Will+Stedman+Log

= **Assignment #2: Article summary** = I'm doing my research paper on the synthesis of teflon, tracing back the historical roots of the molecule and the different ways in which teflon has been synthesized since it's first discovery. I will mention the significance of the molecule in terms of all of the applications beyond nonstick cookware, such as biomedicine.

The present summary will be on the following article:
 * "Polytetrafluoroethylene" W.E. Hanford and R.M. Joyce. Journal of the American Chemical Society. 68, 2082 (1946)**
 * [Full Marks JCB]**

[]
**Introduction **

**Paragraph 1: ** The first paragraph briefly states that Plunkett first discovered polytetrafluoroethlyene, a molecule that possesses unusual properties and is chemically inert, owing to the fact that it is a fluorinated, saturated organic compound. The last sentence states what the paper is going to discuss: a new, improved way of preparing polytetrafluoroethlyene as well as information about the molecule's physical properties.

**Paragraph 2: ** This paragraph states that polytetrafluoroethlyene was first characterized by two authors: Ruff and Bretschneider. They prepared it from tetrafluoromethane while another group prepared it by the dechlorination of sym-dichlorotetrafluoroethane.

**Polymerization ** **Paragraph 3: ** This paragraph briefly describes the first polymerization of tetrafluoroethlyene and how a more controllable polymerization procedure was developed utilizing superatmospheric pressure in the presence of water and polymerization initiators, such as ammonium, sodium, or potassium persulfates.

**Paragraph 4: ** [This paragraph is the first of two paragraphs detailing the method of polymerization of tetrafluorethylene]. The paragraph details how a dilute solution of hydrogen peroxide is loaded into a silver-lined pressure bomb followed by "evacuation" of gas so that tetrafluoroethylene can be loaded. Then, the mixture is heated and agitated and then allowed to cool before the polymer is separated from the aqueous phase by filtration.

**Paragraph 5: ** [This paragraph is the second of two paragraphs detailing the method of polymerization of tetrafluorethylene]. The paragraph details the methods of controlling the polymerization reaction as well as ways in which to mitigate hazards associated with the polymerization of tetrafluorethylene: 1) control temperature, use adequate cooling facilities, provide sufficient agitation, and control pressure of reacton in order to prevent the explosive decomposition of the monomer.

**Properties of Polytetrafluoroehtylene ** **Paragraph 6: ** This is a very long paragraph describing the properties of polytetrafluoroethlyene: it is a highly crystaline linear polymer as evidenced by a) X-ray diffraction patterns, b) the ability to form thin films that are characteristically slippery in texture, c) sharp transition temperature at 327 degrees that shift physica form from a stiff translucent material to a transparent rubbery material. Addtionally, above the transition temperature and under tensile stress, the polymer can undergo deformation and can tear or break, as a result.

**<span style="font-family: 'Arial','sans-serif';">Paragraph 7: ** This paragraph describes how chemically inert polytetrafluoroethlyene is: thermal degradation in air does not include carbonization at temperatures ranging from 450-700 degrees; it's not attacked by strong acids, even at high temperatures. It does state that molten sodium can attack polytetrafluoroethlyene at 200 degrees.

<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%; margin: 0in 0in 10pt;">**<span style="font-family: 'Arial','sans-serif';">Paragraph 8: ** This paragraph describes how polytetrafluoroethlyene is not dissolved in organic solvents, even at elevated temperatures and that this insolubility has prevented accurate measurement of molecular weight of the polymer.

<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%; margin: 0in 0in 10pt;">**<span style="font-family: 'Arial','sans-serif';">Paragraph 9: ** This paragraph describes how polytetrafluoroethlyene has an extremely low dielectric loss factor for a solid and goes on to describe other physical properties such as refractive index and dielectric constant.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">X-Ray Diffraction ** <span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%; margin: 0in 0in 10pt;">**<span style="font-family: 'Arial','sans-serif';">Paragraph 10: ** [This paragraph is the first of two paragraphs detailing the X-ray diffraction data in the paper.] This paragraph describes the X-ray diffraction images of oriented and unoriented polytetrafluoroethlyene films at various temperatures above and below the transition temperature of 327 degrees (one of the only things I could pick up from the data was that at temperatures below the critical temperature, there were oriented and unoriented X-ray diffraction images, demonstrating the cystallinity of the polymer, while at temperatures above the critical temperature there was only an unoriented image, demonstrating the lack of crystallinity.)

<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%; margin: 0in 0in 10pt;">**<span style="font-family: 'Arial','sans-serif';">Paragraph 11: ** [This paragraph is the second of two paragraphs detailing the X-ray diffraction data in the paper.] This paragraph describes the infrared absorption spectrum of a polytetrafluoroethlyene film: there is only one major absorption band at 8-8.7 microns wavelength, indicating the strong presence of C-F bond, with weaker bands at longer wavelengths. The paragraph also attributes the lack of UV absorption to Rayleigh scattering of incident light due to the haze of the polymer film.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">Transition Point ** <span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%; margin: 0in 0in 10pt;">**<span style="font-family: 'Arial','sans-serif';">Paragraph 12 : ** This paragraph is a long paragraph that solely describes the transition point of polytetrafluoroethlyene: the transition temperature of 327 degrees has characteristics of a melting point due to the 1) X-ray diffraction data; 2) the polymer can't be oriented above this temperature; and 3) oriented polymers below this temperature become unoriented after heating above the transition tempearature. The paragraph also states that polytetrafluoroethlyene is different from other thermoplastics in that it does not undergo rapid plastic deformation or demonstrate significant viscous flow above its transition point temperature.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">Structure and Viscosity of Polytetrafluoroethylene ** **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 13 : **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph restates the evidence that polytetrafluoroethylene is a linear polymer that is not cross-linked: 1) it has high degree of crystallinity; 2) it can be oriented, and it has a sharp transition point. The paragraph also discusses the probable structure of polytetrafluoroethylene as an unbranched monomer in the form of –(CF2CF2)-//n.//

**<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 13 : **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph discusses the high melt viscosity of polytetrafluoroethylene. It states that this physical characteristic is likely due to the polymer structure, such as restricted rotation of the carbon atoms in the fluorocarbon chain, rather than due to the chain length.

**<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 14 : **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph discusses how the fluorocarbon structure of polytetrafluoroethylene contributes to restricted rotation of carbon atoms: there is an electrostatic repulsion between CF2 groups, there is steric hindrance between neighboring CF2 groups due to the large size of fluorine (fluorine has almost double the atomic radius of hydrogen). Lastly, the paragraph states that because of this restriction on rotation, the polymer segments can be extremely long, necessitating very high activation energy for viscous flow.

**<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 15: **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph further discusses the high viscous flow characteristic of polytetrafluoroethylene. It re-emphasizes the fact, or idea, that the restriction of rotation of all adjacent carbons within the polymer can lead to an extremely long “statistical flow segment” which would require high activation energies above the temperature of thermal degradation of the polymer.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">Cohesion **

**<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 17: **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph discusses how the substituent fluorine atoms along the polymer creates a strong repulsive force that prevents interchain bonding and, as a result, the molecular cohesion between neighboring polymer molecules is very low. As a result of this low cohesion, the polymer can fracture easily above its transition temperature of 327 degrees but still, because of the strong repulsive forces of the fluorine atoms, there is little interchain bonding.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">Insolubility ** **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 18: **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph contrasts polytetrafluoroethylene with polyethylene: they both are insoluble in organic solvents at room temperature; polytetrafluoroethylene remains insoluble at higher temperatures while polyethylene becomes increasingly soluble by 70 degrees. The authors attribute this insolubility of polytetrafluoroethylene to the very low forces of association between its constituent fluorocarbons and other organic compounds.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">Acknowledgments ** **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 19: **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph is self-explanatory, detailing the acknowledgements of those that have made significant contributions to the paper.

**<span style="font-family: 'Arial','sans-serif'; font-size: 14pt; line-height: 115%;">Summary ** **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">Paragraph 20: **<span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;"> This paragraph summarizes the key points of the paper: 1) an improved method of polymerizing tetrafluoroethylene; 2) the physical properties of polytetrafluoroethylene, including its high melt viscosity, insolubility in organic solvents, low dielectric loss factor, chemical inertness, and the evidence that it is a linear, unbranched crystalline fluorocarbon.

= Assignment #1: 5 Properties Assignment =

//9/30/2010:// [@760mm Hg] || **61.12 C** [@101.325 Pa] || [] [@760mm Hg] || **61.20 C** [@101.325 Pa] || [] [@101.3kPa] || **61.20 C** [@101.3kPa] || [] || **143°F** [does not say at what pressure] assume 101.325Pa || **62°C** || [] [does not say at what pressure] assume 101.325Pa || **61.2°C** || **[]** Oxford University ||  || **61°C** [does not say at what pressure] assume 101.325Pa || **61°C** || [] [] || [|Chloroform_properties_MSDS_Oxford_Stedman.jpg] || [] || [|Chloroform properties_CHEMspider_Stedman.tif] ||
 * 1) Chose chloroform as molecule.
 * 2) Beillstein Query on chloroform:
 * **Secondary Source** || **Primary Source (traced from Secondary)** || **Boiling Point** || Boiling Point (Converted Value) || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * Beilstein || Journal of American Chemical Society || **334.27 K**
 * PRIMARY SOURCE** || [|Chloroform_BP__1_Stedman[1.jpg]] ||
 * Beilstein || Journal of Chemical and Engineering Data || **61.20 C**
 * PRIMARY SOURCE** || [|Chloroform_BP__2_stedman[1.jpg]] ||
 * Beilstein || Journal of Chemical and Engineering Data || **334.35 K**
 * PRIMARY SOURCE** || [|Chloroform_BP__3_stedman[1.jpg]] ||
 * CDC [NIOSH pocket guide to chemical hazards] ||
 * SECONDARY SOURCE [found via Chemspider]** || [|Chloroform_properties_CDC_NIOSH_Stedman.jpg] ||
 * CDC [NIOSH pocket guide to chemical hazards] || NIOSHExperimental Data || **61.2°C**
 * PRIMARY SOURCE (appears as actual measured data but may be duplicate of secondary source above, so will find 1 additional source)** || [|Chloroform_properties_CDC_NIOSH_2_Stedman.jpg] ||
 * The Physical and Theoretical Chemistry Laboratory
 * [found via Chemspider]**
 * ChemSpider ||  ||   || range of experimental values || []
 * Sigma Aldrich ||  ||   || 60.5-61.5 °C || [|SIGMA&N5=SEARCH_CONCAT_PNO|BRAND_KEY&F=SPEC] || [|Sigma_BP.jpg] ||


 * [the first link below does not link to the paper - put the doi JCB]**
 * **Secondary Source** || **Primary Source (traced from Secondary)** || Melting Point || Melting Point (Converted Value) || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * Beilstein || Journal of Chemical Physics || **-63.5 C** || **-63.5 C** || [] || [|Chloroform properties_Beilstein a_Stedman.tif]

[|Chloroform properties_Beilstein b_Stedman.tif] || || **-82°F** || **-63°C** || [] Oxford University ||  || **-63°C** || **-63°C** || [] [|SIGMA&N5=SEARCH_CONCAT_PNO|BRAND_KEY&F=SPECs.] chem.ox.ac.uk/|http://msdhttp://www.sigmaaldrich.com/catalog/ProductDetail.do?lang=en&N4=C7559|SIGMA&N5=SEARCH_CONCAT_ PNO|BRAND_KEY&F=SPECs.chem.ox.ac.uk/ || [|Chloroform_properties_MSDS_Oxford_Stedman.jpg] || [] || [|Chloroform properties_CHEMspider_Stedman.tif] ||
 * Beilstein || Journal of American Chemical Society || **-63.2 C** || **-63.2 C** || []
 * PRIMARY SOURCE** || [|JACS_MP_.jpg] ||
 * CDC [NIOSH pocket guide to chemical hazards] ||
 * SECONDARY SOURCE** || [|Chloroform_properties_CDC_NIOSH_Stedman.jpg] ||
 * CDC [NIOSH pocket guide to chemical hazards] ||  || **-63.5C** || **-63.5C** || **[]**
 * PRIMARY SOURCE (appears as actual measured data but**
 * may be duplicate of secondary source above, so will find 1 additional source)** || [|Chloroform_properties_CDC_NIOSH_2_Stedman.jpg] ||
 * The Physical and Theoretical Chemistry Laboratory
 * [found via Chemspider]**
 * ChemSpider ||  ||   || range of experimental values || []
 * Sigma Aldrich ||  ||   || −63 °C ||   || [|Sigma_MP.jpg] ||

=en&N4=C7559|SIGMA&N5=SEARCH_CONCAT_PNO|BRAND _KEY&F=SPEC || [|Sigma_RI.jpg] ||
 * **Secondary Source** || Refractive Index || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * wolfram alpha || 1.445 || [] || [|] ﻿[|Wolfram_Properties.jpg] ||
 * Sigma Aldrich || 1.445 || []
 * Alfa Aesar || 1.4450 || [] || [|AlfaAesar_Properties.jpg] ||
 * Chemical Land21 || 1.4460 || [] || [|chemicalland21_properties.jpg] ||
 * Oxford MSDS || 1.4459 || [] || [|OxfordMSDS_Properties.jpg] ||
 * Merck Index (Knovel link) || 1.4476 || extremely long link: use screen shot only || [|Merck_Index_Properties.jpg] ||
 * CRC Handbook of chemistry and physics || 1.4459 || __ []+ __

[SEE PAGE 492 for chloroform]
|| [|Chloroform_CRC_properties.jpg] ||

?lang=en&N4=C7559|SIGMA&N5=SEARCH_CONCAT _PNO|BRAND_KEY&F=SPEC || [|Sigma_VP.jpg] || information site) || 159 mm Hg at 20 oC || [] || [|scorecard_Properties.jpg] || Edge site || 30kPa at 20°C = 225 mm Hg || [] || [|engineers_edge_Properties.jpg] ||
 * **Secondary Source** || Vapor Pressure || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * wolfram alpha || 160 mmHg || [] || [|] ﻿[|Wolfram_Properties.jpg] ||
 * Sigma Aldrich || 160 mmHg ( 20 °C) || []
 * Oxford MSDS || 159 mm Hg at 20 C || [] || [|OxfordMSDS_Properties.jpg] ||
 * INCHEM || 21.2kPa at 20°C = 159 mm Hg || [] || [|INCHEM_Properties.jpg] ||
 * Scorecard (pollution
 * Engineers

dictionary (Knovel link) || 1.485 at 20 ° C || link too long || [|Hawleys_Properties.jpg] ||
 * **Secondary Source** || Specific Gravity || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * CDC [NIOSH pocket guide to chemical hazards] || 1.48 || [] || [|Chloroform_properties_CDC_NIOSH_Stedman.jpg] ||
 * INCHEM || 1.48 || [] || [|INCHEM_Properties.jpg] ||
 * Oxford MSDS || 1.48 g cm3 || [] || [|OxfordMSDS_Properties.jpg] ||
 * Cameochemicals || 1.4832 at 68.0 ° F || [] || [|cameochemicals_Properties.jpg] ||
 * Hawley Condensed chemical

.do?lang=en&N4=C7559|SIGMA&N5=SEARCH_CONCAT _PNO|BRAND_KEY&F=SPEC || [|Sigma_Density.jpg] ||
 * **Secondary Source** || Density || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * wolfram alpha || 1.492 g/cm^3 = 1.492 g/ml || [] || [|] [|Chloroform_WolframAlpha_Stedman.jpg] ||
 * Sigma Aldrich || 1.492 g/mL at 25 °C || []
 * Alfa Aesar || 1.492 ??units [most likely g/ml or g/cm^3] || [] || [|AlfaAesar_Properties.jpg] ||
 * CRC Handbook of chemistry and physics || 1.4788 g/cm^3= 1.4788 g/ml at 25 °C || __ []+ __

[SEE PAGE 492 for chloroform]
|| [|Chloroform_CRC_properties.jpg] ||
 * Engineers Edge site || 1.489 Kg/liter = 1.489 g/ml] || [] || [|engineers_edge_Properties.jpg] ||


 * **Secondary Source** || Flash Point || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * wolfram alpha || -22 °C ||  || [|] ﻿[|Wolfram_Properties2.jpg] ||
 * Sigma Aldrich ||  ||   ||   ||
 * Chemical Land21 || "practically not flammable" || [] || [|chemicalland21_properties.jpg] ||
 * Cameochemicals || none || [] || [|cameochemicals_Properties.jpg] ||
 * Oxford MSDS || none || [] || [|OxfordMSDS_Properties.jpg] ||


 * **Secondary Source** || Vapor Density || **Link to Primary/Secondary Source** || **Screen shot of Source** ||
 * Oxford MSDS || 4.1 || [] || [|OxfordMSDS_Properties.jpg] ||
 * INCHEM || 4.12 || [] || [|INCHEM_Properties.jpg] ||