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- 저자 : Isabel Cristina Tessaro (검색결과 2 건)
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A Review on the Mercerization of Natural Fibers: Parameters and Effects
Luchese Claudia Leites,Engel Juliana Both,Tessaro Isabel Cristina 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.3
Natural fi bers are environmentally friendly materials incorporated into polymer matrices as reinforcement agents. Several fi bers are available in nature, such as cotton, jute, sisal, bamboo, hemp, banana, coir, and fl ax. However, in some cases, poor compatibility between fi ber/polymer is observed, limiting their utilization. To overcome this disadvantage, chemical treatments can be applied to the fi bers to alter their chemical composition, surface morphology, and mechanical properties. In comparison with other methods, mercerization is a popular methodology largely used to modify the properties of fi bers once is inexpensive and does not require toxic chemicals. The main modifi cations caused by mercerization regarding chemical composition are the removal of wax, oils, and impurities of the surface of the fi bers, besides a decrease in lignin and hemicellulose contents, and an increase in cellulose content. Fiber surface morphology becomes cleaner, and mechanical parameters, such as tensile strength and rigidity, are generally improved. Although these are some common modifi cations, mercerization process parameters must be well-adjusted to obtain optimized results. Unlike other published articles, this review covers the mercerization parameters adopted for several types of natural fi bers to establish a correlation between the main eff ects of the process on the physical–chemical, morphological, and mechanical properties of the fi bers.
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Supported carbon membranes using poly(ether sulfone) precursor
Ana Katiuce Fellenberg,Cláudia Leites Luchese,Nilson Romeu Marcilio,Isabel Cristina Tessaro 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.3
This research focused on developing membranes using poly(ether sulfone) as polymeric precursor and DMSO as a solvent. The dip-coating technique was used to form a polymeric layer on the alumina ceramic tube, and the pyrolysis was conducted at 700 o C under N2 atmosphere. The structural analyses showed that the supported carbon membranes (SCM) are basically composed of amorphous and turbostratic carbon with graphitic domain, confirming the heterogeneity of the matrix. It was observed from the FTIR and XRD results that the precursor polymer was fully pyrolyzed. The carbon structure obtained presented a microporous character (pore radius equal to 6.2 Å) and a high BET surface area (approximately 400 m2 g1 ). The SCM presented a well-defined selective layer with little or no intrusion in the pores of the support. A higher polymeric concentration promoted an increase in the thickness of the carbon membranes (from 20 m to 36 m). The carbon membranes produced showed high thermal stability, allowing their application in gas separation processes at higher temperatures, up to approximately 400 o C.
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