Preparation and Characterization of Extruded Composites Based on Polypropylene and Chitosan Compatibilized with Polypropylene-Graft-Maleic Anhydride

Development of Cork Biocomposites Enriched with Chitosan Targeting Antibacterial and Antifouling Properties

The demand for bio-based and safer composite materials is increasing due to the growth of the industry, human population, and environmental concerns. In this framework, sustainable and safer cork-polymer composites (CPC), based on green low-density polyethylene (LDPE) were developed using melt-based technologies. Chitosan and polyethylene-graft-maleic anhydride (PE-g-MA) were employed to enhance the CPC's properties. The morphology, wettability, mechanical, thermal, and antibacterial properties of the CPC against Pseudomonas putida (P. putida) and Staphylococcus aureus (S. aureus) were examined. The CPC showed improved stiffness when compared with that of the LDPE matrix, preferably when combined with chitosan and PE-g-MA (5 wt. %), reinforcing the stiffness (58.8%) and the strength (66.7%). Chitosan also increased the composite stiffness and strength, as well as reduced the surface hydrophilicity. The CPCs' antibacterial activity revealed that cork significantly reduces the biofilm on the polymer matrix. The highest biofilm reduction was found with CPC containing cork and 5 wt. % chitosan for both P. putida (54% reduction) and S. aureus (36% reduction), confirming their potential to extend the lifespan of products for packaging and healthcare, among other applications. This work leads to the understanding of the factors that influence biofilm formation in cork composites and provides a strategy to reinforce their behavior using chitosan.

Effect of chitosan addition on the properties of low-density polyethylene blend as potential bioplastic

Plastics based on low-density polyethylene (LDPE) blends generally have limited miscibility, and it is difficult to obtain a homogeneous blend. Although they show excellent properties, their thermal degradation rate is a concern. This work aims to realize a homogeneous blend with higher chitosan concentration, thus expected to increase its degradation properties. An extrusion technique successfully synthesized LDPE and chitosan blends. The mixtures were prepared by adding maleic anhydride (MA) and tert-butyl peroxybenzoate (TBPB) as a compatibilizer and initiator, respectively. The addition of MA and TBPB resulted in homogeneous blends and using chitosan concentration of 40 %wt resulted in better tensile strength and elongation at break. The water uptake increased along with chitosan concentration in the blends. The thermal behavior analysis of the blends conducted by simultaneous TG/DTA revealed that the increase of chitosan concentration tends to improve the blend's thermal degradation slightly. Moreover, chitosan addition resulted in approximately a hundred times larger biodegradability compared to plastics based on LDPE alone.

Effect of maleic anhydride content on physico-mechanical properties of γ-irradiated waste polypropylene/corn husk fibers bio-composites

Biocomposites of waste polypropylene (wPP) with 20 phr (part per 100 parts of [wPP]) corn husk fibers (CHF) as bio-filler were prepared for environmental aspect. Maleic anhydride (MAH) was used, with 5, 10 phr concentration as compatabilizer was carried out. The obtained biocomposites were irradiated by γ radiation ranging from 5 to 25 kGy. Mechanical, physical and thermal properties of the biocomposites were studied to evaluate the effect of CHF addition on the properties of obtained composites. It has been found that there is deterioration in all properties. However, by the addition of MAH, the former properties were improved. The obtained results were confirmed by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM).

Bio- and Fossil-Based Polymeric Blends and Nanocomposites for Packaging: Structure⁻Property Relationship

In the present review, the possibilities for blending of commodities and bio-based and/or biodegradable polymers for packaging purposes has been considered, limiting the analysis to this class of materials without considering blends where both components have a bio-based composition or origin. The production of blends with synthetic polymeric materials is among the strategies to modulate the main characteristics of biodegradable polymeric materials, altering disintegrability rates and decreasing the final cost of different products. Special emphasis has been given to blends functional behavior in the frame of packaging application (compostability, gas/water/light barrier properties, migration, antioxidant performance). In addition, to better analyze the presence of nanosized ingredients on the overall behavior of a nanocomposite system composed of synthetic polymers, combined with biodegradable and/or bio-based plastics, the nature and effect of the inclusion of bio-based nanofillers has been investigated.

HDPE/Chitosan Blends Modified with Organobentonite Synthesized with Quaternary Ammonium Salt Impregnated Chitosan

In this study, blends based on a high density polyethylene (HDPE) and chitosan (CS) were successfully prepared by melt processing, in a laboratory internal mixer. The CS biopolymer content effect (up to maximum of 40%), and, the addition of bentonite clay modified with quaternary ammonium salt (CTAB) impregnated chitosan as a compatibilizing agent, on the properties of the blends was analyzed by Fourier transform-infrared spectroscopy (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analyses (TG), tensile strength, and scanning electron microscopy (SEM). The use of clay modified with CTAB impregnated chitosan, employing a method developed here, improved the compatibility of HDPE with chitosan, and therefore the thermal and some of the mechanical properties were enhanced, making HDPE/chitosan blends suitable candidates for food packaging. It was possible to obtain products of synthetic polymer, HDPE, with natural polymer, chitosan, using a method very used industrially, with acceptable and more friendly properties to the environment, when compared to conventional synthetic polymers. In addition, due to the possibility of impregnated chitosan with quaternary ammonium salt exhibit higher antibacterial activity than neat chitosan, the HDPE/chitosan/organobentonite blends may be potentially applied in food containers to favor the preservation of food for a longer time in comparison to conventional materials.