International Journal of Polymer Science

Plastic has been a dominant material for packaging in recent years but due to its nonbiodegradability, it is causing environmental pollution. Among the plastics used, low-density polyethylene is used abundantly. These plastics can be removed from the environment by recycling into useful products through reinforcing it with natural textile fibers into composite materials. Natural fiber-based composites are ecofriendly and low cost. This research is aimed at manufacturing composite wall tiles from recycled low-density polyethylene reinforced with pineapple leaf fibers (PALF). The PALF was extracted by the retting process followed by mechanical scratching and treated with 5% NaOH to improve the fiber-matrix interaction. The composites were manufactured by the melt-mixing method followed by compression molding. The effects of fiber length and fiber weight proportion on composite properties were investigated using tensile, flexural, impact, and water absorption tests. The study showed that the optimum fiber weight proportion and fiber length for the optimal properties of the composite were achieved at 30% fiber weight proportion and 30 mm fiber length. The maximum tensile strength of 1562 N/mm², flexural strength of 454.9 N/mm², and impact strength of 225.2 J/mm²were obtained. Water absorption of the tiles increased with the increase in both the fiber weight proportion and the fiber length.

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Following preliminary reports that introduced 4-tert-butylbenzhydrylamine resin (BUBHAR) as a novel polymer for use in solid-phase peptide chemistry (SPPS), some physical-chemical properties of its structure, certainly relevant for its application in this methodology, were compared with those of the largely used methylbenzhydrylamine resin (MBHAR). In order to rule out possible MBHAR-related commercial source effects for SPPS, we initially compared MBHAR batches acquired from three different manufacturers with homemade BUBHARs. The bead solvation properties of these two resins in solvents used in thetert-butyl (Boc-based) SPPS technique indicated that the mean swelling values of these solid supports (% volume of solvated bead occupied by the solvent) were 51% and 67% for MBHAR and BUBHAR, respectively. This result strongly suggests a good potential for the latter polymer in terms of application for application in SPPS. In order to move forward with this approach, the synthesis of the carboxy-terminal peptide fragment (Gln-Asn-Cys-Pro-(D-Arg)-Gly-amide) of the antidiuretic hormone, desmopressin ([3-Mpa -Tyr-Phe-Gln-Asn-Cys-Pro-(D-Arg)-Gly-amide],1-[3-mercaptopropionic acid]), which our laboratory is producing routinely in large scale for the Health Secretary of Sao Paulo State. The comparative synthesis was conducted using these two resins with similar substitution degrees (~0.7 mmol/g). In contrast to MBHAR, surprisingly no need for a Gln⟶Asn recoupling reaction was observed when BUBHAR was used. This result might be due to improved solvation of the desmopressin C-terminal Asn-Cys-Pro-(D-Arg)-Gly-segment when bound to this latter resin as observed by microscopic swelling degrees of peptide-resin beads and also by greater mobility detected of peptide chains within the BUBHAR polymer backbone. This finding was determined by comparative electron paramagnetic resonance (EPR) of both peptide resins attaching the amino acid-type paramagnetic 2.2.6.6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (Toac) spin label early introduced by our group.

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壳聚糖及其纳米颗粒（NP）可以从许多真菌物种中提取，并用作生物活性化合物有效的载体。真菌壳聚糖（FC）是从创新收购Fusarium oxysporumgrown mycelia, characterized and used for NP synthesis and loading with bee venom (BV). The nano-FC (NFC) had 192.4 nm mean NP diameter, 38.22% loading capacity, and 92.42% entrapment efficiency. BV release from NFC was pH and time dependent; burst BV release was detected at the first 6 h, followed by gradual releases up to 30 h. The体外anticancer potentiality valuation, of NFC, BV, and NFC/BV nanoconjugates against HeLa cervix carcinoma, revealed that they all had potent dose-dependent anticancer activity; BV/NFC nanoconjugates were the most effective with .The fluorescent staining of treated HeLa cells with BV/NFC nanoconjugates, with DAPI and acridine orange/propidium iodide combination, indicated the appearance of early apoptosis, secondary apoptosis, and secondary necrosis markers and their increment with exposure prolongation. The production of NFC fromF. oxysporumand their loading with BV are strongly counseled for production of potent natural antitumor agent with augmented activity against cervix carcinoma.

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从纤维素酯通常用作制作的电影bio-based food packaging materials. In this work, we studied the incorporation of nine essential oils into cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. The essential oils were derived from lime, nutmeg, eugenol, pimenta berry, rosemary, petitgrain, coffee, anise, and trans-cinnamaldehyde. In almost all cases, the addition of essential oils to cellulose ester reduced tensile strength and Young’s modulus but increased elongation at break. Thus, an essential oil acted like a plasticizer that enhanced the flexibility of the polymer. Essential oils containing limonene and pinenes (e.g., from lime and nutmeg) gave the strongest plasticizing action, whereas essentials oils containing fatty acids (e.g., from coffee) were the weakest plasticizers. The water barrier property was improved the most when essential oils were added to cellulose acetate; however, different cellulose ester/essential oil combinations showed different effects. Whereas most of the essential oils decreased the transparency of the films, eugenol, pimento berry, and anise were notable exceptions. Thus, depending on a specific application, a particular polymer/EO combination can be used to give the optimal performance.

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Dye wastewater from textile industries shows very low biodegradability due to high molecular weight and complex structures of dyes. So far, the most simple method for treatment of this type of wastewater has been coagulation and flocculation. This study determined the removal of turbidity and other pollutants from dye wastewater by mucilage extracted from the peel of dragon fruit (Hylocereus undatus）及其在减少凝结和絮凝（CF）方法中使用合成的化学聚氯化铝（聚合铝）作用。根据烧杯试验使用聚合铝和火龙果粘液在一个连续过程中CF去除浊度的影响。Maximum coagulation efficiencies of PACl were typically observed at pH 4.0-6.0 and PACl concentrations of about 100-150 mg/L depending on types of wastewater, whereas optimal settling times were 30-60 minutes, respectively. The addition of dragon fruit mucilage (0.5-50 mg/L) after PACl (75-245 mg/L) resulted in turbidity removal efficiencies up to 95%. The addition of mucilage extracted from dragon fruit peels was proven to increase turbidity removal efficiency and decrease PACl use. The increase of turbidity removal was often estimated at 10-32%, whereas PACl used was about 3-10% less compared to total PACl needed for obtaining comparable efficiency when used alone. The flocculation activity of mucilage was also compared to polyacrylamide (PAM)—a synthetically organic flocculant. Since the peel of a dragon fruit is an abundant agriculture waste in Vietnam, using its extracted mucilage as a flocculant is an environmentally friendly method.

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The polyethylene terephthalate/carbon nanotube (PET/CNT) nanocomposites were prepared by melt mixing using a twin screw extruder. CNT content was varied up to 5 wt. %. Morphology as well as dynamic mechanical, calorimetric, and rheological properties of the PET/CNT nanocomposites was investigated. Morphological studies indicated that CNT bundles are regularly distributed within the polymer matrix creating a connected network structure which significantly affects the nanocomposite properties. Dynamic mechanical thermal analysis revealed increase in storage and loss modules of the investigated PET nanocomposites by increasing the content of CNTs. Differential scanning calorimetry results demonstrated increase in crystallinity of the investigated PET nanocomposites upon addition of the nanofiller. Rheological studies demonstrated that CNT addition up to 5 wt. % caused increment in complex viscosity and storage modulus. Rheological percolation threshold was observed to be 0.83 wt. % of CNT concentration, respectively.

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