Preparation and Isothermal Crystallization Behavior of Poly(<i>lactic acid</i>)/Graphene Nanocomposites

Abstract

Poly(lactic acid) (PLA)/graphene nanocomposites were prepared by solution blending using chloroform as a mutual solvent. Transmission electron microscopy (TEM) was used to examine the quality of the dispersion of graphene in the PLA matrix. The isothermal crystallization behaviors of PLA and PLA/graphene nanocomposites were investigated by differential scanning calorimetry (DSC). The isothermal crystallization kinetics were analyzed by Avrami model based on the DSC data. The results showed that the well dispersed graphene nanosheets could act as a heterogeneous nucleating agent and lead to an acceleration of crystallization during the PLA isothermal crystallization process. According to the Arrhenius equation, the activation energies were found to be -106.9 and -46.6 kJ/mol for pure PLA and PLA/0.1 wt % graphene nanocomposite, respectively. The crystal morphology were characterized with polarizing optical microscope (POM).

Physical Properties, Crystallization, and Thermal/Hydrolytic Degradation of Poly(L‐lactide)/Nano/Micro‐Diamond Composites

“…The difference may be due to the difference in the NMD particle size and the composite preparation method, i.e., melt‐extrusion 40 and solution‐casting in the present study. The DSC results here indicate that the NMD particles acted as crystallization accelerating agents during heating from room temperature, in consistent with other carbon‐based nano‐strucutred fillers 15–19, 23, 27, 30, 31, 33, 35, 37–39…”

“…The effects of incorporated NMD particles on the crystallization behavior of PLLA was monitored by DSC. The monitoring crystallization during heating is frequently utilized to estimate the effectiveness of crystallization accelerating agents 15–19, 23, 27, 30, 31, 33, 35, 37–39. On the other hand, although the crystallization during cooling is crucial for the actual processing and to determine the effectiveness of crystallization accelerating agents, few investigations have been performed for PLLA‐based materials 15–17.…”

“…multi‐wall carbon nanotube (MWCNT),22–29 and graphene 30–39 are intensively investigated to improve mechanical properties 21, 25, 32, 38 and thermal/hydrolytic degradation‐resistance of PLA‐based materials 16, 20, 27, 32, 34, 39, 40 and to manipulate their hydrolytic degradation behavior. The carbon‐based nano‐structured fillers are known to increase the conductivity 16, 19, 24, 26–28, 38, 39 and accelerate the crystallization of PLLA,15–19, 23, 27, 30, 31, 33, 35, 37–39 which will elevate the crystallinity and thereby the thermal stability of PLA‐based materials, in addition to the effects of incorporated high hardness fillers. Moreover, carbon‐based nano‐structured fillers were utilized to give PLA‐based materials other functionalities such as sensors for volatile organic compounds,28 increased flame retardancy,31 accelerated bone regeneration,29 and increased biocompatibility 36…”

Enhancing Polyvinyl Alcohol Nanocomposites with Carboxy-Functionalized Graphene: An In-Depth Analysis of Mechanical, Barrier, Electrical, Antibacterial, and Chemical Properties

“…A notable rise in the usage of graphene in polymer matrices research [ 19 ] can be attributed to graphene’s outstanding electrical, thermal, and mechanical properties. This novel material, which is formed from a single layer of sp2-bonded carbon atoms arranged in a repeating hexagonal pattern [ 20 , 21 , 22 , 23 ], has revolutionized various fields.…”