Triple‐Shape Polymeric Composites (TSPCs)

Abstract

In this paper, the fabrication and characterization of triple‐shape polymeric composites (TSPCs) that, unlike traditional shape memory polymers (SMPs), are capable of fixing two temporary shapes and recovering sequentially from the first temporary shape (shape 1) to the second temporary shape (shape 2), and eventually to the permanent shape (shape 3) upon heating, are reported. This is technically achieved by incorporating non‐woven thermoplastic fibers (average diameter ∼760 nm) of a low‐Tm semicrystalline polymer into a Tg‐based SMP matrix. The resulting composites display two well‐separated transitions, one from the glass transition of the matrix and the other from the melting of the fibers, which are subsequently used for the fixing/recovery of two temporary shapes. Three thermomechanical programming processes with different shape fixing protocols are proposed and explored. The intrinsic versatility of this composite approach enables an unprecedented large degree of design flexibility for functional triple‐shape polymers and systems.

Shape-memory behavior of cross-linked semi-crystalline polymers and their blends

“…The distinct occurrence of triple-shape effect in polymer composites on the basis of electrospun PCL fibers embedded in an epoxy-based copolymer thermoset system was reported by Luo and Mather [11]. The temperature dependence of SM recovery strain obtained for this system both after two-step programming as well as after one-step programming (OSP) exhibit two well observable steps/decrements in temperature ranges of glass transition of epoxymatrix and of PCL melting.…”

“…Polymer materials, which reveal multiple SME, are highly innovative smart materials, which permit a number of novel engineering, medical, and pharmaceutical applications [9,10]. Because of great importance of aforementioned applications, SM polymer materials with relatively low switching temperatures (T sw ), which are nearly equal to melting temperatures of their crystalline phases, are a matter of particular interest.As an alternative to an expensive synthesis of complex interpenetrating networks and copolymers the multiple SM effects can be also achieved in covalent networks on the basis of polymer blends, if suitable phase morphology can be generated [11][12][13]. The distinct occurrence of triple-shape effect in polymer composites on the basis of electrospun PCL fibers embedded in an epoxy-based copolymer thermoset system was reported by Luo and Mather [11].…”

Design of Triple-Shape Memory Polyurethane with Photo-cross-linking of Cinnamon Groups

“…c n from the tradition triple shape memory generally reported. 20,38,39 Here, we developed a new method to synthesize a triple shape memory system with an easy and controllable method. In this system, there is a wide temperature difference between the soft segment in the polyurethane and the photocross-linked structure from polyurethane hard segment, in which the T m of PCL-diols and the T g of the crosslinking structure of the hard segment can act as the two transition temperatures of the triple shape memory polyurethane.…”

Mechanisms of the Shape Memory Effect in Polymeric Materials

“…On the other hand, a few new shape memory phenomena have been discovered [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], which not only enhance the flexibility of the current shape memory technology, but also add in new dimensions for extended versatility and adoptability. Consequently, a number of novel concepts have been proposed for a range of engineering applications [45,[48][49][50][51][52][53][54], in particular in the field of biomedical engineering as of the last couple of years [24,43,[55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70].…”