Structural testing of polyimide nanocomposite films with SAXS and SVM-PUK

With an increasing number of new nanomaterials being produced, structural testing of materials has become quite important. In this paper, a testing method based on synchrotron radiation small-angle X-ray scattering (SAXS) was proposed to characterize the structural properties of polyimide nanocomposite films. The tested films, which were prepared through an in situ polymerization method, were composed of either a single layer or three layers, and they were doped with TiO2 particles with different particle sizes and weight ratios. The SAXS features of these films were tested, and then a support vector machine (SVM) based on a PUK kernel was used to classify both the single-layer and three-layer nanocomposite films. The experimental results show that in this model, the mean TP rate, precision and F-measure were 0.816, 0.814 and 0.814, respectively, when 10-fold cross-validation was applied, indicating that good classification results were achieved. Namely, the model can be used to effectively differentiate the two kinds of nanocomposite films from each other. Under the same experimental conditions, features and samples, a comparison experiment was carried out among the SVM-PUK testing model; a multilayer perceptron (MLP), a radial basis function (RBF), and a radial basis function network (RBFN) in neutral network models; and J48 and a decision stump (DS) in decision trees. The results show that the estimated performance of this model is superior to the other methods tested. Thus, the method introduced and discussed in this paper can be applied to the nondestructive testing of the structures of polyimide matrix nanocomposite films and automatic testing of the components of other nanocomposite materials.