Thermal and mechanical properties of bio-based plasticizers mixtures on poly (vinyl chloride)

Characterization of Calotropis gigantiea plant leaves biomass-based bioplasticizers for biofilm applications

The present surge in environmental consciousness has pushed for the use of biodegradable plasticizers, which are sustainable and abundant in plant resources. As a result of their biocompatibility and biodegradability, Calotropis gigantiea leaf plasticizers (CLP) serve as viable alternatives to chemical plasticizers. First time, the natural plasticizers from the Calotropis leaves were extracted for this study using a suitable chemical approach that was also environmentally friendly. The XRD results showed a reduced crystallinity index of 20.2 % and a crystalline size of 5.3 nm, respectively. TGA study revealed that the CLP has good thermal stability (244 °C). Through FT-IR study, the existence of organic compounds in CLP can be investigated by key functional groups such as alcohol, amine, amide, hydrocarbon, alkene, aromatic, etc. Further the presence of alcoholic, amino, and carboxyl constituents was confirmed by UV investigation. SEM, EDAX analysis, and AFM are used to examine the surface morphology of the isolated plasticizer. SEM pictures reveal rough surfaces on the CLP surface pores, which makes them suitable for plasticizing new bioplastics with improved mechanical properties. Poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer matrix, was used to investigate the plasticization impact after the macromolecules were characterised. The biofilm PBAT/CLP had a thickness of 0.8 mm. In addition, the reinforcement interface was examined using scanning electron microscopy. When CLP is loaded differently in PBAT, the tensile strength and young modulus change from 15.30 to 24.60 MPa and from 137 to 168 MPa, respectively. CLP-reinforced films demonstrated better surface compatibility and enhanced flexibility at a loading of 2 % when compared to pure PBAT films. Considering several documented characteristics, CLP may prove to be an excellent plasticizer for resolving environmental issues in the future.

Multicriteria optimization of the composition, thermodynamic and strength properties of fly-ash as an additive in metakaolin-based geopolymer composites

This paper presents the construction of intelligent systems for selecting the optimum concentration of geopolymer matrix components based on ranking optimality criteria. A peculiarity of the methodology is replacing discrete time intervals with a sequence of states. Markov chains represent a synthetic property accumulating heterogeneous factors. The computational basis for the calculations was the digitization of experimental data on the strength properties of fly ashes collected from thermal power plants in the Czech Republic and used as additives in geopolymers. A database and a conceptual model of priority ranking have been developed, that are suitable for determining the structure of relations of the main factors. Computational results are presented by studying geopolymer matrix structure formation kinetics under changing component concentrations in real- time. Multicriteria optimization results for fly-ash as an additive on metakaolin-based geopolymer composites show that the optimal composition of the geopolymer matrix within the selected variation range includes 100 g metakaolin, 90 g potassium activator, 8 g silica fume, 2 g basalt fibers and 50 g fly ash by ratio weight. This ratio gives the best mechanical, thermal, and technological properties.

Enteric-coating film effect on the delayed drug release of pantoprazole gastro-resistant generic tablets

Background: Enteric coating films in acidic labile tablets protect the drug molecule from the acidic environment of the stomach. However, variations in the excipients used in the coating formulation may affect their ability to provide adequate protection. This study is the first to investigate the potential effects of coating materials on the protective functionality of enteric coating films for pantoprazole (PNZ) generic tablets after their recall from the market. Methods: A comparative analysis was conducted between generic and branded PNZ products, using pure drug powder for identification. The in vitro release of the drug was evaluated in different pH media. The study also utilized various analytical and thermal techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and confocal Raman microscopy. Results: The in vitro assessment results revealed significant variations in the release profile for the generic product in acidic media at 120 min. DSC and TGA thermal profile analyses showed slight variation between the two products. XRD analysis exhibited a noticeable difference in peak intensity for the generic sample, while SEM revealed smaller particle sizes in the generic product. The obtained spectra profile for the generic product displayed significant variation in peaks and band intensity, possibly due to impurities. These findings suggest that the excipients used in the enteric coating film of the generic product may have affected its protective functionality, leading to premature drug release in acidic media. Additionally, the presence of polysorbate 80 (P-80) in the brand product might improve the properties of the enteric coating film due to its multi-functionality. Conclusions: In conclusion, the excipients used in the brand product demonstrated superior functionality in effectively protecting the drug molecule from acidic media through the enteric coating film, as compared to the generic version.

Bio-based versus synthetic: comparative study of plasticizers mediated stress on Chironomus circumdatus (Diptera-Chironomidae)

Phthalates are used as plasticizers in products made of polyvinyl chloride to increase the flexibility of polymers. Unfortunately, these are known to cause adverse effects on living organisms, and also, fast depletion of petroleum resources calls for the exploration of alternatives as replacements. Recent developments in bio-based plasticizers have led to their use as additives for various applications. As they have received much attention in the past decade, it is crucial to study the effects of these plasticizers on living organisms. Hence, we tried to compare the effects of synthetic plasticizer dioctyl phthalate and bio-based plasticizer ethanolamine on Chironomus circumdatus larvae. Mortality was achieved at a lethal concentration (LC₅₀) value of 0.385 mg/L for ethanolamine and dioctyl phthalate at 0.125 mg/L. Disruption in the level of metabolites along with lipid peroxidation was observed in the larvae exposed to plasticizer mediated stress. To overcome these changes, an increase in the levels of antioxidant enzymes such as Superoxide Dismutase, Catalase, Glutathione Peroxidase and Glutathione Reductase, as well as in the levels of detoxifying enzymes like Glutathione-S-Transferase, Esterases and Mixed Function Oxidase during post-exposure recovery conditions was seen. Alterations in the expression levels of heat shock protein 70 and ecdysone receptor genes were also observed. From the comparative study, it could be concluded that Chironomus circumdatus larvae, to a certain extent, have developed tolerance to both ethanolamine and dioctyl phthalate mediated stress. However, dioctyl phthalate has led to more stress as compared to ethanolamine in these larvae.

Effective, Environmentally Friendly PVC Plasticizers Based on Succinic Acid

The plasticizers used in this study were synthesized from renewable raw materials using succinic acid, oleic acid, and propylene glycol. Four environmentally friendly plasticizer samples were obtained; their chemical structures and compositions were confirmed by gas chromatography (GC) and infrared spectroscopy (FT–IR) analyses, and their physicochemical properties and thermal stability (TGA analysis) were investigated. The obtained ester mixtures were used as poly(vinyl chloride) (PVC) plasticizers and their plasticization efficiency was determined in comparison to traditional, commercially available phthalate plasticizers, such as DEHP (di(2-ethylhexyl phthalate) and DINP (diisononyl phthalate). Mechanical properties and migration resistance were determined for soft PVC with the use of three concentrations of plasticizers (40 PHR, 50 PHR, and 60 PHR). It was observed that the obtained plasticizers exhibited the same plasticization efficiency and were characterized with good mechanical and physical properties in comparison to commercial plasticizers. The tensile strength was approx. 19 MPa, while the elongation at break was approx. 250% for all tested plasticizers at a concentration of 50 PHR. Furthermore, plasticizer migration studies showed that the synthesized plasticizers had excellent resistance to plasticizer leaching. The best migration test result obtained was 70% lower than that for DEHP or DINP. The ester mixture that was found to be the most favorable plasticizer was characterized by good thermal and thermo-oxidative stability (5% weight loss temperature: 227.8 °C in air and 261.1 °C in nitrogen). The results of the research clearly indicate that the synthesized esters can provide a green alternative to toxic phthalate plasticizers.