Shape memory properties numbers

Mather, P.T., Liu, C., 2011. Blends of Amorphous and SemicrystaUine Polymers Having Shape Memory Properties. Patent, PCX number PCT/US2003/032329. 

One interesting alloy of titanium and nickel, called Nitinol, exhibits shape-memory properties. Below a particular temperature (the transformation temperature), the crystal structure of the alloy is such that it can be plastically deformed (martensitic). As the alloy is heated, the crystal structure alters to one that is more ordered and rigid (austenitic), and the deformed metal reverts to its original shape. This effect has been exploited in a number of devices, including a stent (a device used to hold open passageways such as arteries). The stent is placed inside a small-diameter catheter for insertion into the body, where it expands on being warmed to bod y temperature. 

The homopolymerization of the epoxylactone using diethylzinc and tin(ll) 2-ethylhexanoate as catalysts yields only low molecular weight oligomers with an number average molecular weight of less than 2.5 kgmol. However, the copolymeiization with -caprolactone results in flexible crosslinked materials in a one-step synthesis. These copolymers exhibit a near perfect shape memory property, even after repeated bending (72). 

In addition, an adjustment to the specific sample geometries in various applications is needed. There are a number of crucial aspects for a successful translation of SMP technology into industrial applications, such as a standardization of the different methods described for quantification of the shape-memory properties. The recently reported 3-D thermomechanical constitutive model assuming active and frozen phases, representing the multiphase character of thermoplastic SMPs can be an especially fruitful approach for the future development of finite element models for prediction of the thermomechanical behavior. 

Li, G. (2014) A smart sealant made of two-way shape memory polymer. Technology Disclosure Form (OIP number 1504). Office of Intellectual Property, Commercialization Development, Louisiana State University. 

Shape memory materials (SMMs) comprise a class of smart materials able to change their shape following application of an external stimulus. The first materials studied with shape memory behaviour were developed in the middle of the twentieth century. Since then, research into and demand for these materials have both increased, especially in recent years, due to their unique properties, versatility and growing industrial demands. Figure 7.1 shows the total number of scientific publications indexed on ISI Web of Knowledge and the number of research articles about shape memory polymers (SMPs) in the last 30 years in particular, the increase during the last six years is significant. 

Rim is a common and easily achieved shape for most polymers. Shape memory film or foam has a number of applications in laminated smart fabrics. Various properties of SMP films have been investigated such as thermomechanical properties, different structural factors on the physical and water vapour transport properties, " effects of crystal melting, " molecular weight and influence of different processing temperatures. ... 

Nitinol is a nickel-titanium alloy known as memory metal. The name nitinol is derived from the s)mnbols for nickel (Ni), titanium (Ti), and the acronym for the Naval Ordinance Laboratory (NOL), where it was discovered. If an object made out of nitinol is heated to about 500 °C for about an hour and then allowed to cool, the original shape of the object is "remembered," even if the object is deformed into a different shape. The original shape can be restored by heating the metal. Because of this property, nitinol has found many uses, especially in medicine and orthodontics (for braces). Nitinol exists in a number of different solid phases. In the so-called aus-terite phase, the metal is relatively soft and elastic. The crystal structure for the austerite phase can be described as a simple cubic lattice of Ti atoms with Ni atoms occupying cubic holes in the lattice of Ti atoms. What is the empirical formula of nitinol and what is the percent by mass of titanium in the alloy ... 

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