Dissertation > Medicine, health > Basic Medical > Medical science in general > Biomedical Engineering > General issues > Biomaterial

Preparation and in Vitro Degradation of Poly(propylene Fumarate)/(calcium Polyphosphate/calcium Sulphate) Composites

Author XinYu
Tutor YangDeAn
School Tianjin University
Course Materials Science
Keywords poly(propylene fumarate) CaSO4 calcium polyphosphate in vitro degradation composites
CLC R318.08
Type Master's thesis
Year 2012
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In this study, a two-part bone tissue engineering scaffold which consists of solidpoly(propylene fumarate)(PPF) matrix and calcium polyphosphate/calcium sulphate(CPP/CaSO4) filler was investigated. This new material can form pores in situ, andkeep enough compressive strength in a certain time after the pores formed.Poly(propylene fumarate)(PPF) was synthesized by a two-step method, andcharacterized with1H-NMR and GPC. We fabricated calcium polyphosphate powder,and then we investigated on the preparation of porous spherical CPP/CaSO4granules.PPF/CPP/CaSO4composites were formed by using N-vinyl pyrrolidinone (NVP) as acrosslinking monomer, benzoyl peroxide (BPO) as a radical polymerization initiator,N, N-dimethyl-p-toluidine (DMPT) as an accelerator, and CPP/CaSO4granules asfiller. The phase composition of CPP/CaSO4granules sintered at differenttemperatures and degradation product was analyzed by X-ray powder diffraction(XRD); the degradation behavior of composites were investigated by weight loss,water absorption and swelling degree; the morphology change was observed by scanelectron microscope (SEM).The phase composition of CPP/CaSO4granules was effected by sinteringtemperature and CPP/CaSO4ratio. All the armorphous CPP crystallized to β-CPP inthe CPP/CaSO4granules sintered at580℃. Yet, for the CPP/CaSO4granules sinteredat560℃, the more CaSO4content, the less β-CPP crystallization. Thus it can beconcluded that the addition of CaSO4could inhibit the devitrification of CPP.The in vitro biodegradation property of PPF/CPP/CaSO4composites wasexamined by using cylindrical specimens with length of5mm and diameter of6mm.The composite degradated faster with a higher CaSO4content or a higher NVP/PPFratio. The compressive strength decreased with the decrease of NVP/PPF ratio and theincrease of the CaSO4content.

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