Camellia oleifera shells (COS) are commonly discarded as an agricultural by-product. Effective utilization of COS can not only reduce environmental pollution but also enhance the value of the tea-oil industry. The unique composition of COS, with high hemicellulose and low cellulose content, makes it suitable for the production of film materials. In this study, COS holocellulose (COSH) was isolated and treated with four different types of dilute acids (15 % acetic acid, gallic acid, citric acid, and 0.5 % sulfuric acid, 1-24 h, 75 degrees-105 degrees-105 degrees C) to produce barrier films. Among these, citric acid treatment resulted in the strongest and toughest film. By incorporating a brief ultrasonic pretreatment (15 min, 300 w) prior to the citric acid reaction, translucent films were achieved with impressive mechanical properties, showing tensile strength, Young's modulus and elongation at break up to 75.72 MPa, 3306.11 MPa and 8.01 %, respectively. Through a comprehensive analysis of the structure-property relationships, it was discovered that the combined effects of ultrasonic and citric acid treatments disrupted the integrated holocelluose fiber structure and facilitated the formation of a robust hydrogen bond network during the film preparation process. The resulting films exhibited enhanced water vapor barrier properties, antioxidant capacity, and complete decomposition in soil, suggesting the potential application as wraps for fresh fruits.

Plant root-soil mechanical interaction in the application of soil bioengineering such as tree and slope stability has been investigated via centrifuge modelling, utilising root analogues to replicate vegetated soils. Three-dimensional (3-D) printing can be used to model complex root architecture, but the nature of the layer-upon-layer printing process may lead to printed parts of differing tensile behaviour depending on orientation and, consequently, unrealistic simulation of root mechanical reinforcement. This study aimed to assess the strength and stiffness anisotropy of straight root analogues built at varying orientations via three different 3-D printing methods and compare the measured properties with those of real roots. The tensile strength ratios between horizontally- and vertically-printed samples were up to 3.90, 1.27 and 2.57 for fused deposition modelling (FDM), liquid-crystal display (LCD) and Polyjet methods, respectively. Stiffness anisotropy was also more significant in FDM. The relatively higher anisotropy in FDM-printed samples could overestimate the strength and stiffness of most roots in a hypothetical heart-shaped root system, depending on the diameter distribution. Such a physical model may be improved using 45 degrees inclined Polyjet-printed rods.

A novel diphenyl monomer, dimethyl 2,2'-(((ethane-1,2-diylbis(oxy))bis(4-acetyl-3,1-phenylene))bis(oxy))diacetate (EDPD), was synthesized from methyl 2-(4-acetyl-3-hydroxyphenoxy)acetate (MAHA), a 2,4-dihydroxyacetophenonederivative, and combined with 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or p-phenylenedimethanolto afford a series of biodegradable polyesters via melt polymerization. The polyesters were characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The weight-average molecular weight (M-w) of the polyesters varied from 3.2-4.4 x 10(4) g/mol, the glass transition temperature (T-g) from 52 to 80 degrees C, and the 5% decomposition temperature (T-d,T-5%) was in the 334-362 degrees C range. All the samples exhibited high yield strength (53-68 MPa) and elongation at break (230-330%) values, comparable with poly(ethylene terephthalate) (PET), owing to their aromatic character. Degradability testing of the polyesters in soil yielded mass losses reaching up to 7% after 32 weeks. In ecotoxicity testing, earthworms had a survival rate of more than 80% after 14 d of incubation, indicating relatively low toxicity. Overall, the good thermal and mechanical properties, biodegradability and low ecotoxicity of the polyesters make them promising materials for packaging applications, in replacement for PET, thereby promoting carbon neutrality and sustainable development.

Additive manufacturing, commonly known as 3D printing technology, has become one of the mainstream processes in the manufacturing industry due to its advantages over conventional manufacturing, which have piqued the public's interest. This study aims to focus on the influence of thermal conditions on crystallization towards mechanical properties of 3D printed poly(lactic) acid (PLA) degradation samples with 100% infill. As for the degradation profile, the highest weight loss recorded by the samples was 0.7%, observed in samples buried in soil with an abiotic medium for one month. The exposure of degraded samples to high temperature during drying affected their crystallinity, resulting in significant changes in strains, particularly between week 1 and week 2, where strains dropped significantly from 7.33% to 4.28%, respectively. In conclusion, it has been demonstrated that degradation for PLA material still can occur in an abiotic medium, albeit at a slower rate compared to a biotic medium due to the presence of additional microorganisms and bacteria. Besides, the post-heat treatment process on PLA degradation samples affects their crystalline structure, resulting in significant changes in mechanical properties, particularly especially strains. Therefore, it can be concluded that different materials exhibit distinct mechanical properties.

The stability of riverbank slopes is crucial in watershed ecology. The morphology and tensile strength properties of plant roots play a significant role in slope stability, which is of great importance for the ecological stability of riverbanks. The Jinsha and Yalong River basins are the largest hydropower bases in China and are in the ecologically fragile areas of the dry and hot river valleys, yet fewer studies are available on these basins. Further studies on the growth morphology and root mechanical properties of plant roots in the riparian zone at different elevations have not been reported. Therefore, we selected the dominant species of Cynodon dactylon root as the research subject, analyzed the root morphology, and conducted indoor single-root tensile tests to study its root structure and mechanical properties at various elevations. The results showed that the root morphology of Cynodon dactylon was positively correlated with elevation. Compared to low elevations (L and M), the root length increased by 57.3% and 21.47%, the root diameter increased by 24.85% and 13.92%, the root surface area increased by 93.5% and 67.37%, and the total root volume increased by 119.91% and 107.36%. As the elevation gradient increased, the flooding time decreased, leading to more developed plant roots for Cynodon dactylon. The Young's modulus ranged from 148.43 to 454.18 MPa for Ertan Cynodon dactylon roots and 131.31 to 355.53 MPa for Guanyingyan Cynodon dactylon roots. The maximum tensile strength, ultimate tensile strength, ultimate elongation, and Young's modulus of the plant root of the Cynodon dactylon showed a power function relationship with the diameter. The maximum tensile strength increased as the diameter increased, while the remaining properties decreased following a power function relationship. The maximum tensile strength, ultimate tensile strength, and Young's modulus of Cynodon dactylon were positively correlated with elevation, while the ultimate elongation was negatively correlated with elevation. The results elucidate the influence of elevation on the root morphology and mechanical properties of dominant riparian species. This provides a theoretical basis for managing and protecting riparian slopes in ecologically fragile areas.