Shape memory polymers types

Shape memory polymers make up another class of injectable biomaterials for vascular applications, yet are relatively new in the field of endovascular embolization. Shape memory polymers are chemically structured so that they are able to reversibly take on a different physical shape in response to some stimuli (Small et al, 2007). Usually these different shapes include a compact form and an expanded form of the polymer. In the case of endovascular embolization, the expanded polymer can be pre-formed to fit specific contours of an individual aneurysm (Ortega et al, 2007). Upon interacting with some type of stimuli, such as heat or cold, the material is compacted into a shape that can be delivered through a microcatheter. The process of using shape memory polymers to embolize an aneurysm is shown in Fig. 7.5, along with samples of expanded SMPs (Ortega et al, 2007). 

Schematic figures of the shape memory mechanism of the styrene-butadiene-styrene (SBS) triblock copolymer/poly(e-caprolactone) (PCL) blend in (a)-(d). (Adapted from Zhang, H., Wang, H., Zhong, W, and Du, Q. 2009. A novel type of shape memory polymer blend and the shape memory mechanism. Polymer 50 1596-1601. Copyright Elsevier Ltd. Reproduced with permission.)...

Zhang, H., Wang, H., Zhong, W., and Du, Q. 2009. A novel type of shape memory polymer blend and the shape memory mechanism. Polymer 50 1596-1601. 

As mentioned in Chapter 8, some vegetable oil-based polymers exhibit shape memory properties. The discovery of smart materials is one of the revolutionary steps in the held of active materials research. Among different types of smart materials (metals, alloys and ceramics), shape memory polymers (SMPs) have attracted considerable research interest in last few years because of their advantages over other categories of materials, as discussed in Chapter 1. Shape memory polymers which are deformed and... 

Classifying shape memory polymers classification by type of stimulus... 

High performance T -type shape memory polymers... 

Key words T -type shape memory polymers, phase separation, phase morphology, shape memory properties. 

---