Dvokomponentni benzoksazinski materiali iz bio-obnovljivih virov z zmožnostjo oblikovnega učinka

Malnarič, Iris (author), Ručigaj, Aleš (mentor)

Vse večja poraba fosilnih goriv je privedla do njihove omejene razpoložljivosti ter je povzročila onesnaževanje zraka, globalno segrevanje in ostale okoljske probleme. Številne raziskave so zato vedno bolj usmerjene k iskanju polimerov iz obnovljivih virov, ki lahko nadomestijo polimerne materiale na osnovi fosilnih goriv. Iz naravnih surovin se lahko pridobi tudi bio-osnovane benzoksazine, ki imajo zaradi svoje kemijsko zamrežene strukture dober potencial kot polimeri z oblikovnim učinkom (SMP). Ti v zadnjih dveh desetletjih odpirajo možnosti za nova področja uporabe. Pri eksperimentalnem delu sem sintetizirala benzoksazinski monomer na osnovi difenolne kisline in stearilamina ter na osnovi difenolne kisline in Jeffamina D-2000. Njuno kemijsko strukturo sem potrdila z infrardečo spektroskopijo (IR). Za preučevanje vpliva kopolimera benzoksazina iz bio-obnovljivih virov na oblikovni učinek sem s polimerizacijo z odpiranjem obroča pri visokih temperaturah pripravila benzoksazinski kopolimer v različnih masnih razmerjih. Termične lastnosti zamreženih vzorcev sem določila z diferenčno dinamično kalorimetrijo (DSC), s katero sem pridobila potrebne podatke za nadaljnje preučevanje oblikovnega učinka. Uspešnost zamreževanja sem poleg DSC analize preverila še z IR. Potencialno uporabnost in učinkovitost oblikovnega učinka zamreženih kopolimerov sem preverila s cikličnimi upogibnimi testi. S slednjimi sem oblikovni učinek potrdila in ga ovrednotila z razmerjem zadržane oblike (Rf) in razmerjem obnovljene oblike (Rr). Vzorci so tako dosegli dokaj dobro razmerje zadržane oblike (37–95 %) pri sobni temperaturi in visoko razmerje obnovljene oblike (87–100 %) pri 10 C nad temperaturo steklastega prehoda v 1. ciklu po 30 minutah. Dobro razmerje med učinkovitim oblikovnim učinkom in termičnimi lastnostmi je imel kopolimer z masnim razmerjem 50 : 50, saj se je izkazalo, da vzorci z večjo vsebnostjo stearilamina boljše zadržijo obliko, vzorci z večjo vsebnostjo Jeffamina D-2000 pa jo boljše obnovijo. Prav tako sem ugotovila, da vzorci prenesejo vsaj 4 cikle oblikovnega učinka.

• Language: Slovenian
• Keywords: benzoksazin, bio-obnovljivi viri, termične lastnosti, temperatura steklastega prehoda, oblikovni učinek
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2020
• PID: 20.500.12556/RUL-118620
• COBISS.SI-ID: 27083011
• Publication date in RUL: 28.08.2020

Secondary language

• Language: English
• Title: Two-component benzoxazine materials from biorenewable sources with shape memory ability

Abstract

Rapid rate of fossil fuels consumption has led to their limited availability and has caused air pollution, global warming, and other environmental issues. The current research is therefore increasingly focused on seeking polymers from renewable resources that could replace petroleum-based materials. Bio-based benzoxazines can also be obtained from natural raw materials, which, due to their chemically crosslinked structure, have great potential as shape memory polymers (SMP). These have opened up opportunities for new areas of application over the last two decades. In experimental work, benzoxazine monomer based on diphenolic acid and stearylamine and based on diphenolic acid and Jeffamine D-2000 was synthesized. Their chemical structures have been confirmed by infrared spectroscopy (IR). To investigate the effect of benzoxazine copolymer from biorenewable sources on shape memory, benzoxazine copolymer with the ring-opening polymerization at high temperature in various weight ratios was prepared. Thermal properties of the cross-linked samples were studied with differential scanning calorimetry (DSC), which provided necessary data for further studying of the shape memory effect. In addition to DSC analysis, the success of cross-linking was also studied with IR. The cyclic bending tests were employed to evaluate potential applicability and efficacy of the shape memory properties. With tests, the shape memory was confirmed and evaluated with shape fixity ratio (Rf) and shape recovery ratio (Rr). The samples have thus achieved a fairly good shape fixity ratio (37–95 %) at room temperature and a high shape recovery ratio (87–100 %) at 10 C above the glass transition temperature in the first cycle after 30 minutes. Good balance between shape memory performances and thermal properties showed a copolymer with a weight ratio of 50 : 50, as samples with increasing stearylamine content better retained shape, and samples with increasing Jeffamine D-2000 content better restored shape. It was also observed that samples undergo at least 4 shape memory cycles.

• Keywords: benzoxazine, biorenewable sources, thermal properties, glass transition temperature, shape memory