Water Properties in a Novel Thermoswelling Poly(vinyl alcohol) Derivative Hydrogel as Studied by Nuclear Magnetic Resonance and Fourier Transform Infrared Spectroscopy

Langmuir ◽  
2010 ◽  
Vol 26 (16) ◽  
pp. 13607-13613 ◽  
Author(s):  
Jianquan Wang ◽  
Mitsuru Satoh
2010 ◽  
Vol 129-131 ◽  
pp. 837-841 ◽  
Author(s):  
Sheng Hua Lv ◽  
Yan Fen Ma ◽  
Rui Gong ◽  
Xiao Liang Yan ◽  
Ming Ming Hou

Degraded starch was reacted with 4-phenolsuflonate (PHS) in water in the presence of horseradish peroxidase (HRP) catalyst/H2O2/acetylacetone (ACAC) to give starch and PHS graft copolymers. The structure and properties of the graft copolymer are characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR). The retanned leather exhibits excellent increased thickness and softness, good dyeing ability and eligible mechanical properties.


Author(s):  
Zheng Peng ◽  
Ling Xue Kong ◽  
Si Dong Li

The thermooxidative degradation of poly (vinyl alcohol)/silica (PVA/SiO2) nanocomposite prepared with self-assembly monolayer (SAM) technique is investigated by using a thermogravimetry (TG) and Fourier transform infrared spectroscopy coupled thermogravimetry (FTIR/TG). The results show that although the thermooxidative degradation process of prepared nanocomposite is similar to that of the pure PVA, its thermooxidative stability has been greatly improved.


2021 ◽  
Vol 17 (1) ◽  
pp. 132
Author(s):  
Haiyul Fadhli ◽  
Nur Fitria Rohmatul Ummah ◽  
Noveri Rahmawati

<p>Kulit batang <em>Bauhinia semibifida </em>Roxb. telah lama digunakan sebagai obat tradisional oleh masyarakat Melayu Lingga, Kepulauan Riau. Penelitian ini bertujuan untuk mengisolasi dan menguji aktivitas antioksidan senyawa metabolit sekunder dari ekstrak metanol kulit batang <em>B. semibifida </em>Roxb. Tiga isolat murni berupa satu senyawa alkaloid (BR1) dan dua senyawa flavonoid (BR2 dan BR3) telah berhasil diisolasi dengan cara ekstraksi menggunakan metode maserasi dan dilanjutkan fraksinasi dengan metode kromatografi kolom. Uji aktivitas antioksidan dilakukan terhadap isolat dengan metode 2,2 difenil-1-pikrilhidrazil (DPPH). Senyawa isolat BR1 menunjukan IC<sub>50 </sub>&gt;1000 µg/mL dikategorikan tidak aktif sebagai antioksidan, sedangkan senyawa isolat BR2 dan BR3 menunjukan IC<sub>50</sub> 2,92 µg/mL dan 4,39 µg/mL dikategorikan sangat kuat sebagai antioksidan jika dibandingkan dengan vitamin C sebagai kontrol. Berdasarkan evaluasi aktivitas antioksidan senyawa BR2 adalah senyawa pilihan yang dilanjutkan identifikasi dengan spektroskopi <em>Fourier-Transform Infrared Spectroscopy </em>(<em>FTIR</em>) dan <em>Proton Nuclear Magnetic Resonance</em> (<sup>1</sup>H-NMR) sehingga diduga senyawa isolat memiliki struktur dasar senyawa flavonoid.</p><p><strong>Isolation of Secondary Metabolite Compounds of Methanolic Extract of Steam Bark <em>Bauhinia semibifida</em> Roxb. and Their Antioxidant Activites</strong>. Stem bark of <em>Bauhinia semibifida</em> Roxb. has been long consumed as a medicinal herb by Lingga Malaya Ethnic. Therefore, this research aimed to isolate and examines the antioxidant activity of secondary metabolites from methanol extract of stembark of <em>Bauhinia semibifida</em> Roxb. Three pure compounds which are an alkaloid (BR1) and two flavonoids (BR2 and BR3) have been isolated by extraction using maceration method followed by fractionation using column chromatography method. Antioxidant activity assay was carried out by 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) method. Compound BR1 showed IC<sub>50</sub> &gt;1000 µg/mL categorized as inactive as an antioxidant, while compounds BR2 and BR3 showed IC<sub>50</sub> 2.92 µg/mL and 4.394 µg/mL, respectively, categorized as very strong as an antioxidant when compared to vitamin C as a control. Based on the evaluation of the antioxidant activity, the BR2 was selected compound and continued to identification by <em>Fourier-Transform Infrared Spectroscopy </em>(<em>FTIR</em>) and <em>Proton Nuclear Magnetic Resonance</em> (<sup>1</sup>H-NMR) spectroscopy so that the isolate has the basic structure of flavonoid compound.</p>


2019 ◽  
Vol 9 (3) ◽  
pp. 371-380
Author(s):  
Malihe Keramat ◽  
Sara Esteghlal ◽  
Javad Safari ◽  
Mohammad-Taghi Golmakani ◽  
Mohammadreza Khalesi

Introduction: In this study, Persian gum/poly (vinyl alcohol) nanofiber and whey protein isolate/ poly (vinyl alcohol) nanofiber were fabricated using electrospinning system. Materials & Methods: The effects of supplementation of Oliveria decumbens Vent. essential oil on the physicochemical and biological characteristics of the nanofibers were investigated by applying the techniques including antioxidant activity measurement, scanning electron microscopy, viscosity and conductivity tests, and fourier-transform infrared spectroscopy. Results: The results showed that the incorporation of 1% Oliveria decumbens Vent. essential oil to the polymer dispersions causes the formation of thin nanofibers with the least beads. Both types of nanofibers containing essential oil exhibited significant radical scavenging activities up to 76.82±0.36% and 61.09±0.13% for whey protein isolate/poly (vinyl alcohol) nanofiber and Persian gum/poly (vinyl alcohol) nanofiber, respectively. Conclusion: The results of fourier-transform infrared spectroscopy proposed the structurally incorporation of the essential oil into nanofibers to be considered as novel coating film for active packaging technology.


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