在三聚氰胺树脂的制备终期通过调整减压蒸馏的时间制备含水量不同的树脂.保证树脂中高聚物、发泡助剂的质量比一致,在相同发泡条件下制备泡沫样品.通过固含量、凝胶时间,粘温曲线发现树脂预聚体的含水量越低,则固含量越高,树脂活性越大,固化速度快,制得泡沫的密度较大.SEM照片显示,树脂预聚体固含量越大,泡沫孔径越小,且孔径尺寸分布趋于均匀.此外,含水量也会对泡沫骨架的截面微观结构造成影响,含水量越少,骨架截面上的小气孔越多.
Melamine-formaldehyde (MF) resin with different water content was prepared by controlling the time during the process of vacuum distillation.Then, the foam samples were produced under the same processing conditions with the same mass ratio of MF condensate and blowing promoters.The resin was characterized by solid content test, gelation time test and rheological test.The results showed that the lower the water content (WC) is, the higher the solid content (SC) would be.And the curing process was accelerated due to the more reactive resin.In addition, the apparent density of the foam sample was higher.SEM results showed that the cell size became smaller and the distribution of cell was more homogenous when the WC of MF resin decreased.Moreover, the WC of resin also had an influence on the micro-structure of foam skeletons.According to the cross-section of foam skeleton, the lower the WC was, the larger number of micro-voids could be.
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