scholarly journals Synthesis of a Cellulose-Co-AMPS Hydrogel for Personal Hygiene Applications Using Cellulose Extracted from Corncobs

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 236
Author(s):  
Haymanot Enawgaw ◽  
Tamrat Tesfaye ◽  
Kelem Tiessasie Yilma ◽  
Derseh Yilie Limeneh
Keyword(s):  
Thermal Properties ◽  
Sulfonic Acid ◽  
Acid Treatment ◽  
Inhibition Zone ◽  
Personal Hygiene ◽  
Cross Linking ◽  
Swelling Ratio ◽  
Degradation Temperature ◽  
Ft Ir ◽  
Growth Of Bacteria

Cellulose-based hydrogels were prepared by the extraction of cellulose from corncobs after the removal of lignin and hemicellulose with the use of alkali–acid treatment. Acrylate-based hydrogels presently available for personal hygiene uses are not biodegradable. In this study, a biodegradable cellulose-co-AMPS personal hygiene hydrogel was synthesized. The hydrogel was synthesized by graft co-polymerization of 2-acrylamido2-methyl propane sulfonic acid onto corncob cellulose by using potassium persulfate (KPS) as an initiator and borax decahydrate (Na2B4O7·10H2O) as a cross-linking agent. Structural and functional characteristics of the hydrogel such as swelling measurements, antimicrobial tests, FTIR spectra and thermogravimetric analysis were done. The hydrogel showed an average swelling ratio of 279.6 g/g to water and 83.3 g/g to a urine solution with a 97% gel fraction. The hydrogel displayed no clear inhibition zone and did not support the growth of bacteria, Gram-positive or -negative. The FT-IR spectra of the hydrogel confirmed the grafting of an AMPS co-polymer onto cellulose chains. The thermal properties of the hydrogel showed three-step degradation, with a complete degradation temperature of 575 °C.

scholarly journals Ultrasound Assisted Synthesis of Polylimonene and Organomodified-clay Nanocomposites: A Structural, Morphological and Thermal Properties

2020 ◽  
Vol 15 (3) ◽  
pp. 798-807
Author(s):  
Hodhaifa Derdar ◽  
Geoffrey Robert Mitchell ◽  
Zakaria Cherifi ◽  
Mohammed Belbachir ◽  
Mohamed Benachour ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Preparation Method ◽  
Exchange Process ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
X Ray ◽  
Degradation Temperature ◽  
Ultrasonic Assisted ◽  
Ft Ir

Polylimonene-clay nanocomposites (PLM-Mag 2, 3, 6 and 10% by weight of clay) were prepared by mixing Maghnite-CTA+ (Mag-CTA+) and polylimonene (PLM) in solution using ultrasonic irradiation. The catalyst preparation method were studied in order to determine and evaluate their structural, morphological and thermal properties. The Mag-CTA+ is an organophylic montmorillonite silicate clay prepared through a direct exchange process, using green natural clay of Maghnia (west of Algeria) called Maghnite. The Algerian clay was modified by ultrasonic-assisted method using cetyltrimethylammonuim bromide (CTAB) in which they used as green nano-reinforcing filler. Polylimonene was obtained by the polymerization of limonene, using Mag-H+ as a catalyst. The morphology of the obtained nanocomposites was studied by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and infrared spectroscopy (FT-IR). Thermogravimetric analysis (TGA) shows that the nanocomposites have a high degradation temperature (200−250 °C) compared with the pure polylimonene (140 °C). The analyses confirmed the chemical modification of montmorillonite layers and their uniformly dispersion in the polylimonene matrix. Exfoliated structures were obtained for low amounts of clay (2 and 3% by weight), while intercalated structures and immiscible regions were detected for high amounts of clay (6 and 10% by weight). Copyright © 2020 BCREC Group. All rights reserved 

scholarly journals The Preparation, Thermal Properties, and Fire Property of a Phosphorus-Containing Flame-Retardant Styrene Copolymer

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 127 ◽  
Author(s):  
Yu Sun ◽  
Yazhen Wang ◽  
Li Liu ◽  
Tianyuan Xiao
Keyword(s):  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Limiting Oxygen Index ◽  
Chemical Structures ◽  
1H Nuclear Magnetic Resonance ◽  
Phosphorus Containing ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

A 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) acrylate, (6-oxidodibenzo [c,e][1,2] oxaphosphinin-6-yl) methyl acrylate (DOPOAA), has been prepared. Copolymers of styrene (St) and DOPOAA were prepared by emulsion polymerization. The chemical structures of copolymers containing levels of DOPOAA were verified using Fourier transform infrared (FT-IR) spectroscopy and 1H nuclear magnetic resonance (1H-NMR) spectroscopy. The thermal properties and flame-retardant behaviors of DOPO-containing monomers and copolymers were observed using thermogravimetric analysis and micro calorimetry tests. From thermogravimetric analysis (TGA), it was found out that the T5% for decomposition of the copolymer was lower than that of polystyrene (PS), but the residue at 700 °C was higher than that of PS. The results from micro calorimetry (MCC) tests indicated that the rate for the heat release of the copolymer combustion was lower than that for PS. The limiting oxygen index (LOI) for combustion of the copolymer rose with increasing levels of DOPOAA. These data indicate that copolymerization of the phosphorus-containing flame-retardant monomer, DOPOAA, into a PS segment can effectively improve the thermal stability and flame retardancy of the copolymer.

scholarly journals Effect of Organo-Modified Montmorillonite Nanoclay on Mechanical, Thermo-Mechanical, and Thermal Properties of Carbon Fiber-Reinforced Phenolic Composites

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 754
Author(s):  
Jantrawan Pumchusak ◽  
Nonthawat Thajina ◽  
Watcharakorn Keawsujai ◽  
Pattarakamon Chaiwan
Keyword(s):  
Thermal Properties ◽  
Carbon Fiber ◽  
Bending Strength ◽  
Mechanical And Thermal Properties ◽  
Fiber Reinforced ◽  
Heat Resistant ◽  
Degradation Temperature ◽  
Modified Montmorillonite ◽  
Carbon Fiber Reinforced ◽  
Montmorillonite Nanoclay

This work aims to explore the effect of organo-modified montmorillonite nanoclay (O-MMT) on the mechanical, thermo-mechanical, and thermal properties of carbon fiber-reinforced phenolic composites (CFRP). CFRP at variable O-MMT contents (from 0 to 2.5 wt%) were prepared. The addition of 1.5 wt% O-MMT was found to give the heat resistant polymer composite optimum properties. Compared to the CFRP, the CFRP with 1.5 wt% O-MMT provided a higher tensile strength of 64 MPa (+20%), higher impact strength of 49 kJ/m2 (+51%), but a little lower bending strength of 162 MPa (−1%). The composite showed a 64% higher storage modulus at 30 °C of 6.4 GPa. It also could reserve its high modulus up to 145 °C. Moreover, it had a higher heat deflection temperature of 152 °C (+1%) and a higher thermal degradation temperature of 630 °C. This composite could maintain its mechanical properties at high temperature and was a good candidate for heat resistant material.

The Lateral Cross-Linking of Polyurethane Using Grafted Epichlorohydrin and the Impact on the Tensile and Thermal Properties

2016 ◽  
Vol 37 (2) ◽  
pp. 323-331 ◽  
Author(s):  
Yong-Chan Chung ◽  
Byung Hee Lee ◽  
Jae Won Choi ◽  
Byoung Chul Chun
Keyword(s):  
Thermal Properties ◽  
Cross Linking ◽  
The Impact

scholarly journals Synthesis and Characterization of N-Substituted Polyether-Block-Amide Copolymers

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 773
Author(s):  
Jyun-Yan Ye ◽  
Kuo-Fu Peng ◽  
Yu-Ning Zhang ◽  
Szu-Yuan Huang ◽  
Mong Liang
Keyword(s):  
Titanium Isopropoxide ◽  
Decomposition Temperature ◽  
Phenyl Isocyanate ◽  
Cross Linking ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Melt Polycondensation ◽  
Structural Regularity

A series of N-substituted polyether-block-amide (PEBA-X%) copolymers were prepared by melt polycondensation of nylon-6 prepolymer and polytetramethylene ether glycol at an elevated temperature using titanium isopropoxide as a catalyst. The structure, thermal properties, and crystallinity of PEBA-X% were investigated using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, and thermogravimetric analysis. In general, the crystallinity, melting point, and thermal degradation temperature of PEBA-X% decreased as the incorporation of N-methyl functionalized groups increased, owing to the disruption caused to the structural regularity of the copolymer. However, in N-acetyl functionalized analogues, the crystallinity first dropped and then increased because of a new γ form arrangement that developed in the microstructure. After the cross-linking reaction of the N-methyl-substituted derivative, which has electron-donating characteristics, with poly(4,4′-methylenebis(phenyl isocyanate), the decomposition temperature of the resulting polymer significantly increased, whereas no such improvements could be observed in the case of the electro-withdrawing N-acetyl-substituted derivative, because of the incompleteness of its cross-linking reaction.

Serial Extraction Technique of Rich Antibacterial Compounds in Sargassum cristaefolium Using Different Solvents and Testing their Activity

2021 ◽  
Vol 17 ◽  
Author(s):  
Bambang Susilo ◽  
Abd. Rohim ◽  
Midia Lestari W. H.
Keyword(s):  
Antibacterial Activity ◽  
Brown Seaweed ◽  
Inhibition Zone ◽  
Extraction Yield ◽  
Single Step ◽  
Extraction Technique ◽  
Cinnamic Aldehyde ◽  
Antibacterial Compounds ◽  
Ft Ir ◽  
Aldehyde Groups

Background: S. cristaefolium is the brown seaweed extracted using the serial technique with different solvents. Methods: S. cristaefolium powder (50 mesh) was extracted with hexane, ethyl acetate, and methanol respectively. The S. cristaefolium powder residue had been dried before being re-extracted with the next different solvents. Three serial extracts were obtained and named as the 1-stage extract, 2-stage extract, and 3-stage extract. Besides, a single-step extract (extraction using only methanol) was also produced to compare with three serial extracts in antibacterial activity tests (against E. coli and S. aureus). The three serial extracts were detected their antibacterial compounds using GC-MS, LC-HRMS, and FT-IR. Results: The 3-stage extract had the highest extraction yield. On S. aureus, the inhibition zone in all extracts was not significantly different. On E.coli, the highest inhibition zone (5.42±0.14 mm) was the 3-stage extract, indeed it is higher than both antibiotic and a single-step extract. Phenol, 9-Tricosene(Z)-, palmitic acid, and oleamide were contained in all extracts. Other antibacterial compound types, both the 1-stage and 2-stage extracts contained 8 types whilst the 3-stage extract contained the most types (12 types). Particularly, hexyl cinnamic aldehyde and betaine were detected only in the 3-stage extract with the dominant area. The carboxylic acid groups were detected in all extracts to confirm the fatty acid structure. Several cinnamic aldehyde groups were detected only in the 3-stage extract. Conclusions: Thus, the extraction technique serially could produce the 3-stage extract which has the strongest antibacterial activity and the richest antibacterial compounds.

Synthesis of soluble sulfonated polybenzimidazoles derived from 2-sulfonate terephthalic acid

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Qunying Wu ◽  
Guyu Xiao ◽  
Deyue Yan
Keyword(s):  
Terephthalic Acid ◽  
Sulfonic Acid ◽  
Strong Acid ◽  
High Thermal Stability ◽  
Swelling Ratio ◽  
Solution Casting ◽  
Direct Polycondensation ◽  
Acid Base ◽  
Resistance To Oxidation ◽  
Sulfonic Acid Groups

Abstract2-Sulfonate p-terephthalic acid (sTA) was synthesized, and sulfonated polybenzimidazoles (sPBI) were prepared by direct polycondensation of 3,3’- diaminobenzidine (DAB) and sTA with 4,4’-oxybis(benzoic acid) (OBBA) or 2,2’- bis(4-carboxylphenyl)-hexafluoropropane (BCHFP). Thus the ether groups and hexafluoroisopropylidene units were incorporated into the backbone of the sPBI in order to improve the flexibility and solubility. The sPBI based on OBBA showed poor solubility, while the sPBI containing hexafluoroisopropylidene units were soluble in common solvents. sPBI-20 ~ sPBI-60 could form tough and transparent membranes by solution casting. sPBI indicated high thermal stability, the 5% weight loss temperature (T5%) which was higher than 520°C, decreased with the increase of degree of sulfonation. sPBI-20 ~ sPBI-60 showed no glass transition at temperatures lower than 380°C. In addition, sPBI showed low water uptake, low swelling ratio as well as excellent resistance to oxidation. But sPBI exhibited low proton conductivity because of the strong acid-base interactions between basic benzimidazole and sulfonic acid groups.

scholarly journals Evaluation of an Improved Chitosan Scaffold Cross-Linked With Polyvinyl Alcohol and Amine Coupling Through 1-Ethyl-3-(3-Dimethyl Aminopropyl)-Carbodiimide (EDC) and 2 N-Hydroxysuccinimide (NHS) for Corneal Applications

2018 ◽  
Vol 6 (9) ◽  
pp. 1561-1570 ◽  
Author(s):  
Mohamed Ali Seyed ◽  
Kavitha Vijayaraghavan
Keyword(s):  
Cross Linking ◽  
In Vitro Tests ◽  
Human Amniotic Membrane ◽  
Limbal Stem Cells ◽  
Chitosan Scaffold ◽  
Polymeric Chains ◽  
Ft Ir ◽  
Colloidal State ◽  
Corneal Blindness

BACKGROUND: Corneal blindness resulting from various medical conditions affects millions worldwide. The rapid developing tissue engineering field offers design of a scaffold with mechanical properties and transparency similar to that of the natural cornea. AIM: The present study aimed at to prepare and investigate the properties of PVA/chitosan blended scaffold by further cross-linking with 1-Ethyl-3-(3-dimethyl aminopropyl)-carbodiimide (EDC) and 2 N-Hydroxysuccinimide (NHS) as potential in vitro carrier for human limbal stem cells delivery. MATERIAL AND METHODS: Acetic acid dissolved chitosan was added to PVA solution, uniformly mixed with a homogenizer until the mixture was in a colloidal state, followed by H2SO4 and formaldehyde added and the sample was allowed to cool, subsequently it was poured into a tube and heated in an oven at 60°C for 50 minutes. Finally, samples were soaked in a cross-linking bath with EDC, NHS and NaOH in H2O/EtOH for 24 h consecutively stirred to cross-link the polymeric chains, reduce degradation. After soaking in the bath, the samples were carefully washed with 2% glycine aqueous solution several times to remove the remaining amount of cross-linkers, followed by washed with water to remove residual agents. Later the cross-linked scaffold subjected for various characterization and biological experiments. RESULTS: After viscosity measurement, the scaffold was observed by Fourier transform infrared (FT-IR). The water absorbency of PVA/Chitosan was increased 361% by swelling. Compression testing demonstrated that by increasing the amount of chitosan, the strength of the scaffold could be increased to 16×10−1 MPa. Our degradation results revealed by mass loss using equation shows that scaffold degraded gradually imply slow degradation. In vitro tests showed good cell proliferation and growth in the scaffold. Our assay results confirmed that the membrane could increase the cells adhesion and growth on the substrate. CONCLUSION: Hence, we strongly believe the use of this improved PVA/chitosan scaffold has potential to cut down the disadvantages of the human amniotic membrane (HAM) for corneal epithelium in ocular surface surgery and greater mechanical strength in future after successful experimentation with clinical trials.

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