Rheological, Morphological and Mechanical Studies of Sustainably Sourced Polymer Blends Based on Poly(Lactic Acid) and Polyamide 11.

Fatma Walha,Khalid Lamnawar,Abderrahim Maazouz,Mohamed Jaziri

doi:10.3390/polym8030061

Abstract

The objective of this study was to gain a deep understanding of composition and compatibilization effects on the properties of entirely sustainably sourced polymer blends based on polylactide (PLA) and polyamide 11 (PA11). Generally, PLA cannot challenge regular commodity polymers due to its weak thermo-mechanical properties and its poor elongation properties. With this work, however, we present a promising route to overcome these drawbacks in order to enhance the processability of PLA: blending the polymer with various compositions of other ductile biopolymers such as PA11, as well as mixing PLA/PA11 blends with various amounts of a chain extender, Joncryl ADR®-4368, containing reactive epoxy functions, in a laboratory-scale twin-screw extruder. The effects on the rheological, morphological and mechanical properties were investigated. Results showed that a “self compatibilization” between PLA and PA11 chains can occur but it was found to be insufficient, contrary to recent work reported in the literature. The role of Joncryl as a compatibilizer for the PLA/PA11 system has been demonstrated by the significant decrease of particle size and interfacial tension as well as the improvement of ductile properties. Moreover, a new relaxation peak appeared in the relaxation spectrum, indicating the generation of a copolymer at the polymer-polymer interface.

Highlights

In the past decade, biopolymers or polymers issued from renewable resources have attracted significant attention for their potential to reduce dependence on petroleum-based materials and their potential applications in packaging, the medical field and the agricultural fields [1,2,3].Among these sustainably sourced polymers, polylactide (PLA) has proven to be the most attractive and useful choice since it has a good cost structure, the best availability and excellent transparency [4].Most industrial PLAs are linear thermoplastic polymers that are biocompatible, resorbable and biodegradable under industrial composting conditions [5,6]
We studied the impact of incorporating various amounts of a multifunctional epoxide (Joncryl) on the interfacial properties of PLA/polyamide 11 (PA11) blends using two different mixing strategies: (I) in situ reactive extrusion of all components at the same time; and (II) modification of PLA with epoxide functions followed by addition of PA11
In order to ensure that Joncryl acted as a compatibilizer for the PLA/PA11 blends, the Han plot was investigated (Figure 14)

Summary

Introduction

Biopolymers or polymers issued from renewable resources have attracted significant attention for their potential to reduce dependence on petroleum-based materials and their potential applications in packaging, the medical field and the agricultural fields [1,2,3].Among these sustainably sourced polymers, polylactide (PLA) has proven to be the most attractive and useful choice since it has a good cost structure, the best availability and excellent transparency [4].Most industrial PLAs are linear thermoplastic polymers that are biocompatible, resorbable and biodegradable under industrial composting conditions [5,6]. Biopolymers or polymers issued from renewable resources have attracted significant attention for their potential to reduce dependence on petroleum-based materials and their potential applications in packaging, the medical field and the agricultural fields [1,2,3] Among these sustainably sourced polymers, polylactide (PLA) has proven to be the most attractive and useful choice since it has a good cost structure, the best availability and excellent transparency [4]. Despite all these advantages, PLA suffers from poor thermal stability, significant brittleness and low melt strength, which limit its wide-spread use, especially for packaging applications (film blowing) [8,9]. The blending of different polymers is an efficient and cost-effective strategy for developing new polymeric materials with diversified and desirable properties [13]

Objectives

Methods

Results

Conclusion