Fracture Toughness Improvement of Poly(lactic acid) Reinforced with Poly(ε-caprolactone) and Surface-Modified Silicon Carbide

Jie Chen,Tian-Yi Zhang,Soo-Jin Park,Fan-Long Jin

doi:10.1155/2018/6537621

Abstract

In this study, bio-based poly(lactic acid) (PLA)/polycaprolactone (PCL) blends and PLA/PCL/silicon carbide (SiC) composites were prepared using a solution blending method. The surface of the SiC whiskers was modified using a silane coupling agent. The effects of the PCL and SiC contents on the flexural properties, fracture toughness, morphology of PLA/PCL blends, and PLA/PCL/SiC composites were investigated using several techniques. Both the fracture toughness and flexural strength of PLA increased by the introduction of PCL and were further improved by the formation of SiC whiskers. Fracture surfaces were observed by scanning electron microscopy, which showed that the use of PCL as a reinforcing agent induces plastic deformation in the PLA/PCL blends. The SiC whiskers absorbed external energy because of their good interfacial adhesion with the PLA matrix and through SiC-PLA debonding in the PLA/PCL/SiC composites.

Highlights

Poly(lactic acid) (PLA) is a biodegradable, bioabsorbable, and renewable thermoplastic polyester that can be obtained by the ring-opening polymerization of lactide [1,2,3,4]
Despite its high tensile modulus and strength, PLA has poor toughness due to its stiff backbone chain, which limits its use in many fields. us, blending with a ductile biodegradable polymer and addition of inorganic fillers has previously been reported as methods to improve the toughness of PLA [8,9,10]
PCL has high flexibility, with a low glass transition temperature and melting point. e toughness of PLA is improved when blended with PCL, which acts as a plasticizer, and the resulting blend is likely to retain its biodegradability [11,12,13,14]

Summary

Introduction

Poly(lactic acid) (PLA) is a biodegradable, bioabsorbable, and renewable thermoplastic polyester that can be obtained by the ring-opening polymerization of lactide [1,2,3,4]. Us, blending with a ductile biodegradable polymer and addition of inorganic fillers has previously been reported as methods to improve the toughness of PLA [8,9,10]. Several researchers have reported the preparation of biodegradable PLA/PCL blends with outstanding mechanical and physical properties. Urquijo et al studied the effect of melt processing conditions on phase structure, morphology, and mechanical properties of PLA/PCL blends [19]. Eir results showed that the fracture toughness of PLA was significantly increased with the addition of functionalized silica nanoparticles. E effects of the PCL and SiC contents on the mechanical properties, fracture toughness, and morphology of the prepared PLA/PCL blends and PLA/PCL/SiC composites were investigated by mechanical testing and scanning electron microscopy (SEM) Bio-based PLA/PCL blends and PLA/PCL/ SiC composites with low PCL and SiC contents were prepared by a solution blending method. e effects of the PCL and SiC contents on the mechanical properties, fracture toughness, and morphology of the prepared PLA/PCL blends and PLA/PCL/SiC composites were investigated by mechanical testing and scanning electron microscopy (SEM)

Experimental

Sample Preparation

Results and Discussion