| The group IIA metal oxides and hydroxides are used to thicken unsaturated polyester resin (UPR), and then the curing characteristics of UPR are studied in the dissertation in order to provide essential data and researching methods for the development and application of molding compounds.Firstly, the effects of initiators and LPA on the gel time, curing time and peak temperatures in the curing reaction of UPR were studied by SPI method and differential scanning calorimetry(DSC), and the curing characteristics were analyzed in kinetics angle.The results showed that TBPB was used as initiators in the curing system, curing temperature was 120℃and post-curing temperature was 180℃; LPA would be layered because of bad compatibility with UPR during the curing reaction; Kinetics parameters were E=74.3 kJ.mol-1, A =1.71*109, n=0.916 respectively; Reaction extents reached around 0.7 when UPR was cured in the isothermal DSC, the curing reactions converted from kinetics control into diffusion control.Secondly, several important factors which affected the thickening characteristics of UPR paste, such as the kinds of thickening agents, the contents of thickening agents,temperatures, thickening time, water contents and compound thickening agents were investigated, and then the right thickener was chosen by comparison; It concluded the thickening mechanism of UPR by acid value titration, FTIR and GPC measurement.The results indicated that magnesium oxide had a better thickening effect than other thickening agents for UPR system, the suitable content were 2～4 phr ; The thickening temperature was 40℃, Minim water could accelerate early thickening, but postponed later thickening; calcium hydroxide would postpone early thickening, but promoted later thickening; acid value titration and FTIR analysis elucidated the carboxylic acid end group took part in thickening reaction accompanied with the formation of water, which resulted in intermolecular hydrogen bonding. GPC... |
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