Experimental Evaluation of the Rheological Properties of Veriflex®Shape Memory Polymer

Abstract

Shape memory polymers (SMPs) are materials with a great potential for future use in smart materials and structures. When heated from cold state (below the transformation temperature, which can either be the glass transition temperature or the melting temperature of the polymer) to hot state (above the transformation temperature) they undergo transformation which can be compared with martensitic transformation of shape memory alloys. This process induces great changes of the mechanical properties and some shape memory phenomenon can be observed. This study is an experimental evaluation of the mechanical properties of SMP Veriflex ® under different test conditions. Veriflex ® was chosen because of its easy accessibility. Furthermore its properties are similar to epoxy resins which make it very suitable for usage in a wide variety of technical applications. Dynamic mechanical analysis (DMA) was used to determine evolution of the viscoelastic properties versus temperature and frequency under cyclic harmonic loading. The glass transition temperature clearly appears in a range from 45°C to 60°C depending on loading frequency. The glass transition is noticeably marked by an impressive decrease in the storage modulus of about 4 decades. The master curve of Veriflex ® was created and allows the time-temperature superposition to be constructed for this material. Thermo-mechanical working cycle of SMP with 100% elongation was also experimentally tested. Finally results from all these experimental investigations were used to design a demonstrator showing the possibility of application in engineering and especially for shape control.