Recent Changes

Tuesday, May 20

  1. page Silk-E-SKE edited ... c. Weaving spider silk properly could make it indestructible Cross-Linking Cross linking oc…
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    c. Weaving spider silk properly could make it indestructible
    Cross-Linking
    Cross linking occurs with hydrogen bonds form with oxygen and hydrogen. Cross linking allows building up of these chains to bond together in big groups on the same plane. This results in the structures strength. The hydrogen that holds the helix together makes the silk have strength. Cross linking is the way that silk can be visable and durable .
    MLA Citations
    Kaplan, David L. "Silk Polymer Designs for Improved Expression and Processing." Defence Technical Information Ccenter 28 009 2007 http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA473922.
    (view changes)
  2. page Silk-E-SKE edited ... b. Composed of protein molecules c. Weaving spider silk properly could make it indestructible…
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    b. Composed of protein molecules
    c. Weaving spider silk properly could make it indestructible
    Cross-Linking
    MLA Citations
    Kaplan, David L. "Silk Polymer Designs for Improved Expression and Processing." Defence Technical Information Ccenter 28 009 2007 http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA473922.
    (view changes)
    2:17 pm
  3. page Silk-E-SKE edited ... Silk Structural Characteristics ... as silk. Silk is a natural polymer and it is found …
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    Silk
    Structural Characteristics
    ...
    as silk. Silk is a natural polymer and it is found in spyders and silkworms.
    {chemproj1.jpg}
    These three acids bond to create the polymer. When they are all connected they look like this:
    ...
    This is a picture of how two amino acids bond to start the silk formation:
    {condensation_bonding.jpg}
    Physical and Chemical Characteristics
    1. Triangular prism like structure
    2. Triangular cross section with rounded corners
    3. Lights hit it at many angles, allowing it to have a natural shine
    4. Very strong but loses up to 20% of strength when wet
    5. Smooth soft texture, but not slippery
    6. Tension is due to covalent peptide bonds
    7. Spider silk
    a. Stretch up to 40% without breaking
    b. Composed of protein molecules
    c. Weaving spider silk properly could make it indestructible

    MLA Citations
    Kaplan, David L. "Silk Polymer Designs for Improved Expression and Processing." Defence Technical Information Ccenter 28 009 2007 http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA473922.
    (view changes)
    2:13 pm
  4. page Silk-E-SKE edited ... These three acids bond to create the polymer. When they are all connected they look like this:…
    ...
    These three acids bond to create the polymer. When they are all connected they look like this:
    {chemproj2.jpg}
    This is a picture of how two amino acids bond to start the silk formation:
    {condensation_bonding.jpg}

    MLA Citations
    Kaplan, David L. "Silk Polymer Designs for Improved Expression and Processing." Defence Technical Information Ccenter 28 009 2007 http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA473922.
    (view changes)
    2:06 pm
  5. page Kevlar - B- ahkg edited ... Cross linkage does occur within this polymer, which has a great affect on it. It makes it stro…
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    Cross linkage does occur within this polymer, which has a great affect on it. It makes it strong and durable.
    Kevlar can be used for many different things. It is used in the production of bullet proof vests, tires, racing sails, rope and cables, audio equipment, brakes, and many other things. The fact that is can absorb vibrations, is very strong, and bullet proof makes it very useful.
    History- Stephanie Kwolek’s research with high performance chemical compounds for the DuPont Company led to the development of a synthetic material called Kevlar which is five times stronger than the same weight of steel. Kevlar, patented by Kwolek in 1966, does not rust nor corrode and is extremely lightweight. Many police officers owe their lives to Stephanie Kwolek, for Kevlar is the material used in bullet proof vests. Other applications of the compound include underwater cables, brake linings, space vehicles, boats, parachutes, skis, and building materials.
    Chemical properties-
    Fibers of Kevlar consist of long molecular chains produced from PPTA (poly-paraphenylene terephthalamide). There are many inter-chain bonds making the material extremely strong. Kevlar derives part of its high strength from inter-molecular hydrogen bonds formed between the carbonyl groups and protons on neighboring polymer chains and the partial pi stacking of the benzenoid aromatic stacking between stacked strands. The presence of salts and certain other impurities, especially calcium, could interfere with the strand interactions and caution is used to avoid inclusion in its production. Kevlar usually forms into silk planes because of its rigid crystallize.
    (view changes)
    9:00 am
  6. page Nylon66-D-ahes edited ... Cross- Linkage does not occur in the process of forming Nylon. Nylon is renewable and recycl…
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    Cross- Linkage does not occur in the process of forming Nylon.
    Nylon is renewable and recyclable because it can be broken apart to form new nylon or a new product. Nylon is recycled frequently to make carpets. Only some kinds of nylon are biodegradable (nylon 6,6 IS biodegradable).
    {making_nylon.gif}
    Linking of Monomers:
    Nylon is made from monomers adipoyl chloride and hexamethylene diamine.
    Nylon 6,6 Linking of Monomers: Dehydration
    COOH acid group on each end and react with other molecules which are partially made of amine (NH2). Dehydration synthesis because there is one H from COOH and with one H from Amine (the other one stays), which forms H2O, so it links by form of dehydration.
    ...
    Monomers: Dehydration
    Amine is placed one end, acid is located on the other and is polymerized to form a chain.
    In both types, the linking begins with an aqueous solution of monomers and then goes through polymerization, spinning, drawing or draw-texturing.
    Explanation of Picture:
    The Carbon’s are the central atom. (The green ones). Hydrogen is represented as white. The oxygen is red and the nitrogen is blue. Hydrogen is linked to the amine but then separates and OH separates from the acid, then this becomes H20, water, so dehydration synthesis occurs to link the bonds together.
    {Nylon6_and_Nylon_66.JPG}
    Characteristics of Nylon:
    Very strong
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    Highly Resilient- Flexible
    Very durable
    ...
    of Nylon:
    {5922_tn.jpg} {bonded_nylon.jpg}

    Used in carpets, clothing, luggage, car parts, tights.
    Bedspreads, curtains, upholstery
    (view changes)
    5:57 am
  7. file making_nylon.gif uploaded
    5:56 am
  8. file bonded_nylon.jpg uploaded
    5:27 am

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