Super-Toughened Poly(lactic Acid) with Poly(ε-caprolactone) and Ethylene-Methyl Acrylate-Glycidyl Methacrylate by Reactive Melt Blending.

Ao-Lin Hou,Jin-Ping Qu

doi:10.3390/polym11050771

Ao-Lin Hou, Jin-Ping Qu

Open Access

https://doi.org/10.3390/polym11050771

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Journal: Polymers	Publication Date: May 1, 2019
Citations: 28	License type: CC BY 4.0

Affiliation: South China University of Technology

Abstract

In recent years, poly(lactic acid) (PLA) has attracted more and more attention as one of the most promising biobased and biodegradable polymers. However, the inherent brittleness significantly limits its wide application. Here, ternary blends of PLA, poly(ε-caprolactone) (PCL) with various amounts of ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer were fabricated through reactive melt blending in order to improve the toughness of PLA. The effect of different addition amounts of EMA-GMA on the mechanical properties, interfacial compatibility and phase morphology of PLA/PCL blends were studied. The reactions between the epoxy groups of EMA-GMA and carboxyl and hydroxyl end groups of PLA and PCL were investigated thorough a Fourier transform infrared (FT-IR). The miscibility and thermal behavior of the blends were studied through a dynamic mechanical analysis (DMA), differential scanning calorimetric (DSC) and X-ray diffraction (XRD). The phase morphology and impact fracture surface of the blends were also investigated through a scanning electron microscope (SEM). With the addition of 8 phr EMA-GMA, a PLA/PCL (90 wt %:10 wt %)/EMA-GMA ternary blend presenting a suitable multiple stacked phase structure with an optimum interfacial adhesion exhibited an elongation at break of 500.94% and a notched impact strength of 64.31 kJ/m2 with a partial break impact behavior. Finally, the toughening mechanism of the supertough PLA based polymers have been established based on the above analysis.

Highlights

Due to the constant consumption of traditional plastic, diminishing oil reserves and increasing plastic waste will threaten the ecological environment
With the addition of 8 phr ethylene-methyl acrylate-glycidyl methacrylate (EMA-glycidyl methacrylate (GMA)), a Poly(lactic acid) (PLA)/PCL (90 wt %:10 wt %)/EMA-GMA ternary blend presenting a suitable multiple stacked phase structure with an optimum interfacial adhesion exhibited an elongation at break of 500.94% and a notched impact strength of 64.31 kJ/m2 with a partial break impact behavior
Figure analysis was employed to prove that the reaction existed in the PLA/PCL/EMA-GMA

Summary

Introduction

Due to the constant consumption of traditional plastic, diminishing oil reserves and increasing plastic waste will threaten the ecological environment. Considerable attention has been paid to biodegradable polymers, mainly owing to an increasing interest in the preservation of the environment and the substitution of petrochemical polymers [1,2]. Poly(lactic acid) (PLA), an aliphatic polyester, one of the most promising and potential renewable bio-based polymers produced from renewable sources such as corn [3], has been widely applied in biomedical applications, such as the drug delivery system and surgical suture [4], because of its excellent biocompatibility, good biodegradability and high mechanical strength [5,6]. The inherent deficiencies of PLA, including its natural brittleness and poor elongation at break, narrow processing window and low melt strength, largely limit its further application [7].

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