Catalysis
Jonas B Biagini; Joao Henrique Zimnoch dos Santos
Abstract
The determination of Ti+4 in Ziegler–Natta catalysts is highly relevant for industrial plants that use Ziegler–Natta (ZN) catalysts based on TiCl4 as a source of titanium. The catalyst preparation step requires analytical monitoring during the dilution process for the morphological effect ...
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The determination of Ti+4 in Ziegler–Natta catalysts is highly relevant for industrial plants that use Ziegler–Natta (ZN) catalysts based on TiCl4 as a source of titanium. The catalyst preparation step requires analytical monitoring during the dilution process for the morphological effect according to the relationship between the Ti+3 and Ti+4 concentrations in the polymerization process, which in turn depend on a variety of intended grades for different market applications. Spectrophotometry in the visible region was evaluated as a potential analytical technique for the quantification of Ti+4 in ZN catalysts. The present study proposes the use of an easily accessible, reliable and low-cost validated instrumental method for Ti+4 determination. Therefore, the technical details regarding sample preparation, instrumental analytical parameters and performance characteristics of the method were descriptively addressed. The quantitative evaluation of performance parameters (namely, specificity, linearity, detection and quantification limits, precision, accuracy and robustness) demonstrated successful results compared with the theoretical values of the studied reference sample. The precision of the method by visible spectrophotometry was estimated at 0.4% for the relative error, and the accuracy presented within an IC of 95% for the LOC ± 1.7 mmolTi/L for the average concentration of 339.5 mmolTi L-1 in reference to the Tyzor ® TnBT sample with a theoretical concentration of 337 mmol L-1 study solution from this work. The method was shown to be a supporting tool for quantitative Ti+4 species determination in the control of industrial processes.
Polymer chemistry
Anirban Bhar; Akshay Kumar Dey; Deepshikha Datta; Oliva Roy; Soumyadeep Routh; Arindam Mandal; Biswajit Kamila
Abstract
The global packaging industry is primarily influenced by polyolefinic materials, such as polyethylene (PE) and polypropylene (PP), which offer a combination of durability, flexibility, and cost-effectiveness. These materials have transformed modern packaging through their lightweight offerings for food, ...
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The global packaging industry is primarily influenced by polyolefinic materials, such as polyethylene (PE) and polypropylene (PP), which offer a combination of durability, flexibility, and cost-effectiveness. These materials have transformed modern packaging through their lightweight offerings for food, medical, and industrial uses. The widespread employment of non-biodegradable plastics poses substantial challenges in waste management due to their persistent presence and significant contribution to plastic pollution. This review examines the characteristics, applications, and ecological implications of polyolefins, with a particular focus on their importance in packaging. This paper examines recent advancements in biodegradable alternatives and chemical recycling methods, aiming to address the environmental challenges presented by plastic waste. Integrating natural fillers into polyolefin composites can boost biodegradability without compromising functionality. The review highlights the importance of a circular economy approach, which emphasizes sustainable practices for transforming polyolefin waste into valuable resources. This analysis explores the advantages and disadvantages of polyolefins to guide future research and sustainable packaging policy.
Composites and nanocomposites
Negin Sadat Jalili; Bahereh T. Marouf; Ali Bakhshi-Zadeh; Reza Bagheri
Abstract
The aim of the current study was to first make two compatibilizers, i.e., maleic anhydride grafted polypropylene (PP-g-MA), based on a homo-and a block copolymer. Then, these custom made compatibilizers were incorporated in PP/nanoclay composites made via direct and two-step masterbatch techniques. The ...
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The aim of the current study was to first make two compatibilizers, i.e., maleic anhydride grafted polypropylene (PP-g-MA), based on a homo-and a block copolymer. Then, these custom made compatibilizers were incorporated in PP/nanoclay composites made via direct and two-step masterbatch techniques. The influence of compatibilizer/nanoclay ratio was examined in the direct method. In the two-step processing technique, the compatibilizer content was divided to two parts such that the first part was used when making the masterbatch and the second part was incorporated in the second step when the masterbatch was diluted by the polymer matrix. The characterizations via titration test and Fourier-transform infrared (FTIR) spectroscopy revealed a higher degree of grafting reaction when homo-polymer was used for synthesizing PP-g-MA. In the next step, nanocomposites containing 3 wt.% nanoclay with three different PP-g-MA (both types)/nanoclay ratios of 1:1, 2:1, and 3:1 were made using a co-rotating twin screw extruder. X-ray diffraction (XRD) analysis was done to evaluate morphology and tensile and impact, and tests were performed to evaluate the mechanical properties of the PP samples. Based on the results, maleic anhydride grafted homo-polypropylene (HPP-g-MA) and the composition containing HPP-g-MA/nanoclay ratio of 2:1 with 7.69% improvement in Young’s modulus was reported as the recommended compatibilizer and ratio for applications. Finally, five nanocomposite samples with identical composition were made in two steps. A masterbatch containing 15 wt.% nanoclay was made first and then, it was diluted with PP to reduce the nanoclay content to 3 wt.%. All samples containing 6 wt.% PP-g-MA, but the method of addition of compatibilizer was different. In one sample, the whole compatibilizer was added into the masterbatch. In another sample, the entire PP-g-MA was added in the second stage of compounding. In the other three samples, the addition of compatibilizer was divided between the two stages of the process. The results of the study showed that the highest improvement of elastic modulus (24.26%) was obtained when the majority of the compatibilizer was added in the second step of production. This was associated with the best dispersion of nanoclay platelets in the PP matrix.
