Diffusion coefficient of CO2 in polypropylene  

Posting by fabricio on April 17, 2008 at 14:29:27.

I would like to now a relationship between the diffusion coefficient of carbon dioxide (CO2) in atactic and isotactic polypropylene (PP) and the system temperature.


          follow up posts
    On 04/17/2008 composite agency posts: Hi Fabricio,

    In order to place your diffusion / permeability question in the appropriate context could you tell us little more about the industrial application of your question? Such as: sort of process streams? chemical or civil structure, etc.

    Regards,


    [responses: 2]

      On 04/17/2008 fabricio posts: I work in an oil company, in this business there is a device call "riser" which consist in a pipe with many layer (~6). the last layer is make in many types of polymers for example, nylon 11, PVDF and PP. I am studyng permeability of gas (CO2) from internal side of the pipe (bore) through this layer. for this, a need to find a relationship the coefficient diffusion with the temperature, can you help me?
      [responses: 1]
        On 04/17/2008 composite agency posts: The activation energy for diffusion is between 33 and 42 kilo Joule, dependent on whether atactic or isotactic polypropylene is used, and the degree of pp crystallinity. If the crystalline volume fraction increases, the activation energy for diffusion increases.

        The carbon dioxide diffusivity coefficient is in the order of 1 E-11 to 5 E-11 at a system temperature of 25 degrees Celsius and 1 bar system pressure.

        The carbon dioxide solubility in polypropylene is 2E-1 [m3 stp / m3 bar].

        Find more information on activation energy and diffusivity, solubility, and permeability calculations with regard to coatings and multilayer plastic materials in the following postings: "effect of temperature": www.composite-agency.com/messages/403.html
        [responses: 0]


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