Influence of Chain-Extension Reaction on Stereocomplexation, Mechanical Properties and Heat Resistance of Compressed Stereocomplex-Polylactide Bioplastic Films

Abstract

Stereocomplex polylactide (scPLA) films were prepared by melt blending of poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) with and without an epoxy-based chain extender before compression molding. The obtained scPLA films were characterized through differential scanning calorimetry, X-ray diffractometry (XRD), tensile testing and dimensional stability to heat. XRD patterns revealed that all the scPLA films had only stereocomplex crystallites. The obtained results showed that the chain-extension reaction improved mechanical properties of the scPLA films, however, it suppressed stereocomplexation and heat resistance.

Appraisal of ε‐Caprolactam and Trimellitic Anhydride Potential as Novel Chain Extenders for Poly(lactic acid)

“…The XRD diffractogram of the neat PLA reveals a semi‐crystalline material and shows an intense diffraction peak at 2 θ = 11.6° corresponding to the (110) crystal lattice, and many other minor diffraction peaks at 14°, 17.3°, 20°, 22.4°, and 23.8° related to the (103), (110/200), (203), (210), and (220) planes of PLA, respectively. All these reflections imply the coexistence of characteristic diffraction peaks for both stereocomplex and homocrystallites, which are consistent with trigonal and pseudo‐orthorhombic structures of PLA . Because the DSC thermograms seem to be consistent with a highly predominant pseudo‐orthorhombic structure where the crystals adopt a helical conformation for the α‐form, it is suggested to be the more prevalent conformation of the neat PLA .…”

Role of stereocomplex in advancing mass transport and thermomechanical properties of polylactide

“…They found that increasing the PDLA ratio from 0 to 20 wt% could significantly reduce the expansion ratio from 28.3 to 1.7. Similarly, Baimark and Kittipoom 157 reported the dimensional stability for SC-PLA films with different PLLA/PDLA ratios, where PLLA/PDLA 60/40 blend with 51.2% SC crystallinity possessed comparable dimensional stability as high heat-resistance PP. These results indicated that the SC could influence the nonlinear viscoelasticity of PLA as result of the physical networking structure, such as creep, which is essential for analyzing the long-term performance and extending durable applications of PLA at elevated temperatures, but not yet widely studied.…”

The Effect of Mold Conditions on Heat Resistance of Injection-Molded Stereocomplex Polylactide-b-polyethylene Glycol-b-Polylactide Bioplastic

“…In situ chain-extended PLLA-PEG-PLLA with MFI of 26 g/10 min (190 o C, 2.16 kg) was synthesized by ring-opening polymerization of L-lactide monomer in the presence of 2.0 phr Joncryl  ADR4368 (chain extender) according to our previous work [30]. PDLA with number-average molecular weight and dispersity index of 90,000 g/mol and 2.8 from GPC respectively, was synthesized as described in our previous work [25].…”