Hybrid Green Bionanocomposites of Bio-based Poly(butylene succinate) Reinforced with Pyrolyzed Perennial Grass Microparticles and Graphene Nanoplatelets

Effect of Incorporation of Graphene Nanoplatelets on Physicochemical, Thermal, Rheological, and Mechanical Properties of Biobased and Biodegradable Blends

This work aimed to study the effect of the incorporation of graphene nanoplatelets (GRA 0.5% and 1% (w/w)) on the matrices of biobased polymers composed of starch-based materials (B20) and poly(butylene succinate) (PBS) using pine rosin (RES) as a compatibilizer. Three formulations were produced (B20/RES/PBS, B20/RES/PBS/GRA0.5%, and B20/RES/PBS/GRA1%), and their mechanical properties (tensile, flexural, hardness, and impact), rheological behavior, thermal properties (thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC)), chemical analysis (Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy), and contact angle were evaluated. Hardness (Shore D), tensile, and flexural moduli increased, whereas elongation at break and toughness decreased as GRA content increased. FTIR studies strongly supported the existence of interactions between polymeric matrices and the large surface area of GRA. The viscosity flow curves were well fitted to the Cross-Williams-Landel-Ferry (Cross-WLF) model, and the three formulations exhibited non-Newtonian (shear-thinning) behavior. The analysis of water contact angles indicated that the formulation surfaces have hydrophilic behavior. All the samples are thermally stable, and the results of this study can be used to optimize the application of biobased graphene-based composites for applications in injection molding industries.

Synthesis and Study of Fully Biodegradable Composites Based on Poly(butylene succinate) and Biochar

Biodegradable polymers offer a promising alternative to the global plastic problems and especially in the last decade, to the microplastics problems. For the first time, samples of poly(butylene succinate) (PBSu) biocomposites containing 1, 2.5, and 5 wt% biochar (BC) were prepared by in situ polymerization via the two-stage melt polycondensation procedure. BC was used as a filler for the PBSu to improve its mechanical properties, thermal transitions, and biodegradability. The structure of the synthesized polymers was examined by ¹H and ¹³C nuclear magnetic resonance (NMR) and X-Ray diffraction (XRD) along with an estimation of the molecular weights, while differential scanning calorimetry (DSC) and light flash analysis (LFA) were also employed to record the thermal transitions and evaluate the thermal conductivity, respectively. It was found that the amount of BC does not affect the molecular weight of PBSu biocomposites. The fine dispersion of BC, as well as the increase in BC content in the polymeric matrix, significantly improves the tensile and impact strengths. The DSC analysis results showed that BC facilitates the crystallization of PBSu biocomposites. Due to the latter, a mild and systematic increase in thermal diffusivity and conductivity was recorded indicating that BC is a conductive material. The molecular mobility of PBSu, local and segmental, does not change significantly in the biocomposites, whereas the BC seems to cause an increase in the overall dielectric permittivity. Finally, it was found that the enzymatic hydrolysis degradation rate of biocomposites increased with the increasing BC content.

Synthetic Biopolymers and Their Composites: Advantages and Limitations-An Overview

Recently, polymer science and engineering research has shifted toward the development of environmentally benign polymers to reduce the impact of plastic leakage on the ecosystems. Stringent regulations and concerns regarding conventional polymers are the main driving forces for the development of renewable, biodegradable, sustainable, and environmentally benign materials. Although biopolymers can alleviate plastic-related pollution, several factors dictate the utilization of biopolymers. Herein, an overview of the potential and limitations of synthetic biopolymers and their composites in the context of environmentally benign materials for a sustainable future are presented. The synthetic biopolymer market, technical advancements for different applications, lifecycle analysis, and biodegradability are covered. The current trends, challenges, and opportunities for bioplastic recycling are also discussed. In summary, this review is expected to provide guidelines for future development related to synthetic biopolymer-based sustainable polymeric materials suitable for various applications.

Hybrid biocomposites from polypropylene, sustainable biocarbon and graphene nanoplatelets

Polypropylene (PP) is an attractive polymer for use in automotive parts due to its ease of processing, hydrophobic nature, chemical resistance and low density. The global shift towards eliminating non-renewable resource consumption has promoted research of sustainable biocarbon (BioC) filler in a PP matrix, but this material often leads to reduction in composite strength and requires additional fillers. Graphene nano-platelets (GnPs) have been the subject of considerable research as a nanofiller due to their strength, while maleic anhydride grafted polypropylene (MA-g-PP) is a commonly used compatibilizer for improvement of interfacial adhesion in composites. This study compared the thermo-mechanical properties of PP/BioC/MA-g-PP/GnP composites with varying wt.% of GnP. Morphological analysis revealed uniform dispersion of BioC, while significant agglomeration of GnPs limited their even dispersion throughout the PP matrix. In the optimal blend of 3 wt.% GnP and 17 wt.% BioC biocontent, tensile strength and modulus increased by ~19% and ~22% respectively, as compared to 20 wt.% BioC biocomposites. Thermal stability and performance enhancement occurred through incorporation of the fillers. Thus, hybridization of fillers in the compatibilized matrix presents a promising route to the enhancement of material properties, while reducing petroleum-based products through use of sustainable BioC filler in composite structures.

Extrusion of Polymer Nanocomposites with Graphene and Graphene Derivative Nanofillers: An Overview of Recent Developments

This review is focused on the recent developments of nanocomposite materials that combine a thermoplastic matrix with different forms of graphene or graphene oxide nanofillers. In all cases, the manufacturing method of the composite materials has been melt-processing, in particular, twin-screw extrusion, which can then be followed by injection molding. The advantages of this processing route with respect to other alternative methods will be highlighted. The results point to an increasing interest in biodegradable matrices such as polylactic acid (PLA) and graphene oxide or reduced graphene oxide, rather than graphene. The reasons for this will also be discussed.