The Influence Of Processing Parameters On Mechanical Properties Of PLA/PCL Blend Microcellular Materials

Biopolymer microcellular materials have been widely used in the processing of tissue engineering scaffolds due to their high cell density,controllable cell size,uniform size distribution and degradability.The supercritical fluid batch microfoaming technique is a physical foaming method.It is widely used in the foaming molding of biopolymer because of no harmful solvent introduction and no pollution.Tissue engineering scaffolds require a certain degree of mechanical strength to provide carriers for cells and regenerated tissues to maintain normal human life.Therefore,it is of great significance to investigate the mechanical properties and formation mechanism of biopolymer microcellular materials for the processing and application of tissue engineering scaffolds.In this paper,the influence of foaming process parameters on the mechanical properties of PLA/PCL blend microcellular materials was studied by single factor experiment,and the relationship between cell morphology and mechanical properties was analyzed.The relationship between foaming process parameters and mechanical properties was established by using cell structure as the bridge.The main work and conclusions are as follows:(1)The effect of processing parameters on mechanical properties of PLA/PCL blends microcellular materials.The effects of saturation pressure,saturation time and foaming temperature on the mechanical properties of microcellular materials were studied by single factor methond.The results show that : with the increase of saturation pressure,the tensile strength and elongation at break of microcellular materials increase and the elastic modulus decreases for the case that the content of PLA is high;the tensile strength of microcellular materials decreased,the elongation at break increased,and the elastic modulus increased first and then decreased for the case that the content of PLA is low.With the increase of saturation time,the tensile strength and elastic modulus of PLA/PCL blends microcellular materials decreased first and then increased,the elongation at break of microcellular materials increased first and then decreased for the case that the content of PLA is high;the elongation at break of microcellular materials decreased for the case that the content of PLA is low.With the increase of foaming temperature,the elongation at break of microcellular PLA/PCL blends decreased,the tensile strength of microcellular materials decreased,and the elastic modulus increased first and then decreased for the case that the content of PLA is high;the tensile strength and elastic modulus of microcellular materials decreased first and then increased for the case that the content of PLA is low.(2)The effect of cell morphology on mechanical properties of PLA/PCL blends microcellular matterials.The effects of cell morphology(cell average size,cell density)and relative density on the mechanical properties of microcellular materials were investigated by single factor experiment methond.The relationship between foaming parameters and mechanical properties of microcellular materials was established by using cell morphology as a bridge.Changing the different process parameters such as saturation pressure,foaming temperature and saturation time,the relationship of cell average size,cell density,and relative density with the mechanical properties of the PLA/PCL blends microcellular materials can be obtained.The relationship between the morphology and mechanical properties of the microcellular materials was established.The results indicate : the tensile strength and elastic modulus of the microcellular materials decreased with the increase of the cell average size,and increased with the increase of cell density for the case that of the content of PLA is high;the tensile strength and elastic modulus of microcellular materials increased with the increase of average cell size,but decreased with the increase of cell density for the case that of the content of PLA is low.The tensile strength and elastic modulus of microcellular materials decrease rapidly with the decrease of relative density,so the relative density is the key factor affect the mechanical properties of microcellular materials.