Study On The Preparation And Properties Of Starch-based Porous Materials By Ice Templating Method

Tissue engineering is an interdisciplinary that applies the principles of bioscience and engineering science to repair or regenerate defected tissue or organ to maintain or improve tissues and organs function.The fundamental feature of tissue engineering lies in that the repair and reconstruction functions are based on the support and reinforcement provided by the porous scaffold material where repairing is needed.Moreover,it is important that the scaffold material should be non-toxic and biodegradable with high porosity and interconnected porous structure to provide possibility for induced differentiation and growth of cells.Therefore,it is a big question,in tissue engineering to reproduce the ideal three-dimensional porous scaffold.To solve this problem,in-situ observation of directional solidification is utilized to study the morphology evolution in real time during directional solidification of PVA aqueous solution with different mass fractions under different pulling speeds and a certain amount of knowledge of the influence of the two variables on the morphology of ice crystals.On this basis,the synthetic polymer polyvinyl alcohol(PVA)and the nature polymer chitosan were utilized to blend with starch respectively,and preparation of the starch/PVA porous material and starch/chitosan porous material were achieved by ice-templating method,which was followed by morphological characterization of the material and the physical and biological properties tests.The main conclusions are listed below:(1)For starch/PVA porous materials,the pore size decreased with the increment of PVA mass fraction.With the increment of starch mass fraction,the pore shape is also altered,and clusters emerged when the starch content reached 15wt.%.With the increment of pulling speed,the pore size also decrease and the pore morphology transformed from long pores to circular pores.(2)For starch/PVA porous materials,the pores of the starch/chitosan material exhibited lamellar morphology.And the increment of chitosan content resulted in a decrease in lamellar spacing of the material,the thickness of the lamellar structure reached maximum when the content of chitosan increase to 3wt.%.The maximum porosity of starch/chitosan porous material is 91.02%..(3)The compression test results indicate that the compressive strength of starch/PVA porous material and starch/chitosan porous materials increase with the increment of pulling speed.The compressive strength of starch/PVA porous material increases exponentially with the increase of PVA content,and the maximum compressive strength reach 4.80 MPa.The compressive strength of the starch/chitosan porous material is 1.18 MPa maximum.(4)The starch/PVA porous material and starch/chitosan porous materials exhibit good hydroscopicity,which could be tuned by altering the content of additives.Furthermore,the starch-based porous material had good biodegradability and biocompatibility and is proved to be a nice alternative for porous material in tissue engineering scaffold.