Performance of Gelatin Films Reinforced with Cloisite Na+ and Black Pepper Essential Oil Loaded Nanoemulsion

The concern about consuming eco-friendly products has motivated research in the development of new materials. Therefore, films based on natural polymers have been used to replace traditional polymers. This study consists of a production of films based on gelatin reinforced with black pepper essential oil-loaded nanoemulsions and Cloisite Na+. The films were characterized by water vapor permeability, mechanical and thermal properties, surface contact angle, X-ray diffraction and scanning electron microscopy. It was observed that the films containing the nanoemulsion have higher permeability values and an increase in their mechanical resistance. The addition of nanoclay contributed to an increase in the surface hydrophobicity of the film and an increase in the tensile strength, at break, by about 150%. The addition of essential oil nanoemulsions led to an increase in thermal stability. The presence of clay dispersion contributed to the formation of a surface that was slightly rougher and grainier. The addition of the black pepper essential oil nanoemulsion resulted in an increase in porosity of the gelatin matrix. Through X-ray diffraction analysis, it was possible to conclude that both the polymeric gelatin matrix and the essential oils nanoemulsion are intercalated with the clay dispersion.

Performance of Gelatin Films Reinforced with Cloisite Na+ and Black Pepper Essential Oil Loaded Nanoemulsion

The concern about consuming eco-friendly products has motivated research in the development of new materials. Therefore, films based on natural polymers have been used to replace traditional polymers. This study consists of a production of films based on gelatin reinforced with black pepper essential oil-loaded nanoemulsions and Cloisite Na+. The films were characterized by water vapor permeability, mechanical and thermal properties, surface contact angle, X-ray diffraction and scanning electron microscopy. It was observed that the films containing the nanoemulsion have higher permeability values and an increase in their mechanical resistance. The addition of nanoclay contributed to an increase in the surface hydrophobicity of the film and an increase in the tensile strength at break by about 150%. The addition of essential oil nanoemulsions led to an increase in thermal stability. The presence of clay dispersion contributed to the formation of a surface that was slightly rougher and grainier. The addition of the black pepper essential oil nanoemulsion resulted in an increase in porosity of the gelatin matrix. Through X-ray diffraction analysis, it was possible to conclude that both the polymeric gelatin matrix and the essential oils nanoemulsion are intercalated with the clay dispersion.

In-Line Rheo-Optical Investigation of the Dispersion of Organoclay in a Polymer Matrix during Twin-Screw Compounding

The dispersion mechanisms in a clay-based polymer nanocomposite (CPNC) during twin-screw extrusion are studied by in-situ rheo-optical techniques, which relate the CPNC morphology with its viscosity. This methodology avoids the problems associated with post extrusion structural rearrangement. The polydimethylsiloxane (PDMS) matrix, which can be processed at ambient and low temperatures, is used to bypass any issues associated with thermal degradation. Local heating in the first part of the extruder allows testing of the usefulness of low matrix viscosity to enhance polymer intercalation before applying larger stresses for clay dispersion. The comparison of clay particle sizes measured in line with models for the kinetics of particle dispersion indicates that larger screw speeds promote the break-up of clay particles, whereas smaller screw speeds favor the erosion of the clay tactoids. Thus, different levels of clay dispersion are generated, which do not simply relate to a progressively better PDMS intercalation and higher clay exfoliation as screw speed is increased. Reducing the PDMS viscosity in the first mixing zone of the screw facilitates dispersion at lower screw speeds, but a complex interplay between stresses and residence times at larger screw speeds is observed. More importantly, the results underline that the use of larger stresses is inefficient per se in dispersing clay if sufficient time is not given for PDMS to intercalate the clay galleries and thus facilitate tactoid disruption or erosion.

The no-tillage, with crop rotation or succession, can increase the degree of clay dispersion in the superficial layer of highly weathered soils after 24 years

Clay dispersion is directly related to water erosion, especially during detaching and dragging of particles. No-till is one of the most important strategies for soil and water conservation in tropical and sub-tropical regions, and when associated with crop rotation, may reduce the degree of clay dispersion. The study aimed to evaluate, after 24 years, the effect of different soil management systems and crop systems on the degree of clay dispersion of a Rhodic Ferralsol. The experimental design was completely randomized in a 4x2 factorial scheme, with four soil managements (continuous no-tillage, no-tillage with chiseling every three years, disk plowing followed by light harrowing and heavy disking followed by light harrowing) and with two crop systems (crop succession and rotation). The degree of clay dispersion was evaluated and associated with soil chemical attributes from layer 0.00-0.10 m. The degree of clay dispersion is affected by the soil management systems with no effect of crop systems. The soil management system with the lowest soil disturbance (continuous no-tillage) has a higher degree of clay dispersion than the ones that disturb the soil, regardless of the agricultural implement used or soil disturbance intensity. The soil electrochemical imbalance, primarily caused by soil potential acidity, is positively correlated to the increase in the degree of clay dispersion of the superficial soil layer under continuum no-tillage.

Farm systems, soil chemical properties, and clay dispersion in watershed áreas

The objective of this work was to evaluate the effect of different farm systems on clay dispersion and its relationship with soil chemical properties and the no-tillage system participatory quality index (IQP), in watershed areas in the west of the state of Paraná, Brazil. The farm systems evaluated were: no-tillage; no-tillage with crop succession; no-tillage with soil disturbance; and conventional system. In addition, the farm systems were evaluated for their IQP. Soil samples were collected at 0.0-0.20-m soil depth, in 40 agricultural areas and in 6 native forests considered as references. The degree of clay dispersion, total organic carbon, pH (CaCl2), exchangeable potassium (K+), available phosphorus (P), exchangeable calcium and magnesium (Ca2++Mg2+), and potential acidity (H+Al3+) were determined. A linear multiple regression model was fitted by the method of least squares. The averages of clay dispersion degree per watershed were compared at 5% probability. The farm systems were compared by Scott-Knott’s test. Soil chemical properties showed a higher influence on clay dispersion than the different farm systems assessed. The no-tillage system alone showed the highest content of organic carbon, which was similar to those of the native areas. The conventional system and the no-tillage system with soil disturbance showed a lower IQP and a higher degree of clay dispersion than the areas with the no-tillage system alone. The IQP allows distinguishing the conventional system from the no-tillage system.