Preparation and Characterization of Cellulose Acetate Film Reinforced with Cellulose Nanofibril

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.

Functional Nanocomposite Films of Poly(Lactic Acid) with Well-Dispersed Chitin Nanocrystals Achieved Using a Dispersing Agent and Liquid-Assisted Extrusion Process

The development of bio-based nanocomposites is of high scientific and industrial interest, since they offer excellent advantages in creating functional materials. However, dispersion and distribution of the nanomaterials inside the polymer matrix is a key challenge to achieve high-performance functional nanocomposites. In this context, for better dispersion, biobased triethyl citrate (TEC) as a dispersing agent in a liquid-assisted extrusion process was used to prepare the nanocomposites of poly (lactic acid) (PLA) and chitin nanocrystals (ChNCs). The aim was to identify the effect of the TEC content on the dispersion of ChNCs in the PLA matrix and the manufacturing of a functional nanocomposite. The nanocomposite film’s optical properties; microstructure; migration of the additive and nanocomposites’ thermal, mechanical and rheological properties, all influenced by the ChNC dispersion, were studied. The microscopy study confirmed that the dispersion of the ChNCs was improved with the increasing TEC content, and the best dispersion was found in the nanocomposite prepared with 15 wt% TEC. Additionally, the nanocomposite with the highest TEC content (15 wt%) resembled the mechanical properties of commonly used polymers like polyethylene and polypropylene. The addition of ChNCs in PLA-TEC15 enhanced the melt viscosity, as well as melt strength, of the polymer and demonstrated antibacterial activity.

Type and magnitude of non-compliance and adulteration in neroli, mandarin and bergamot essential oils purchased on-line: potential consumer vulnerability

Thirty-one samples of essential oils used both in perfumery and aromatherapy were purchased to business-to-consumers suppliers and submitted to standard gas chromatography-based analysis of their chemical composition. Their compliance with ISO AFNOR standards was checked and revealed, although ISO AFNOR ranges are relatively loose, that more than 45% of the samples analyzed failed to pass the test and more than 19% were diluted with solvents such as propylene and dipropylene glycol, triethyl citrate, or vegetal oil. Cases of non-compliance could be due to substitution or dilution with a cheaper essential oil, such as sweet orange oil, blending with selected compounds (linalool and linalyl acetate, maybe of synthetic origin), or issues of aging, harvest, or manufacturing that should be either deliberate or accidental. In some cases, natural variability could be invoked. These products are made available to the market without control and liability by resellers and could expose the public to safety issues, in addition to commercial prejudice, in sharp contrast with the ever-increasing regulations applying to the sector and the high demand of consumers for safe, controlled and traceable products in fragrances and cosmetic products.

Thermal Properties of Plasticized Cellulose Acetate and Its β-Relaxation Phenomenon

Cellulose acetate (CA), an organic ester, is a biobased polymer which exhibits good mechanical properties (e.g., high Young’s modulus and tensile strength). In recent decades, there has been significant work done to verify the thermal and thermomechanical behaviors of raw and plasticized cellulose acetate. In this study, the thermomechanical properties of plasticized cellulose acetate—especially its ββ-relaxation and activation energy—were investigated. The general thermal behavior was analyzed and compared with theoretical models. The study’s findings could be of special interest, due to the known ββ-relaxation dependency of some polymers regarding mechanical properties—which could also be the case for cellulose acetate. However, this would require further investigation. The concentration of the plasticizers—glycerol triacetate (GTA) and triethyl citrate (TEC)—used in CA ranged from 15 to 40 wt%. DMTA measurements at varying frequencies were performed, and the activation energies of each relaxation were assessed. Increasing plasticizer content first led to a shift in ββ-relaxation temperature to highervalues, then reached a maximum before declining again at higher concentrations. Furthermore, the activation energy of the ββ-relaxation constantly rose with increases in plasticizer content. The trend in the ββ-relaxation temperature of the plasticized CA could be interpreted as a change in the predominant phase of the overlapping ββ-relaxation of the CA itself and the αα′-relaxation of the plasticizer—which appears in the same temperature range. The plasticizer used (GTA) demonstrated a higher plasticization efficiency than TEC. The efficiencies of both plasticizers declined with increasing plasticizer content. Additionally, both plasticizers hit the saturation point (in CA) at the lowest studied concentration (15 wt%).

Intravitreal Administration of Acetyl Triethyl Citrate and Benzyl Benzoate Is Retinotoxic in Rabbits but Not in Cynomolgus Monkeys

Sustained drug delivery formulations are developed to reduce dose frequency while maintaining efficacy of intravitreal (ITV) administered therapeutics. Available safety data for components novel to the eye’s posterior segment may be limited, requiring preclinical assessments to identify potential toxicities. We evaluated the in vivo and in vitro safety of two solvents, acetyl triethyl citrate (ATEC) and benzyl benzoate (BB), as novel sustained delivery formulations for ITV administration. In vivo tolerability was assessed following ITV administration of ATEC and BB to rabbits and cynomolgus monkeys. In rabbits, ITV solvent administration resulted in moderate to severe retinal toxicity characterized by focal retinal necrosis and/or degeneration, sometimes accompanied by inflammation, with a clear association between the physical presence of the solvent and areas of retinal damage. In contrast, solvent administration in monkeys appeared well tolerated, producing no histologic abnormalities. Toxicity in primary human retinal pigment epithelial cells, characterized by cellular toxicity and mitochondrial injury, corroborated the retinal toxicity in rabbits. In conclusion, ITV solvent depots of ATEC or BB result in chemical and focal retinal toxicity in rabbits, but not monkeys. Additional investigation is needed to demonstrate a sufficient margin of safety prior to use of ATEC or BB in ITV drug products.