Phase transition—molecular weight polymers

Another explanation of the increase in the major glass transition 126) of SIN s relates to the retention of low molecular weight polymer of one component by the other phase. In this case low molecular weight fractions of the epoxy may be trapped in the rubber. When the epoxy is at its gel point, there is still much low molecular weight epoxy resin that has not reacted. At the point when the n-butyl acrylate is still mostly... 

Breadth of Phase Transition. The abruptness or width of the coexistence region of the order-disorder transition has also been estimated theoretically. For a monodisperse solution of a relatively high molecular weight polymer, an intrinsic coexistence region, ATc, exists because of standard flnite-size fluctuation effects. Numerical calculations yield the result (22)... 

The Borstar process involves the use of two cascaded reactors. In the first stage, ethylene is polymerized in supercritical propane by the addition of a transition metal catalyst in a loop reactor, which leads to low-molecular-weight polyethylene. The reaction mixture is then transferred into a gas-phase reactor in which high-molecular-weight polymers are formed. The direct result of this two-stage process is an intimate mixing of the two polymer fractions, which differ in their molar masses. 

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