Water sorption in thin films of high-temperature polyimides: the effect of imidization history
Water sorption in thin films of high-temperature polyimides: the effect of imidization history
复制标题
高温聚酰亚胺薄膜中的水吸附：酰亚胺化历史的影响
DOI：
10.1088/0954-0083/6/4/003
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
C. Gryte
中科院分区：
文献类型：
--
作者：
M. Ree;H. Han;C. Gryte
在230- 400 ℃的不同温度下，由相应的聚酰胺酸前体通过热酰亚胺化1-10小时制备了10-50埃厚的PMDA-ODA和BPDA-PDA聚酰亚胺。用重量法研究了它们的吸水行为。在PMDA-ODA和BPDA-PDA的吸水遵循一个几乎Fickian过程，尽管由于有序和不太有序相的形态异质性。水聚集或增塑在吸水率与湿度图上非常微弱。两种聚酰亚胺的吸水性高度依赖于酰亚胺化历史。扩散系数和吸水率都是亚胺化温度和时间的减函数。这主要是由于高温酰亚胺化提高了整体结晶度，因为它们的高rT性质。PMDA-ODA的扩散系数和吸水率分别为（1.0-3.0）× 10-9 cm ~ 2·s ~（-1）和0.4- 4.5wt%，PMDA-ODA的扩散系数和吸水率分别为（0.9-3.0）× 10-9 cm ~ 2·s ~（-1）和0. I2- 2.40重量%，取决于湿度、磷化历史和膜厚度。通过考虑它们的形态和对水的化学亲和力的差异来解释聚酰亚胺的吸水性之间的差异。
PMDA-ODA and BPDA-PDA polyimides in 10-50 Atrn thick films were prepared from the respective poly(amic acid) precursor by thermal imidization for 1-10 h at various temperatures over 230-400C. Their water sorption behaviours were studied in detail by gravimetry. Water sorption in both PMDA-ODA and BPDA-PDA followed a nearly Fickian process in spite of the morphological heterogeneity due to the ordered and less ordered phases. Water clustering or plasticization was very weakly evident on the water uptake versus humidity plots. Water sorption in both polyimides was highly dependent upon imidization history. Both diffusion coefficient and water uptake are decreasing functions of imidization temperature and time. This resulted mainly from the enhancement of overall crystallinity by high-temperature imidization because of their high-rT nature. The diffusion coefficient and water uptake were (1.0-3.0) x 10-9 cm2 s-1 and 0.4-4.5 wt% for PMDA-ODA and (0.9-3.0)x 10-cm2s-' and 0. I2-2.40wt%, depending on humidity,/iihidization history and film thickness. The differences between the water sorptions of the p'olyimides are interpreted by considering the differences in their morphologies and chemical affinities to water.