title: Performance test of Nano-HA/PLLA composites for interface fixation.
abstract: OBJECTIVE
  By in situ polymerization of poly-L-lactic acid (PLLA) and nano-hydroxyapatite (Nano-HA), and finding the best proportion of composite, so as to get ideal interface fixation material.
  
  
  METHODS
  According to a certain ratio (the mass fraction of Nano-HA, respectively, is 0%, 10%, 20%, 30% and 40%), composite PLLA and Nano-HA by in situ polymerization, and test the performance of this kind of new type of interface fixation such as, bending strength,compressive strength, elastic modulus, scanning electron microscopy (SEM) and degradation experiments in vitro. Then observe its mechanical properties, microstructure, the dispersion of Nano-HA in the PLLA and degradation rate of composite materials.
  
  
  RESULTS
  1. Mechanical tests show that with the increase of Nano-HA content, the tensile strength decreases and the elastic modulus increases; with Nano-HA content of 20%, the bending strength of composite materials presents the peak value (156.8 MPa). 2. SEM scan shows the fracture surface of pure PLLA is relatively smooth; with Nano-HA content of 10%, the fracture surface shows a large number of dimples, and is obvious rough; with Nano-HA content of 20%, the fracture surface is uneven, forming a large number of dimples; with Nano-HA content of 30% or more, the fracture surface becomes more flat, and there are some small dimples. 3. Degradation experiments in vitro show the following: as the degradation time goes on, the pH values of degradation liquid is gradually reduced and the mechanical properties of composite materials also gradually have some decay.
  
  
  CONCLUSIONS
  With Nano-HA content of 20%, the interface fixation material has a better mechanical properties and degradation properties. According to the best ratio, prepare Nano-HA/PLLA composite artificial materials with good performance.
authors: Department of Surgery, Guangzhou Medical University , Guangzhou , P. R. China.
authors: Weimin
authors: W
authors: Zhu
authors: Jianghong
authors: J
authors: Huang
authors: Wei
authors: W
authors: Lu
authors: Qifeng
authors: Q
authors: Sun
authors: Liangquan
authors: L
authors: Peng
authors: Wenzhe
authors: W
authors: Fen
authors: Hao
authors: H
authors: Li
authors: Yangkan
authors: Y
authors: Ou
authors: Haifeng
authors: H
authors: Liu
authors: Daping
authors: D
authors: Wang
authors: Yanjun
authors: Y
authors: Zeng
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D001842:Bone and Bones / Q000293:injuries / Q000601:surgery; D017886:Durapatite / Q000737:chemistry*; D005593:Fracture Fixation, Internal; D050723:Fractures, Bone / Q000601:surgery; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry*; D055595:Mechanical Phenomena; D053761:Nanocomposites / Q000737:chemistry*; D011091:Polyesters; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D013710:Tendons / Q000601:surgery
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D017886:Durapatite
keywords: in situ polymerization; interface screw; nano-hydroxyapatite; poly-L-lactic acid