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Properties of Hydrogels and Aerogels Prepared from Resorcinol/Formaldehyde
|關鍵字:||氣凝膠;冷凍乾燥;水凝膠;間苯二酚-甲醛樹脂;Aerogels;Freeze drying;Hydrogels;Resorcinol-formaldehyde resins||Project:||林業研究季刊, Volume 38, Issue 1, Page(s) 47-57||摘要:||
In this study, RF hydrogels were prepared by mixtures of resorcinol (R), formaldehyde (F), and water (W). The RF aerogels were made from RF hydrogels by dehydrating with freeze drying. The effect of the molar ratio of F/R and W/R on the properties of RF hydrogels and aerogels were investigated. The results showed that the polycondensation reaction between resorcinol and formaldehyde could be carried out in the system with a large amount of water to form hydrogels at a sealed environment. Increasing the malar ratio of W/R, the time needed for gelation prolonged and the compression strength of hydrogel decreased. However, increasing the malar ratio of F/R, the gel time could be shortened but which had no obvious influence on the mechanical properties of hydrogels. FTIR analysis results of aerogel showed that the higher the F/R molar ratio, the higher substituted degree of aromatic ring of resorcinol did. DSC analysis showed an endothermic peak due to the thermal activity of molecular chain during the heat scanning. Increasing the malar ratio of F/R, the water re-absorption capability of aerogels decreased, the weight loss after acetone dissolving increased. TGA results showed that the heat resistance of aerogel decreased with the molar ratio of W/R and F/R increasing.
|Appears in Collections:||林業研究季刊 第38卷 第01期|
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