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Triacetin (TA) is a solvent commonly used in pharmaceutical and food applications, and as a plasticizer in bioplastics such as poly(lactic acid) (PLA) and cellulose acetate (CA). L-lactide is the monomer used in the ring-opening polymerization of PLA. The structure of TA emulsions stabilized by a cellulose hydrogel (CH) was imaged in this study. The emulsions were prepared by mechanical homogenization or a two-step process with subsequent high-pressure homogenization (HPH). The two-step process yielded smaller TA droplets and a more homogeneous CH dispersion. The images demonstrate that emulsion stabilization is due to CH particles adsorbed at the TA–water interface. The ester hydrolysis of TA and a lactide/TA solution by two industrially important lipases, from Candida rugosa (CRL) and Burkholderia cepacia (BCL), was investigated, assessing the effect of CH as an emulsion stabilizer. Mechanically homogenized TA emulsions were effectively hydrolyzed. Lactide was found to inhibit the enzymatic hydrolysis of TA. This inhibition was mitigated by CH for CRL-catalyzed hydrolysis but not for BCL catalysis. These results indicate a synergistic effect of CH stabilization on the interfacial activation of CRL. Thise effect may also be relevant for the biodegradation of bio-derived plastics and their fibrous cellulose composites.

In this study, cellulose acetate (CA)/cellulose nanofibril (CNF) film was prepared via solvent casting. CNF was used as reinforcement to increase tensile properties of CA film. CNF ratio was varied into 3, 5, and 10 phr (parts per hundred rubbers). Triacetin (TA) and triethyl citrate (TC) were used as two different eco-friendly plasticizers. Two different types of solvent, which are acetone and N-methyl-2-pyrrolidone (NMP), were also used. CA/CNF film was prepared by mixing CA and CNF in acetone or NMP with 10% concentration and stirred for 24 h. Then, the solution was cast in a polytetrafluoroethylene (PTFE) dish followed by solvent evaporation for 12 h at room temperature for acetone and 24 h at 80 °C in an oven dryer for NMP. The effect of solvent type, plasticizers type, and CNF amount on film properties was studied. Good dispersion in NMP was evident from the morphological study of fractured surface and visible light transmittance. The results showed that CNF has a better dispersion in NMP which leads to a significant increase in tensile strength and elastic modulus up to 38% and 65%, respectively, compared with those of neat CA. CNF addition up to 5 phr loading increased the mechanical properties of the film composites.

Malaysia’s biodiesel production is rapidly increasing, resulting in an excess of crude glycerol that has limited usage in local industries. Based on the present circumstances, converting glycerol into higher-value products like acetin through acetylation is a beneficial alternative. In the presence of suitable catalysts, the acetylation of glycerol with acetic acid yields three distinct varieties of acetins which are monoacetin (MA), diacetin (DA), and triacetin (TA). Monometallic and bimetallic catalysts copper and nickel deposited on activated carbon were prepared via wet impregnation method. Catalyst properties were investigated by various techniques such as FT-IR, SEM-EDX, BET and NH3-TPD. The acetylation reaction was carried out in a 250 mL double neck round bottom flask at 90 °C for 60 minutes. Copper-Nickel incorporated activated carbon has shown higher activity for glycerol conversion (94.5%) and higher selectivity towards monoacetin and diacetin.

The e-liquids used in electronic cigarettes (E-cigs) consist of propylene glycol (PG), vegetable glycerin (VG), nicotine, and chemical additives for flavoring. There are currently over 7,700 e-liquid flavors available, and while some have been tested for toxicity in the laboratory, most have not. Here, we developed a 3-phase, 384-well, plate-based, high-throughput screening (HTS) assay to rapidly triage and validate the toxicity of multiple e-liquids. Our data demonstrated that the PG/VG vehicle adversely affected cell viability and that a large number of e-liquids were more toxic than PG/VG. We also performed gas chromatography-mass spectrometry (GC-MS) analysis on all tested e-liquids. Subsequent nonmetric multidimensional scaling (NMDS) analysis revealed that e-liquids are an extremely heterogeneous group. Furthermore, these data indicated that (i) the more chemicals contained in an e-liquid, the more toxic it was likely to be and (ii) the presence of vanillin was associated with higher toxicity values. Further analysis of common constituents by electron ionization revealed that the concentration of cinnamaldehyde and vanillin, but not triacetin, correlated with toxicity. We have also developed a publicly available searchable website (www.eliquidinfo.org). Given the large numbers of available e-liquids, this website will serve as a resource to facilitate dissemination of this information. Our data suggest that an HTS approach to evaluate the toxicity of multiple e-liquids is feasible. Such an approach may serve as a roadmap to enable bodies such as the Food and Drug Administration (FDA) to better regulate e-liquid composition.

Most electronic-cigarette liquids contain propylene glycol, glycerin, nicotine and a wide variety of flavors of which many are sweet. Sweet flavors are classified as saccharides, esters, acids or aldehydes. This study investigates changes in cariogenic potential when tooth surfaces are exposed to e-cigarette aerosols generated from well-characterized reference e-liquids with sweet flavors. Reference e-liquids were prepared by combining 20/80 propylene glycol/glycerin (by volume fraction), 10 mg/mL nicotine, and flavors. Aerosols were generated by a Universal Electronic-Cigarette Testing Device (49.2 W, 0.2 Ω). Streptococcus mutans (UA159) were exposed to aerosols on tooth enamel and the biological and physiochemical parameters were measured. E-cigarette aerosols produced four-fold increase in microbial adhesion to enamel. Exposure to flavored aerosols led to two-fold increase in biofilm formation and up to a 27% decrease in enamel hardness compared to unflavored controls. Esters (ethyl butyrate, hexyl acetate, and triacetin) in e-liquids were associated with consistent bacteria-initiated enamel demineralization, whereas sugar alcohol (ethyl maltol) inhibited S. mutans growth and adhesion. The viscosity of the e-liquid allowed S. mutans to adhere to pits and fissures. Aerosols contained five metals (mean ± standard deviation): calcium (0.409 ± 0.002) mg/L, copper (0.011 ± 0.001) mg/L, iron (0.0051 ± 0.0003) mg/L, magnesium (0.017 ± 0.002) mg/L, and silicon (0.166 ± 0.005) mg/L. This study systematically evaluated e-cigarette aerosols and found that the aerosols have similar physio-chemical properties as high-sucrose, gelatinous candies and acidic drinks. Our data suggest that the combination of the viscosity of e-liquids and some classes of chemicals in sweet flavors may increase the risk of cariogenic potential. Clinical investigation is warranted to confirm the data shown here.

Wheat bran (WB) was investigated as potential filler for controlling the plasticizer migration in poly(lactic acid) (PLA)/poly(butylene succinate adipate) (PBSA) binary blends (with 60 wt.% of PLA and 40 wt.% of PBSA). The migration process of three different biobased and biodegradable plasticizers [Triacetin (TA), acetyl tri-n-butyl citrate (ATBC) and oligomeric lactic acid (OLA)] was investigated adding them at a fixed amount of 10 wt.%. TA revealed the greater mass loss over the time as confirmed from the calculation of the diffusion coefficients. The addition of WB in different amount (from 10 to 30 wt.%) revealed its tendency to influence the diffusion process in a manner strictly dependent on its content. The great dimensions of the WB, however, weaken the material suggesting to adopt a preliminary dimensional reduction of the filler to mitigate the negative effect observed on the mechanical properties. From this study emerged the WB potential to be used as filler for controlling the plasticizer migration, thus suggesting a possible valorization of this waste byproduct in biobased and biodegradable materials.

BackgroundTobacco companies are offering cigarettes with ‘concept’ descriptor names that suggest sensation and/or flavour properties (eg, Marlboro ‘Velvet Fusion’). Little has been known about the identities and levels of flavour chemicals in such cigarettes.MethodsThirty-three filter cigarette variants from 27 packs (including two sampler packs with four variations each) from Canada and Mexico were analysed (rod + filter) for 177 flavour chemicals plus triacetin, a filter plasticiser and possible flavourant. Five brands of US mentholated filter cigarettes were also analysed.ResultsTwenty-seven of the 33 cigarettes (all were Mexican variants) were categorised as ‘menthol-plus’: significant menthol (3.0–11.9 mg/cigarette), plus varying amounts (0.32–3.4 mg/cigarette) of total other flavour chemicals (TOFCs) (excludes triacetin). For 10 of the 27, TOFCs >1.0 mg/cigarette. For 7 of the 27, the TOFCs profile was categorised as containing total fruit flavour compounds (TFFCs) >1.0 mg/cigarette. One Mexican variant was categorised as ‘menthol-only’ (TOFCs ≤0.15 mg/cigarette). All menthol-plus and menthol-only cigarettes contained one or two optional-crush capsules in their filters (crushed prior to analysis). All five Canadian brand variants were ‘non-flavoured’. All five US brand variants were ‘menthol-only’.ConclusionsAll but one of the ‘concept’ descriptor cigarettes from Mexico were ‘menthol-plus’. While the Canadian cigarettes complied with Canada’s flavour chemical ban, concept descriptors on the packs may increase appeal. Given the scale of the problem posed by menthol alone, health officials seeking to decrease the appeal of smoked tobacco should examine the extent to which ‘concept descriptor’ cigarettes using ‘menthol-plus’ flavour profiling together with artful descriptors are furthering the problem of smoked tobacco.

This study investigated the valorization of glycerol through triacetin (TA) production via glycerol esterification with acetic acid using reactive distillation (RD). The conventional TA production typically involved multiple unit operations, leading to process complexity and high costs. A simplified TA production process based on the appropriate design for RD was developed. The simulation results, validated by a robust kinetic model, demonstrated the high accuracy to predict glycerol conversion and TA purity. The optimized RD required only 32 theoretical stages using an acetic acid to glycerol feed molar ratio of 3:1, glycerol feed at the 2nd stage, acetic acid feed at the 31st stage, a reflux ratio of 7, and a bottom to feed ratio of 0.25 under column pressure of 0.7 bar without an entrainer. This configuration achieved the remarkable performance, with a 99.20% glycerol conversion, 99.41% TA selectivity, and 99.00% TA purity. The number of unit operations of RD process was reduced to 50%, leading to acquiring only 79.16% of the capital cost as compared to the conventional method. This finding highlights the economic advantage of the RD process, offering a sustainable, cost-effective, and scalable alternative for large-scale TA production.

This study deals with the development of 3D printable bionanocomposites using poly(lactic acid) (PLA) with ≤ 2% D-lactic acid content and cellulose nanofibrils (CNFs). The CNFs were extracted from the waste sawdust of Eucalyptus grandis via chemical and mechanical techniques. Thermogravimetric analysis (TGA) revealed that the CNFs were thermally stable within the intended processing temperature ranges. In this study, a combination of solvent casting and melt extrusion techniques was adopted in the production of PLA containing 1 wt% and 3 wt% CNFs. The neat PLA filament was brittle and frequently broke during fused deposition modelling (FDM) 3D printing. However, the incorporation of triacetin as a green plasticizer resulted in improved filament flexibility and eliminated the inherent brittleness. TGA analysis revealed a slight reduction in the degradation temperature of the bionanocomposites when compared to neat polymer; however, all the specimens were thermally stable within the processing temperature. The scanning electron microscopy images of the 3D printed specimens revealed the presence of voids across the fracture surfaces. The tensile analysis of 3D printed specimens revealed that the PLA/CNF bionanocomposites exhibited higher tensile modulus, and elongation (strain) when compared to PLA-based specimens. The tensile strength of the 3D-printed 1 wt% bionanocomposite specimen was 12% higher than that of the neat specimen, whereas the 3 wt% bionanocomposite remained comparable to neat PLA. In summary, the morphological, tensile and 3D printing analysis revealed that the bionanocomposite filaments possessed adequate roundness, flexibility, and strength. The as-prepared filaments performed well under low printing temperatures without warping.

Periodontitis is a widespread oral health problem caused by bacterial infections that lead to tooth loss and other systemic diseases. The aim of this study was to provide an alternative treatment for periodontitis by developing a metronidazole-loaded in situ forming matrix (ISM) using camphor as its matrix former. Five-percent w/w metronidazole dissolved in N-methyl pyrrolidone (NMP) with varying concentrations of camphor (30–50% w/w) and triacetin (0–25% w/w) were used. The physicochemical properties and antimicrobial activities of formulations were evaluated. Results showed that as the percentage of camphor increased, viscosity, density, contact angle, surface tension, and force of injection increased, while water tolerance decreased. The same trend was observed when increasing the triacetin concentration. The optimal metronidazole-loaded ISM was obtained at 40% w/w camphor and 5% w/w triacetin, which prolonged the release of metronidazole up to 6 days with Fickian diffusion release profile. The higher concentration of triacetin slowed down the phase inversion that led to an incomplete formation of the matrix and resulted in an inefficiently prolonged release of the metronidazole. Antimicrobial activities demonstrated that the developed formulation efficiently inhibited periodontitis-induced microorganisms including Porphyromonas gingivalis , Staphylococcus aureus , Escherichia coli , and Candida albicans . The metronidazole-loaded camphor-based ISM has potential as a new drug delivery system for periodontitis treatment. Graphical Abstract