Study On Modification Of Thermal Insulation Phenolic Foams

Phenolic foam has high practical value in petrochemical industry transportation, frozen insulation and high-rise buildings, due to its extraordinary flame-retardant, heat resistance, self-extinguishing of flame, non-toxic and dimensional stability when burning. But as thermosettting foam, Phenolic foam has the weakness of fragility and easily dregs, which seriously restricts its aplication in reality. In this article, on the basis of study on phenolic foam by seniors, proper modifiers and modified methords were chose to enhance the property of phenolic foam.After the primarily exploration of the preparation procedure of phenolic foam, we studied the modification of phenolic foam by NBR latex, montmorillonoid, carbon fibers, SiO2particles, silica sol and silicone oil, and found the modified methords corresponding to different modifiers, at the same time, the modified phenolic foam was characterized by TEM, SEM, XRD and TG as well. Based on the difference of modified mechanism, we discussed and contrasted our modification separately, according to our researchs we found that the influence of different modifiers was different, which opens the door to its diversity application.As a prepolymer, NBR latex tends to flocculation in its modified process, in order to ensure NBR’s homodisperse, we need to increase resin viscocity so that the flocculation can be redispersed by stronge shear force in stiring process. Meanwhile, we found in our study that the curing activity of phenolic resin was decreased, thanks to the addition of NBR latex. When the content of NBR latex was less than9%, the compressive strength and impulse strength of modified foam tended to rise, but the water absorption and oxygen index of modified foam were little changed.In the phenolic foam modified by montmorillonoid and carbon fibers montmorillonoid was exfoliated into individual layers with a thickness of20-40nm which possess a certain orientation, and this structure was benefit to its thermostability. What’s more, due to the good affinity between carbon fibers and phenolic, mechanical property of modified foam was greatly enhanced.In the research of phenolic foam modification by SiO2particles, silica sol and silicone oil, SiO2particles and silica sol were obtained by hydrolyzing of tetraethoxysilane(TEOS), but owing to the difference of hydrolyzing condition, the silicon dioxide we got was of different shape and crystalline. And then, we contrasted the mechanical property and modified mechanism of phenolic foams modified by the three modifiers, the results showed that the phenolic foam modified by SiO2particles and silica sol had a higher compressive strength and impulse strength, but a lower obturator. And those modified by silicone oil had a stable increase of mechanical property. More over, none of the three modified methords caused the decline of thermostability.