Difference between revisions of "Team:TU Darmstadt/Project/Chem/Methods"
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+ | <h1>Synthesis of prepolymers and characterization</h1> | ||
+ | <p> </p> | ||
+ | <h2>Thermal polyesterification of itaconic acid (IA), polyethylene glycol 400 (PEG-400)</h2> | ||
+ | <p> </p> | ||
+ | <p> </p> | ||
+ | <p>Polymers were prepared in dependence on the experimental procedures of <em>Barrett et al.</em><sup>[1]</sup></p> | ||
+ | <p>The procedure requires exact masses. Therefore an analytical balance (4 decimal places) was used and if not otherwise stated PEG as well as itaconic acid were pre-dried before use on a high vacuum line (< 10<sup>-3</sup> mbar) overnight.</p> | ||
+ | <p>To avoid contamination with oxygen during the reaction and to remove produced water, common Schlenk technique was applied. As inert gas argon was used.</p> | ||
+ | <p> </p> | ||
+ | <h3>A1</h3> | ||
+ | <p><em>Date: </em>02/06/15 – 03/06/15</p> | ||
+ | <p><em>Lab members: </em>AW, SZ</p> | ||
+ | <p> </p> | ||
+ | <p><em>Preparation process:</em></p> | ||
+ | <p>A 50 mL Schlenk flask was loaded with 1.213 g (3.033 mmol, 1 eq.) PEG-400 and 0.395 g (3.032 mmol, 1 eq.) itaconic acid and flushed with argon. Within 20 minutes the mixture was heated up to 100 °C with an oil bath and stirred under argon atmosphere. As a colorless melt had formed the vacuum was applied (3·10<sup>-2</sup> mbar) and the mixture was stirred at 100 °C for 17 h. The slightly yellow viscous liquid was cooled down to room temperature. </p> | ||
+ | <p>For a picture of A1 see appendix.</p> | ||
+ | <p> </p> | ||
+ | <p><em>Analysis:</em></p> | ||
+ | <p>No further analyses were performed.</p> | ||
+ | <p> </p> | ||
+ | <h3>A2</h3> | ||
+ | <p><em>Date: </em>09/06/15 – 10/06/15</p> | ||
+ | <p><em>Lab members: </em>FR, SJ</p> | ||
+ | <p> </p> | ||
+ | <p><em>Preparation process:</em></p> | ||
+ | <p>A 25 mL Schlenk tube was loaded with 2.169 g (5.422 mmol, 1 eq.) PEG-400, 0.705 g (5.420 mmol, 1 eq.) itaconic acid and capped with a septum. Within an hour the mixture was heated up to 145 °C with an oil bath and stirred under argon atmosphere. As a colorless melt had formed the vacuum was applied (< 10<sup>-3</sup> mbar) and the mixture was stirred at 145 °C for 24 h. The slightly yellow viscous liquid was cooled down to room temperature.</p> | ||
+ | <p>For a picture of A2 see appendix.</p> | ||
+ | <p> </p> | ||
+ | <p><em>Visual Observations:</em></p> | ||
+ | <p>During the reaction itaconic acid recrystallised on the flask surface which wasn’t dipped into the oil bath. Therefore the ratio between itaconic acid and PEG-400 has changed.</p> | ||
+ | <p> </p> | ||
+ | <p><em>Analysis:</em></p> | ||
+ | <p>The product was analyzed by differential scanning calorimetry DSC to identify the glass transition (T<sub>g</sub>) temperature.</p> | ||
+ | <p>The T<sub>g</sub> of A2 is -4.7 °C.</p> | ||
+ | <p> </p> | ||
+ | <p>Figure 1: DSC- Plot of A2. The T<sub>g</sub> of A2 is -4.7 °C</p> |
Revision as of 08:54, 16 September 2015
Contents
Synthesis of prepolymers and characterization
Thermal polyesterification of itaconic acid (IA), polyethylene glycol 400 (PEG-400)
Polymers were prepared in dependence on the experimental procedures of Barrett et al.[1]
The procedure requires exact masses. Therefore an analytical balance (4 decimal places) was used and if not otherwise stated PEG as well as itaconic acid were pre-dried before use on a high vacuum line (< 10-3 mbar) overnight.
To avoid contamination with oxygen during the reaction and to remove produced water, common Schlenk technique was applied. As inert gas argon was used.
A1
Date: 02/06/15 – 03/06/15
Lab members: AW, SZ
Preparation process:
A 50 mL Schlenk flask was loaded with 1.213 g (3.033 mmol, 1 eq.) PEG-400 and 0.395 g (3.032 mmol, 1 eq.) itaconic acid and flushed with argon. Within 20 minutes the mixture was heated up to 100 °C with an oil bath and stirred under argon atmosphere. As a colorless melt had formed the vacuum was applied (3·10-2 mbar) and the mixture was stirred at 100 °C for 17 h. The slightly yellow viscous liquid was cooled down to room temperature.
For a picture of A1 see appendix.
Analysis:
No further analyses were performed.
A2
Date: 09/06/15 – 10/06/15
Lab members: FR, SJ
Preparation process:
A 25 mL Schlenk tube was loaded with 2.169 g (5.422 mmol, 1 eq.) PEG-400, 0.705 g (5.420 mmol, 1 eq.) itaconic acid and capped with a septum. Within an hour the mixture was heated up to 145 °C with an oil bath and stirred under argon atmosphere. As a colorless melt had formed the vacuum was applied (< 10-3 mbar) and the mixture was stirred at 145 °C for 24 h. The slightly yellow viscous liquid was cooled down to room temperature.
For a picture of A2 see appendix.
Visual Observations:
During the reaction itaconic acid recrystallised on the flask surface which wasn’t dipped into the oil bath. Therefore the ratio between itaconic acid and PEG-400 has changed.
Analysis:
The product was analyzed by differential scanning calorimetry DSC to identify the glass transition (Tg) temperature.
The Tg of A2 is -4.7 °C.
Figure 1: DSC- Plot of A2. The Tg of A2 is -4.7 °C