Study On The Preparation And Properties Of Thermoplastic Elastomer SEEPS For Human Tongue

With the improvement of the material living standard,the problem of obesity and its complications caused by excessive intake of high-fat food with good taste was becoming increasingly serious.For obese patients,a good taste of low-fat food was a common method to solve the problem.However,it was crucial to evaluate the properties of the mouthfeel by different age groups.Therefore,this paper mainly studied the characterization of tongue deformation properties and surface properties of people of different age groups,prepared biomimetic materials with different properties,and studied the factors affecting the friction properties of sticky food,which will provide technical reference for the research and development of functional food of different age groups.Firstly,the method of testing and characterization of the deformation property of human tongue was studied,that is,a measuring device for in-situ deformation of soft material was constructed.And the validity of the method was verified by the MFT-5000 test rig.What's more,the deformation of soft material was simulated by the finite element method and the elastic modulus was obtained.The equivalent thickness volume modulus(IVMET)was used to characterize the deformation properties of soft materials.The results showed that the in-situ deformation measurement can effectively characterize the deformation properties of soft materials.The instantaneous volume modulus of the soft material decreases sharply with the thickness ratio and then got stable with the depth-thickness ratio.The thickness of the material has a great influence on the elastic modulus of the soft material obtained by the finite element method,so the deformation properties of the soft material cannot be effectively characterized.However,IVMET can be used to characterize the deformation properties of the soft material.The tongue structure and its stress state affected the IVMET,and IVMET at the tension state was significantly higher than that at the relaxation state.At the same time,different age groups affected the IVMET of the human tongue.Secondly,the thermoplastic elastomer(SEEPS-TPE)of styrene-b-ethylene-ethylenepropylene-b-styrene(SEEPS)was selected as oral biomimetic material to investigate the effects of the addition of Talc on the hardness,tensile properties,deformation properties and surface properties of SEEPS-TPE.The surface morphology model containing human tongue was prepared and its surface properties were studied.The results showed that the hardness of biomimetic materials were positively correlated with the addition of Talc.The tensile strength,elongation at break and permanent elongation of SEEPS-TPE all increased first and then decreased with the increase of Talc.The optimal tensile properties of SEEPS-TPE were obtained when the addition of Talc reached 25 phr.IVMET decreased with the addition of paraffin oil and increased with the addition of Talc.With the increase of paraffin oil,the surface roughness and peak value difference of SEEPS-TPE decreased,and the surface hydrophobicity increased.The surface contact angle of micro convex SEEPS-TPE was positively correlated with elongation.With the increase of Talc,the surface roughness of SEEPS-TPE decreases first and then increases,the surface peak value changes irregularly,and the surface hydrophobicity decreases.The surface morphology of SEEPS-TPE was different from that of human tongue model,but the surface roughness and the peak value of micro convex body were still in the same order of magnitude.Finally,the friction performance of sticky food on SEEP-TPE was studied,that was,the salad dressing with different fat content and the mixture of salad dressing and artificial saliva were used as the lubrication medium,and the ceramic ball and SEEP-TPE were used as the friction pair.The friction performance test was carried out on the MFT-5000 test rig under different working conditions.The results showed that the average coefficient of friction of salad dressing decreases with the increase of velocity,and decreases first and then increases with the increase of load.The average coefficient of friction with the low-fat dressing was higher than that with the high-fat dressing.In view of the difference of tongue IVMET in different age groups,it was found that the friction properties of salad dressing were different based on SEEPS-TPE friction pairs with different performance.The research results will provide a reference for the research of functional food in different age groups.