Design, build-up and optimization of a fast quenching device for polymeric thin film

Abstract

In this work an innovative apparatus for the characterization of polymer solidification under very high cooling rates (up to thousand of K/s) is described, according to the continuous cooling transformation approach adopted in metallurgy for studying structure development in metals. The proposed model experiment is addressed to design a method for the characterization of non-isothermal solidification behaviour, encompassing typical cooling conditions of polymer processing. Only temperature history determines the structure formed, as melt solidification takes place in quiescent conditions. With respect to the device previously developed by the authors [1, 3] the present equipment presents the following features: - reduced size (30*30*20 cm); - higher heating rates, by using two electrical resistances supported on ceramic plates; - higher cooling rates, carried out through water sprays at very high pressures (120 bar); - thermal insulation of the sample from the sample holder via the application of two wave springs; - automatic control and synchronization of the whole sequence of operations: transfer of the sample from the melting (heating) zone to the cooling (spray) chamber via rotation (it was via sliding in the previous version); - very high heat transfer coefficients, up to 7*10(5) W/m(2)K