复合材料孔隙形成机理、影响机制及试验表征

The formation and influence mechanism as well as experimental characterization of composite porosity

摘要:

针对常见复合材料孔隙问题，从机械夹杂形核理论与经典形核理论分析了孔隙的形成与影响机制，并通过具体试验对孔隙形貌、分布、大小进行了试验表征，结果表明：纤维浸润性差、蒸汽分子的滞留及交联反应时的分子挥发是孔隙形成的主要原因；较低固化压力条件（低于0.2MPa），对复合材料内部孔隙的消除作用不大，随固化压力提高，复合材料孔隙率及孔隙大小下降明显；利用数学拟合方法，得到孔隙率、孔隙大小与系统压力之间存在三次幂函数递减变化关系；本文为复合材料在制造过程中的工艺优化设计提供了理论与试验支撑。

Abstract:

In view of the common issue of composite porosity, the formation and influence mechanism of composite porosity are elucidated from the aspects of mechanical mixed nucleation theory and classic nucleation theory. The characterization of porosity morphology, distribution and size are conducted through specific test. The results show that: poor wettability of fibers, retention of vapor molecules and molecular volatilization generated during the crosslinking reaction are the main reasons of porosity formation. The lower cure pressures have a little effect on eliminating the porosity. With the increase of cure pressure, the porosity factor and porosity size decrease significantly. With the method of data fitting, the relations of porosity factor, porosity diameter and cure pressure are obtained, and the power function relations of three times are existed among them. This paper provides a theoretical and experimental support for optimizing the design of composites manufacturing process.