Effects of alkaline treatment and kinetic analysis of agroindustrial residues from grape stalks and yerba mate fibers

Borsoi, Cleide; Júnior, Marcos Aurélio Dahlem; Beltrami, Lílian Vanessa Rossa; Hansen, Betina; Zattera, Ademir J.; Catto, André Luís

doi:10.1007/s10973-019-08666-y

Cited by 22 publications

(11 citation statements)

References 50 publications

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“…However, the peaks are overlapped by those of YM signals and are therefore not visible. Similar behavior was observed in studies by Liu et al 20 and Khanjanzadeh et al 43 After the alkaline treatment, it was verified that intensity of the peaks at 1608 and 1240 cm −1 decreased, which indicates that the alkaline treatment led to the partial removal of components such as lignin and hemicellulose 13,34,36 …”

Section: Resultssupporting

confidence: 85%

“…In Figure 1(b), where are observed the composites with the incorporation of 30 wt% YM, with and without treatment or using PP‐g‐MA, the bands referring to hydroxyl groups (─OH) appears in the region of 3070–3600 cm −1 and 1730–1608 cm −1 , which are related to the lignin present in YM 13,34,36 . No significant changes was observed in the spectrum in the characteristic regions of the PP structure, observed at 2800–3000 cm −1 .…”

Section: Resultsmentioning

confidence: 95%

“…For surface modification using silane and alkaline treatment, YM residues were ground in a knife mill (Marconi, Willey MA340) and classified in a particle size system, between −60 + 100 Tyler mesh. The APTS surface modification process was based on studies by 12,20,34–37 . A hydroalcoholic solution (80/20 [vol/vol] ethanol/distilled water) at pH 4, adjusted with acetic acid, was used to prehydrolyze the silane (5 wt% in relation to YM mass) for 1 h under magnetic stirring.…”

Section: Methodsmentioning

confidence: 99%

“…After pre‐hydrolysis, the YM residues were added to the hydroalcoholic solution, stirring for 2 h at room temperature (approximately 25 ± 2°C), and then filtered and washed with water and ethanol. The drying was carried out in an oven at 80°C for 24 h. The methodology used for the alkaline treatment was based on studies by Borsoi et al, 34 where NaOH 10% solution (wt/vol) was used. The YM remained in the NaOH solution in proportions of 20:1 (solution:YM) by weight for 90 min at 50°C.…”

Section: Methodsmentioning

confidence: 99%

“…Alkaline treatment with aqueous sodium hydroxide (NaOH) is the chemical modification most commonly used for natural fibers as reinforcement with thermoplastic polymers. The alkaline treatment results in the ionization of the hydroxyl group in the alkoxides, leading to the degradation of hemicellulose and partially of lignin, pectins, waxes, and oils, providing an exposure of the reactive OH groups on the fiber surface 15,18,34 . Besides that, the alkaline treatment increases the number of reactive sites, increasing the amount of cellulose exposed on the fiber surface 15 …”

Section: Introductionmentioning

confidence: 99%

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Effect of different surface treatments on polypropylene composites reinforced with yerba mate fibers: Physical, mechanical, chemical, and morphological properties

Borsoi

Hansen

Gemmer

et al. 2021

J of Applied Polymer Sci

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This study presents the preparation of post‐consumer polypropylene (r‐PP) composites filled with 30 wt% yerba mate (YM) stick particles. To improve the fiber–matrix adhesion, three surface treatments were performed: alkaline treatment with sodium hydroxide (NaOH) and use of 3‐aminopropyltriethoxysilane (APTS) and maleic anhydride graft polypropylene copolymer (PP‐g‐MA) as coupling agents. Mechanical properties including tensile, flexural, and impact resistance were determined, and chemical (Fourier transform infrared spectroscopy [FTIR]), physical (water absorption), and morphological analyses were performed. The main findings show that the treatments were efficient in improving the mechanical properties of the composites, with emphasis on the r‐PP/YM30/APTS and r‐PP/YM30/PP‐g‐MA composites, which proved to be superior in tensile, flexion and impact strength and absorption of water compared to the untreated composite. The morphological analysis showed a better interaction between the fiber and the polymeric matrix for the composites with YM/APTS and YM/PP‐g‐MA, which corroborates the results of tensile and flexural strength, as well as with the spectra of FTIR in which the chemical modification of the fibers is observed. However, the results show that these treatments are promising in obtaining composites with recycled matrix with better properties.

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Section: Resultssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of different surface treatments on polypropylene composites reinforced with yerba mate fibers: Physical, mechanical, chemical, and morphological properties

Borsoi

Hansen

Gemmer

et al. 2021

J of Applied Polymer Sci

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Influence of surface treatments and coupling agents on the thermal and thermo‐mechanical properties of yerba mate/post‐consumer polypropylene composites

et al. 2021

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The main objective of this work is to evaluate an interaction between yerba mate fibers (YM) and post-consumption polypropylene (r-PP) using the surface treatments and coupling agent. YM fibers were submitted to two different surface treatments: alkaline solution (NaOH 10%) and 3-aminopropyltriethoxysilane (APTS) (5 wt%). The influence of 5 wt% addition of maleic anhydride (MA)-grafted polypropylene copolymer (PP-g-MA) coupling agent in the composite processing was also evaluated. YM of 30 wt% was loaded into r-PP by extrusion, and then the specimens were prepared by injection molding. The results showed that all treatments were effective in improving thermal stability increase the maximum degradation temperature by approximately 5 C, as also confirmed by differential scanning calorimetry analysis. Composite with PP-g-MA presented the greater increase in thermal stability and in the crystallization index (approximately 46% in relation to the r-PP/YM30 composite). DMA analysis revealed increases in the storage and loss moduli and a decrease in the damping factor for all composites produced with treated fibers and coupling agent. The enhancement of the analyzed properties of these composites is related to the better interfacial adhesion between YM fiber and r-PP, which was confirmed by scanning electron microscope micrographs.

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Chemical Modifications of Natural Fiber Surface and Their Effects

AL-Oqla

Alaaeddin²

2022

Bast Fibers and Their Composites

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Effects of alkaline treatment and kinetic analysis of agroindustrial residues from grape stalks and yerba mate fibers

Cited by 22 publications

References 50 publications

Effect of different surface treatments on polypropylene composites reinforced with yerba mate fibers: Physical, mechanical, chemical, and morphological properties

Effect of different surface treatments on polypropylene composites reinforced with yerba mate fibers: Physical, mechanical, chemical, and morphological properties

Influence of surface treatments and coupling agents on the thermal and thermo‐mechanical properties of yerba mate/post‐consumer polypropylene composites

Chemical Modifications of Natural Fiber Surface and Their Effects

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