Study Of Controlling Latent Curing Reaction Of Thermosetting Resins And Its Applications

Latent curing systems are widely used in industrial applications such as adhesion,coating,and composites.Despite many attempts to improve the practicality of the dormant reaction systems,majority of the commercially available latent products still use particulate hardeners or liquid compounds with blocked active groups.In this paper,we describe a new thermal latent curing concept basing on the reaction equilibrium in a homogeneous solution.FT-IR spectral measurements and rheological experiments suggest that the reaction between BF and amine is reversible and the reaction equilibrium stabilizes the curing mixture for a long time at low temperature.With heating the reaction equilibrium is broken by the formation of a polymer network,resulting in a rapid cure to thermoset resin.In addition,results of tensile strength,DMA and TGA showed that the cured resins have good practical value.The petrochemical industry have exacerbated the consumption of petroleum resources and waste pollution.The replacement of petroleum-based chemicals by renewable resources becomes important for the sustainable development.In this paper,we use epoxy soybean oil to prepare latent curing systems,and preparecomposite materials by using waste cotton garments or waste newspapers as fillers via a hot press molding method.,It was found that when the molar ratio of epoxy and epoxy soybean oil was 3:1,environmentally friendly composites of high mechanical strength,thermal stability and no phase separation between the matrix and filler can be obtained.In this paper,the latent mechanism based on the reaction equilibrium was proposed,and the feasibility and availability were verified.The preparation of environment friendly composites is importanton environment protect,waste reuse and reduce energy consumption.