ANALYSIS ON INFILTRATIVE CHARACTERISTICS OF DEFORMABLE POROUS MATAL RUBBER MATERIAL AND PARAMATERS IDENTIFICATION

The effect of deformation of porous material on infiltrative performance is investigated. Based on Darcy theory and Boit principle, the Reynolds equation and mathematical expression of deformable metal rubber （MR） material under laminar flow are obtained according to the change of porosity of metal rubber. It is shown that the throttle of MR material is dependent on its porosity and diameter of metal wires. It will be of great value for the application of MR in throttle field.

Oxygen transmission of modified natural rubber,poly(lactic acid) and chitosan porous structures for wound dressing

Oxygen is a significant factor essential to provide the additional energy source for the wound repairing process.Many polymeric materials have been employed recently in wound dressing such as natural rubber(NR)[1],poly(lactic acid)(PLA)and chitosan[2]because of their biocompatibility and biodegradability.In this study,the oxygen transmission rate(OTR)of modified NR,PLA and chitosan porous structure was determined.The comparison for their OTR was investigated.

Potential Application of Entangled Porous Titanium Alloy Metal Rubber in Artificial Lumbar Disc Prostheses

Entangled Porous Titanium Alloy Metal Rubber(EPTA-MR)was used as a nucleus pulposus material in the design of non-fusion intervertebral disc prosthesis for the first time.A novel artificial lumbar intervertebral disc prosthesis was designed by reconstructing the lumbar model with reverse engineering technology,and the biomechanical behavior of the prosthesis was simulated under varied working conditions.The nucleus pulposus size was determined by the actual size of human prosthesis.EPTA-MR samples with different densities were prepared by medical titanium alloy wire experimental studies were conducted on static stiffness,damping energy consumption,and fatigue life.The results indicated that the static stiffness of EPTA-MR could reach approximately 1500 N mm and its loss factor remained higher than 0.2,and the variation range was relatively small,with excellent vibration damping capacity and bearing capacity.Among them,the overall performance of EPTA-MR with a density of 2.5 g em 3 was closer to that of the physiologic intervertebral disc.A macro experiment of five million fatigue vibration tests combined with microstructure observation exhibited a wear rate of only 0.9396 g-MC with no noticeable change in the internal micro-morphology.Therefore,the EPTA-MR has a broad application prospect as the nucleus pulposus material of artificial intervertebral disc prosthesis.

Soft-template synthesis of hierarchically porous structured polydimethylsiloxane toward flexible capacitive pressure sensor

Flexible pressure sensors play an important role in the field of monitoring, owing to their inherent safety and the fact that they are embedded at the material level. Capacitive pressure sensors have been proven to be quite versatile, with the ability to change the sensitivity and monitoring range by modifying the pore structure of the dielectric layer(elastic modulus). In this paper, capacitive pressure sensors are devised, comprising hierarchical porous polydimethylsiloxane. Due to the inherent hollow and hierarchical micropore structure, the capacitive pressure sensor allows operation at a wider pressure range(~1000 kPa) while maintaining sensitivity(6.33 MPa-1) in the range of 0–300 k Pa. Subsequently, the capacitance output model of the sensor is optimized, which provides an overall approximation of the experimental values for the sensor performance. Additionally, the signal response of the“break up the whole into parts”(by analysis of the whole sensor in parts) is simulated and outputted by the finite element analysis. The simplified analysis model provides a good understanding of the relationship between the local pressure and the signal response of the pressure sensor. For practical applications, seal monitoring and rubber wheel pressure array system are tested, and the proposed sensor shows sufficient potential for application in large deformation elastomer products.