Abstract

Hydroxyapatite(HAP) has been extensively used in clinics for such as bone tissue repair because of its outstanding performance. But, whether HAP can be utilized in other fields still remains unknown, for example leather making. In the present work HAP was synthesized using a hydrothermal method with diammonium hydrogen phosphate and calcium nitrate as phosphorus and calcium precursors respectively. The Fourier transform infrared spectroscopy analysis of products shows that HAP can be produced using the wet-chemical method. The condition optimization test results indicated that high purity HAP can be obtained when the reaction was carried out at 80°C and pH11 with surfactant added and ultrasonic treatment for 8 hours. To study the effect of HAP on cow hide and whether it can be used as tanning agent, vitro and vivo tests of adding HAP into cow hide were conducted. The cow hide was first treated in the wet end process of leather making and then cut into several parts. The parts were treated using different HAP addition methods and the experimental results were compared under different conditions. Fourier transform infrared spectroscopy analysis indicated that HAP can react with the cow hide using both methods. Cow hide physicochemical properties were improved after reaction with HAP, the thermal stability was especially enhanced. The thermal shrinkage temperature of the treated hide was 78°C which was higher than the sample in the control group of 54°C. The hide tensile strength was greatly enhanced because HAP penetrated into the hide and reacted on hide collagen. So, HAP has the potential to be used as chrome-free tannage. This meant that the modification of cow hide by HAP was feasible and HAP tannage or HAP combination tannage was of practical significance.