Moisture Uptake Rate Research Articles

Thermodynamic and cloud evolution in a cold-air outbreak during HALO-(AC)3: quasi-Lagrangian observations compared to the ERA5 and CARRA reanalyses

Abstract. Arctic air masses undergo intense transformations when moving southward from closed sea ice to warmer open waters in marine cold-air outbreaks (CAOs). Due to the lack of measurements of diabatic heating and moisture uptake rates along CAO flows, studies often depend on atmospheric reanalysis output. However, the uncertainties connected to those datasets remain unclear. Here, we present height-resolved airborne observations of diabatic heating, moisture uptake, and cloud evolution measured in a quasi-Lagrangian manner. The investigated CAO was observed on 1 April 2022 during the HALO-(AC)3 campaign. Shortly after passing the sea-ice edge, maximum diabatic heating rates over 6 K h−1 and moisture uptake over 0.3 gkg-1h-1 were measured near the surface. Clouds started forming and vertical mixing within the deepening boundary layer intensified. The quasi-Lagrangian observations are compared with the fifth-generation global reanalysis (ERA5) and the Copernicus Arctic Regional Reanalysis (CARRA). Compared to these observations, the mean absolute errors of ERA5 versus CARRA data are 14 % higher for air temperature over sea ice (1.14 K versus 1.00 K) and 62 % higher for specific humidity over ice-free ocean (0.112 g kg−1 versus 0.069 g kg−1). We relate these differences to issues with the representation of the marginal ice zone and corresponding surface fluxes in ERA5, as well as the cloud scheme producing excess liquid-bearing, precipitating clouds, which causes a too-dry marine boundary layer. CARRA's high spatial resolution and demonstrated higher fidelity towards observations make it a promising candidate for further studies on Arctic air mass transformations.

Soil warming-induced reduction in water content enhanced methane uptake at different soil depths in a subtropical forest

Global warming can significantly impact soil CH4 uptake in subtropical forests due to changes in soil moisture, temperature sensitivity of methane-oxidizing bacteria (MOB), and shifts in microbial communities. However, the specific effects of climate warming and the underlying mechanisms on soil CH4 uptake at different soil depths remain poorly understood. To address this knowledge gap, we conducted a soil warming experiment (+4 °C) in a natural forest. From August 2020 to October 2021, we measured soil temperature, soil moisture, and CH4 uptake rates at four different soil depths: 0–10 cm, 10–20 cm, 20–40 cm, and 40–60 cm. Additionally, we assessed the soil MOB community structure and pmoA gene (with qPCR) at the 0–10 and 10–20 cm depths. Our findings revealed that warming significantly enhanced soil net CH4 uptake rate by 12.28 %, 29.51 %, and 61.05 % in the 0–10, 20–40, and 40–60 cm soil layers, respectively. The warming also led to reduced soil moisture levels, with more pronounced reductions observed at the 20–40 cm depth compared to the 0–20 cm depth. At the 0–10 cm depth, warming increased the relative abundance of upland soil cluster α (a type of MOB) and decreased the relative abundance of Methylocystis, but it did not significantly increase the pmoA gene copies. Our structural equation model analysis indicated that warming directly regulated soil CH4 uptake rate through the decrease in soil moisture, rather than through changes in the pmoA gene and MOB community structure at the 0–20 cm depth. In summary, our results demonstrate that warming enhances soil CH4 uptake at different depths, with soil moisture playing a crucial role in this process. Under warming conditions, the drier soil pores allow for better CH4 penetration, thereby promoting more efficient activity of MOB.

Reduction of polystyrene/polyurethane plastic wastes from the environment into binders for water-resistant emulsion paints

Waste management is fundamental to resource and environmental sustainability. Expanded polystyrene (EPS) and polyurethane (PU) waste plastics were recycled and applied as binder in emulsion paint formulation. The recycled polystyrene (rPS) and polyurethane (rPU) were blended into composite resins, where toluene was used as the solvent. The blends of rPS and rPU were optimized, while some physicochemical properties of the composite blends (rPS/PU) were evaluated. The results showed that the incorporation of rPU into rPS increased the viscosity (1818 mPa–3924 mPa), rate of gelation (dry-to-touch time: 15 min–0.25 min), moisture content (2.7%–8.1%), moisture uptake (3.2%–5.0%), solid content (48%–53.4%) and density (0.82 g/cm3 to 1.050.82 g/cm3) of the rPS/PU composite resins. Characterization was carried out using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and atomic force microscopy (AFM). The results summarily showed that there are interactions among the rPS and rPU molecules in the composite, where complimentary structural and morphological characteristics were also achieved. The composite resin also exhibited superior bond strength (0.5–4.24 Mpa) on wood, cast mortar, ceramic, and steel surfaces due to its stronger intra- and inter-surface interactions compared to the neat rPS resin. The composite resin was used as a binder in the formulation of emulsion paint. The paint exhibited stronger resistance to water, among other superior properties, when compared to the paints formulated using neat rPS and conventional polyvinyl acetate (PVA) resins. The reduction of plastic waste in this study holds potential for the production of highly water-resistant emulsion paint for outdoor and indoor applications.

Optimization of pelletization process conditions and binder concentration for production of fuel pellets from oat hull and quality evaluation

Conversion of low-value agricultural residues into biofuels, especially fuel pellets is a promising technique, and the fuel pellet can be used for combustion, co-combustion in boilers and furnace for the generation of heat and power in power plants. Bio-based additives such as mustard meal and bio-oil derived from softwood via pyrolysis have been used as binder for the formulation of oat hull pellets. Central composite design was used to find the different conditions of formulation as well as to optimize the formulation for high quality pellet. Three parameters including the concentration (wt.%, db) of mustard meal (10–20), bio-oil (5-15) and water (8-12) were used as input factors while the response factors were durability index, hardness, relaxed density and moisture uptake rate of fuel pellets. The highest durability, density and mechanical strength was found for pellet formed from 15 wt% of bio-oil, 10 wt% of mustard meal and 8 wt% of water. Pyrolysis bio-oil is the most influential factor that significantly affected pellet properties while the effect of mustard meal as binder is frivolous. Moreover, pelletization operating conditions were also optimized using pelletization force (3000–4500 N), die temperature (90–110°C) and relaxation time (15–60 s) while the die diameter was constant at 6 mm. The pellet quality improved with higher die temperature and pelletization force, but the effect of holding time is insignificant. Computed tomography (CT) analysis reveal that addition of bio-oil significantly decreased the porosity of pellet and thus contributed in enhancing the mechanical strength of pellets.

Preparation and evaluation of ciprofloxacin solid dispersion tablets developed from stearic acid, Polyethylene Glycol 4000 and Soluplus

Ciprofloxacin is a fluoroquinolone antibiotic with a broad spectrum of activity used for the treatment of various bacterial infections and is characterized by poor aqueous solubility and low permeability. The aim of this study is to formulate and characterize ciprofloxacin solid dispersions using hydrophilic and lipophilic matrices for improved product qualities and drug delivery. Ciprofloxacin hydrochloride tablets were formulated as solid dispersions by melting and solvent evaporation in tablet moulds using varying concentrations of stearic acid (10-40 %w/w), Polyethylene glycol 4000 (PEG 4000) (10-40 %w/w) and Soluplus® (10-20 %w/w as ethanolic solution) as components. The prepared tablets were evaluated for weight uniformity, friability, hardness, Fourier transform-infrared spectroscopy (FT-IR), moisture uptake, swelling index, disintegration time and dissolution rate, using standard methods and optimization techniques. The results showed uniform solid dispersion weights with friability, hardness, moisture uptake and swelling index of 0.4-0.5%, 3.0-7.5 kgf, mostly <20% and 1-71%, respectively. The formulations were chemically stable with no transformational interactions between components. Formulations without stearic acid disintegrated within 30 min whereas those containing the lipid broke up after more than 1 h. Drug release studies showed high immediate release in tablets without stearic acid but with cumulative steady state release higher in formulations with 10 %w/w Soluplus and different concentrations of stearic acid and PEG 4000. In conclusion, ciprofloxacin was presented as solid dispersion tablets with modified physicochemical attributes for improved drug delivery.
 Keywords: Ciprofloxacin; solid dispersion; drug delivery

Assessment of The Hygroscopic Behaviour of Proton-Conducting Ionic Liquids: Kinetics, Conductivity and Electrochemical Analysis

We report the synthesis of five proton-conducting ionic liquids (PCILs) by a neutralization reaction. The proton transfer from the corresponding Brønsted acid to the respective base was confirmed by FT-IR spectroscopy. The Karl-Fischer titration was used to measure the water contents of the PCILs exposed to air for different time intervals at a relative humidity of 36 ± 5% and 31 ± 5 °C. The rate of moisture uptake by the PCILs increased with the increase of their time of exposure to air and follows pseudo-first-order kinetics. The conductivity analysis reveals that the PCILs’ ionic conductivities further rise with increasing water contents and temperature. The conductivity data were fitted with the Arrhenius equation and activation energies (Ea) were deduced. The electrochemical analysis of the triethylammonium dihydrogen phosphate, TEADHP shows that the liquid has a wide (2.8 V) electrochemical window (EW) at the Pt electrode at 60 °C and 5% water. The EW becomes narrower as the temperature and water content of the TEADHP increase due to the increase in the rate of the water electrolysis. The data showed that during positive-going scans, Pt-oxides were formed due to the oxidation of water in the PCIL which plays an electrocatalytic role during formic acid oxidation in the medium.

Fractional Importance of Various Moisture Sources Influencing Precipitation in Iran Using a Comparative Analysis of Analytical Hierarchy Processes and Machine Learning Techniques

Studying the moisture sources responsible for precipitation in Iran is highly important. In recent years, moisture sources that influence precipitation across Iran have been studied using various methods. In this study, moisture uptake rate from individual sources that influences precipitation across Iran has been determined using the (E − P) values obtained by the FLEXPART model for the 1981–2015 period. Then, moisture uptake rate from individual sources has been used as independent parameters to investigate the fractional importance of moisture sources that influence precipitation in Iran using analytical hierarchy process (AHP) as well as machine learning (ML) methods including artificial neural networks, Decision Tree, Random Forest, Gboost, and XGboost. Furthermore, the average annual precipitation in Iran was simulated using ML methods. The results showed that the Arabian Sea has a dominant fractional influence on precipitation in both wet (November to April) and dry (May to October) periods. Simulation of precipitation amounts using the ML methods presented accurate models during the wet period, whereas the developed models for the dry period were not adequate. Finally, validation of the accuracy of the ML models using RMSE and R2 values showed that the models developed using XGboost had the highest accuracy.

Complementary effects of torrefaction and pelletization for the production of fuel pellets from agricultural residues: A comparative study

Torrefaction is an effective technique to produce high quality coal-like material, which can be used as a substitute of coal in combustion or gasification processes. Combination of torrefaction and pelletization can be a promising technique for production of fuel pellet for long term storage and overseas transportation without deterioration of its quality. In the current study, two production pathways (I: co-pelletization of torrefied biomass, II: torrefaction of biomass pellet) have been compared in terms of fuel pellet quality (physical, mechanical, thermal, and hydrophobicity). Characteristics of pellets produced via co-densification of canola hull, oat hull with mustard meal were investigated. Although up to 75 wt% of oat hull/canola hull was successfully pelletized with mustard meal, 50:50 ratio of oat hull/ canola hull: mustard meal was optimum ratio based on pellet properties. Co-pelletization of torrefied biomass with raw biomass makes competitive quality pellet without use of external additives, high temperature and high pressure. Additionally, the higher heating value, energy density, hydrophobicity increased, and atomic ratios (H/C and O/C) decreased after torrefaction in both cases. Synchrotron-based computed tomography showed that porosity and diameter of cavity enlarged significantly for torrefied pellet than that for pellet produced from torrefied biomass. However, the moisture uptake rate for torrefied pellet is lower than that for torrefied biomass pellet. Higher heating values of pellet were more or less similar for pellets obtained from both pathways. In terms of energy consumption throughout the whole procedure, scheme II is slightly more intense as it requires more energy during grinding while scheme I requires more energy for pelleting. Therefore, co-pelletization of torrefied biomass was more effective considering overall energy consumption and fuel pellet product quality.

Characteristics of torrefied fuel pellets obtained from co-pelletization of agriculture residues with pyrolysis oil

Agricultural wastes have the potential to contribute to global energy by converting low value by-products to high value products e.g. fuel pellets, which can be used for heat and power generation. In this study, co-pelletizing characteristics of canola hull, oat hull and barley straw with water were investigated while pyrolysis bio-oil was used as binder. Co-pelletization has been conducted using bench-scale extruder. Canola hull was used as base feedstock due to having a small portion of oil (8 wt%) which provides lubricating effects during pelletization. Increase in biomass to water mass ratio, increased the mechanical strength and durability of pellets but pellets yield decreased. The optimum biomass to water mass ratio was found 2.5. Pyrolysis bio-oil worked as effective additives, enhanced the flow properties, made extrusion smooth, advanced the internal structure of pellet by facilitating strong interlocking of particles, and thus boosted the physical firmness of fuel pellet. Results showed that co-pelletization of oat hull and barley straw with canola hull was optimum for 30 wt% of oat hull or barley straw, but pelletization was successful for up to 45 wt% of those feedstocks. Microwave torrefaction was conducted to boost up the hydrophobicity and higher heating value of pellet. Torrefied pellet showed higher heating value, higher energy density, higher carbon content, lower atomic ratio, lower moisture uptake rate compared to untreated pellet. Synchrotron-based computed tomography shows that porosity increased by up to 39% after torrefaction. Additionally, to assess the mechanical, physical and chemical properties of pellet, various characterization methods were employed.

Soy meal adhesive with high strength and water resistance via carboxymethylated wood fiber-induced crosslinking

Soy meal-based wood adhesive has received much interest for its environmentally friendly properties, as it is thought to provide an effective alternative to conventional formaldehyde-based wood adhesives. However, the abundant hydrophilic groups and weak internal structure result in poor water resistance and low bonding strength of soy meal-based wood adhesives. In this study, bio-based carboxymethylated wood fibers (CMWFs) were used to develop a high-performance soy meal-based adhesive. Wood fibers (WFs) were pre-treated via carboxymethylation to endow WFs with abundant carboxyl groups and facilitate their dispersion in soy protein matrix. CMWFs containing abundant carboxyl groups served as a multiple “crosslinking core” and effectively cross-linked with soy protein side-chain, resulting in the construction of a stable adhesive system. The modified soy meal-based adhesive exhibited excellent bonding strength and water resistance. In particular, tension tests indicated that the water-resistant bonding strength of the adhesive modified with CMWFs reached 1.69 MPa, which was 160% higher compared with the unmodified adhesive; the wood failure percentage of the plywood bonded by CMWF-modified soy meal-based adhesive was as high as 100%. Moisture uptake and residual rate tests indicated that high water resistance of the adhesive was achieved. This design provides a facile and sustainable strategy for developing high-performance soy meal-based adhesives.

Determination of paper plaster hygrothermal performance: Influence of different types of paper on sorption and moisture buffering

The study focuses on the moisture buffering properties of paper plaster. Two questions are under consideration in this article. Firstly, how the paper used influences the properties (dry density, drying shrinkage) of paper plaster, and secondly, what the material sorption and moisture buffering properties of paper plaster are.Two different dry density sized groups of densities approx. 140–150 kg/m3 (glossy paper and egg cartons) and 240–250 kg/m3 (printer paper and newsprint). Shrinkage properties were 10–14% (in diameter) for printer paper, 3–4% for glossy paper and egg carton, and 5.6% for newsprint.The results of the tests carried out in a climate chamber show that paper plaster adsorbs water vapour well - more than clay plaster, which is often used as a good moisture buffering material. The maximum moisture content was 961 g/m2 and as a minimum of 726 g/m2. The moisture uptake rate was higher on the first day of RH change than on other days.Paper plaster is an outstanding water buffering material [2.11–2.99 g/(m2·%RH)] belonging to the moisture buffering class presented by Nordtest method as “excellent".The results demonstrate that the moisture buffering properties of paper plaster when different papers are used do not differ significantly. It means that all the paper materials used in the study can be used to make paper plaster. Therefore, sorting paper before making paper plaster is not necessary.

Morphology, mechanical properties, and biodegradability of all‐cellulose composite films from oil palm empty fruit bunch

AbstractPalm oil plantations are very important in that they supply vegetable oil globally. However, increased production of palm oil prompts the accumulation of large lignocelluloses residues in the form of oil palm empty fruit bunch (OPEFB). This study explored the advantages of using OPEFB in the production of all‐cellulose composite (ACC) films. The isolation process of the raw OPEFB fiber was carried out using a chemical process to extract OPEFB nanocellulose. ACC films from OPEFB and microcrystalline cellulose (MCC) were prepared using a dimethylacetamide (DMAC) and lithium chloride solvent system whereby the partially dissolved cellulose was transformed into the matrix phase surrounding the remaining nondissolved fiber. ACC films with 1% (wt/vol) OPEFB and 3% (wt/vol) MCC were prepared and the effects of chemical treatment of the OPEFB cellulose on the mechanical properties, crystalline structure, morphology, moisture absorption and soil biodegradability of the ACC film were investigated. The tensile strength of the ACC film was tremendously improved by chemical treatment. For instance, when acetic acid was used to treat the nanocellulose, the resultant film showed 279% increment in tensile strength value. However, formic acid‐treated films demonstrate greater moisture uptake and soil biodegradation rate. The findings could be related to the alterations of hydroxyl group composition in the nanocellulose and variation in dissolution rate of the nanocellulose during chemical treatment.

Impact of kaolin on physicomechanical properties of density-graded cement bonded paperboards

Paperboards of thickness 0.6 cm with densities of 0.8, 0.9, and 1.0 g/cm3 were produced from waste papers mixed with cement and kaolin. Printing and corrugated waste papers were employed in the proportions of 50.0/25.0/25.0, 50.0/37.5/12.5, and 50.0/12.5/37.5 (paper/cement/kaolin), respectively. The dimensional and strength properties of the boards were investigated. The values obtained range from 0.40 to 0.94 g/cm3, 51.19 to 68.10%, 0.14 to 3.10%, 0.01 to 1.69 Nmm-2, and 119.98 to 567.32 Nmm-2 for observing the density, water absorption, thickness swelling, modulus of rupture, and modulus of elasticity, respectively. The board of proportion 25/25 of kaolin/cement was densest with high strength. As the nominal density and kaolin content were increased from 12.5 to 37.5%, an increase was observed in density and strength properties. Similarly, as the proportion of kaolin and cement content were increased, the rate of moisture uptake to cavity decreased. This study shows that boards from printing papers were more dimensionally stable than corrugated papers. It revealed that printing papers could be better raw material for manufacture paperboard than corrugated papers. Information provided in this study could be used as a guideline for the manufacture of paperboard reinforced with kaolin as an additional constituent for quality improvement.

Novel Coating Technologies to Reduce Rate of Moisture Absorption of Phosphate and Phosphate/Urea Substrates

One of the most significant challenges in handling bulk materials like fertilizer substrates is the affinity of the substrate components to adsorb moisture. This affinity is further exaggerated when blended with other substrates, as well as when stored in regions with elevated humidity. Examples of this are seen when combining phosphate substrates (DAP, MAP, SSP etc.) with nitrogen-containing substrates (ammonium sulfate, urea etc.) to produce various grades of NPK. The combination of these substrates can increase the rate of deliquescence or moisture uptake in granular fertilizers, which can either lead to mushiness observed on the surface of fertilizer granules, mass gain due to absorption into granules, and even increased caking tendencies.

Is Hygrothermal Aging of Construction Polymer Composites a Reversible Process?

This paper presents the effects of wet/dry cycling loading on the moisture uptake behavior of a Fibre Reinforced Polymer (FRP) composite used in the civil engineering sector. FRP samples of various dimensions were cut from an ‘off-the-shelf’ pultruded flat sheet and conditioned in a cyclic hygrothermal environment. A series of 3 consecutive moisture absorption-desorption cycles lasting for 153 days were carried out to investigate the moisture uptake behavior of FRPs. The hygrothermal procedure consisted of immersion in 60°C distilled water until saturation and consecutively drying in a 60°C oven until equilibrium was reached. After the 1st desorption cycle, it was found that FRP samples lose a significant amount of mass due to chemical decomposition, the extent of which increases as wet/dry cyclic loading progresses. The effective mass loss leads to a subsequent significant increase in the rate of moisture uptake. Mechanical behavior of the FRPs aged at 40°C, 60°C and 80°C for 224 days is examined at both ‘wet’ and ‘dry’ states to reveal the reversible and irreversible effects of moisture uptake. It was revealed that the effects of 40°C hygrothermal aging on mechanical performance are reversible when moisture is removed.

Waterborne polyurethanes from castor oil-based polyols for next generation of environmentally-friendly hair-styling agents

Commercial hair-styling spray is often formulated with multiple components that contribute to toxicity and environmental pollution. In this work, a series of bio-based waterborne polyurethanes (CWPU) as hair styling agent were prepared from castor oil-based polyols. The resulting polyurethane dispersions exhibit excellent storage stability for at least 24 months. The effects of the castor oil functionality and chain extender structure on the particle size of the polyurethane dispersions were systematically investigated. Hair-styling performance and skin irritation tests on animals were also carefully performed to assess styling performance and safety of these CWPUs. A series of CWPU films was successfully prepared to study the relationship between the structure and performance of the bio-based polymer films. The resulting films show low moisture uptake rate, high transmittance, hydrophilicity and good mechanical properties. When CWPU films exhibit Young’s modulus >50 MPa, elongation at break in the 15–300 % range, and moisture uptake <4 %, these samples exhibit good hair-styling performance, and even better than commercial hair spray product. The skin irritation test is also proved that there is no evidence of skin irritation for these CWPUs which hold great promise for hair styling applications.

Water Uptake and Its Effects on Mechanical and Acoustic Properties of flax/polypropylene Composite

ABSTRACT The effects of moisture on the mechanical and acoustic properties of flax fibers embedded in polypropylene (PP) were investigated in the present study. Flax/PP and hybrid flax-carbon/PP samples were immersed in water at controlled temperatures. The water intake over time in flax/PP was shown to approach Fickian behavior at room temperature while hybrids showed strong deviations. Through hybridization with 13% carbon fibers, water uptake in flax-carbon PP was reduced by 25%. For thin hybrid laminates, positioning carbon fibers at the outer edges caused no significant difference in the rate of moisture uptake. Micrographic analysis revealed that carbon fiber bundles are more susceptible to resin deficiency in flax-carbon/PP hybrids due to its densely packed thin fibers. The stiffness of moisture-saturated flax/PP samples was 50% lower than dry specimens, with 35% increase in failure strain. The tensile strength, however, was almost unaffected, and both, dry and wet samples, exhibited similar damage characteristics. The stiffness reduction affected the acoustic performance: the resonant frequency was reduced, and the STL were lowered in the stiffness-controlled frequency domain. To determine the unknown water uptake at saturation, an accelerated method was presented as an alternative time-efficient solution for designers.

Effect of molasses binder on the pelletization of food waste hydrochar for enhanced biofuel pellets production

In this study, molasses was used as binder for the pelletization of hydrochar to enhance the fuel and storage properties. The basic fuel properties of the pellets including the proximate analysis and the higher heating value (HHV) were evaluated. The compressive strength was assessed and binding surface of the pellets was analyzed by SEM and ZIESS microscope, and the moisture uptake and combustion properties were analyzed by TG. The results suggested that, with molasses addition from 10% to 20%, the HHV of pellets was decreased while the mass density and energy density of the pellets significantly increased to a range of 947.1–1301.9 kg/m3 and 23.55–33.40 GJ/m3, respectively. The “sold bridge” formation from molasses by recrystallization of sugar enhanced the tensile strength of the pellets, with 260–20% exhibiting the highest value (6.44 MPa), while the maximum load distance of the molasses pellets decreased. In addition, the molasses binder also delayed the moisture uptake rate and slightly increased the EMC content which depended more on the HTC temperature. The combustion analysis showed that the molasses binder decreased the ignition temperature (17–42 °C), and the maximum mass lose rate decreased about 0.6–0.8%/°C, indicating that molasses pellets was combusted in a moderate process. The results suggested that molasses binder assisted pelletization of hydrochar from food waste had potentials for the preparation as solid biofuel.

Hydrothermal aging of bio-based poly(lactic acid) (PLA) wood polymer composites: Studies on sorption behavior, morphology, and heat conductance

Abstract This work examines the moisture sorption, the morphology, and the thermal conductivity of fully bio-based composites, namely wood flour (WF) filled poly(lactic acid) (PLA), to better understand hydrothermal deterioration and potential for long-term application. Composites containing varying WF content (0%, 10%, and 30% filler by weight) were conditioned in either a fully submerged state or a fully desiccated state at four temperatures: (a) 7 °C, (b) 25 °C, (c) 35 °C, and (d) 47 °C. Results indicate that an increase in temperature typically corresponded to an increase in the rate of moisture uptake and percent crystallinity. Higher fiber contents also typically resulted in an increase in the rate of moisture uptake and thermal conductivity. Signs of deterioration, such as cracking at low temperatures and discoloration at high temperatures were noticed for these composites. Environmental impact assessments suggest the desired application and environmental exposures for these bio-based composites could drive constituents used. While the ease of production and the popularity of PLA facilitate the potential use of PLA WPCs, these composites would be expected to exhibit deterioration under high moisture conditions even at ambient temperatures.

Preparation and characterization of biocomposite films of carrageenan/locust bean gum/montmorrillonite for transdermal delivery of curcumin.

Introduction: Skin can be used as a site for local and systemic drug administration. Diffusion of drugs through the skin has led to the development of different transdermal drug delivery systems. Curcumin is a wound healing and anti-inflammatory agent. Curcumin was incorporated into biocomposite films of carrageenan (κC)/locust bean gum (LBG)/ montmorillonite (MMT) prepared by a solvent casting method. Methods: Film-forming solutions were prepared by adding and 2.5% v/v of propylene glycol and MMT (30% w/w). The curcumin loaded polymer composite transdermal films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Mechanical properties in terms of tensile strength and extensibility were studied. Films were also evaluated for moisture content, moisture uptake, thickness, folding endurance, swelling ratio and water vapor transmission rate (WVTR). Results: κC and κC/L40 showed the highest percent cumulative release of 80.42±1.61% and 69.38±1.26% among all of the polymer composite transdermal films in 8 hours and 24 hours respectively. Conclusion: In vitro release profiles showed that increasing concentration of LBG and MMT sustained the release of the drug from the polymer composite transdermal films. Decreased percent cumulative release as the concentration of LBG and MMT increases in polymer composite transdermal film.