The Preparation And Performance Of Hydroxyapatite/chitosan/silicone Rubber Composite Materials

Hydroxyapatite is commonly used in clinic as a material of bone substitute.As the most important apatite-type material among organic non-metallic ones,which can make tight combines with bone tissue in a short time for its excellent bioactivity,biocompatibility,boon conductibility.Although the hydroxyapatite has high intensity of pressure,it is prone to brittle fracture and fatigue damage. Hydroxyapatite particles are too loose to shape,and it is very inconvenient to operate. Moreover,the characteristic of hydroxyapatite particles cause the loss of implanted materials.These shortcomings limit its applications in bone repair or bone substitute under load.As a kind of biodegradable cation amylase,Chitosan has cancer resistance and an effect of inflammation diminished as a natural biomaterial,which can promote the adsorption and multiplication of several histiocyte.The composite material which was prepared with hydroxyapatite and chitosan can get excellent boon inductivity and biodegradable speed matching.This composite also has some shortcomings,The combine of hydroxyapatite and chitosan on the interface isn't very well,the distribution of the particle isn't homogeneous and the composite is prone to brittle fracture.Silicone rubber is commonly used in clinical filled materials for it's good mechanical properties,stable physical and chemical properties,easy-molded shape,easy disinfection and preservation and so on.But silicone rubber is hydrophobic and has low osteogenic activity,and patients have the feeling of foreign body after implantation.Silicone rubber is an inert material,and it is poorly combined with organization.Silicone rubber is prone to form a integumentum,and the contracture will occur under certain condition,and there is inflammatory,cell infiltration in the integumentum.In this paper,the composite materials were prepared with chitosan and addition-cured high-temperature vulcanized silicone rubber.The surface of chitosan was treated with the hexamethyldisilazan,and the effects of different methods of hexamethyldisilazan treatment on the properties of the chitosan were studied. Furthermore,the effects of the composite materials prepared with the chitosan treated with the hexamethyldisilazan were studied.The results showed that,the composite materials have the best mechanical properties when the treatment temperature is about 80℃,the reaction time is about 48 hours and the amount of hexamethyldisilazan is about 70wt%of chitosan.In this paper,hydroxyaptite/chitosan composite materials were prepared by coprecipitation method using phosphoric acid,calcium hydroxide and chitosan.The composite is analyzed by IR,X-ray methods,the results showed that the hydroxyaptite contains carbonic acid and similar to the phosphorite in the nature bone.In this paper,the three-element composite materials were prepared with hydroxyaptite/chitosan treated with hexamethyldisilazan and addition-cured high-temperature vulcanized silicone rubber.The effects on the mechanical properties of the composite materials prepared with the treated hydroxyaptite/chitosan were researched.The results showed that,the three-element composite materials have the best mechanical properties when the treatment temperature is about 80℃,the reaction time is about 48 hours and the amount of hexamethyldisilazan is about 25wt%of hydroxyaptite/chitosan.In this paper,the effects of different amount of hydroxyaptite/chitosan on the properties of the three-element composite materials were studied.The results showed that with the increasing of the hydroxyaptite/chitosan,the mechanical properties such as tensile strength,tear strength were reduced.The effects of different amount of hydroxyaptite/chitosan on the fatigue strength of the three-element composite materials were studied.The results showed that with the increasing of hydroxyaptite/chitosan,the endurance bending strength of the composite materials had fallen rapidly.When the hydroxyaptite/chitosan amount was 30wt%of the composite materials,its frequency of six crack had been less than 1000.The effects of different amount of hydroxyaptite/chitosan on the surface wettability of the composite materials were studied.The results showed that with the increasing of hydroxyaptite/chitosan,the composite materials' surface wettability was increased.When the hydroxyaptite/chitosan amount was 20wt%of the composite materials,the wetting angle was less than 90°.At the same time,swelling degree of the composite materials was increased with the increasing of hydroxyaptite/chitosan.