1 Int J Mater Sci Res.
ISSN: 2638-1559
Volume 1 • Issue 1 • 1000101
International
Journal of Material Science and Research
Research Article Open Access
Synergistic Effects of Chain Extender and Nanoclay
on the Crystallization Behaviour of Polylactide
Mohammadreza Nofar*
Department of Metallurgical & Materials Engineering, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University,
Maslak/Istanbul, 34469, Turkey
Article Info
*Corresponding author:
Mohammadreza Nofar
Department of Metallurgical & Materials
Engineering
Faculty of Chemical and Metallurgical
Engineering
Istanbul Technical University
Maslak/Istanbul, 34469
Turkey
E-mail: nofar@itu.edu.tr
Received: March 29, 2018
Accepted: April 9, 2018
Published: April 16, 2018
Citation: Nofar M. Synergistic Effects of
Chain Extender and Nanoclay on the
Crystallization Behavior of Polylactide. Int J
Mater Sci Res. 2018; 1(1): 1-8.
doi: 10.18689/ijmsr-1000101
Copyright: © 2018 The Author(s). This work
is licensed under a Creative Commons
Attribution 4.0 International License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the
original work is properly cited.
Published by Madridge Publishers
Abstract
The crystallization behavior of polylactide (PLA) with various branching degrees and
nanoclay contents were investigated using a differential scanning calorimeter (DSC).
The dispersion quality of nanoclay within PLA and reactivity of chain extender with PLA
molecules were analyzed using X-ray diffraction (XRD) and Fourier transform infrared
spectroscopy test (FT-IR), respectively.
The results showed that chain branching in PLA produced higher crystallinity and
fastened its slow crystallization kinetics. Also, the effects of processing (i.e., the same
compounding process through a twin-screw extruder as for the PLA nanocomposites)
on the crystallinity of “as received” PLAs were investigated to better compare them with
the PLA nanocomposites. The results showed that the addition of nanoclay in different
loadings did not have a significant effect on the melt crystallization of linear PLA.
However, as the clay loading increased in half-branched and fully branched PLA’s the
reduced molecular mobility started to hinder the crystallization started to be hindered
due to the reduced molecular mobility. This threshold occurred at lower clay loadings in
fully branched PLA as the mobility started to be limited earlier. On the other hand, clay
could improve even the linear PLA’s crystallinity during isothermal treatments. On the
other hand, branched PLA’s processing significantly improved crystallinity due to the
completion of chain-branching reactions during the processing. The effects of chain
branching and nanoclay on PLA’s isothermal melting crystallization kinetics at different
temperatures were also studied using Avrami analysis.
Keywords: Polylactide; PLA; Branching; Chain extender; Nanoclay; Crystallization.
Introduction
Most current polymers and plastics are derived from fossil fuels. After being
consumed, these polymer products become waste material in the environment, where
they do not degrade. Consequently, global efforts are being made to create green and
biodegradable polymers. Newly, biodegradable and biocompatible polymers that have
reasonable properties are receiving increasing attention from researchers with
biomedical and environmental points of view. Due to its renewable sources and
biocompatibility, polylactide (PLA) is one of the polymers that have received much
attention. PLA could be a promising candidate for many applications such as packaging,
and can be used in place of many other non-degradable polymers [1-6].
Currently, PLA’s slow crystallization behavior and low melt strength are of its most
challenging drawbacks that limits its processing. Even in isothermal treatment, which
PLA may encounter in extrusion and injection molding processes, it is difficult to achieve
sufficient crystallinity [7-11]. This structural parameter is paramount in such polymer
ISSN: 2638-1559