Difference between revisions of "Team:TU Darmstadt/Project/Chem/Methods"

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<h1>Synthesis of prepolymers and characterization</h1>
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<p>&nbsp;</p>
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<h2>Thermal polyesterification of itaconic acid (IA), polyethylene glycol 400 (PEG-400)</h2>
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<p>&nbsp;</p>
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<p>&nbsp;</p>
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<p>Polymers were prepared in dependence on the experimental procedures of <em>Barrett et al.</em><sup>[1]</sup></p>
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<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 (&lt; 10<sup>-3</sup> mbar) overnight.</p>
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<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>
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<p>&nbsp;</p>
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<h3>A1</h3>
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<p><em>Date: </em>02/06/15 &ndash; 03/06/15</p>
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<p><em>Lab members: </em>AW, SZ</p>
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<p>&nbsp;</p>
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<p><em>Preparation process:</em></p>
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<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&nbsp;mmol, 1 eq.) itaconic acid and flushed with argon. Within 20 minutes the mixture was heated up to 100 &deg;C with an oil bath and stirred under argon atmosphere. As a colorless melt had formed the vacuum was applied (3&middot;10<sup>-2</sup> mbar) and the mixture was stirred at 100 &deg;C for 17 h. The slightly yellow viscous liquid was cooled down to room temperature.&nbsp;</p>
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<p>For a picture of A1 see appendix.</p>
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<p>&nbsp;</p>
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<p><em>Analysis:</em></p>
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<p>No further analyses were performed.</p>
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<p>&nbsp;</p>
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<h3>A2</h3>
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<p><em>Date: </em>09/06/15 &ndash; 10/06/15</p>
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<p><em>Lab members: </em>FR, SJ</p>
 +
<p>&nbsp;</p>
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<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&nbsp;mmol, 1&nbsp;eq.) itaconic acid and capped with a septum. Within an hour the mixture was heated up to 145 &deg;C with an oil bath and stirred under argon atmosphere. As a colorless melt had formed the vacuum was applied (&lt; 10<sup>-3</sup> mbar) and the mixture was stirred at 145 &deg;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>&nbsp;</p>
 +
<p><em>Visual Observations:</em></p>
 +
<p>During the reaction itaconic acid recrystallised on the flask surface which wasn&rsquo;t dipped into the oil bath. Therefore the ratio between itaconic acid and PEG-400 has changed.</p>
 +
<p>&nbsp;</p>
 +
<p><em>Analysis:</em></p>
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<p>The product was analyzed by differential scanning calorimetry DSC to identify the glass transition (T<sub>g</sub>) temperature.</p>
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<p>The T<sub>g</sub> of A2 is -4.7 &deg;C.</p>
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<p>&nbsp;</p>
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<p>Figure 1: DSC- Plot of A2. The T<sub>g</sub> of A2 is -4.7 &deg;C</p>

Revision as of 08:54, 16 September 2015

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