Research On Relational Mechanical Properties Of PA6/PTT Alloy

Alloying (or blending) is a very important way for modifying the present existing basic resin. By alloying new polymers with high performance can be obtained through combination of superior properties of the component materials. Polymer alloy is a kind of special composite whose matrix phase and dispersed phase are all polymers. Nowadays, researchers generally place their interests on the preparation, physical and chemical characterization and application of polymer alloys. There are fewer studies relative to mechanical aspects of the materials except for some measurements and comparisons of strength and toughness, and using simple blending principle to estimate the mechanical properties. Combining mechanical theories with polymer material science and physical science, our workgroup has invented a technically innovative method to prepare polymeric nano-composites in-situ. Employing homogenization and mean field theory, multi-scale model is set up to study the mechanical behaviour of the nano-polymer-composites. Using the structural model, macro effective mechanical properties of typical semi-crystalline polymer such as PA6 has been studied Enlightened by these ideas and theories, typical polymer alloy, PA6/PTT, is prepared in the present research. Chemical and physical characterizations to the materials are performed to support the structural model constructed on the base of general self-consistent Mori-Tanaka theory. Macro effective modulus of the polymer alloys is calculated. Comparisons of the results with the experimental data indicate that micro-mechanical model is relatively satisfactory for calculating macro effective elastic modulus of the polymer alloys when volume fraction of the dispersion phase is low. Using creep aging theory, creep internal stress is introduced to explain the difference of creep behaviors between pure PA6 and PA6/PTT alloys at room temperature. Mechanism of internal stress on improving the creep resistance of the materials is discussed. By comparing the mechanical performance synthetically, alloying shows relatively better modifying effect when weight fraction of PTT is 20%.