Shape-Memory Behavior of Poly(L-Lactide)/Poly(ε-Caprolactone) Blends

Abstract

Poly(L-lactide) and poly(ε-caprolactone) (PLLA/PCL) blends with various weight ratios were compounded by melt mixing and their shape memory properties were investigated. The thermal properties, surface morphology and dynamic mechanical properties of the blends were characterized. The results demonstrate that the introduction of PCL improves the process of crystallization of PLLA whereas the reverse situation is for PCL. PLLA/PCL blends were found to exhibit an immiscible behavior from the characterizations of surface morphology. DMA tests show the blends with different weight ratios have different transition temperatures. The properties of blends provide the basis of owning shape memory behavior. The strain recovery ratio (Rr) of PLLA/PCL blend with the weight ratio of 1:3 was about 95% within 22s, whereas the Rr of other blends were less than 75% within 23~30s. It was found that lower transition temperature combined with increased crystallization of PLLA with the increasing PCL content contribute to such a good shape memory effect.

Thermally-activated shape memory effect on biodegradable nanocomposites based on PLA/PCL blend reinforced with hydroxyapatite

“…Dong et al [23] reported a pioneering work on shape-memory material based on PLLA/PCL blends in 2011. They reported that PLLA/PCL blend with the weight ratio of 1:3 presents a R r of about 95% within 22s.…”

Anisotropic Shape Memory Behaviors of Polylactic Acid/Citric Acid–Bentonite Composite with a Gradient Filler Concentration in Thickness Direction

“…In recent years, biodegradable SMPs are of increasing interest for applications in various areas. − Many works have reported that polylactic acid (PLA) and its copolymers have a mild SM effect. , In order to further improve the performance, clays such as kaolinite, montmorillonite, halloysite, etc., have been employed to prepare PLA-based SM composites. Before composite preparation, organic modification for clays is necessary to be done because the surface treatment not only enhances the compatibility between clays and PLA but also helps to achieve a uniform dispersion of clays.…”

Shape memory elastomers: A review of synthesis, design, advanced manufacturing, and emerging applications

“…Molecular architecture or molecular deformation mechanism, is another essential factor in achieving shape memory behavior 52,53 . The molecular architecture of SMEs must consist of net‐points (the hard phase or fixed phase) and switching units (the soft phase or reversible phase), which allow the structure to be deformed, maintained, and recovered under applied force and external activation 54,55 . Recently, Chien et al 56 studied shape memory characteristics of SME‐based waterborne biodegradable polyurethane.…”

“…52,53 The molecular architecture of SMEs must consist of net-points (the hard phase or fixed phase) and switching units (the soft phase or reversible phase), which allow the structure to be deformed, maintained, and recovered under applied force and external activation. 54,55 Recently, Chien et al 56…”