User:Elizabeth Ghias/Notebook/Experimental Chemistry/2012/09/07: Difference between revisions

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Trial 3 (Film 5) - mass of pan and lid = 0.04880 g, mass of pan and lid with material = 0.05132 g
Trial 3 (Film 5) - mass of pan and lid = 0.04880 g, mass of pan and lid with material = 0.05132 g
<u>Crosslinking Reactions</u>
After 90 minutes in the oven:
* Film 2 - color remained the same, film became harder/more brittle
* Film 4 - color changed from clear to black/red depending on the thickness of the film.  Thicker portions of the film were darker than thinner parts, which appeared red.  The black parts of the film were very hard, while the thinner parts of the film were more flexible.
* Film 5 - color changed from clear to black, film became harder/more brittle
* Film 6 - color changed from clear to black, film became harder/more brittle
* Film 7 - Film remained the same




==Notes==
==Notes==
This area is for any observations or conclusions that you would like to note.
 
* The color change from clear to black is the result of the crosslinking that occurred in the presence of the acid.
* Film 7 remained the same because a weak acid was added, not a strong acid.




Revision as of 13:27, 10 September 2012

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Objective

To conduct Differential Scanning Calorimetry and to complete the cross-linking reactions conducted last week.


Description

Differential Scanning Calorimetry

  1. The masses of three DSC pans and lids were measured.
  2. 3 ± 0.3 mg of film (Films 1, 3, and 5 were used, see below) were added to each pan.
  3. Each pan and lid were placed into the press.
  4. The three samples were placed into the DSC in spaces 6,7, and 8.
  5. The DSC was run for the each of the three trials with the following program:
    1. Equilibrate (20.00°C)
    2. Ramp (20°C/min to 240°C/min)
    3. Ramp (20°C/min to 20°C/min)
    4. Isothermal (5 minutes)
    5. Repeat steps 2 to 4


Crosslinking Reactions

0.2 g of Films 2,4,5,6, and 7 (See below for list of films) were placed into an oven set to 90°C for 90 minutes.


List of Films

  • Film 1 = 0.5110 g PVA (MW = 22,000) in 3 mL H2O, no acid
  • Film 2 = 1.0084 g PVA (MW = 22,000) in 6 mL H2O, no acid
  • Film 3 = 0.5078 g PVA (MW = 22,000) in 3 mL H2O, with 3 drops of HCl
  • Film 4 = 1.0044 g PVA (MW = 22,000) in 6 mL H2O, with 3 drops of HCl
  • Film 5 = 0.5066 g PVA (MW = 22,000) in 3 mL H2O, with 0.05 g succinic acid and 3 drops of HCl
  • Film 6 = 0.50 g PVA (MW = 22,000) in 3 mL H2O, with 0.05 g Maleic acid and 3 drops of HCl
  • Film 7 = 1.0010 g PVA (MW = 22,000) in 6 mL H2O, with 3 drops of phosphoric acid
  • Film 8 = 0.5053 g PVA (MW = 22,000) in 3 mL H2O, with 3 drops of phosphoric acid


Data

<Differential Scanning Calorimetry

Trial 1 (Film 1) - mass of pan and lid = 0.05002 g, mass of pan and lid with material = 0.05285 g

Trial 2 (Film 3) - mass of pan and lid = 0.04993 g, mass of pan and lid with material = 0.05317 g

Trial 3 (Film 5) - mass of pan and lid = 0.04880 g, mass of pan and lid with material = 0.05132 g


Crosslinking Reactions

After 90 minutes in the oven:

  • Film 2 - color remained the same, film became harder/more brittle
  • Film 4 - color changed from clear to black/red depending on the thickness of the film. Thicker portions of the film were darker than thinner parts, which appeared red. The black parts of the film were very hard, while the thinner parts of the film were more flexible.
  • Film 5 - color changed from clear to black, film became harder/more brittle
  • Film 6 - color changed from clear to black, film became harder/more brittle
  • Film 7 - Film remained the same


Notes

  • The color change from clear to black is the result of the crosslinking that occurred in the presence of the acid.
  • Film 7 remained the same because a weak acid was added, not a strong acid.


Use categories like tags. Change the "Course" category to the one corresponding to your course. The "Miscellaneous" tag can be used for particular experiments, as instructed by your professor. Please be sure to change or delete this tag as required so that the categories remain well organized.



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