| 3D printing technology has developed rapidly in recent years,and represents the development direction of advanced manufacturing technology.However,kinds of materials for 3D printing are very limited and far from satisfaction to the needs of rapidly developing technology and application,especially in biomedical fields.Poly(propylene fumarate)(PPF)owns the basic properties of 3D printing materials and has been widely used in biomedical engineering,which have a high research and application value.This paper explored the feasibility of applying PPF composite material system as a new kind of 3D printing material.Firstly,Synthesis process was optimized by two steps way.Dimethyl fumarate and 1,2-Propylene glycol were used as raw materials,ZnCl2 as catalyst and hydroquinone as polymerization inhibitor.Materials were reacted at 140 °C for 12 h to obtain the PPF oligomer,and further reacted at 200 °C under vacuum for 3 h.The yield of PPF reached 69.4%.Infrared spectrum and nuclear magnetic resonance hydrogen spectrum analysis were utilized to confirm the molecular structure.By gel permeation chromatography,the number average molecular weight Mn of the synthesized product was 5408 and the polymerity distribution index(PI)was 1.57.Secondly,the thermal curing properties of PPF were systematically studied.By optimizing initiator types and adding proportion,auxiliary crosslinking monomer type and adding ratio and curing temperature,we found that with benzoyl peroxide(BPO)as initiator,N-vinyl pyrrolidone(NVP)as the auxiliary crosslinking monomer,the obtained PPF composite system has excellent curable properties.In addition,the curing time,gel content,thermal stability,moisture absorption,compressive strength,in vitro degradation rate and the influence of the cytotoxicity of the PPF composite material were also studied in detail by several factors such as BPO addition ratio,NVP content and heat curing temperature.The results showed that the optimal mass fraction of PPF,NVP,BPO was 85,15,5,while PPF was used as the main body.This PPF composite material system pocessed good liquidity,and the shortest curing time(3s)at 200 °C.After curing the PPF composite,the gel content reached 75.6%,the compressive strength reached 5.57 MPa,which was equal to compression strength of the human cancellous bone.After curing the PPF composites,material in 45 °C environment with relative humidity RH of 89% for 72 h,the moisture absorption rate was only 4.71% and the swelling degree was only 18.15% in vitro degradation experience for 72 h,which showed good dimensional stability.TG analysis results showed that the composite material had a weight loss rate of less than 0.83% within 250 °C,and it had good thermal stability under the condition of thermal curing temperature(180~200 °C)for 3D printing materials.In vitro simulated degradation experiments,PPF curing material had excellent biodegradability,and its degradation rate increased with BPO content reduction or NVP content increased,and it can be adjusted within a certain range.In vitro degradation for 4 weeks,PPF curing resin degradation weight loss rate can reach 13.46%.Cytotoxicity experiments showed that the material cytotoxicity was rated asⅠand showed non-toxic to 3T3 cells even when the concentration of PPF curing resin material is up to 100 mg/m L,which satisfied the biosafety requirements of material.The modified FDM printing device was used to carry out 3D printing molding experiments with optimized PPF composites.The nasal prepared formed rapidly,and had smooth surface,complete three-dimensional structure and suitable strength.Therefore,the PPF composites could meet the requirements of heat curing molding device and has broad application prospects. |
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