Papers by Keyword: Microencapsulation

Abstract: This research aims to develop self-healing coatings using a microencapsulation technique. Microcapsules were synthesized by polymerizing isocyanate-based shell materials (pTDI, pMDI, and TDI) with HDI derivatives as the core substances. The study focused on evaluating the effect of precursor types and stirring speeds on the morphology and particle size of the microcapsules. Among the tested materials, microcapsules with TDI shells and HDI biuret cores exhibited optimal structural characteristics, including clear core encapsulation and spherical shape. FTIR analysis confirmed the successful formation of polyurethane shells. Stirring speed was found to significantly influence particle size: increasing speed reduced microcapsule size up to a point, but excessive speed (800 rpm) led to aggregation and size increase due to turbulence. The synthesized microcapsules show potential for improving the corrosion resistance and durability of coatings through autonomous repair, contributing to longer service life and reduced maintenance costs in industrial applications.

Abstract: Microparticle protein delivery system using alginate and cellulose derivative (HPC, HEC and CMC) composite system was prepared using external gelation with vibration technology. Bovine serum albumin (BSA) as a model protein was encapsulated using these biodegradable materials. This preparation showed an increase in encapsulation efficiency in comparison to the samples where pure alginate was used as the encapsulating material. Compared with the other microparticles, the 50:50 alginate/HEC samples exhibited significant encapsulation efficiency. Consequently, its release rate in the acidic medium was comparatively substantial and higher cumulative release in the simulated intestinal fluid (SIF) medium at the end of the dissolution study was observed to be high at around 86.17%.

Abstract: The challenge of self-healing coating is the mechanical integrity of the coating system embedded with microcapsules. This paper emphasis the mechanical integrity of self-healing coating embedded with microencapsulated vegetable oil (waste sunflower oil). The mechanical integrity of the coating system was determined by the bending and Vickers test. The microencapsulation of waste sunflower oil was successfully produced microcapsules with a mean diameter of 1 μm and a rough shell structure that matchable to embedded in coating matrix. The embedment of microcapsules into the coating matrix has generated self-healing performance with ability to self-heal after 5 days. The mechanical integrity of coating system was increased and demonstrated higher maximum stress (654.25 N/mm2) and higher hardness value (4.40 HV) as compared to the reference sample. It can be concluded that, the microencapsulated waste sunflower oil as an alternative natural vegetable oil to be embedded in the coating system to generate self-healing performance and induce higher mechanical integrity. This finding was able to contribute to the advancement of the future of metal coating industries.

Abstract: Microencapsulation of drugs is used for a long time to improve their properties. It was carried out a comparative assessment of the physical and physicochemical methods of microencapsulation on the example of some drugs. The spray drying method was selected from the physical methods. Physicochemical method based on simple coacervation was implemented by changing the solvent. A study and comparison of the properties of the products were obtained by UV and IR spectroscopy, liquid chromatography, electron microscopy. It was carried out a comparative assessment of the release profile of the active substance from microcapsules obtained by various methods. Using the example of furacilin microcapsules has been shown an increase in the biological activity of substances encapsulated in water-soluble polymers. The particle size distribution was determined by analyzing their trajectories. The main advantages and disadvantages of the two investigated encapsulation methods are outlined.

Abstract: The presented work presents the results of the studies carried out to elucidate the possibility of obtaining by the microencapsulation method of powdered polyetheretherketones and spherical copolyetheretherketones recommended for use in 3D-printing. The influence of temperature-time and concentration parameters, the reaction medium on the size of microencapsulated particles of polyetheretherketones and copolyetheretherketones was determined. It was determined that the bulk density of microencapsulated particles of polyetheretherketone and copolyetheretherketones is 8-10 times higher than similar unencapsulated ones.

Abstract: Microencapsulation of natural vegetable oil as a self-healing agent on metal coating became demanded lately. This paper underlines the microcapsule containing natural and wastes sunflower oil as a self-healing agent that was fabricated for the backbone of corrosion coatings. The results in this paper indicated the distinguished potential of waste sunflower oil as compared to natural sunflower oil. The diameter of microcapsules synthesized from natural sunflower oil and waste sunflower oil both in range of 3-4 µm. The shell of microcapsules microencapsulated from natural sunflower oil showed rough micro-structure while the shell of microcapsules microencapsulated from waste sunflower oil showed smooth micro-structure. The main parameter studied in this research was the varient of stirring speed during the process of microencapsulation. The involvement of stirring speed starts from 200 to 400 rpm. The microcapsules undergo varient of stirring speed analyzed on the yield and core content of microcapsules. The microcapsules from natural produced 29-50% while waste resources bring 26-48% of yield productions. The core content of microencapsulated natural sunflower oil generates 55-64% core content as comparing with waste sources which produce 56-67% of core content. It can be concluded that it was proved that sunflower oil could be considered as an alternative resource for self-healing agent in metal coating either encapsulated from natural or waste raw materials. The incorporation of green and natural material as a self-healing agent significantly influences the sustaining the environment to the safest stage.

Abstract: This paper emphasizes the characterization on the microencapsulation of sunflower oil as self-healing agent. In-situ polymerization method mainly implicates in the microencapsulation process. The analysation of microencapsulated sunflower oil via prominent characterization of yield of microcapsules, microcapsules characteristics and Fourier Transmission Infa-Red Spectroscopy (FTIR). The prime optimization used was reaction time of microencapsulation process in the ranges of 2, 3 and 4 h. The higher reaction time of microencapsulation process resulted in a higher yield of microcapsules. The yield of microcapsules increases from 46 to 53% respectively by the increasing of reaction time from 2 to 4 h. The surface morphology study associating the diameter of microcapsules measured to analyse the prepared microcapsules. It was indicated that microcapsules were round in shape with smooth micro-surfaces. It was discovered that the diameter of microcapsules during microencapsulation process after 4 h reaction time was in average of 70.53 μm. This size was measured before filtering the microcapsules with solvent and dried in vacuum oven. Apparently, after filtering and drying stage, the diameter of microcapsules specifically identified under Field Emission Scanning Electron Microscopy (FESEM) showing the size of 2.33 μm may be due to the removing the suspended oil surrounded the microcapsules. Sunflower oil as core content and UF as shell of microcapsules demonstrated the proven chemical properties on characterization by FTIR with the stretching peak of 1537.99 - 1538.90 cm^-1 (-H in-CH₂), 1235.49 - 1238.77 cm^-1 (C-O-C Vibrations at Ester) and 1017.65 - 1034.11 cm^-1 (C-OH Stretching Vibrations). It was showed that sunflower oil can be considered as an alternative nature resource for self-healing agent in microencapsulation process. The characterization of microencapsulated sunflower oil using in-situ polymerization method showed that sunflower oil was viable healant to be encapsulated and incorporated in metal coating.

Abstract: Microencapsulation by spray drying is offered to prevent volatilization or degradation of lemongrass essential oil as food additives and ingredients in traditional medicines. In this process, oil is contained in microcapsules by enclosing with wall material. Although gum arabic is commonly used according to its encapsulation efficiency and stability, its cost is more expensive. This experiment used cassava starch for wall material because it was cheaper than gum and could get optimized condition for microencapsulation of lemongrass essential oil. The 3 factors of microcapsulation consisting of the mass ratio of CS:GA, mass ratio of wall: core materials, and inlet temperatures were optimized for maximum response, the process yield (PY) and encapsulation efficiency (EE) using response surface methodology. The results concluded that the highest weight replacement of cassava starch and gum arabic at 2.4:1, wall:core ratio 3.4-4.0:1 with inlet air temperature about 180 °C for spray drying was the optimal condition for was higher than 70 % PY and 85 % EE.

Abstract: Lactobacillus rhamnosus GG is commonly used as probiotic dietary supplements that show poor survival rate in dairy products during processing, storage and gastrointestinal tract, however, using encapsulated probiotics could be an interesting option. Spray drying is the most widely used encapsulation technique in the food industry. It offers the attractive advantage of microencapsulation in low operating costs, high quality and stability, rapid solubility and continuous operation. The encapsulating agent of microcapsules affects probiotic survival. The aim of this study was to optimize the microencapsulation of Lactobacillus rhamnosus GG (LGG) by spray drying using whey protein and glutinous rice starch as encapsulating agents. The composition ratio between glutinous rice starch and whey protein and spray drying parameter of inlet temperature was evaluated using response surface methodology (RSM). These results showed that 80 % of glutinous rice starch replacement in whey protein wall and inlet temperature of 143°C provided the desired LGG microcapsules with high percentage of process yield (over 74.44 ± 3.95%) and survival rate (over 97.83 ± 2.01%).

Abstract: Hypertension, which often dubbed as “silent killer”, is a global health problem due to high prevalence worldwide and led to several diseases such as coronary heart attack and stroke. To treat this disease, nifedipine (NIF) is usually being consumed to reduce the high blood pressure into normal. However, the repetitive dosage of this drug may cause a side effect that can lower the effectiveness of this treatment. Thus, the controlled drug delivery system is utilized to increase the effectivity of NIF with the optimal daily dose. In this research, the polyblend of poly (lactic acid) (PLA) and poly (Ɛ-caprolactone) (PCL) was synthesized to encapsulate NIF using oil-in-water (o/w) solvent evaporation method, while the emulsion stirring speed, Tween 80 concentration, dispersion time, and emulsion time were varied to find the optimum conditions for composing the microcapsule. Throughout this research, the optimum conditions of microcapsule production have occurred in a stirring speed of 700 rpm, dispersion time of 1 hour, Tween 80 concentration of 0.5%, and emulsion time of 1 hour. Furthermore, the drug efficiency value was determined at 97.40%. Finally, the microcapsule size was observed at 20-23 μM, with the 23.19 μM was determined as the optimum size of the respective microcapsule.