Development of Flax- and Hemp-based Polylactic Acid Films for Bioplastic Applications
Bibliographic record
Abstract
Plastic, widely used for packaging fresh food, poses environmental risks. It threatens marine and terrestrial ecosystems, while also contributing to global greenhouse gas emissions. To tackle this problem, bioplastics has emerged as a promising alternative to traditional plastics. Bioplastics, such as polylactic acid (PLA), offer advantages like wide availability, cost- effectiveness, and non-reliance on petroleum. PLA is non-toxic, biodegradable, strong, and has excellent film-forming properties, making it suitable for single-use applications like food packaging. Bioplastics holds promise, but sustainable raw material sources are necessary. Saskatchewan's crop production yields agricultural biomass, like flax straw, which can enhance the province's agriculture industry. While hemp is increasingly grown in Saskatchewan, its biomass quality may not meet high-quality fiber production standards. The utilization of excess agricultural by-products in composites remains unexplored, with limited studies on agricultural waste utilization for composite creation.\nIn this work, the effects of particle size, loading and treatment (alkali and acetylation) of biomass fillers on the mechanical, moisture absorption, vapor barrier, and surface wettability characteristics of the flax and hemp-based PLA films have been studied. The study emphasizes the importance of optimizing the particle size, treatment, and loading of fillers to achieve desirable properties for specific applications. This study has explored the addition of alkali and acetylation treated fillers of particle sizes <75 μm and 149-210 μm to the PLA films and compared the properties of the treated films with untreated ones. The addition of untreated flax fillers did not improve the tensile strength and elongation at break of flax bioplastic, and Young's modulus decreased as the filler loading increased. However, alkali-treated flax fillers showed an improvement in tensile strength at 2.5% and 5% loading. Acetylation treatment improved elongation at break at lower loading percentages but became less effective as the percentage of filler loading increased. The addition of flax fillers, whether untreated or alkali- treated, resulted in a decrease in tensile strength and Young's modulus. However, at 2.5% and 5% filler loadings, both untreated and alkali-treated fillers increased the elongation at break of the films. For hemp fillers, the tensile strength and elongation at break decreased with an increase in filler content for particle sizes smaller than 75 μm. However, Young's modulus increased by 10% loading and then started decreasing. For hemp fillers of particle size 149- 210 μm, the tensile strength and Young's modulus decreased at all filler loadings, while the elongation at break increased until 5% loading and then started reducing. These trends can beattributed to factors such as changes in crystallinity, interfacial adhesion, and the presence of defects. The addition of fillers to bioplastics increased moisture absorption and water vapor permeability (WVP), with a more pronounced effect observed in untreated fillers compared to treated ones. The water contact angle of the films decreased as the filler content increased for both particle sizes. However, the decrease in water contact angle was more prominent for untreated fillers compared to treated ones.\nThe balance between the ability of the filler particles to fill gaps between polymer chains and the formation of a more porous structure as loading percentage increases should be carefully considered when selecting bioplastics for specific applications. Therefore, it is essential to consider several factors such as particle size, treatment, and loading of the filler and their interaction while designing bioplastics with tailored properties for various applications.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".