On 04/17/2008 Composite Analytica
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/https://composite-analytica.com/messages/403.html