Preparation And Performance Of Polyamide 1010/Hydroxyapatite Porous Scaffold Materials

Bone defects caused by congenital deficiencies,accidents and other factors are more and more severe and causes tremendous suffering to patients.In order to alleviate this phenomenon,bone repair materials came into being and received widely attention.Hydroxyapatite(HA)is the main inorganic component of human body,which has many advantages,such as biological activity,good biocompatibility,the bone conduction,non-toxic,etc.However,poor mechanical properties make it greatly restricted in clinical application.On the other hand,polyamide(PA)has good mechanical properties and has the same amide bond and carboxyl group structure as collagen.The composites of PA and HA can improve the deficiency of the mechanical properties of HA,besides,it has high bionic properties,which makes it a promising bone repair material with good performance.A series of PA1010/HA composites with different HA content were prepared by melt blending method.The structural changes of PA1010/HA composites were studied by FTIR.The results showed that hydrogen bonding was found between HA hydroxyl and PA1010 amide.The distribution of HA in PA1010/HA composites was observed by EDS.The results showed that the distribution of HA in the PA1010matrix was relatively homogeneous.The melting crystallization behavior and thermal stability of PA1010/HA composites were studied by DSC and TG.The results showed that the addition of HA reduced the T_m and?H_f of PA1010 composites slightly,and the PA1010/HA composites had good thermal stability.The physical-mechanical tests of PA1010/HA composites show that HA has an obvious enhancement effect on PA1010 in composites.What's more,with the increase of HA content,mechanical property was enhanced.When the HA's content was 40 wt%,the tensile strength and flexural strength increased by about 33.4%and 98.3%,respectively.Based on the PA1010/HA composites material,porous scaffold materials were prepared by chemical foaming method and rapid prototyping technique,and their properties were studied.The PA1010/HA porous scaffold material was prepared by injection molding with azo dimethyl amide(AC).The effect of AC on the structure of PA1010/HA composites was studied by ATR and XRD,and the results showed that the addition of AC and foaming process had no effect on the chemical structure of PA1010/HA.Through the calculation and analysis of porosity of PA1010/HA porous scaffold material,it is showed that the pore structure and porosity of PA1010/HA porous scaffold material can be controlled by adjusting the dosage of the AC foaming agent.When the dosage of AC is 2.5 wt%,the bubble hole is homogeneous,the pore size is100-200?m,and the porosity is 21.6%.When the dosage of AC foaming agent is 7.5wt%,the pore size is about 300-500?m and the porosity is about 38.7%.Considering the comprehensive mechanical properties,it is more suitable as a scaffold material when the foaming agent content is 2.5wt%.The PA1010/HA porous scaffold material were prepared by molten deposition rapid prototyping(FDM),and the effects of the printing layer thickness,printing speed and forming angle on the mechanical properties were studied.The results showed that the machine runs stably when the printing speed is 50 mm/s,and the mechanical properties of the samples are best when the printing layer thickness is 0.1mm,the tensile and bending samples's forming angle is 45°,and the compression sample is printed vertically.The effect of HA content on the mechanical properties of FDM samples was investigated.The results showed that when the content of HA was20 wt%,the samples quality were the best and its'mechanical properties were stable.Influence of pore size on the mechanical properties of porous scaffolds of FDM sample was studied.It showed that the mechanical properties decreased with the increase of the pore size.The results of optical microscope show that the actual aperture of the PA1010/HA porous scaffold material has a certain deviation from the theoretical aperture,and there is a certain porosity fusion and aperture plugging phenomenon.The results of porosity tests showed that the porosity of PA1010/HA porous scaffold material increased with the increase of pore diameter,and the actual porosity is slightly higher than the theoretical void ratio.