Application of IC thermography during the polyester curing in model molds

U ovom radu proučavana je reakcija očvršćivanja nezasićenih poliestera u valjkastim kalupima zagrijavanim u uljnoj i zračnoj kupelji. Glavni problem prilikom egzotermne reakcije očvršćivanja čini generacija topline te značajno povećanje temperature unutar kalupa. Dodatkom inertnog punila smanjen je udio reaktivne komponente u smjesi posljedica čega je redukcija količine generirane topline u odnosu na čistu smolu. Predložen je matematički model u svrhu simuliranja reakcije očvršćivanja. Validacija modela izvršena je usporedbom sa eksperimentalno izmjerenim temperaturama u središtu kalupa. Provedeno je termografsko ispitivanje reakcije očvršćivanja u modelnim kalupima. Svrha provedbe samog snimanja jest određivanje temperaturnih profila, budući da se unutar samog kalupa za vrijeme reakcije javlja temperaturni gradijent koji se proteže od središta do stijenke kalupa što može dovesti do formiranja termosetnog proizvoda nejednolikih svojstava. Izazov samoj metodi predstavljaju male dimenzije kalupa kao i činjenica da su kalupi napravljeni od materijala niske emisivnosti (polirani bakar).Curing of unsaturated polyester was studied experimentally in a cylindrically shaped copper mold heated with hot air and oil. Considering that the cure reaction is exothermic, the encountered problems are heat generation and increasing temperatures during the reaction. Introduction of an inert filler decreased the number of reactive components and, as the result, reaction heat was lower than in the case of pure resin. Mathematical model is proposed in order to simulate curing process of unsaturated polyester resin in cylindrical mold. The suggested mathematical model has been verified by temperature measurements during the cure reaction in the center of mold at various temperature of heating. Thermographic testing of the curing reaction of a polyester resin sample in model molds was carried out. The purpose of the thermographic recording is to determine the temperature profiles, since a temperature gradient extends from the center to the mold wall during the reaction, which can lead to unequal properties of the final product. The challenge to the thermographic method lies in the fact that the mold is made of low emissivity material (polished copper) and that the mold dimensions are small