Chemical Treatment of Bio-Derived Industrial Waste Filled Recycled Low-Density Polyethylene: A Comparative Evaluation

Photoluminous Response of Biocomposites Produced with Charcoal

Due to the possible effects of global warming, new materials that do not have a negative impact on the environment are being studied. To serve a variety of industries and outdoor applications, it is necessary to consider the impact of photoluminosity on the performance of biocomposites in order to accurately assess their durability characteristics and prevent substantial damage. Exposure to photoluminosity can result in adverse effects such as discoloration, uneven surface, loss of mass, and manipulation of the intrinsic mechanical properties of biocomposites. This study aims to evaluate general charcoal from three pyrolysis temperatures to understand which charcoal is most suitable for photoluminosity and whether higher pyrolysis temperatures have any significant effect on photoluminosity. Porosity, morphology, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy of charcoal were analyzed. Charcoal obtained at a temperature of 800 °C demonstrates remarkable potential as a bioreinforcement in polymeric matrices, attributable to its significantly higher porosity (81.08%) and hydrophobic properties. The biocomposites were characterized for flexural strength, tensile strength, scanning electron microscopy (SEM), FTIR, and x-ray diffraction (XRD). The results showed an improvement in tensile strength after exposure to photoluminosity, with an increase of 69.24%, 68.98%, and 54.38% at temperatures of 400, 600, and 800 °C, respectively, in relation to the treatment control. It is notorious that the tensile strength and modulus of elasticity after photoluminosity initially had a negative impact on mechanical strength, the incorporation of charcoal from higher pyrolysis temperatures showed a substantial increase in mechanical strength after exposure to photoluminosity, especially at 800 °C with breaking strength of 53.40 MPa, and modulus of elasticity of 4364.30 MPA. Scanning electron microscopy revealed an improvement in morphology, with a decrease in roughness at 800 °C, which led to greater adhesion to the polyester matrix. These findings indicate promising prospects for a new type of biocomposite, particularly in comparison with other polymeric compounds, especially in engineering applications that are subject to direct interactions with the weather.

New Synthesis Routes toward Improvement of Natural Filler/Synthetic Polymer Interfacial Crosslinking

Among the critical issues dictating bio-composite performance is the interfacial bonding between the natural fibers and polymer matrix. In this regard, this article presents new synthesis routes comprising the treatment and functionalization of both date palm powder (DPP) filler and a polypropylene (PP) matrix to enhance filler–polymer adhesion in the newly developed bio-composites. Specifically, four bio-composite forms are considered: untreated DPP filled PP (DPP-UT/PP), treated DPP filled PP (DPP-T/PP), treated DPP filled functionalized PP using 2-isocyanatoethyl methacrylate (DPP-T/PP-g-IEM), and treated and functionalized DPP using 4-toluenesulfonyl chloride filled functionalized PP using 2-acrylamide ((DPP-T)-g-TsCl/PP-g-AcAm). The functional groups created on the surface of synthesized PP-g-IEM react with activated hydroxyl groups attached to the filler, resulting in chemical crosslinking between both components. Similarly, the reaction of TsCl with NH₂ chemical groups residing on the mating surfaces of the filler and polymer generates an amide bond in the interface region. Fourier transform infrared spectroscopy (FTIR) is used to confirm the successful coupling between the filler and polypropylene matrix after applying the treatment and functionalization schemes. Owing to the introduced crosslinking, the DPP-T/PP-g-IEM bio-composite exhibits the best mechanical properties as compared to the neat polymer, unfunctionalized polymer-based bio-composite, and (DPP-T)-g-TsCl/PP-g-AcAm counterpart. The applied compatibilizers assist in reducing the water uptake of the manufactured bio-composites, increasing their durability.

Physical and Mechanical Characterization of Titica Vine (Heteropsis flexuosa) Incorporated Epoxy Matrix Composites

Titica vine (Heteropsis flexuosa) is a typical plant of the Amazon region commonly used for making baskets, bags, brooms and furniture, owing to its stiff fibers. In spite of its interesting properties, there is so far no reported information regarding the use of titica vine fibers (TVFs) in engineering composite materials. In this work, the TVF and its epoxy composites were for the first time physically, thermally and mechanically characterized. Additionally, the effect of two kinds of chemical treatments, one with sodium carbonate and one with calcium lignosulfonate, as well as different volume fractions, 10, 20, 30 and 40 vol%, of TVF-reinforced composites were assessed for corresponding basic properties. The thermogravimetric results of the composites reveal enhanced thermal stability for higher TVF content. In addition, the composite incorporated with 40 vol% of TVFs treated with sodium carbonate absorbed 19% more water than the composites with untreated fibers. By contrast, the calcium lignosulfonate treatment decreased water absorption by 8%. The Charpy and Izod impact tests showed that the composites, incorporated with the highest investigated volume fraction (40 vol%) of TVF, significantly increased the absorbed energy by 18% and 28%, respectively, compared to neat epoxy. ANOVA and Tukey statistical analyses displayed no direct influence of the chemical treatments on the energy absorption of the composites for either impact tests. SEM images revealed the main fracture mechanisms responsible for the performance of TVF composites.

Evaluation of Novel Compatibility Strategies for Improving the Performance of Recycled Low-Density Polyethylene Based Biocomposites

The interfacial compatibility of the natural filler and synthetic polymer is the key performance characteristic of biocomposites. The fillers are chemically modified, or coupling agents and compatibilisers are used to ensure optimal filler-polymer compatibility. Hence, we have investigated the effect of compatibilisation strategies of olive pits (OP) flour content (10, 20, 30, and 40%wt.) filled with recycled low-density polyethylene (rLDPE) on the chemical, physical, mechanical, and thermal behaviour of the developed biocomposites. In this study, we aim to investigate the filler-polymer compatibility in biocomposites by employing novel strategies for the functionalisation of OP filler and/or rLDPE matrix. Specifically, four cases are considered: untreated OP filled rLDPE (Case 1), treated OP filled rLDPE (Case 2), treated OP filled functionalised rLDPE (Case 3), and treated and functionalised OP filled functionalised rLDPE (Case 4). In general, the evaluation of the performance of biocomposites facilitated the application of OP industrial waste as an eco-friendly reinforcing agent for rLDPE-based biocomposites. Furthermore, surface treatment and compatibilisation improved the properties of the developed biocomposites over untreated filler or uncoupled biocomposites. Besides that, the compatibilisers used aided in reducing water uptake and improving thermal behaviour, which contributed to the stability of the manufactured biocomposites.