Application of Carbon Nanodots from Cocoa Husk Waste to Improve the Mechanical Properties of Cellulose-Carrageenan-Based Biodegradable Films

Due to their unique structure and tuneable physical, optical, and electronic properties, carbon nanodots (CDs) become one of the perfect nano‐materials in many fields such as biomarkers, optical sensing, and catalysis. The application of CDs in modifying polymers has also attracted much interest. In this work, a simple process was employed for introducing CDs to modify natural rubber (NR) latex. Glucose was applied as the precursor to prepare CDs by hydrothermal method, subsequently, the crude CDs were directly added to NR latex at a very lower concentration to prepare NR/CDs films. The results of mechanical properties demonstrate that the 500% modulus, tensile and tear strength of NR composites are significantly improved by the introduction of CDs. When the theoretical loading of CDs is 2 phr, the tensile strength and tear strength of NR/CDs film reach to 33.1 MPa and 56.4 N/mm, and improve 17.8% and 29.4% than NR without CDs respectively. It is particularly noteworthy that when the amount of CDs is higher than 1.5 phr, the heat‐aging resistance of NR has been enhanced. It has been confirmed by crosslink density, dynamic mechanical analysis, and Fourier Transform Infrared Spectrometer analysis that CDs have a certain confinement effect on the mobility of rubber molecular segments through physical adsorption and chemical crosslinking. The Tube model theory was employed to calculate parameters of the network structure of NR/CDs films (based on the stress–strain curves), the results indicate that CDs give NR film more chemical crosslinking points and less entanglement network.Highlights The crude carbon nanodots are used to modify NR latex at a lower concentration The mechanical properties of NR films are obliviously improved The heat‐aging resistance of NR has been enhanced by adding carbon nanodots higher than 1.5 phr The Tube model theory are employed to analysis the crosslink network CDs give NR film more chemical crosslinking points and less entanglement network

Use of plastic food packaging has long been debated due to its negative environmental impact. As a result of this, the need to develop sustainable and biodegradable packaging continuously grows, particularly that using plant-based materials. The study was undertaken to develop biodegradable film from Pine Needle Fiber (PNF), Cassava Starch (CS), Polyvinyl Alcohol (PVOH) blend through a casting technique. It aimed to standardize the process for preparation of biodegradable packaging films physical, mechanical, and biodegradable properties. The mechanical properties and biodegradability of the resulting CS-PVOH/PNF films were evaluated. The films demonstrated improved tensile strength and elongation at break, with optimal values of 10 MPa Tensile Strength and 191% Elongation. The Soil Burial Method showed rapid biodegradation, with all films degrading within 10 days. Water absorption tests revealed a decrease in water absorption with increasing PNF content, confirming the suitability of the CS-PVOH/PNF films as eco-friendly, flexible packaging materials with desirable mechanical and biodegradable properties. On the other hand, expanding the fiber and starch extent in film framework decayed both rigidity and percent extension at break of the film. The results revealed that addition of pine needle fibre has lowered water absorption and increased the Tensile Strength and Elongation as compared to films without pine needle fibre. Considering all the parameters it can be said that the biodegradable film (CS-PVOH/PNF) mix was developed which can be viewed as reasonable, adaptable by a straightforward and harmless to the ecosystem cycle.

The tendency to use biocompatible packages, such as biodegradable films, is growing since they contain natural materials, are recyclable and do not cause environmental pollution. In this research, cold water fish gelatin and carboxymethyl cellulose were combined for use in edible films. Due to its unique properties, gelatin is widely used in creating gel, and in restructuring, stabilizing, emulsifying, and forming foam and film in food industries. This research for the first time modified and improved the mechanical properties of cold water fish gelatin films in combination with carboxymethyl cellulose. Cold water fish gelatin films along with carboxymethyl cellulose with concentrations of 0%, 5%, 10%, 20% and 50% were prepared using the casting method. The mechanical properties were tested by the American National Standard Method. Studying the absorption isotherm of the resulting composite films specified that the humidity of single-layer water decreased (p < 0.05) and caused a reduction in the equilibrium moisture of these films. In the mechanical testing of the composite films, the tensile strength and Young’s modulus significantly increased and the elongation percent significantly decreased with the increase in the concentration of carboxymethyl cellulose. Considering the biodegradability of the films and the improvement of their mechanical properties by carboxymethyl cellulose, this kind of packaging can be used in different industries, especially the food industry, as an edible coating for packaging food and agricultural crops.

The production of biodegradable films has been studied to be a substitute of conventional plastics. The use of starch in biodegradable films are of great interest and starch modification improves an increase to the mechanical properties the film. The mechanical properties were evaluated by Dynamic Mechanical Analysis (DMA). The aim of this study is to determine the mechanical properties of biodegradable films produced from native and chemically modified potato starch. The starch was extracted and subjected to chemical modification by oxidation in different concentrations of active chlorine. The biodegradable films were prepared with starch and glycerol as plasticizer, and were observed with an optical microscope to evaluate the morphology and their relationship with the strength. The tensile tests were performed at 80oC to evaluate the mechanical properties by means of stress-strain curves. The morphology of biodegradable potato starch films shows that the starch granules were partially gelatinized during the film formation. As the elastic modulus is a property which determines the stiffness of the material, by means of he DMA analysis it can be seen that oxidation results in beneficial changes in the mechanical properties of the films, because the modulus increased from 346.70 MPa for the native starch to 651.75 MPa to oxidized starch with 1.5% of active chlorine, respectively.

در تحقیق حاضر بمنظور بهبود خواص فیزیکی و مکانیکی فیلم‌های زیست تخریب‌پذیر خوراکی ترکیب کردن دو پلیمر کربوکسی‌متیل‌سلولز (CMC) و کتیرا مورد مطالعه قرار گرفت. کربوکسی‌متیل‌سلولز و کتیرا با نسبت‌های 25:75، 50:50 و 75:25 با یکدیگر ترکیب شده و میزان نفوذپذیری به بخار آب، درصد حلالیت، خواص مکانیکی و ریزساختار آنها ارزیابی گردید. نتایج نشان داد که در میان سه نسبت مرکب دو پلیمر، میزان استحکام کششی در نسبت 50:50 نسبت به دو ترکیب دیگر بیشتر بود طوری که مقدار آن در نسبت های 50:50، 25:75 و 75:25، به ترتیب 59/44، 82/32 و 59/26 مگاپاسکال بوده است. نفوذپذیری به بخار آب در ترکیب 50:50 و 75:25 نسبت به ترکیب 25:75 از شرایط بهتری برخوردار بود. ویژگی حلالیت در آب در سه فیلم ترکیبی تفاوتی با یکدیگر نداشتند ولیکن دارای کیفیت بهتری نسبت به فیلم خالص CMC بودند طوری که مقدار 52 الی 58 درصد نسبت به فیلم خالص CMC کاهش معنی‌داری را در میزان حلالیت به نمایش گذاشتند. همچنین، ترکیب کردن دو پلیمر در نسبت‌های مختلف توانست از میزان حساسیت فیلم‌ها نسبت به رطوبت بکاهد. بطورکلی، از نتایج این تحقیق دریافت می شود که ترکیب کردن دو پلیمر می تواند برخی ویژگی‌های فیزیکی- مکانیکی فیلم خوراکی تهیه شده از کربوکسی‌متیل‌سلولز- کتیرا را بهبود بخشد.

Molecular docking simulation, drug pharmacokinetics and synthesis of carbon nanodots from phytochemicals against isoenzymes of cancer

Biodegradable plastic production has been developed for a long time by researchers. Data from Ministry of Industry in 2017 stated Indonesia's plastic production reached 3.9 million tons/ year. In this study, the raw materials used came from untapped waste, namely coffee skin, biodiesel-waste glycerol and shrimp-shells chitosan. In this research, biodegradable plastic films have been produced with the addition of glycerol and coffee skin waste with chitosan concentration variations of 0, 2, 4, 6, and 8%. After the optimum conditions were obtained by comparing the elongation and tensile strength values, then the variations in coffee skin waste were added with a weight of 0, 2, 4, 6, and 8 g. Tensile strength and elongation values with variations of chitosan were 0.2-1.87 MPa and 0.22-0.15%, respectively. Whereas the variation of tensile strength and elongation coffee skins were 1.8-0.27 MPa and 0.14-0.2%, respectively. The optimum conditions for producing biodegradable plastic films were obtained with variations of chitosan 4% and 2 g coffee skin with tensile strength and elongation values of 0.98 MPa and 0.16%. The tensile strength and elongation data produced from biodegradable plastic was still below the standard value of commercial plastic or synthetic plastic (HDPE) with values of tensile strength and elongation of 28.64 MPa and 6.5186% respectively.

Carbon nano dots (CNDs) has received a lot of attention in recent years due to their potential use in various kinds of applications. Many conventional chemical methods have been used to synthesis CNDs, but these processes have several drawbacks, such as hazardous by products, harsh chemicals, and high costs. To overcome these issues, green chemistry has an importance in the development of CNDs. Thus, it is essential to explore green synthesis approaches for production the CNDs. In this context, a novel precursor using flavonoid extraction from Moringa oleifera leaves is proposed. Moringa oleifera is the "magic tree" which contains many bioactive compounds such as flavonoids, especially in its leaves. Natural flavonoids and glycosides with specific components of structure can bind to metal ions. The content of bioactive compounds such as total flavonoids found in Moringa oleifera leaves is 172.10mg/g. In addition, carbon (47.34%), nitrogen (51.67%), and sulfur (0.99%) are also the main composition. Then, the carbon nanodots (CNDs) synthesized in this research were moderated by flavonoid extract from Moringa oleifera using the hydrothermal method. The technique is easy, ecologically friendly, and requires neither specialized device or reagents. In practice, the CNDs produced are almost circular, with an average diameter of 3.49nm. Furthermore, we enhanced synthesis CNDs - Fla with heteroatoms of nitrogen (N) and sulfur (S). They display a broad excitation-emission spectrum, excitation-dependent emission, and extraordinary fluorescence. Therefore, the synthesis of CNDs using flavonoids from Moringa oleifera as precursors would be a great potential candidate for the development of novel types of heavy metals sensing.

Effect of processing parameters on the properties of transglutaminase-treated soy protein isolate films

Plastic film is an important resource in agricultural production, but it takes hundreds of years to degrade completely in natural environment. The large-scale use of plastic film will inevitably lead to serious environmental pollution. One way to solve the problem is to develop a substitutable mulching film, such as a biodegradable film that can ultimately be decomposed to water, carbon dioxide, and soil organic matter by micro-organisms. In this study, a 2-year experiment was conducted to determine the degradation properties of a biodegradable plastic film, including degradation rate, surface microstructure, tensile strength and elongation at break, and the effects of different mulching treatments on soil temperature and maize yield. The mulching experiment was conducted with three different biodegradable plastic films with different degradation rates, using a common plastic film and a non-mulched treatment as control. With the addition of the additives for degradation in the biodegradable plastic films, the degradation rates increased significantly, which were 7.2%-17.8% in 2017 and 18.1%-35.2% in 2018 after maize harvesting. However, the degradation occurred mainly on the ridge side. The decrease in tensile strength and elongation was proportional to the degradation rate of the degradable film. The SEM results indicated that the surface microstructures of the biodegradable films were loose and heterogeneous after maize harvesting. Biodegradable plastic film mulching increased the soil temperature at soil depths of 5 cm, 15 cm, and 25 cm, over the maize’s entire growth period, by 3.1°C-3.2°C in 2017 and 1.2°C-2.1°C in 2018 compared with the non-mulched treatment. The biodegradable plastic film increased the maize yield by 10.4%-14.3% in 2017 and 11.6%-24.7% in 2018. The soil temperature and maize yield increases were statistically significant; however, with respect to maize qualities, there were no statistically significant increases among the five treatments. This study shows that biodegradable plastic film can be used as a substitute for common plastic film. However, the ingredients in biodegradable plastic films should be improved further to ensure that they can be degraded completely after crop harvest. Keywords: biodegradable plastic film, film mulching, degradation properties, soil temperature, maize yield DOI: 10.25165/j.ijabe.20201302.5360 Citation: Zhang W W, Wang L H, Zhou J Q, Zhu K L, Sun S J. Degradability of biodegradable plastic films and its mulching effects on soil temperature and maize yield in northeastern China. Int J Agric & Biol Eng, 2020; 13(2): 146–153.

Carbon nanodots (CNDs) are 0D-carbon nanomaterials with distinct fluorescence properties. Due to the poor understanding of the fluorescent origin and its connection to the structural complexity of CNDs, the full potential in applications of CNDs is still in a stagnant stage. Herein, we present the photoluminescence properties of two CNDs prepared from di-ammonium citrate and tri-ammonium citrate. Synthesis of CNDs was done by pyrolysis of ammonium citrates at 180 °C and 40 h under ambient conditions. We monitored the pyrolysis process using thermogravimetric analysis (TGA) both under air and inert atmospheres, which allowed for the proposal of reaction stoichiometry and structural analyses of CNDs in combination with spectroscopic means. Both CNDs possess strong photoluminescence (PL) emissions at ∼450 nm upon excitation at 365 nm. Concentration-dependent PL emission kinetics were studied to reveal both nanoparticle-like behaviors of CNDs with the enhancement of PL emission upon dilution and aggregation-induced quenching of PL emission that is common for molecular fluorophores. Quenching of CNDs’ emission with the benzophenone as a triplet sensitizer or an acceptor and the dimethoxy benzene as a donor was also studied to present additional PL emission dynamics of CNDs in support of the proposed structure for CNDs. The extensive aggregation and stacking of the proposed CNDs structure were verified using molecular dynamics simulations.

Carbon nanodots (CNDs) are interesting materials due to their intrinsic fluorescence, electron-transfer properties, and low toxicity. Here, we report a sustainable, cheap, and scalable methodology to obtain CNDs from sugarcane syrup using a domestic microwave oven. The CNDs were characterized by infrared spectroscopy, dynamic light scattering, atomic force microscopy, absorption, and emission spectroscopies. The CNDs have 3 nm in diameter with low polydispersity and are fluorescent. A fluorescent hydrogel–CNDs composite was obtained using gelatin polypeptide as the polymeric matrix. The new hydrogel–CNDs composite was incorporated in the cavities of a double-clad optical fiber using an innovative approach that resulted in a microstructured polymer optical fiber with intrinsic fluorescence. This work shows a promising alternative for the fabrication of fluorescent materials since the CNDs synthesis is sustainable and environmentally friendly. These CNDs might substitute the rare-earth and other heavy metals of high cost and toxicity, which are usually incorporated in double-clad fibers for applications on lasers, amplifiers, and spectroscopy.

In temperate regions soil solarization with plastic films represents a valuable alternative to the use of methyl bromide for the control of soil borne diseases. However, large quantities of wastes are derived by plastic materials used for solar heating, whose inappropriate management could affect negatively the whole agro-ecosystem. Use of biodegradable films, which spontaneously start up a degradation process after their soil application, could represent a potential solution to these disposal problems. Greenhouse and open field experiments were undertaken in 2002 and 2003 in Southern Italy with the aim to assess the effect of soil solarization with a corn starch-based biodegradable plastic film on soil temperature, root-knot nematode (Melodogyne spp.) and weed control and crop yield, in comparison with EVA and LDPE plastic films. Mechanical and spectroradiometrical properties of the films were also studied. Use of biodegradable films resulted effective, particularly in greenhouse, for the control of nematodes and weeds improving yield and quality of melon fruits.

فیلم زیست تخریب‌پذیر ترکیبی با استفاده از پلی‌وینیل الکل- صمغ قدومه شیرازی با نسبت 60 به 40 با افزودن شش غلظت مختلف گلیسرول (%70-20) به روش قالب‌گیری ساخته شد. ویژگی‌های فیلم شامل ضخامت، دانسیته، میزان رطوبت، جذب رطوبت، حلالیت در آب، زاویه تماس قطره آب، رنگ، نرخ عبور بخار آب و خواص مکانیکی آنها مورد اندازه‌گیری قرار گرفت. در ضمن از آزمون‌های طیف‌سنج مادون‌قرمز و میکروسکوپ الکترونی نیز برای بررسی برهمکنش‌های شیمیایی و ویژگی‌های ریزساختار فیلم‌ها استفاده شد. افزایش غلظت گلیسرول بطور معنی‌داری (05/0 >P) باعث افزایش ضخامت، میزان رطوبت، جذب رطوبت، حلالیت در آب، دانسیته، شفافیت، کاهش زاویه تماس، نفوذپذیری به بخار آب و کدورت گردید. افزایش غلظت گلیسرول بر پارامترهای رنگ نیز اثر گذاشت، بطوری که میزان روشنایی و زردی فیلم را بترتیب از 90 به 4/94 و از 5/0 به 3/1 افزایش و میزان قرمزی را از 9/0 به 5/0 کاهش داد. بطور کلی فاکتورهای رنگی شامل اندیس سفیدی، اندیس زردی و میزان اشباعیت رنگ افزایش و اختلاف رنگ نمونه‎ها با پلیت سفید کاهش یافت. آزمون مکانیکی فیلم‌ها نشان داد که مقاومت کششی از 6/64 به 2/13 و مدول یانگ نیز از 892 به 85/156 مگاپاسکال کاهش و درصد کشیدگی از 1/2 به 47/15 درصد افزایش یافت. افزایش غلظت گلیسرول، نفوذپذیری به بخار آب را تا بیش از 7/4 برابر افزایش داد. با افزایش غلظت گلیسرول تغییر اندکی در ساختار فیلم‌ها مشاهده شد. فیلم‌ها با نسبت بالاتر گلیسرول تصاویر ریزساختار با سطوح یکنواخت و بدون منفذی را نشان دادند.

The global trend in packaging is shifting towards environmentally friendly, natural materials that decompose easily. Among the bio-based packaging materials, starch is a renewable, biodegradable, bio-compatible, and easily accessible source. However, starch-based biodegradable films depict weak mechanical properties compared with synthetic polymers. This problem can be solved by incorporating reinforcement fillers into the starch matrix. Palmyrah fruit (Borassus flabellifer L.) waste can be a good source to obtain fillers due to its high cellulose content. The aim of the study was to investigate the reinforcement of starch-based biodegradable films with the incorporation of pure cellulose nanofiber (CNF) obtained from palmyrah fruit fiber (PFF). Chemical treatments such as alkaline treatment (4% NaOH), bleaching [1% Ca(OCl)2], and acid hydrolysis (10 moldm-3 H2SO4) were done successively to obtain pure CNF from PFF. CNF was characterized using FTIR and particle size distribution (PSD) was analyzed by granulometry. The yield of CNF from PFF was 37.890±0.008 %. The results of FTIR depicted CNF was synthesized successfully. Five different biodegradable films were prepared by varying the amount of palmyrah tuber starch (4.5-2.5 w/w %) and CNF (0.0-2.0 w/w %) while the amount of glycerin (1.5 w/w %) and gelatin (1 w/w %) were kept constant. PSD results revealed that nano-sized CNF (10-100 nm) was synthesized successfully. The optimized film was selected based on the tensile strength and low water vapor transmission rate. Optimized film formulation, with palmyra tuber starch (3 w/w %) and CNF (1.5 w/w %) showed desirable physical, mechanical and optical properties, including the thickness, moisture content, water vapor transmission rate, water uptake, transparency at 600 nm, water activity, water solubility and tensile strength of 0.192±0.004 mm, 11.07±0.04 %, 3.870±0.005 g/m2.day, 22.34±0.05 %, 3.97±0.01 %, 0.440±0.001, 51.68±0.140 % and 9.55 MPa respectively. All films showed excellent soil biodegradability within two weeks. In conclusion, palmyra fruit CNF can be effectively used to reinforce starch-based biodegradable packaging films.