Morphology, Crystallization and Thermal Behaviors of PLA-Based Composites: Wonderful Effects of Hybrid GO/PEG via Dynamic Impregnating

Abstract

Abstract:In this paper, a dynamic impregnating device, which can generate supersonic vibration with the vacuum-adsorbing field, was used to prepare the hybrid graphene oxide (GO)/polyethylene glycol (PEG). Interestingly, the hybrid GO/PEG under dynamic impregnating and/or internal mixing was introduced into poly-(lactic acid) (PLA) matrix via melting-compounding, respectively. On one hand, compared with the internal mixing, the hybrid GO/PEG with the different component ratio using dynamic impregnation had a better dispersed morphology in the PLA matrix. On the other hand, compared with the high molecular weight (M w ) of PEG, the hybrid GO/PEG with low M w of PEG had better an exfoliated morphology and significantly improved the heat distortion temperature (HDT) of the PLA matrix. Binding energies results indicate that low M w of PEG with GO has excellent compatibility. Dispersed morphologies of the hybrid GO/PEG show that the dynamic impregnating had stronger blending capacity than the internal mixing and obviously improved the exfoliated morphology of GO in the PLA. Crystallization behaviors indicate that the hybrid GO/PEG with the low M w of PEG based on dynamic impregnating effectively enhanced the crystallinity of PLA, and the cold crystallization character of PLA disappeared in the melting process. Moreover, the storage modulus and loss factor of the PLA-based composites were also investigated and their HDT was improved with the introduction of hybrid GO/PEG. Furthermore, a physical model for the dispersed morphology of the hybrid GO/PEG in the PLA matrix was established. Overall, the unique blending technique of hybrid GO/PEG via dynamic impregnating is an effective approach to enhance the property range of PLA and is suitable for many industrial applications.

A feasible strategy to constructing hybrid conductive networks in PLA‐based composites modified by CNT‐d‐RGO particles and PEG for mechanical and electrical properties

“…And then, the hybrid CNT‐d‐RGO and PEG as a function of specific component ratio ( w CNT‐d‐RGO : w PEG was 1:4) were premixed by tumbling in a plastic zip‐lock bag to obtain the premix. Next, a novel dynamic impregnating device, as shown in Figure , which generates supersonic vibrating and vacuuming force field, was successfully used to compound the CNT‐d‐RGO/PEG . Firstly, the premix mentioned above was placed in a constant temperature cavity of 90°C and melted at vacuuming condition at a pressure of 0.05 MPa for 15 minutes.…”

“…Vacuuming impregnation, which is an environmentally friendly process, has been frequently used to prepare the porous structure of inorganic‐organic hybrid shape‐stability phase‐change storage energy materials in the past years . In previous studies, we first designed and constructed a supersonic vibration‐assisted dynamic vacuuming device, which generates the synergy effect of vacuuming impregnation and supersonic vibration force field to enhance the dispersion morphology and package capacity among different materials. In terms of the aforementioned issues, such as slow crystallization rate and low toughness of PLA and inferior dispersion of a variety of modifiers within the PLA phase, we have revealed that the hybrid inorganic‐organic particles prepared by dynamic impregnating can resolve the barriers during the PLA process.…”

The effect of poly(ethylene glycol) mixed with poly(l‐lactic acid) on the crystallization characteristics and properties of their blends

“…Among the thermoplastic aliphatic polyesters, poly( l ‐lactic acid) (PLLA) presents excellent biodegradability, biocompatibility and bioresorbability along with transparency and low toxicity . Standard‐grade PLLA is also characterized by high modulus and strength but is brittle and rigid in nature with poor toughness and low melt strength which lead to difficulties in demoulding . To extend its application range and large‐scale production in biomedical and packaging fields, its inherently hydrophobic nature, poor heat resistance and slow degradation rate and crystallization kinetics need to be further controlled.…”

“…In PLLA blends, PEG acts as a plasticizer of the PLLA rigid phase, reducing the intermolecular force and enhancing the mobility of polymer chains, thus improving the fluidity, ductility, flexibility and consequently the crystallization capacity of PLLA . Moreover, it has been reported that PEG increases the crystallization temperature of PLLA during cooling from melt or decreases the half‐time of crystallization under isothermal crystallization . Fully understanding and controlling the crystallization behaviour of PLLA, and the effect of PEG on this behaviour, play a decisive role in optimizing processing conditions, mechanical properties, thermal resistance and degradation rate of final products.…”

“…The constant temperature profile in each zone of the barrel of the extruder controls the melt viscosity of PEG and PLLA, the way they interact and the crystallization behaviour of the extrudate. The effect on PLLA crystallization capacity and properties, as well as PEG migration within the PLLA matrix, depends upon the PEG molecular weight and content in the blends …”