Evolution And Irradiation Control On Matrix Of Copper/LDPE Composite

Being effective, safe, economic, intrauterine and simple, reversible device (IUD) is one of the most popular contraceptive methods that were used all around the world. Recently, Cu-IUD has been widely investigated and employed due to great contraceptive effect of copper.The copper/low-density polyethylene (Cu/LDPE) composite is one kind of new IUD materials, because it has many kinds of merits to become the hot spot of the present IUD research. Currently the research of the metal/polymer composite focused on the second phase, by regulating the second phase to change the crystallinity, mechanical properties and anti-aging properties, and on the research of matrix is less, and on the research of evolution of matrix is also less.The first aim of our work is to investigate the structure variation in matrix of copper/low-density polyethylene (Cu/LDPE) nanocomposite in the simulated uterine solution by means of potentiodynamic polarization measurement, atomic force microscope and electrochemical impedance spectroscopy. The results indicated that significant structure variation of the polyethylene matrix took place when the time of potentiostatic polarization. For the study of copper / low-density polyethylene composites, polyethylene is not only a mechanical support role, but also play the role of copper ion releasion channel, so the polyethylene matrix changes are unfavorable to use of the IUD copper ion releasion and mechanical properties.The second aim of our work is to investigate the property and structure of composite under different doses gamma irradiation. As the radiation dose increased, elongation at break and tensile strength are decreased, and tensile strength decreased significantly, the contact angle of the material is from typical hydrophobic into hydrophilic. The average size of free volume becomes smaller. Cross-linking structure existing in the LDPE can be seen from SEM image, under the high radiation dose(400KGy), the cross-linking structure cannot be seen, which indicates that at higher radiation doses, rupture of the molecular chain take place.Composites immersed in nitric acid is to accelerate the releasing of copper corrosion, with the corrosion of copper and the releasing of copper ions, the leaving skeleton of polyethylene matrix will change, especially the material which was not irradiated. In the soaking process, elongation at break decreases significantly, the tensile strength lowers slightly, degree of crystallinity decreases greatly, SEM of matrix shows some collapse, lamellar structure and a large number of micron-size holes appear, and many large voids interconnect into valleys, releasing rate of copper ions has greatly changed. The breaking elongation, tensile strength, crystallinity of the lower dose of irradiation material have decreased in the soaking process, minor than the un-irradiation material, smaller amount of lamellar structure, micron-size holes, etc, the elongation and tensile strength of material with higher dose material did not decrease but increased in the immersion process, the crystallinity unchanged, and there were few micro-structure holes, releasing rate of copper ions was stable, all aspects of performance and structure show jarless.