Non-Isothermal Reaction Calorimetry

Anionic polymerization of L6 in aliphatic solvents was monitored on-line using both isothermal and non-isothermal reaction calorimetry in combination with Vis-spectrometry. 

The temperature governs the calorimetric signature of this process and the analysis of the heat released, in combination with other off-line techniques, allows to discern the sequence of the events involved and to quantify the heat released in each event. 

This rapid process can be tempered either by successive or continuous addition of the chain initiator. In the first case, the overall heat evolution is split into a number of smaller distinct sequences and spread over the time scale. At the same temperature, each sequence presents the same shape of heat evolution with the corresponding overall evolution. In the second case, a steady state of heat evolution is achieved, whose amplitude and half-width are proportional to the feeding rate of Cl. 

Concomitantly scanning one or more variables should be an alternative route for controlling both the average molecular weight and the particle size distribution. This aspect is still under investigation. 

Stratula-Vahnoveanu and Cl. Vasiliu-Oprea, Polym. Plast. Techn-Eng., 2002, 41 (5) 981. 

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Figure 12 Non-isothermal reaction calorimetry on anionic polymerization of L6 using the successive injections method of contacting the catalytic species...

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