scholarly journals Negative effect of clay fillers on the polyvinyl alcohol biodegradation: technical note

2019 ◽  
Vol 26 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Martin Jurca ◽  
Markéta Julinová ◽  
Roman Slavik
Keyword(s):  
Polyvinyl Alcohol ◽  
Technical Note ◽  
Degree Of Hydrolysis ◽  
Organic Modifier ◽  
Modified Montmorillonite ◽  
Negative Effect ◽  
Hydrolysis Of

Abstract This work focuses on polyvinyl alcohol (PVA) biodegradation in the presence of mineral clays in an aqueous aerobic environment. PVA with a degree of hydrolysis of 88% and 72% was used for the experiments. The selected group of mineral clays (nanofillers for polymers) of montmorillonite (MMT) Cloisite® Na+; organo-modified montmorillonite (OMMT) Cloisite® 20A, Cloisite® 30B; waste kaolin; kaolin; and zeolites were prepared by synthesis of the aforementioned kaolins. The level of biodegradation was measured using a respirometer, Micro-Oxymax, and evaluated according to CO2 production. Results of this test indicate a negative effect on PVA biodegradability in the presence of MMT Cloisite® Na+ and Cloisite® 30B. It has been found that PVA biodegradability in the presence of no adapted inoculum was adversely affected by the biocidal effects of the organic modifier of Cloisite® 30B. In this case, PVA 88-8 biodegradation decreased by 71% and PVA 72-10 biodegradation dropped by 58%. Furthermore, the sorption of PVA on the Cloisite® Na+ in the range of 40%–45% was demonstrated in the following research.

Hybrid Bioactive Glass-Polyvinyl Alcohol Prepared by Sol-Gel

2008 ◽  
Vol 587-588 ◽  
pp. 62-66 ◽  
Author(s):  
Hermes S. Costa ◽  
Alexandra A.P. Mansur ◽  
Edel Figueiredo Barbosa-Stancioli ◽  
Marivalda Pereira ◽  
Herman S. Mansur
Keyword(s):  
Mechanical Properties ◽  
Polyvinyl Alcohol ◽  
Bioactive Glass ◽  
Sol Gel ◽  
Degree Of Hydrolysis ◽  
Bioactive Glasses ◽  
Composite Foams ◽  
Composition Ratios ◽  
Hybrid Scaffolds ◽  
Hydrolysis Of

Bioactive glasses are materials that have been used for the repair and reconstruction of diseased bone tissues, as they exhibit direct bonding with human bone tissues. However, bioactive glasses have low mechanical properties compared to cortical and cancellous bone. On the other hand, composite materials of biodegradable polymers with inorganic bioactive glasses are of particular interest to engineered scaffolds because they often show an excellent balance between strength and toughness and usually improved characteristics compared to their individual components. Composite bioactive glass-polyvinyl alcohol foams for use as scaffolds in tissue engineering were previously developed using the sol-gel route. The goal of this work was the synthesis of composite foams modified with higher amounts of PVA. Samples were characterized by morphological and chemical analysis. The mechanical behavior of the obtained materials was also investigated. The degree of hydrolysis of PVA, concentration of PVA solution and different PVA-bioactive glass composition ratios affect the synthesis procedure. Foams with up to 80 wt% polymer content were obtained. The hybrid scaffolds obtained exhibited macroporous structure with pore size varying from 50 to 600 µm and improved mechanical properties.

Flexible polyvinyl alcohol/2-hydroxypropanoic acid films: effect of residual acetyl moieties on mechanical, thermal and antibacterial properties

2015 ◽  
Vol 35 (4) ◽  
pp. 319-327 ◽  
Author(s):  
Martina Hrabalikova ◽  
Martha Merchan ◽  
Solongo Ganbold ◽  
Vladimir Sedlarik ◽  
Pavel Valasek ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Polyvinyl Alcohol ◽  
Antibacterial Properties ◽  
Degree Of Hydrolysis ◽  
Mechanical And Thermal Properties ◽  
Hydrolysis Degree ◽  
Flexible Films ◽  
Agar Diffusion Test ◽  
Extended Interaction ◽  
Hydrolysis Of

Abstract This work ascertains the effect of the degree of hydrolysis of polyvinyl alcohol under extended interaction with 2-hydroxypropanoic acid (lactic acid). Systems based on three different types of polyvinyl alcohol matrices (of hydrolysis degree 80, 88 and 98 mol%) and lactic acid were characterized according to their physicochemical, mechanical and thermal properties. An agar diffusion test and the dilution and spread plate technique were conducted to facilitate antibacterial activity to counteract Staphylococcus aureus and Escherichia coli. A mathematical model was applied to the experimental data to estimate the antibacterial efficacy of the resultant flexible films.

Polarographic study of hydrolysis of [8-lysine]vasopressin and its derivatives with blood serum of pregnant women

1980 ◽  
Vol 45 (4) ◽  
pp. 1099-1108 ◽  
Author(s):  
Mikuláš Chavko ◽  
Michal Bartík ◽  
Evžen Kasafírek
Keyword(s):  
Blood Serum ◽  
Pregnant Women ◽  
Degree Of Hydrolysis ◽  
Polarographic Study ◽  
Ph Optimum ◽  
Lysine Vasopressin ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Vasopressin Analogues

A polarographic study of the hydrolysis of [8-lysine]vasopressin and some hormonogens of the vasopressin series with the blood serum of women in the last week of pregnancy was studied. The dependence of hydrolysis on pH (pH optimum: 7.4-7.50, substrate concentration (Km 1.2 . 10-5M), pH stability and thermal stability were determined. The rate of hydrolysis of individual vasopressin analogues decreases in the order: [8-lysine]vasopressin > Nα-glycyl-prolyl[8-lysine]-vasopressin > Nα-leucyl-[8-lysine]vasopressin > Nα-alanyl-[8-lysine]vasopressin > Nα-phenyl alanyl-[8-lysine]vasopressin > Nα-diglycyl-[8-lysine]vasopressin > Nα-prolyl-[8-lysine]vasopressin > Nα-triglycyl-[8-lysine]vasopressin > Nα-sarcosyl-glycyl-[8-lysine]vasopressin. The degree of hydrolysis gradually increases to a multiple with the length of the pregnancy in consequence of the presence of oxytocine. However, vasopressin is also hydrolysed to a small extent with the enzymes from the blood sera of non-pregnant women. Under similar analytical conditions oxytocin was not hydrolysed with the sera of non-pregnant women and therefore oxytocin is a more suitable substrate than vasopressin for polarographic determination of serum oxytocinase.

Research on Enzymatic Hydrolysis of Whey Protein

2013 ◽  
Vol 411-414 ◽  
pp. 3205-3209
Author(s):  
Fang Qian ◽  
Lei Zhao ◽  
Shu Juan Jiang ◽  
Guang Qing Mu
Keyword(s):  
Enzymatic Hydrolysis ◽  
Whey Protein ◽  
Degree Of Hydrolysis ◽  
Quadratic Regression ◽  
Orthogonal Regression ◽  
Single Factor Analysis ◽  
Verification Test ◽  
Enzyme Dosage ◽  
Hydrolysis Conditions ◽  
Hydrolysis Of

Based on single factor analysis for the enzymatic hydrolysis of whey protein, papain was selected as the optimal enzyme and its enzymatic hydrolysis conditions were optimized by the quadratic regression orthogonal rotary test. The orthogonal regression model for degree of hydrolysis (DH) to three factors including temperature (X1), time (X2), enzyme dosage (X3) was established as follow: DH=10.40+0.22X1+0.30X2+1.31X3+0.019X1X2+0.011X1X3-0.039X2X3-0.39X12-0.16X22-0.40X32, Verification test showed a DH of 11.7% was obtained at the optimal hydrolysis condition of 56.6°C, 113.8 min and enzyme 8213.7 U /g protein, which basically consisted with the model theoretical value.

scholarly journals The Influence of Surfactant (SDS) on the Adsorption Properties of Polyvinyl Alcohol and Polyethylene Glycol in an Alumina/Solution System

2002 ◽  
Vol 20 (6) ◽  
pp. 573-582 ◽  
Author(s):  
S. Chibowski ◽  
M. Paszkiewicz ◽  
M. Wiśniewska
Keyword(s):  
Polyethylene Glycol ◽  
Polyvinyl Alcohol ◽  
Adsorption Layer ◽  
Sodium Dodecyl ◽  
Adsorption Properties ◽  
Degree Of Hydrolysis ◽  
Ionic Polymers ◽  
Solution System ◽  
Molecular Weights ◽  
Polymer Surfactant

The influence of sodium dodecyl sulphate (SDS) on the adsorption properties of non-ionic polymers, i.e. polyethylene glycol (PEG) and polyvinyl alcohol (PVA), at the Al2O3/solution interface was studied. Measurements for various molecular weights and for various amounts of functional groups on the polymer macromolecules were undertaken and the results obtained discussed in the light of these variations. Studies of the mutual interactions of the polymer–surfactant system in aqueous solution were helpful in explaining the equilibria involved in the Al2O3/polymer solution system in the presence of SDS. The thickness of the adsorption layer was determined by viscometric methods and the influence of the degree of hydrolysis of PVA on the structure of the adsorption layer demonstrated.

scholarly journals Preparation of Antioxidant Enzymatic Hydrolysates from Honeybee-Collected Pollen Using Plant Enzymes

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Margarita D. Marinova ◽  
Bozhidar P. Tchorbanov
Keyword(s):  
Radical Scavenging ◽  
Total Phenolic ◽  
Degree Of Hydrolysis ◽  
Enzymatic Hydrolysates ◽  
Phenolic Contents ◽  
Scavenging Capacity ◽  
Plant Enzymes ◽  
Hydrolysis Of ◽  
Proline Iminopeptidase ◽  
Dietary Food

Enzymatic hydrolysates of honeybee-collected pollen were prepared using food-grade proteinase and aminopeptidases entirely of plant origin. Bromelain from pineapple stem was applied (8 mAU/g substrate) in the first hydrolysis stage. Aminopeptidase (0.05 U/g substrate) and proline iminopeptidase (0.03 U/g substrate) from cabbage leaves (Brassica oleracea var. capitata), and aminopeptidase (0.2 U/g substrate) from chick-pea cotyledons (Cicer arietinum L.) were involved in the additional hydrolysis of the peptide mixtures. The degree of hydrolysis (DH), total phenolic contents, and protein contents of these hydrolysates were as follows: DH (about 20–28%), total phenolics (15.3–27.2 μg/mg sample powder), and proteins (162.7–242.8 μg/mg sample powder), respectively. The hydrolysates possessed high antiradical scavenging activity determined with DPPH (42–46% inhibition). The prepared hydrolysates of bee-collected flower pollen may be regarded as effective natural and functional dietary food supplements due to their remarkable content of polyphenol substances and significant radical-scavenging capacity with special regard to their nutritional-physiological implications.

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