Journal of Applied Research in Chemical-Polymer Engineering

Abstract Research subject: Contact lens-based drug delivery is expected to be more efficient due to sustained release of drug and increased residence time in the tear film. In particular, hydrogel has been applied in contact lenses due to impressive function such as biocompatibility, wettability and optical transparency. Nevertheless, hydrogel lenses suffer from low oxygen permeability. To reduce the shortage of oxygen supply, the silicone-based polymers were used to improve the oxygen permeability. Vitamin E as a diffusion barrier could be introduced into silicone hydrogel contact lenses to extend drug release due to its lipophilic barrier.
Research approach: In this research, poly(3-(methacryloyloxy)propyltris(trimethyl-siloxy) silane-co-2-hydroxyethyl methacrylate) (poly(TRIS-co-HEMA)) copolymers were synthesized in order to evaluate the potential of these copolymers to be used as contact lens materials. The obtained copolymers were characterized using Fourier transform infrared spectroscopy, transmittance analysis, contact angle measurement and water content. The vitamin E was incorporated into copolymer films and the effect of vitamin E loading on extended drug delivery for diclofenac sodium were examined.
Main results: The equilibrium water content (EWC) of the synthesized poly(TRIS-co-HEMA) copolymers were proportional to the hydrophilic PHEMA content. The maximum value of surface hydrophilicity was 56.4°, corresponding to an equilibrium water content of 39%. Poly(TRIS-co-HEMA) films exhibited high transparency in the visible light wave range. Incorporation of vitamin E did not have significant impact on the wettability, EWC and transparency of the copolymer films. The results showed that with vitamin E loading in the copolymer film, the diclofenac release time could be increased to 90 h, which was a 3 fold increase compared to the diclofenac release duration by copolymer film without vitamin E loading. The vitamin E loaded poly(TRIS1-co-HEMA8) copolymer films could be very useful vehicles for extended drug delivery of diclofenac.

Abstract Research subject: Based on the reports in the past few years, more than 60% of burn-related deaths occur due to infection and bacterial growth at the wound site. Biocompatible nanofiber wound dressings containing antimicrobial compounds can enhance the healing process of burn wounds. This study aimed to investigate the effect of polylactic acid (PLA) nanofibers loaded with Nigella sativa extract on burn wound healing and their antimicrobial activity.
Research approach: Polylactic acid (PLA) nanofibers were fabricated via electrospinning from a polymeric solution of PLA dissolved in a chloroform: dimethylformamide solvent mixture with a volume ratio of 3:7. The optimal solution concentration (12 w/v%) was determined based on rheometry tests and scanning electron microscopy imaging to obtain uniform, bead-free fibers with optimized diameter. Physical properties, including swelling behavior and hydrolytic degradation, were investigated. The release of Nigella sativa extract from the nanofibers over 48 hours was measured, and antimicrobial activity against Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive) was assessed. Additionally, extract-loaded and extract-free nanofibers were applied to burn wounds in an animal model for 14 days, and the wound healing process was monitored by periodic imaging.
Main results: The results showed that PLA nanofibers containing Nigella sativa extract exhibited approximately 69% release within 48 hours, more than a one-log reduction in bacterial population, and a 30–35% improvement in wound closure rate in the animal model. The performance of the extract-loaded nanofibers was comparable to silver sulfadiazine ointment. These findings demonstrate that the developed nanofibers provide a biocompatible and effective antimicrobial wound dressing for burn healing applications.

Abstract Research subject: In the present study, a series of polyurethane foams were synthesized based on polybutylene succinate (PBS) and hexamethylene isocyanate (HDI) using the salt leaching method. Polymer characterization, thermal behavior, and foam structure were studied. Such biodegradable foams, mostly aliphatic polyesters, could be applied in biomaterial and biomedical fields.
Research approach: PBS-diol was synthesized via a two-step method: esterification and polycondensation. Then, hexamethylene isocyanate (HDI) was added to produce polyurethane. Reaction progress was followed using FTIR spectra. Cerium oxide (CeO2) nanoparticles, 0.1, 0.25 and 0.5 wt.%, were added to the reactor in the final stage of synthesis. On completion of the reaction, NaCl salt, with a size of 170 μm, was added. Consequently, salt leaching was performed to produce foam. Dimethyl formamide (DMF) was added to reduce the viscosity of the mixture. Polymer characterization was performed using spectroscopy, thermal behavior was analyzed via differential scanning calorimetry, and foam structure was examined using scanning electron microscopy. DSC curves reveal the existence of secondary crystallization. SEM images show the produced foam cells.
Main results: The molecular weight of polybutylene succinate was approximately 1800 g/mol. This material, named PBS-diol, and hexamethylene isocyanate (HDI) were reacted to produce polyurethane. Reaction progress was followed using the isocyanate peak at 2265 cm-1, which decreased and diminished at the end of the reaction in the FTIR spectra. The reaction mostly occurred within 60–120 min after HDI addition. Structural variation was studied using HNMR spectra. Inspection of DSC cooling curves shows crystallization peaks for hard and soft segments. Non-isothermal crystallization kinetics were studied using the modified Avrami model. An asymmetric three-dimensional crystal structure was predicted. SEM images show 170 μm cells which are comparable to the initial diameter of the salt.

Abstract Research subject: Poly (vinyl chloride) (PVC) is non-biodegradable, and the widespread use of conventional plasticizers, particularly phthalates, in its formulation poses significant risks to human health and the environment. In this research, various blends of PVC and poly (lactic acid) (PLA) with different ratios were prepared in an internal mixer. The effect of PLA content, as well as the influence of various plasticizers including dioctyl phthalate (DOP), dioctyl adipate (DOA), epoxidized soybean oil (ESO), and chlorinated paraffin wax, on the mechanical and biodegradability properties was investigated. Furthermore, the role of a compatibilizer in improving the distribution of the PLA phase and increasing the compatibility between the polymers was evaluated.
Research approach: Tensile testing and dynamic mechanical analysis (DMTA) were performed to study the mechanical behavior. Scanning electron microscopy (SEM) imaging was used to examine the morphology and the distribution of the PLA phase. In addition, a biodegradability test was carried out to analyze the degradation behavior of samples in the environment.
Main results: The results indicated that the PVC/PLA(90/10)-DOP blend exhibited a suitable distribution of the PLA phase within the PVC matrix, whereas a poor distribution of PLA in PVC was observed in the PVC/PLA(80/20)-DOP blend. The addition of a compatibilizer to the PVC/PLA(80/20)-DOP sample led to increased uniformity in the PLA phase distribution and improved tensile strength. Samples with higher PLA content showed greater biodegradability behavior, suggesting the role of PLA as a degradability-enhancing agent. The comparison of different plasticizers indicated that several of the ones used in this research exhibit properties comparable to DOP and may be considered as effective substitutes for it. The findings suggest that the simultaneous use of PLA and appropriate plasticizers such as ESO, along with the application of a compatibilizer, is an effective method for producing PVC samples with enhanced mechanical and biodegradability properties.

Abstract The protective coatings and flexible packaging industries play a pivotal role in modern society. They contribute to human health, safety, comfort, and economic progress. Initially, these materials were produced from naturally occurring components; however, they have since evolved into intricate compositions designed to fulfill various performance criteria.  Currently, the majority of these materials are discarded in landfills, and their carbon content cannot be recovered or reused efficiently. In recent years, database statistics show a steady increase in research related to functional coatings, reflecting the growing interest in innovative and sustainable solutions. The global focus on reducing reliance on fossil fuel products and mitigating environmental impacts is accelerating efforts to integrate renewable resources into coating technologies. These technologies utilize bio-based raw materials, including biopolymers and natural oils, as well as biodegradable materials derived from microorganisms, plants, and animals. To address environmental concerns, leading coatings and packaging manufacturers have launched scientific and technical research to improve the sustainability of their products. Ongoing research focuses on the development of bio-derived materials, the adoption of energy-efficient manufacturing processes, the design of long-lasting products, and the use of sustainable and renewable resources. In addition, companies seek financial and competitive advantages through proactive internal initiatives. This highlights the urgent need for a circular economy model that overcomes current limitations in recycling and decomposition technologies. The authors stress the significance of comprehending society's tendency to prioritize and value sustainability, along with the financial and competitive advantages that may result from adopting proactive in-house efforts.

Abstract Research subject: The formulation of sublimation inkjet inks based on disperse dyes requires precise control of dispersion stability and rheological behavior to achieve consistent print quality and printer compatibility. One of the main challenges in this field is establishing an appropriate balance between polymeric dispersants and low-molecular-weight surfactants to prevent sedimentation, viscosity fluctuations, and surface tension instability. This study investigates the influence of nonionic surfactant concentration on the physical characteristics, dispersion stability, and rheological behavior of Disperse Blue 359 in aqueous sublimation inkjet ink formulations.
Research approach: Dye concentrates were prepared using a jar mill in the presence of a polymeric dispersant, glycerol, and deionized water. The concentration of the nonionic surfactant was varied from 0 to 7.1 wt%. The samples were characterized in terms of color strength by UV-vis spectrophotometry, particle size by dynamic light scattering, surface tension by the Wilhelmy method, and rheological behavior by a rotational rheometer. Dispersion stability was also monitored by turbidity measurements over different time intervals.
Main results: The results revealed that the simultaneous presence of the polymeric dispersant and the nonionic surfactant significantly improved the stability and flowability of the system. Specifically, the sample with the optimally concentrated surfactant exhibits turbidity oscillation of less than 30 NTU and a viscosity below 8.5 cp, while the surfactant-free sample experiences a turbidity reduction exceeding 500 NTU over the test duration and a viscosity above 17 cp. At an optimal surfactant concentration of approximately 3.6 wt%, the particle size reached its minimum, color strength reached its maximum, and dispersion stability was maximized. Conversely, both higher and lower surfactant concentrations led to particle aggregation, increased turbidity, and diminished print quality. These findings highlight the critical importance of accurately tuning the ratio of surfactant to dispersant in designing reliable sublimation inkjet inks with desirable optical and rheological properties.