopu diplomske naloge smo izdelali preprosto napravo za demonstracijo lezenja različnih polimernih materialov. Naprava omogoča merjenje pri konstantni temperaturi in pri različnih napetostih. V sklopu diplomske naloge smo izmerili pet različnih materialov: 2 gumi z različno trdoto, polivinilklorid (PVC), polietilen nizke gostote (LDPE) in termoplastični poliuretan (TPU). Teste smo izvajali pri časih od 250 do 900 sekund, lastnosti gume z višjo trdoto in polivinilklorida pa smo izmerili tudi v časovnem območju 45000 sekund. Rezultate dobljene s pomočjo preproste naprave, smo primerjali z rezultati, dobljenimi s pomočjo komercialne naprave. Primerjava meritev je pokazala, da se izdelana naprava lahko uporablja za oceno časovno odvisnih lastnosti polimernih materialov, vendar pa meritve na preprosti napravi podcenjujejo voljnost v povprečju za 20,2 %.

• Language: Slovenian
• Keywords: lezenje, voljnost, viskoelastičnost, polimeri, časovno odvisne lastnosti
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Publisher: [T. Skalar]
• Year: 2018
• PID: 20.500.12556/RUL-102558
• UDC: 678.7:539.3(043.2)
• COBISS.SI-ID: 16296219
• Publication date in RUL: 02.09.2018

Secondary language

• Language: English
• Title: Demonstration of the creep of polymeric materials using simple device

Abstract

The properties of polymeric materials at constant load change with time. At constant stress, material deformation increases with time. The process of increasing the deformation with time at constant stress is called creep, while the material property, which results from this behavior, is called creep compliance. Within the thesis, we composed a simple device for demonstrating the creep behavior of various polymer materials. The device allows measurements at constant temperature and various stress levels. Within the thesis, we measured five materials: two rubbers with different hardness, polyvinyl chloride (PVC), low density polyethylene (LDPE) and thermoplastic polyurethane (TPU). The tests were carried out on a time scale from 250 to 900 seconds. The properties of rubber with higher hardness and polyvinyl chloride were measured in the time range of 45000 seconds. The results obtained with simple device were compared with the results obtained on a sophisticated commercial device. The comparison of the measurements has shown that the simple device can be used to estimate the time-dependent properties of polymeric materials; however, the measurements on this device underestimate the creep compliance on average by 20.2 %.

• Keywords: creep, creep compliance, viscoelasticity, polymers, time-dependent properties