Application of Stereology Methods to the Description of the Morphology of Polyurethaneureas

Abstract

This paper presents the application of stereology methods to the description of morphological properties of polyurethaneurea (PUU) domains. Stereology methods are used inter alia in the analysis of internal structure images and surface layer of materials and in description of their fractures. The work analyses images of fracture surfaces obtained in the cracking process. The paper also describes application of stereology methods to the analysis of domain structure of polyurethaneureas. Using scanning electron microscopy technique, fracture images of polymers cooled down in liquid nitrogen have been obtained. Such images provide interesting information on fracture morphology. Fracture images of polyurethaneurea samples allow for analysis of three-dimensional structure of these materials. The paper presents images of fractures obtained using different techniques of sample preparation. From the point of view of the description of domain structure in examined polyurethaneureas, breaking of PUUs containing crystalline phase frozen in liquid nitrogen, followed by their ageing, turned out to be the most advantageous method. Quantitative analysis of the images of fracture structure obtained with that technique allowed us to explain the mechanism of processes occurring during reactions of crystalline prepolymers with water and to investigate relationships between domain characteristics and properties of examined materials. Stereology methods were also found to be useful in comparative analysis of PUU structures with containing various rigid segments.