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Plastic mulching for agricultural purposes is a technique which began in the last century and since then its use has been perfected. The fragments of some large‐scale mulch films used may accumulate in the soil, release toxic substances, and affect soil microbial activity. The environmental problems generated by fragments of plastic films accumulated in soil have prompted the development and large‐scale use of biodegradable plastic mulch films. The aim of this work is to develop biodegradable plastic mulch films from poly(butylene adipate co‐terephthalate (PBAT), sugarcane residue, and carnauba wax and to evaluate its biodegradation when buried in soil. The films, obtained by flat extrusion, contained 2.5 and 5.0% sugarcane residue and 0 and 2.0% carnauba wax. Their biodegradation after burial in soil was monitored by mass loss, visual inspection, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Our data show biodegradation in soil to increase with sugarcane residue content and to be independent on carnauba wax addition. This behavior, confirmed by visual inspection, FTIR and SEM images, was associated with the biodegradability of lignocellulosic residues as microorganisms tend to attack this component first, thus eroding fiber/matrix interface and facilitating bio disintegration. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48240.

High-density polyethylene/modified bentonite clay/polar compatibilizer nanocomposites were prepared through the melt intercalation process. The clay was organophilizated using different percentages of quaternary ammonium salt 100, 125, and 150 % based cation exchange capacity of the clay. The nanocomposites were prepared in a counter-rotating twin-screw extruder and then specimens were injection molded. For the evaluation of flammability of the test system was used for burning in the horizontal position according to the norm (Underwriters Laboratories, UL94HB) and to the method of cone calorimeter. The thermal behavior of nanocomposites was evaluated by thermogravimetry and X-ray diffraction techniques, and transmission electron microscopy were used to characterize the morphology and analyze the degree of expansion of the clays prepared and the degree of exfoliation of nanocomposites. It was observed that the percentage of ammonium salt and the compatibilizer polar influence on the final properties of the systems and consequently improving the thermal stability and reducing the flammability of the matrix.

In this work, biocomposites of poly (3-hydroxybutyrate) (PHB) / calcium carbonate from Rhea Americana eggshells were prepared and the effects of the addition of the inorganic filler in the polymeric matrix were assessed. The residue (powder) of the eggshell calcined at 400 ºC or in natura was inserted into a PHB solution for preparation of films via casting. Powder samples were characterized by X-Ray Fluorescence (XRF), X-Ray diffraction (XRD) and Thermogravimetry (TG/ DTG) and films were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) and biodegradation tests according to the ASTM G 160-03 norm: the results were reported as weight loss and visual inspection by optical microscopy (OM). From the results of the XDR, it was perceived that the peaks in the diffractograms of the powder obtained by milling the Rhea Americana eggshells corresponded to the diffraction patterns of the Calcite crystals, which is a calcium carbonate polyform, and that the calcination preserved the crystalline structure, maintaining the calcium carbonate in the samples. For the biocomposites, a peak characteristic to the calcium carbonate in 29.57º was detected, indicating the insertion of the filler to the polymer matrix. Through SEM the presence of small agglomerates, probably due to polymer particles that were not dissolved, was observed for the pure PHB film. With the addition of the filler in natura a greater porosity was formed in the surface of the biocomposite films, and with the calcined filler, homogeneous films with reduced porosity were obtained. From the weight loss and OM results, it was observed that the filler inserted into the polymeric matrix catalyzes the biodegradation process up to 60 days evaluation in different ways, depending on the type of sample used.

PolyTech, Prospect CT, USAResumo: Compósitos de PP/argila/PP-g-MA/erucamida contendo 5% (em peso) de argila montmorilonita organofílica (Cloisite 20A), 5 e 15% de PP-g-MA como agente compatibilizante e 0, 0,5% e 1% de cis-13-docosenamida (erucamida) como agente co-intercalante, foram preparados por intercalação no estado fundido. Concentrados de argila e compatibilizantes foram processados em misturador interno e em seguida diluídos com a matriz de polipropileno em extrusora de dupla rosca corrotacional. Os compósitos foram caracterizados através das propriedades mecânicas, difração de raios X e microscopia óptica. Os resultados indicaram o efeito reforçante da argila organofilizada. A presença de co-intercalante aumentou significativamente a distância interlamelar da argila em todos os compósitos, em geral, não afetando notavelmente o comportamento mecânico dos compósitos. Por microscopia óptica foi possível observar o efeito dispersivo do perfil de rosca utilizado, que promoveu a quebra dos aglomerados de argila. Palavras-chave: Polipropileno, nanocompósitos, co-intercalante, propriedades mecânicas. Effect of CIS-13-Docosenamide Cointercalation on the Morphology and Mechanical Properties of Polypropylene/Organoclay CompositesAbstract: PP/organoclay/PP-g-MA/erucamide composites with 5% commercial organo-montmorillonite (Cloisite 20A), 5 and 15% maleated polypropylene as compatibilizer, and 0, 0.5 and 1% erucamide as a co-intercalating agent were prepared by melt intercalation. A masterbatch of compatibilizer and organoclay was compounded in an internal mixer and then diluted in the polypropylene matrix in a corotating twin-screw extruder. The compounds were characterized by x-ray diffraction, optical microscopy and mechanical properties. Results indicate that the organoclay acted as a reinforcer. Addition of the co-intercalating agent significantly increased the interlayer spacing of the clay, without notably affecting the mechanical behavior of the composites. Optical microscopy showed the dispersive effect of the screw profile used, which promoted the breaking of clay agglomerates.

Biodegradable polymers represent an alternative to the conventional ones. The polyhydroxybutyrate (PHB) is one of the most used biodegradable polymers. However, PHB presents narrow processing window, which limits its applicability. The development of PHB composites offers a solution for that drawback. In this work, PHB and hollow glass microspheres (HGMs) composite films are developed. Subsequently, the films are characterized, and the biodegradability of the films is determined by the Sturm test. A suitable distribution and intermediate dispersion of the filler throughout the matrix are observed, while adhesion between the components is not achieved. The HGM does not significantly affect the thermal properties of the systems, however, decreases the degree of crystallinity. In addition, the composite films present small values of elongation and tensile strength than the pure PHB film. Finally, the HGM modified the mechanism of biodegradation; however, there was no change in the rate of biodegradation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47195.