A Facile Approach toward Thermoplastic Triple‐Shape Memory Polymers

Abstract

In this work, a ternary blend of polyolefin elastomer (POE), lauric acid (LA), and poly(ε‐caprolactone) (PCL) with triple‐shape memory effect (triple‐SME) is reported. LA and PCL exhibit distinct thermal transitions and construct two reversible switching networks capable of fixing and releasing different temporary shapes under a mild condition. The ternary blend shows excellent triple‐shape memory properties and good toughness. Besides, the permanent shape can be reconfigured by a simple thermal treatment. These particular features make the novel blend a competitive candidate for diverse applications. And the creative combination of crystalline small molecule and semicrystalline polymer expands the freedom for producing triple‐shape memory polymers (triple‐SMPs).

4D Printing of Triple-Shape Memory Cyanate Composites Based on Interpenetrating Polymer Network Structures

“…7,8 Three-phase blending can also achieve a triple-shape memory effect. 9,10 Another way to obtain TSMP is copolymerization after blending resins to form heterogeneous cross-linking structures and broad glass transition regions. 11−13 The third one is the formation of dynamic covalent bonds in the resin, using the bond fracture and formation to achieve a triple-shape memory effect.…”

“…At present, there are four main methods to prepare TSMP. The first is to blend two resins to make the polymer with a wide glass transition region. , Three-phase blending can also achieve a triple-shape memory effect. , Another way to obtain TSMP is copolymerization after blending resins to form heterogeneous cross-linking structures and broad glass transition regions. − The third one is the formation of dynamic covalent bonds in the resin, using the bond fracture and formation to achieve a triple-shape memory effect. − The last is to achieve a triple or quadruple SME through the structural design of multiple materials, such as bilayers, laminates, and segmented structures. − For amorphous SMP, two well-separated glass transition peaks are necessary for the polymers to have outstanding triple-shape memory behaviors. The TSMP prepared by the above methods has a broad glass transition region, and the two glass transition peaks do not separate or overlap in a large area.…”

Smart Shape Memory Polyurethane with Photochromism and Mechanochromism Properties

“…[1][2][3][4][5][6][7][8][9] There are several types of SMP materials, and they can be divided into thermally, electrically, photo, magnetically, and chemically actuated SMPs. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] At present, most SMPs are thermally actuated, and they are heated to a shape memory transition temperature T trans (T trans is the shape memory transition temperature, which is the glass transition temperature or melting transition temperature). Then, the temporary shape of the SMP is fixed by maintaining the external force and reducing the temperature to below T trans .…”

Triple‐shape memory materials based on cross‐linked ethylene‐acrylic acid copolymer and ethylene‐vinyl acetate copolymer

“…The most common triple-SMP is designed by introducing two polymers to endow the blend two transition temperatures and the strategies can be achieved by grafting, copolymerization, blending and interpenetrating polymer network. [25] For example, Zhang et al [26] prepared the ternary blend of polyolefin elastomer, lauric acid (LA), and poly(ε-caprolactone) (PCL) and the blend showed excellent shape fixity ratio (SF 1 > 95%, SF 2 > 95%) and shape recovery ratio (SR 1 > 95%, SR 2 > 90%); and the different transition temperatures were provided by the crystallization/melting transitions of LA and PCL. Cuevas et al [27] prepared the blend based on the poly cyclooctene (PCO) and polyethylene (PE) and the prepared materials showed the brilliant shape fixity ratio (SF 1 is about 95%, SF 2 is about 90%) and shape recovery ratio (SR 1 is about 95%, SR 2 > 95%).…”