Plastic Film Research Articles

Development and characterization of camel gelatin films: Influence of camel bone age and glycerol or sorbitol on film properties

This study developed and evaluated camel bone gelatin films (CBGFs) with glycerol or sorbitol as plasticizers. Gelatin extracted from the bones of camels (Camelus dromedarius) at ages ranging from 2.5 to 7 years was used. A comprehensive analysis was conducted, evaluating a range of properties including thickness, moisture sorption capacity, water vapor permeability (WVP), infrared spectral characteristics, light absorption behavior, solubility, as well as mechanical and thermal attributes. This thorough examination allowed for a nuanced understanding of the diverse characteristics exhibited by the camel gelatin samples across different age groups. The results indicated that camel age, glycerol, and sorbitol had a significant impact on the properties of the film (P < 0.05). Tensile strength ranged from 0.32 MPa to 3.99 MPa, while the percentage of elongation at break varied from 89.42 % to 2.68 %. Film color (lightness, L) ranged from 21.39 to 41.33. Glycerol and sorbitol plasticized films were 100 % water soluble. Moisture sorption increased with temperature (25 °C, 35 °C, and 45 °C), with sorbitol films retaining less water. WVP was low in films from old camel bones and high in glycerol-plasticized CBGF-2.5Y and CBGF-4.5Y. Thermal analysis showed a melting temperature between 158.60 °C and 174.10 °C, depending on bone age and plasticizer. These films demonstrate promise for use in food packaging, coatings, and pharmaceutical applications.

Effect of functional fillers in solvent‐free polyurethane adhesives: Processing and characterization

AbstractThe present work is focused on the study of polyurethane adhesives in the presence of functional fillers (encapsulated enzymes) intended to make them degradable. This is part of a general strategy aiming to recycle multilayer films for packaging, at their end of life, by means of separating the constituent layers as a result of adhesives degradation. Primarily, it was found that the presence of small quantities of functional filler greatly affects both, the quality of the coating process and the kinetics of the adhesive curing. The former, because of the dependency on particle size distribution, leads to high variations in thickness and mechanical properties of multilayers and, the latter, because of a significant catalytic effect (higher curing rates). Indeed, an assessment of the adhesives' kinetics by rheology showed that the pot‐life and the cross‐over point (G′ = G″) for the enzyme‐containing system were obtained three times faster in comparison to the control formulation. These findings were also confirmed by differential scanning calorimetry measurements. On the other hand, by reducing and homogenizing the filler's particle size using separated sieved material (≤50 μm), improvements in coating control as well as in the quality and final properties of the multilayers were evidenced.Highlights Recycling multilayer plastic films for flexible packaging. Encapsulated enzymes to degrade the polyurethane adhesive in specific conditions. The presence of functional fillers affects the coating process. Process optimization to ensure the coating quality control.

Quantification of degree of interactions during co-pyrolysis of nine typical carbonaceous wastes

Organic municipal waste is a mixture of carbonaceous feedstock and cross-interaction of volatiles in their co-pyrolysis has been well documented, but quantifying their extent of interactions in co-pyrolysis is difficult. In this study, the ratio of char yield from co-pyrolysis to calculated average of pyrolysis of single feedstock was used as an indicator to probe the interaction in co-pyrolysis of every two typical carbonaceous wastes (sawdust, rice, spinach, chicken manure, office paper, corrugated paper, plastic bottles/films, fiber towel) at 550 °C. The results indicated that the co-pyrolysis of sawdust and corrugated paper had the highest degree of interaction (0.44). Sawdust and rice with ash-rich feedstock (spinach, chicken manure and office paper) resulted in dominance of gasification reactions to reduce char production in co-pyrolysis process. In comparison, the organics from the degradation of spinach and corrugated/office paper could react with the derivatives (mostly radicals) of plastic bottle (PET), plastic film (PE) or fiber towel (polyesters) via secondary condensation to generate more char. The chicken manure with high ash content hardly forms char of enhanced yield during its co-pyrolysis with other feedstocks. The enhancing char yield through secondary condensation generally resulted in additional oxygen-containing deposit on char and reduced thermal stability, which was the opposite to the formation of char with dominance of gasification. Co-pyrolysis of varied feedstock also led to change of morphologies of char via filling mechanism or formation of organics.

Evaluation of Thermoplastic Starch Contamination in the Mechanical Recycling of High-Density Polyethylene

This research highlights the importance of addressing bioplastic contamination in recycling processes to ensure the quality of recycled material and move towards a more sustainable circular economy. Polyethylene (PE) is a conventional plastic commonly used in packaging for which large amounts of waste are produced; therefore, PE is generally recycled and has an established recycling process. However, the contamination of biodegradable polymers in the PE waste stream could impact recycling. This study, therefore, focuses on polyethylene (PE) that has been polluted with a commercial thermoplastic starch polymer (TPS), as both materials are used to produce plastic films and bags, so cross-contamination is very likely to occur in waste separation. To achieve this, recycled PE was blended with small quantities of the commercial TPS and processed through melt extrusion and injection molding, and it was further characterized. The results indicate that the PE-TPS blend lacks miscibility, evidenced by deteriorated microstructure and mechanical properties. In addition, the presence of the commercial TPS affects the thermal stability, oxidation, and color of the recycled PE.

Estimation of Intercepted Solar Radiation and Stem Water Potential in a Table Grape Vineyard Covered by Plastic Film Using Sentinel-2 Data: A Comparison of OLS-, MLR-, and ML-Based Methods.

In the framework of precision viticulture, satellite data have been demonstrated to significantly support many tasks. Specifically, they enable the rapid, large-scale estimation of some viticultural parameters like vine stem water potential (Ψstem) and intercepted solar radiation (ISR) that traditionally require time-consuming ground surveys. The practice of covering table grape vineyards with plastic films introduces an additional challenge for estimation, potentially affecting vine spectral responses and, consequently, the accuracy of estimations from satellites. This study aimed to address these challenges with a special focus on the exploitation of Sentinel-2 Level 2A and meteorological data to monitor a plastic-covered vineyard in Southern Italy. Estimates of Ψstem and ISR were obtained using different algorithms, namely, Ordinary Least Square (OLS), Multivariate Linear Regression (MLR), and machine learning (ML) techniques, which rely on Random Forest Regression, Support Vector Regression, and Partial Least Squares. The results proved that, despite the potential spectral interference from the plastic coverings, ISR and Ψstem can be locally estimated with a satisfying accuracy. In particular, (i) the OLS regression-based approach showed a good performance in providing accurate ISR estimates using the near-infrared spectral bands (RMSE < 8%), and (ii) the MLR and ML algorithms could estimate both the ISR and vine water status with a higher accuracy (RMSE < 7 for ISR and RMSE < 0.14 MPa for Ψstem). These results encourage the adoption of medium-high resolution multispectral satellite imagery for deriving satisfying estimates of key crop parameters even in anomalous situations like the ones where plastic films cover the monitored vineyard, thus marking a significant advancement in precision viticulture.

Synthesis and application of environmental plasticizers based on benzene polyacid ester

AbstractUsing benzene‐1,3,5‐tricarboxylic acid, trimellitic anhydride, 2‐propylheptanol and 2‐ethylhexanol as raw materials, four kinds of environmental plasticizers were prepared, which were used as additives for polyvinyl chloride (PVC) products. Compared with commercially available di (2‐ethylhexyl) phthalate (DOP), di (2‐ethylhexyl) terephthalate (DOTP), and tributyl citrate (TBC), the application performance and plasticizing performance were compared. The structure of the target product was analyzed by fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy to verify the fingerprint region of the molecular structure of the product. The properties of plasticized PVC films were tested by thermal weight loss analysis, oven thermal aging test, migration and volatility resistance test, DMA analysis, and scanning electron microscopy. The plasticizing mechanism was confirmed through quantum chemical calculations, and the results of the calculations were in line with the migration outcomes. The results showed that compared with commercially available plasticizers, benzene polyacid ester plasticizers had better thermal stability, and better cold resistance in the polar environments, suitable for high‐temperature and water‐based environments.Highlights The four plasticizers prepared in this study were compared with reference plasticizers, and the plasticizing mechanism was validated through quantum chemical calculations. The PVC film plasticized with benzene polyacid ester prepared in this study demonstrates outstanding thermal stability, surpassing certain plasticizers reported in current literature. Benzene polyacid esters plasticized PVC film has migration stability under various conditions, it has great potential in packaging and other applications.

Growth and Yield of Summer Squash (Cucurbita pepo L.) as Influenced by Different Coloured Plastic Mulches in the Tarai Region of Uttarakhand

Summer squash is a short-duration vegetable crop with off-season nature and high economic returns per unit area. However, the early crop growth season encounters a number of abiotic stresses like low temperature and frost, which adversely affect the marketable yield and quality of the fruits. This dependency on natural factors restricts the scope of its profitable cultivation, thereby making it necessary to bring more area under protected cultivation. Coloured plastic mulches are an important component of protected cultivation, which are designed to modify the microclimate at the plant and soil levels so as to increase crop production and productivity, as well as quality of the produce, to meet the demands of the consumers. Keeping these considerations in view, the present field investigation was conducted at the Vegetable Research Centre of G. B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand) during the rabi season of 2019-20 to study the effect of different coloured plastic mulches on the growth and yield of summer squash (Cucurbita pepo L.). The experiment comprised nine treatments (bi-coloured plastic mulches) replicated thrice in a randomised block design. Results revealed that use of different coloured plastic films significantly influenced the growth and yield parameters of summer squash. Red coloured plastic mulch (V1) recorded the maximum values for fruit length (30.78 cm), fruit yield plant-1 (1975.8 g), fruit yield plot-1 (39.51 kg) and total marketable fruit yield (365.52 q ha-1), while biodegradable film of silver-black colour (V7) and black plastic mulch (V4) recorded the maximum plant height (cm) and plant spread (cm), respectively. The maximum diameter of the fruit (110.13 mm) was recorded under black coloured plastic mulch. Considering the prevalent climatic conditions of the tarai region of Uttarakhand, red coloured plastic mulch can be recommended for commercial cultivation of summer squash for obtaining higher fruit yields.

Acclimatization and Foraging of Native Brazilian Stingless Bees in Arenas with Covering Materials of Different Spectral Properties.

The use of Meliponini for crop pollination in protected environments is practically non-existent. One of the reasons is the difficulty of acclimatizing Meliponini to the temperature and light conditions inside greenhouses. We investigated how covering materials used in greenhouses, which filter different intensities of ultraviolet (UV) light, affect the foraging behaviors, flight orientation, attraction to walls and ceilings, and mortality of Scaptotrigona cf. postica (Letreille), Frieseomelitta varia (Lepeletier), and Melipona quadrifasciata (Lepeletier). The experiments were conducted in 5.3 m3 arenas covered with four types of plastic films that do not polarize sunlight, with UV transmittance levels ranging from 0.1 to 54%, compared to a transparent glass control. The temperature inside the arenas varied between treatments, from 27 ± 3°C to 31 ± 2°C. All three species collected resources and returned to the colony, regardless of the covering material. However, the proportion of this behavior, the number of bees attracted to the ceiling and wall, and mortality varied among treatments and/or throughout the confinement days for each species. Melipona quadrifasciata and F. varia acclimatized better to the confined environments than S. cf. postica and showed consistent resource collection behavior throughout the confinement days in all tested materials, except for the one that filtered around 90% of UV. In all three species, the mortality gradually decreased throughout the confinement days. The results indicate that the choice of covering material, considering its optical characteristics, can be crucial to ensure greater effectiveness of the pollination services provided by stingless bees in protected systems.

EFFECTS OF RAINWATER HARVESTING PRACTICES ON BIOMASS YIELD AND MORPHOMETRIC TRAITS OF SORGHUM (Sorghum bicolor L. Moench) IN SEMI-ARID KITUI COUNTY, KENYA

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: Sorghum is an important source of fodder in the semi-arid areas of Kenya. However, its biomass yield has remained low due to the low soil moisture content which is associated with low rainfall. &lt;strong&gt; Objective:&lt;/strong&gt; To evaluate the synergistic effects of combining rainwater harvesting practices on biomass yield and the morphometric traits of sorghum in semi-arid Kitui County. &lt;strong&gt;Methodology&lt;/strong&gt;: The study was conducted in a randomized complete block design under rainfed conditions between March and August 2021 at the Research Farm of South Eastern Kenya University. It had twelve treatments, including three farming systems (conventional flat planting, ridge and furrow, and zai pits) with three soil mulching types (transparent plastic film mulch, black plastic film mulch, and grass mulch). The farming systems without mulching were used as control treatments. Data were subjected to analysis of variance and means were separated using Fisher’s protected Least Significant Difference test at 0.05 %. &lt;strong&gt;Results:&lt;/strong&gt; The zai pits with black plastic film mulch and flat planting with grass mulch had the highest and lowest moisture content of 68.65% and 52.5% respectively compared to flat planting. The highest biomass yield was observed in ridge-furrow with black plastic film mulch (3283.33kg ha-&lt;sup&gt;1&lt;/sup&gt;) and ridge–furrow with transparent plastic film mulch (3266.03) and was not significantly different. The lowest biomass yield was recorded in conventional flat planting and zai pits and was not significantly different. In all treatments, there was a significant increase (p ≤ 0.05) in morphometric traits. &lt;strong&gt;Implications: &lt;/strong&gt;The farming system and the type of soil mulching determined the increase of soil moisture content, biomass yield, and morphometric traits. &lt;strong&gt;Conclusion&lt;/strong&gt;: Combining ridge-furrow and black plastic mulch is recommended to improve the biomass yield of sorghum in semi-arid Kitui County, and other areas with similar agroecological conditions.&lt;/p&gt;

Plastic film mulch use efficiency in agricultural production: a regional analysis in China

Plastic film mulch use efficiency in agricultural production: a regional analysis in China

Alfalfa Cultivation Patterns in the Yellow River Irrigation Area on Soil Water and Nitrogen Use Efficiency

Establishing lucerne field is an efficient way to protect natural steppes, alleviate conflicts between meadows and livestock, and promote the development of animal husbandry. However, problems such as extensive field management, valuing yield over quality, and low resource utilization are endemic in production. Exploring reasonable cultivation patterns can contribute to improving the current situation of artificial grassland production and promoting the high-quality development of husbandry and prataculture. Lucerne the field experiment was carried out in Jingtai, Gansu Province, China in 2021–2022; this study compared and analyzed the effects of three cultivation patterns—ridge tillage with plastic film mulching (PM), ridge tillage with biodegradable film mulching (BM), and traditional flat planting (FP)—on soil water, heat, and fertilizer, as well as lucerne growth, yield, quality, and water and nitrogen use efficiency. The results show that: (1) during the growth period of lucerne, PM and BM treatments augment the average moisture content of the soil layer of 0–120 cm by 31.19% and 24.03% compared to the FP treatment, respectively. In the soil layer of 0–40 cm, PM and BM treatments abate the soil moisture content of the ridges by an average of 19.29% and 7.89% compared to that in the ditches, respectively. In the soil layer of 40–120 cm, PM and BM treatments elevate the soil moisture content of the ridges by 4.40% and 4.65% on average compared to that in the ditches, respectively. The average soil temperature in a soil layer of 5–25 cm shows PM &gt; BM &gt; FP. In contrast with the FP treatment, PM and BM treatments increase the soil temperature of the ridges by an average of 1.87 °C and 0.96 °C and decrease that of the ditches by an average of 0.47 °C and 0.46 °C, respectively. After two years of planting, the three cultivation patterns all promote the soil nutrient content. Compared to the FP treatment, PM and BM treatments increase the organic matter content by 9.94% and 19.94%, respectively. (2) Ridge tillage with film mulching can evidently stimulate the growth of lucerne and enhance yield and quality. Compared to the FP treatment, PM and BM treatments enhance plant height by an average of 15.37% and 4.04%, stem diameter by an average of 34.14% and 14.58%, yield by an average of 21.20% and 14.77%, crude protein content by an average of 13.47% and 7.68%, and relative feed value by an average of 8.71% and 4.41%, respectively. (3) During the two-year growing period, the irrigation amount of lucerne was 508.60–615.30 mm, and the evapotranspiration was 563.70–761.80 mm. Compared to the FP treatment, PM and BM treatments hoist water use efficiency by an average of 43.50% and 17.56%, nitrogen partial factor productivity by an average of 21.20% and 15.22%, and net income by an average of 14.78% and 11.05%, respectively. In summary, in ridge tillage, both ordinary film mulching and biodegradable film mulching can create a favorable soil environment for lucerne growth and heighten production effect. The former has a better effect on advancing the lucerne production effect, and the latter exhibits superior performance in improving soil fertility.

Film mulching counteracts the adverse effects of mild moisture deficiency, and improves the quality and yield of Cyperus esculentus. L grass and tuber in the oasis area of Tarim Basin.

Plastic film mulching (PFM) and deficit irrigation (DI) are vital water-saving approaches in arid agriculture. Cyperus esculentus is a significant crop in dry zones. However, scant data exists on the impacts of these water-saving methods on C. esculentus yield and quality. Using randomized block experiment design. Three irrigation strategies were tested: CK (standard irrigation), RW20 (20% water reduction), and RW40 (40% water reduction). Mulchin treatments included film mulching (FM) and no film mulching (NFM). Results revealed substantial effects of film mulching and drip irrigation on soil nutrients and physical properties, with minor influence on grass, root, and tuber stoichiometry. PF treatment, DI treatments, and their interaction significantly affected C. esculentus forage and tuber yields. Initially, grass and tuber yields increased and then decreased with reduced irrigation. The highest yields were under RW20 (3716.31 and 4758.19 kg/ha). FM increased grass and tuber yield by 17.99% and 8.46%, respectively, over NFM. The water reduction augmented the biomass distribuiton of the leaf and root, while reducing the tuber biomass in NFM. FM significantely impacted grass ether extract content, while reduced water influenced grass and tuber crude protein and tuber ether extract content. Mild water stress increased ether extract, crude protein, and soluble matter in grass and tubers, while excessive RW decreased them. Integrating soil traits, nutrients, yield, and quality, findings indicate C.esculentus yield and quality primarily hinge on soil water content, pond hydrogenase, and electrical conductivity. Based on this results, the recommended strategy is to reduce irrigation by 20% for cultivating C. esculentus in this area.

Chemical, Mechanical, and Wettability Properties of Bioplastic Material from Manihot esculenta Cassava–Chitosan Blends as Plastic Alternative

AbstractThe extensive use and disposal of various petroleum‐derived plastics has become a major cause of environmental pollution. The urgent need for sustainable materials to address plastic waste have resulted in the production of biodegradable plastics. In this study, a biodegradable plastic film is produced by incorporating chitosan with starch from Malaysian cassava (Manihot esculenta), utilizing the multihydroxyl properties of cassava starch. The results show that the addition of chitosan as a filler in cassava starch improves the physicochemical properties of the material, producing a bioplastic film with high compressive strength and resistance to water molecules. The contact angle of the developed biopolymer has been improved – from θ = 67.4° to θ = 97.8° – with the addition of the –NH functional group in the molecule, as confirmed by attenuated total reflectance Fourier‐transform infrared spectroscopy (v = 1555 cm−1). The tensile strength of bioplastic increases with chitosan content, proving its greater rigidity compared to bioplastic without chitosan. Additionally, the fastest biodegradation rate (9 days) occurs in the composition with high amounts of cassava in a ratio of 6:4 (cassava:chitosan). The bioplastic produced in this study readily decomposes in the environment, making it more sustainable, eco‐friendlier, and providing an alternative to mitigate the use of single‐use thermoplastics.

Polyethylene and sulfa antibiotic remediation in soil using a multifunctional degrading bacterium

To obtain a multifunctional bacterium that can effectively degrade polyethylene (PE) and sulfonamide antibiotics (SAs), PE and SAs were selected as the primary research objects. Multifunctional degrading bacteria were isolated and screened from an environment in which plastics and antibiotics have existed for a long time. An efficient degrading strain, Raoultella sp., was screened by measuring the degradation performance of PE and SAs. We analyzed the changes in the microbial community of indigenous bacteria using 16S rRNA. After 60 d of degradation at 28 °C, the Raoultella strain to PE degradation rate was 4.20 %. The SA degradation rates were 96 % (sulfonathiazole, (ST)), 86 % (sulfamerazine, (SM)), 72 % (sulfamethazine, (SM2)) and 64 % (sulfamethoxazole, (SMX)), respectively. This bacterium increases the surface roughness of PE plastic films and produces numerous gullies, pits, and folds. In addition, after 60 d, the contact angle of the plastic film decreased from 92.965° to 70.205°, indicating a decrease in hydrophobicity. High-throughput sequencing analysis of the degrading bacteria revealed that the Raoultella strain encodes enzymes involved in PE and SA degradation. The results of this study not only provide a theoretical basis for further study of the degradation mechanism of multifunctional and efficient degrading bacteria but also provide potential strain resources for the biodegradation of waste plastics and antibiotics in the environment.

CO2 measurement in aquaria using a plastic film colourimetric indicator

The preparation of a colourimetric, plastic film indicator is described, based on the extrusion of low-density polyethylene, LDPE, mixed in with a small amount (5 wt%) of a CO2 sensitive pigment, which is blue and yellow in the absence and presence of CO2, respectively. The pigment comprises a mixture of a pH-indicator dye, Xylenol Blue, XB, with a base, tetrabutyl ammonium hydroxide, coated onto nanoparticles of silica. The extruded XB-LDPE film exhibits a reversible sensitivity towards dissolved CO2, units: %CO2, and a striking colour change over the key operating range, 1–2 %CO2, that needs to be maintained to keep both the fish and any plant-life healthy in an aquarium at 25 °C. The CO2 sensitivity of the XB-LDPE indicator is independent of the pH and ionic strength of the water under test and so can be used to measure %CO2 in sea- and fresh-water aquaria. Digital photography coupled with digital colourimetric analysis, DCA, is used to quantify the response of the XB-LDPE indicator in aquarium sea- and freshwater, and a user-friendly macro is provided to make this process simple to effect. The XB-LDPE indicator offers an attractive, faster, more stable, and much more informative alternative to the popular current, qualitative, drop-checker method for measuring %CO2. The possible use of the XB-LDPE indicator to measure %CO2 in natural waters is discussed.

Study of Humic Acid Organic Liquid Mulching Film on Promoting Green Agriculture Development

Mulching film is an important measure to promote agricultural production income and increase, the current widely used plastic mulching film has high stability, difficult to decompose, resulting in "agricultural white pollution", the development and application of degradable mulching film has become a solution. This case focuses on the study of organic multifunctional liquid mulching film with humic acid as the main raw material, which plays a unique role in promoting biological activity and soil improvement, the application of "liquid" spray film, the integration of fertilizer, pesticides, mulching film in one multi-functional comprehensive effect, to clarify its functional characteristics, alternative feasibility and the promotion of green agricultural development, and put forward the existing problems and countermeasures. This paper provides technical support and practical demonstration for the elimination of exogenous pollutants in farmland, and looks forward to the broad application prospects of this liquid mulch film in environmental protection and other aspects.

Pyrolysis of plasticized films based on soy protein, denatured by different substances

Polymer films based on soy protein isolate (SPI) were obtained using the thermo-pressing method. Plasticizers and denaturing agents were added to ensure better the film-forming properties and reduce the fragility of the resulting materials. Glycerol, sorbitol and their mixture were used for plasticization, while solutions of alkali (potassium hydroxide), surfactants of natural origin (sodium coco sulfate) and reducing agent (sodium sulfite) were used for denaturation. By combining different types of plasticization and denaturation, a series of samples were obtained and compared with a sample based on raw soy protein. In addition to the obvious differences in the appearance of the films, the processes of their thermal degradation, studied by pyrolysis mass spectrometry, also differed significantly. In fact, unprocessed soy protein has the highest thermal stability with the temperature of the most intensive decomposition equal to 270 °С, which can decrease to 200 °С under the conditions of denaturation and plasticization. Despite the increase in the number of film components, the amount of volatile decomposition products decreases (from 86 to 32), as well as the molecular weight of the heaviest of them (from 169 to 74). This is a sign of a change in the mechanism of soy protein degradation due to denaturation and plasticization caused by transformations in its supramolecular structure, such as unfolding and extension of macrochains with increased availability of functional groups. The pyrolytic behavior of some protein samples plasticized with sorbitol is closest to that of untreated soy protein, which may indicate a lower plasticizing efficiency of sorbitol with longer molecules than glycerol. The interpretation of the recorded mass spectra of the volatile pyrolysis products showed that the thermal degradation of protein materials is dominated by processes such as decarboxylation, dehydration, deamination and decarbonylation, while in the presence of plasticizers the splitting of their own molecules also becomes dominant. The characteristic mass spectra of protein films denatured by surfactants also contain ionic fragments of relatively high molecular weight, probably derived from sodium coco sulfate molecules.

Thin, disposable, antibacterial, heat-pressed photocatalytic plastic films

The production of several different thin, highly flexible, disposable, antibacterial, photocatalytic plastic films is described. A thin layer of a semiconductor photocatalyst, SC, powder is partially embedded in a thin (ca. 30 μm), highly flexible film of low-density polyethylene, LDPE, by heat-pressing the two together. The resulting SC/LDPE film is then tested for photocatalytic activity, via the photo-oxidised bleaching of methylene blue, MB, and photocatalysed antibacterial activity, via its inactivation of Escherichia coli, E. coli. The SCs tested include, P25 TiO2, high surface area Tronox rutile TiO2, low surface area rutile TiO2, ZnO and WO3. The MB test results reveal photocatalytic activities of the SC/LDPE films are, P25 TiO2 > ZnO > rutile TiO2 ≈ Tronox rutile TiO2 > WO3, which suggest the kinetics depend largely on the redox potential of the photogenerated conductance band electrons. In contrast, the E. coli deactivation results show that the order of activities of the SC/LDPE films, in the dark and (with an increased rate) upon illumination, are, Tronox rutile TiO2 > P25 TiO2 > ZnO > WO3 > rutile TiO2, which is similar to the variation in roughness factor, Rf. It appears that rough films are better at deactivating E. coli, not only under illumination, via both a photocatalytic and thermal mechanism, but also in the dark, via a ‘bed-of-nails’/shear stress physical mechanism. Encouragingly, in most cases, the photocatalysed antibacterial activity exhibited by the SC/LDPE films is not much (ca. 74 %) lower when a cool white fluorescent rather than UVA lamp is used (UVA irradiance = 47 μW/cm2 and 1.5 mW/cm2, respectively). The Tronox rutile TiO2 film was also found to be effective in deactivating another Gram-negative bacterium and, to a lesser extent, two Gram-positive bacterial species. The potential of these thin plastic films with a notable antibacterial activity under room light and in the dark is discussed briefly.

Hydrogenolysis of Poly(Ethylene-co-Vinyl Alcohol) and Related Polymer Blends over Ruthenium Heterogeneous Catalysts.

The hydrogenolysis of polymers is emerging as a promising approach to deconstruct plastic waste into valuable chemicals. Yet, the complexity of plastic waste, including multilayer packaging, is a significant barrier to handling realistic waste streams. Herein, we reveal fundamental insights into a new chemical route for transforming a previously unaddressed fraction of plastic waste - poly(ethylene-co-vinyl alcohol) (EVOH) and related polymer blends - into alkane products. We report that Ru/ZrO2 is active for the concurrent hydrogenolysis, hydrogenation, and hydrodeoxygenation of EVOH and its thermal degradation products into alkanes (C1-C35) and water. Detailed reaction data, product analysis, and catalyst characterization reveal that the in-situ thermal degradation of EVOH forms aromatic intermediates that are detrimental to catalytic activity. Increased hydrogen pressure promotes hydrogenation of these aromatics, preventing catalyst deactivation and improving alkane product yields. Calculated apparent rates of C-C scission reveal that the hydrogenolysis of EVOH is slower than low-density polyethylene. We apply these findings to achieve hydrogenolysis of EVOH/polyethylene blends and elucidate the sensitivity of hydrogenolysis catalysts to such blends. Overall, we demonstrate progress towards efficient catalytic processes for the hydroconversion of waste multilayer film plastic packaging into valuable products.

Thermalization of Mesh Reinforced Ultra-Thin Al-Coated Plastic Films: A Parametric Study Applied to the Athena X-IFU Instrument.

The X-ray Integral Field Unit (X-IFU) is one of the two focal plane detectors of Athena, a large-class high energy astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Program. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that operate at ~100 mK inside a sophisticated cryostat. To prevent molecular contamination and to minimize photon shot noise on the sensitive X-IFU cryogenic detector array, a set of thermal filters (THFs) operating at different temperatures are needed. Since contamination already occurs below 300 K, the outer and more exposed THF must be kept at a higher temperature. To meet the low energy effective area requirements, the THFs are to be made of a thin polyimide film (45 nm) coated in aluminum (30 nm) and supported by a metallic mesh. Due to the small thickness and the low thermal conductance of the material, the membranes are prone to developing a radial temperature gradient due to radiative coupling with the environment. Considering the fragility of the membrane and the high reflectivity in IR energy domain, temperature measurements are difficult. In this work, a parametric numerical study is performed to retrieve the radial temperature profile of the larger and outer THF of the Athena X-IFU using a Finite Element Model approach. The effects on the radial temperature profile of different design parameters and boundary conditions are considered: (i) the mesh design and material, (ii) the plating material, (iii) the addition of a thick Y-cross applied over the mesh, (iv) an active heating heat flux injected on the center and (v) a Joule heating of the mesh. The outcomes of this study have guided the choice of the baseline strategy for the heating of the Athena X-IFU THFs, fulfilling the stringent thermal specifications of the instrument.