The effects of supercritical carbon dioxide on the degradation and antimicrobial properties of PLA biocomposite

Biopolymer products that is biodegradable presently attracting an attention from researchers and industry. The biodegradable packaging based on polylactic acid (PLA), durian skin fibre (DSF), epoxidized palm oil (EPO) and incorporated with cinnamon essential oil (CEO) as antimicrobial agent have been developed and showed to be a promising field of research. This paper reported the effects of supercritical carbon dioxide on the degradation and antimicrobial properties of PLA biocomposite films produced via solvent casting. The biocomposites underwent supercritical carbon dioxide (SCCO2) treatment at two different conditions under 40 °C temperature and at 100 bar and 200 bar pressure. Water absorption test showed that the untreated PLA biocomposite absorbed most water as compared to treated PLA biocomposite with SCCO2 at 5.1%. This is due to the hydrophilic nature of the fibre that absorbed water molecules. Soil burial test showed that the treated PLA biocomposite possessed the highest value of weight losses after 80 days with 97.8%. Biocomposite with the presence of CEO demonstrated antimicrobial activity against both gram-positive and gram-negative bacteria. This showed that SCCO2 significantly improved the properties of PLA biocomposite films. The supercritical fluid treatment of PLA biocomposite could be an alternative for active packaging industries to ensure that the packaging product meets the requirement by consumers as well as being an eco-friendly product

Optimizing tensile strength of PLA-Lignin Bio-composites using machine learning approaches

It is imperative to accurately estimate the final performance of composite parts during the initial design phase of the manufacturing process. In generating sustainable bio composites with superior mechanical properties such as tensile strength, the combination of fillers and plasticizers, as well as their concentration in the mixture, are always deemed crucial. In order to reduce the number of experimental runs and their associated costs and timescales, statistical optimization of the core design elements has become increasingly important. The filler and plasticizer concentrations of extruded bio composites were adjusted in this study utilizing both statistical (analysis of variance (ANOVA) and response surface methodology (RSM)) and machine learning (Multilayer Perceptron (MLP)) approaches. Initial ANOVA results indicated that lignin, epoxidized palm oil (EPO), and their respective combinations were the most influential factors in enhancing the durability of lignin/polylactic acid (PLA) bio composites. In this work, RSM and MLP were used to model and predict the data in order to maximize the various solutions and establish the nonlinear relationship between the concentration of lignin and EPO

4D printing: historical evolution, computational insights and emerging applications

Four-dimensional printing (4DP) has gained tremendous interest in the field of materials and manufacturing due to its shape changing properties. Unlike three-dimensional printing (3DP) fabricated with a stationary objects, 4DP allows a 3D printed objects to transform itself to another configuration in response to external energy inputs such as thermal, magnetic, solvent, light or other environmental factors. Utilizing the aforementioned capabilities of 4DP, scientists from various disciplines have investigated a wide range of 4DP with proofs-of-concept. Despite numerous initiatives, 4DP still requires additional developments to meet the industrial applications. This review exercise is therefore aimed to highlight the historical evolution, computational insights and emerging application of 4DP. The review begins by presenting historical evolution and basic fundamental elements of 4DP. The review also presents computational overview on 4DP. Furthermore, different emerging applications of 4DP are highlighted to enlighten the readers. The current challenges of 4DP and future perspectives are critically discussed. Finally, the findings of this review tends to structure research efforts in the next one decade toward the creation of sophisticated 4DP products that will meet the needs of consumers and industry

Optimization of component in solution casted polylactic acid biocomposite by response surface methodology

The significant value of renewable resources used for food packaging has motivated consumer demand, thereby driving consumers to pay closer attention to biodegradable packaging applications. Polylactic acid (PLA) together with durian skin fibre (DSF), epoxidized palm oil (EPO) and cinnamon essential oil (CEO) have been used to produce thin film via the solution casting method. This research study was conducted to optimise the potential effect of DSF content, EPO content and CEO content by determining the tensile properties of PLA biocomposites. The design of experiments (DOE) via response surface methodology was used to analyse the results. The optimum values for the tensile properties of PLA biocomposite were found at 3 wt% DSF, 5 wt% EPO and 1 wt% of CEO. The optimum tensile strength and tensile modulus of PLA composite were 24.9 MPa and 375.9 MPa, respectively. The DSF content influences the tensile properties of PLA biocomposite, followed by the EPO content and CEO content based on the analysis of variance. The P-value of both responses in the design of experiments is less than 0.05 which verifies that the tensile properties model is significant. The coefficient, R2, for tensile strength is 0.8908, while the coefficient result of the tensile modulus is 0.8916

Novel soda lignin/PLA/EPO biocomposite: a promising and sustainable material for 3D printing filament

Polylactic acid (PLA) has been extensively used in 3D printing due to its low melting temperature and minimal warping. This study investigated the reinforcement of PLA filament with soda lignin from oil palm empty fruit bunches (OPEFB) in the presence of epoxidised palm oil (EPO) as 3D printable filament. The alkaline extraction method was carried out used sodium hydroxide (NaOH), followed by precipitation with mineral acids utilising one-factor-at-a-time (OFAT). The highest extraction yield was 30 % using 1 M NaOH and 20 % phosphoric acid. Fourier transforms infra-red (FTIR) confirmed the removal of lignin in the absence of 1740 cm⁻1 and 1513 cm⁻1 peaks. Scanning electron microscopy images revealed rough surface and less voids observed at the cross-section of filament. The addition of 1 phr lignin and 5 phr EPO (PLAE1) showed improvement in thermal and mechanical properties, with higher Tₒ around 5 °C and 10 % crystallinity. Brittleness is reduced by 5 % for PLAE1 compared to unfilled PLA due to increase of elongation at break. Rheology analysis revealed that PLA/lignin filament appeared to be more viscous, shown by lower complex viscosity of roughly 100 Pa compared to 800 Pa for PLA at 1 rad/s. PLAE1 exhibiting decreased in brittleness by 4 %, and high impact strength of 37 %. Dynamic mechanical analysis revealed that PLAE1 had lower rigidity than unfilled PLA with lower damping factor and storage modulus of 1.67 and 1.54 GPa. The findings revealed that the PLAE1 biocomposite has potential as alternative filament for sustainable 3D printing

Influence of nanocomposites in extrusion-based 3D printing: A review

3D printing is a process used in a variety of industries. This has the potential to replace traditional method of fabrication in the coming years. However, 3D printed parts with a single type of raw material frequently lack robustness, resulting in failed prints. Therefore, enhancing the properties of the materials is critical for applications in a variety of fields. The synergistic combination of nanoparticles (NPs) and 3D printing technologies particularly extrusion based 3D printing may enable the creation of architecture and devices with unprecedented levels of functional integration. This review reports recent developments in the use of nanocomposites (NCs) with 3D printing technology. The outlooks and several important issues in this area are also discussed with the anticipation that this will provide additional insights to the research community