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Abstract: The rheological properties in terms of melt rheology and extrudate swell of low-density polyethylene (LDPE) filled with sodium chloride (NaCl) of varying particle size (i.e., 45, 75, and 125μm) in the range of 5–25 wt.% were investigated by capillary rheometry. The real shear stress increased monotonously with increasing apparent shear rate, with the rate of change decreasing with increasing apparent shear rate. At an apparent shear rate greater than about 400s−1, the real shear stress increased with increasing salt content and, at a given apparent shear rate, the real shear stress increased slightly with increasing salt particle size. The shear viscosity decreased monotonously with increasing real shear rate. Regardless of the salt content, the extrudate swell increased with the initial increase in the apparent shear rate to reach a plateau value. After a critical apparent shear rate in the range of 500–1200s−1, and regardless of the salt particle size, the extrudate swell decreased with increasing salt content. Lastly, the extrudate swell tended to be suppressed when a capillary die with a high L/D ratio was used. [Copyright &y& Elsevier]

Abstract: Melt rheology and extrudate swell of isotactic polypropylene (iPP) filled with titanium (IV) oxide (TiO2) nanoparticles of varying content (i.e., 5–30 wt.%) and surface characteristics [i.e., uncoated, silica (SiO2)-coated, and stearic acid-coated] during capillary melt-extrusion were investigated. The wall shear stress of both the iPP melt and the melts that contained nanoparticles increased in a non-linear, decreasing-rate manner with increasing apparent shear rate. The incorporation of the nanoparticles generally increased the wall shear stress of the melts, with stearic acid-coated ones exhibiting the least variation in the property values. The shear viscosity, when plotted with the real shear rate on a log–log scale, exhibited a linear, decreasing function with the real shear rate. Clearly, the iPP melts containing stearic acid-coated TiO2 nanoparticles exhibited the lowest shear viscosity values. Lastly, the extrudate swell of the iPP melt and the melts that had been filled with nanoparticles was found to increase with increasing apparent shear rate, while it was found to decrease generally with the addition and increasing amount of nanoparticles. [Copyright &y& Elsevier]

Abstract: The melt rheological and extrudate swelling behavior of neat low-density polyethylene (LDPE) and blends of LDPE and ethylene–octene copolymer (EOC) was investigated using capillary rheometry at 185.0±0.5°C. Dies having different length-to-inner diameter (L/D) ratios were used (i.e., 5/1, 10/11, 10/2, and 30/2mm/mm, respectively). For a given sample material, the real shear stress was observed to increase with increasing real shear rate, and, for a given real shear rate, the real shear stress was generally observed to increase with the addition and increasing amount of EOC. All of the sample materials exhibited the shear-thinning behavior. Both the tensile stress and the elongational viscosity were found to decrease with increasing elongational rate. Generally, both the tensile stress and the elongational viscosity increased with the addtion and increasing amount of EOC, with an exception for the 85/15 and 80/20 LDPE/EOC blends which exhibited a reversed order. Lastly, the extent of extrudate swelling of the sample materials in the small dies (i.e., inner diameter=1mm) was greater than that in the larger ones (i.e., inner diameter=2mm) and the use of a longer die also helped suppress the extent of the extrudate swelling. [Copyright &y& Elsevier]

Melt rheology and extrudate swell of isotactic polypropylene (iPP) filled uncoated and stearic acid-coated CaCO3 nanoparticles in various amounts of filler (i.e. from 5 to 25wt%) during capillary melt-extrusion were investigated. The wall shear stress for both neat iPP and iPP compounds increased in a non-linear manner with increasing apparent shear rate. The apparent shear viscosity for all of the samples investigated was found to decrease in a non-linear manner with increasing apparent shear rate. Addition of uncoated CaCO3 nanoparticles was responsible for increasing the apparent shear viscosity of the compounds, while stearic acid-coated ones did not affect the apparent shear viscosity of the iPP matrix as much. The percentage of extrudate swell was found to increase with increasing apparent shear rate in a non-linear manner, while it was found to increase linearly with increasing wall shear stress. Lastly, the percentage of extrudate swell was found to be a decreasing function of the filler loading. [Copyright &y& Elsevier]

• Organic farming grapples with drought, demanding efficient crop selection. • Molecular techniques revolutionize selection, expediting drought-resistant crop identification. • This review delves into molecular tech's role in streamlining drought-resistant crop selection in organic agriculture. • This exploration guides towards drought-resistant crop varieties, promoting sustainability amidst climate unpredictability. Drought, an ever-looming threat to agriculture, is of paramount concern in organic crop production. The traditional methodologies employed for screening and selecting drought-resistant crops are characterized by their laborious and time-intensive nature. However, the integration of molecular techniques has wrought a revolutionary transformation, expediting the identification and precise selection of crop varieties resilient to drought stress. This review explores the intricate relationship between molecular technologies and the imperative to streamline the screening and selection process for drought-resistant crops in organic agriculture. The advantages of these molecular methodologies are delved into, revealing the potential to accelerate the breeding of crops capable of withstanding the challenges posed by water scarcity. However, this exploration is full of challenges. From scalability issues to cost-effectiveness, ethical implications, and environmental impact, a comprehensive examination is crucial for a nuanced understanding of integrating these technologies into the organic crop production landscape. Moreover, this review extends beyond the present, casting a discerning eye toward the prospects of molecular techniques in pursuing sustainable agriculture. The potential for refinement, overcoming challenges, and synergies with other emerging technologies is crucially considered as a resilient and environmentally conscious agricultural future is envisioned. In essence, this exploration serves as a comprehensive guide, shedding light on the transformative power of molecular techniques in navigating the intricate path towards drought-resistant crop varieties, thereby fostering sustainable practices in the face of an increasingly unpredictable climate. [ABSTRACT FROM AUTHOR]

The polylactic acid is modified with porous silica-containing varying amount of capsicum oleoresin. The effect of accelerated weathering on the polymer degradation, thermomechanical, antibacterial, and rheological properties was studied. The accelerated weathering test was performed for 260 and 520h. The prepared composites show antimicrobial activity against gram-positive and gram-negative bacteria. The tensile strength, modulus, and percentage crystallinity of the composites increased by 17, 7, and 33% respectively with the addition of 1.54 wt% of capsicum oleoresin impregnated porous silica. On the other hand, the incorporation of capsicum oleoresin impregnated porous silica reduced shear modulus and shear viscosity of the composite films. The accelerated weathering, reduced tensile properties, thermal stability, and rheological properties; however, the percentage crystallinity was increased due to the chain scission of the polymer chains. The combination of ultraviolet irradiation, temperature, and humidity caused by the weathering test marginally reduced the antibacterial properties of the polymer films. [ABSTRACT FROM AUTHOR]

• Waste management assessment on recycling of PP and PLA composites have been studied. • PP/sisal fiber and PLA/sisal fiber composites were recycled for four times. • The tensile strength and modulus of PP composites were not affected by recycling. • PLA based composites show a decrease in mechanical properties after first recycling. • The crystallinity of PLA and PLA composites dramatically increased with recycling. • Water absorption increases with fiber content but decreases with recycling. The effect of recycling on the thermo-mechanical and water absorption behavior of polypropylene (PP)/sisal fiber and polylactic acid (PLA)/sisal fiber composites were studied. The PP-based non-biodegradable composites and PLA-based biodegradable composites were recycled for four times. The effect of recycling was determined by examining the morphology, thermo-mechanical properties, and water absorption behavior and the obtained results were compared. The results showed that the incorporation of sisal fibers in the PP and PLA matrix enhances the tensile modulus and percentage crystallinity of the composites. The tensile strength and modulus of the sisal fiber reinforced PP composites were not affected with recycling. Even though the tensile properties of PLA and PLA/sisal fiber reinforced composites are superior to PP and PP/sisal fiber composites, the PLA-based composites show a dramatic decrease in tensile strength and modulus after the first recycling due to the degradation of the polymer. The thermal stability of the PP/sisal fiber composites was not affected by the repeated recycling process. On the other hand, the PLA-based composites with higher sisal fiber content show a bit lower thermal stability after recycling. The PP-based composites show fluctuations in percentage crystallinity with recycling. On the other hand, a remarkable increase in percentage crystallinity for PLA and PLA-based composites was observed with increasing recycling times. Water diffusion study divulges that the diffusion of water into the polymer composites was reduced with recycling, irrespective of the polymer matrix. [ABSTRACT FROM AUTHOR]

Abstract: The present contribution reports an investigation on the effect of the addition of titanium(IV) oxide (TiO2) with diverse surface characteristics [i.e. neat, silica (SiO2)-coated and stearic acid-coated] and various contents (ranging from 5 to 30wt%) on non-isothermal melt-crystallization, subsequent melting behavior and mechanical properties of filled isotactic polypropylene (iPP). The cooling rate used ranged between 5 and 30°Cmin−1.The crystallization exotherm for all of the samples investigated became larger and shifted towards a lower temperature as the cooling rate increased. The crystallization peak temperature (T p) values for all of the iPP samples filled with neat TiO2 nanoparticles were slightly greater than those of the neat iPP and were not affected by the variation in the filler content. For iPP samples filled with stearic acid-coated TiO2 nanoparticles, the T p values were not much different from those of the neat iPP. For iPP samples filled with 5, 20, and 30wt% SiO2-coated TiO2 nanoparticles, marked differences in the T p values in comparison with those of the neat iPP were observed. Together with the Avrami analysis, the nucleation ability of the various fillers investigated can be ranked as follows: SiO2-coated TiO2 nanoparticles >neat TiO2 nanoparticles >stearic acid-coated TiO2 nanoparticles. Lastly, the presence of the nanoparticles caused the rigidity of the resulting composites to increase (especially when the filler content was greater than or equal to 20wt%. [Copyright &y& Elsevier]