Thermo-mechanical-chemical Behaviors Of Enzyme-degradable Shape Memory Composite And Shape Memory Properties

One of the most promising fields of shape memory polymers is biomedicine.Shape memory polymer can be driven by temperature and humidity,and can also be driven by electromagnetic field and ultrasonic wave.These polymers show great potential in both in vitro and in vivo studies.Their biocompatibility,and in some cases their biodegradability,make them excellent choices for minimally invasive surgery and driveable biomedical device design.Compared with heat responsive shape memory polymers,enzyme driven shape memory polymers can restore their original shape without exceeding body temperature,which avoids tissue damage and the inability to use body temperature to drive shape recovery.Due to the lack of quantitative description of the behavior characteristics of enzymatic degradation shape memory composites under thermal mechanical chemical coupling,this paper mainly studies enzymatic degradation shape memory composites(EDSMC)and establishes the corresponding thermo-mechanical-chemical coupled constitutive model.The main research works and innovations are as follows:(1)in the framework of finite deformation,a continuum model considering mass diffusion,enzyme degradation reaction,super elastic viscoplastic deformation and mutual coupling is established.Then,the thermal mechanical chemical behavior and shape memory properties of the enzymatic degradation shape memory composites(EDSMC)were analyzed.(2)A homogenization model considering crystal plasticity is established,and a hysteresis coefficient is introduced into the diffusion equation to consider the hysteresis response caused by molecular effect.Then,the mechanical behavior of polycaprolactone(PCL),which is an important component of enzyme degradable shape memory composites(EDSMC),was tested and calculated in three different enzyme concentration solutions.