Heat transfer in model molds during crosslinking of thermosets

U ovom radu povedena je analiza očvršćivanja i prijenosa topline nezasićenih poliestera u valjkastom kalupu grijanim toplim zrakom i uljem (glicerol). Vođenje topline kroz kalup ispitivano je mjerenjem temperature u središtu uzorka tijekom očvršćivanja. Prijenos topline sa zraka na stjenku kalupa je konvekcijski, a s ulja na stjenku kalupa kondukcijski. Kinetika reakcije je određena u diferencijalnom pretražnom kalorimetru pri izotermnim i dinamičkim uvjetima rada. Na osnovi provedenih eksperimenata u kalupu i nezavisnih kinetičkih ispitivanja može se dobiti potpunija slika procesa očvršćivanja u valjkastom kalupu s time da se stečene spoznaje mogu primijeniti i pri modeliranju proizvodnih kalupa u industriji. Promjena temperature tijekom očvršćivanja po presjeku uzorka rezultat su istovremenog prijenosa topline i kemijske reakcije. Pokazalo se da predloženi matematički model dobro opisuje eksperimentalno izmjerene temperature tijekom reakcije u središtu valjkastog kalupa.Analysis of curing and heat transfer of unsaturated polyester in a cylindrical mold heated with hot air and oil (glycerol) was studied. Heat conduction through the mold was examined by measuring the temperature at the centre of the sample during the curing. Heat transfer from air to the surface of the mold from the conveying, and from oil to the surface of the mold by conduction. The kinetics of the reaction is determined by the differential scanning calorimeter in isothermal and dynamic conditions. Based on experiments in a mold and independent kinetic tests complete picture of the process of curing in cylindrical mold can be obtained provided that the acquired knowledge can be applied in modelling of production molds in the industry. The change in temperature during curing along cross-section of the sample is a result of simultaneous heat transfer and chemical reaction. Finally, proposed mathematical model describes the experimentally measured temperatures during the reaction in the centre of a cylindrical mold very well