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.

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.

Super toughened renewable poly(lactic acid) based ternary blends system: effect of degree of hydrolysis of ethylene vinyl acetate on impact and thermal properties

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72681-72691 ◽  
Author(s):  
V. H. Sangeetha ◽  
Ravi babu Valapa ◽  
S. K. Nayak ◽  
T. O. Varghese
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Poly Lactic Acid ◽  
Ternary Blend ◽  
Degree Of Hydrolysis ◽  
Ternary Blends ◽  
System Effect ◽  
Hydrolysis Of

Effect of hydrolysed EVA on PLA ternary blend systems.

Polyvinyl alcohol/chitosan/montmorillonite nanocomposites preparation by freeze/thaw cycles and characterization

2014 ◽  
Vol 22 (2) ◽  
pp. 75-96 ◽  
Author(s):  
Elena Părpăriţă ◽  
Cătălina N. Cheaburu ◽  
Silvia Florica Pațachia ◽  
Cornelia Vasile
Keyword(s):  
Polyvinyl Alcohol ◽  
Near Infrared ◽  
Antibacterial Properties ◽  
Thermal Characteristics ◽  
Chemical Imaging ◽  
Inorganic Nanoparticles ◽  
Mechanical And Thermal Properties ◽  
Freezing And Thawing ◽  
Promising Alternative ◽  
Freeze Thaw

Abstract Polyvinyl alcohol (PVA) and chitosan (CS) based hydrogels are often chosen to obtain hydrogels as being considered non-toxic for human body. The present study aims the preparation and physical chemical characterisation of hydrogels based PVA and CS by using an environmental friendly method i.e. freeze/thaw. In this method the only parameters affecting the hydrogels’ properties is the PVA concentration in solution, time and number of cycles of freezing / thawing. Repeated freezing and thawing cycles resulted in production of a highly elastic polyvinyl alcohol hydrogel with higher degree of crystallization. Adding chitosan in polyvinyl alcohol hydrogel is giving to the newly formed material, biocompatibility and antibacterial properties due to the free amino groups of chitosan. Higher mechanical and thermal characteristics of PVA/CS based hydrogels were obtained by addition of a small amount of inorganic nanoparticles (montmorillonite clay, C30B) into the matrix (i.e. 1%). Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), near-infrared chemical imaging spectroscopy (NI-CI), X-ray diffraction (XRD), thermogravimetric analysis (TG), swelling and rheological measurements were used to characterize the polyvinyl alcohol/chitosan/montmorillonite properties. The swelling degree increased with decreasing chitosan content in hydrogels and the variation is opposite in nanocomposites, decreasing after introducing the nanoclay. The swelling behaviour was influenced by the presence of the nanoparticles. The plasticizer effect of the nanoparticles was reflected by obtaining a more compact hydrogel network with higher mechanical and thermal properties. The proposed materials can be a promising alternative in biomedical applications

scholarly journals Enzymatic hydrolysis (pepsin) assisted by ultrasound in the functional Properties of hydrolyzates from different collagens

2018 ◽  
Vol 48 (3) ◽  
Author(s):  
Alessandra Roseline Vidal ◽  
Carine da Fonseca Cechin ◽  
Rogério Luis Cansian ◽  
Renius de Oliveira Mello ◽  
Michele Mantelli Schmidt ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Enzymatic Hydrolysis ◽  
Functional Properties ◽  
Degree Of Hydrolysis ◽  
Gram Negative Bacteria ◽  
Gram Positive Bacteria ◽  
Hydrolysis Degree ◽  
Lower Protein ◽  
Hydrolysis Of ◽  
Fiber Sample

ABSTRACT: Enzymatic hydrolysis (pepsin) assisted with or without ultrasound in the functional properties of hydrolyzates from different collagens were analyzed. Degree of hydrolysis, antioxidant activity (DPPH) and antimicrobial activity (MIC) were assessed. The treatment that resulted in greater antioxidant activity for the fiber sample was with the use of 4% of enzyme and concomitant ultrasound (40.7%), leading to a degree of hydrolysis of 21.7%. For the powdered fiber sample the hydrolysis treatment with use of 4% of enzyme resulted in lower protein content (6.97mg/mL), higher degree of hydrolysis (19.9%) and greater antioxidant activity (38.6%). The hydrolyzates showed inhibitory capacity against gram-negative bacteria Salmonella choleraesuis and gram-positive bacteria Staphylococcus aureus. It can be concluded that enzymatic hydrolysis concomitant or not with the use of ultrasound increased the functionality of the fiber and powdered fiber samples, for the other samples its use as supplementary treatment was not productive, due to the worse results of antioxidant activity (DPPH) reported. However, it provided greater hydrolysis degree.

The Effects of Strains Inoculation Amount on the Degree of Hydrolysis of Fermented Tilapia Scraps Mixed with Soybean Meal

2013 ◽  
Vol 781-784 ◽  
pp. 711-716 ◽  
Author(s):  
Yun Wang ◽  
Peng Zhi Hong ◽  
Ping Yang ◽  
Huan Ming Liu ◽  
Wei Hong ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Soybean Meal ◽  
High Performance ◽  
Raw Material ◽  
Size Exclusion ◽  
Degree Of Hydrolysis ◽  
Hydrolysis Degree ◽  
Orthogonal Experiments

Mixed strains were used to increase the hydrolysis degree of materials during fermenting. Tilapia scraps and soybean meal were mixed by 1:1 and Bacillus subtilis, yeast and lactic acid bacteria were added. The optimal quantity of strains was determined by hydrolysis degree through single factor experiments and orthogonal experiments. After all, The molecular weight distribution of raw material and products was analyzed by high performance size exclusion chromatography (HPSEC). The results showed that the optimum conditions were as follows: the inoculation amount of Bacillus subtilis, the yeast and the lactic acid bacteria was 0.6‰, 0.06‰ and 0.0015‰, respectively. And the hydrolysis degree of materials increased from 10.3% to 27.3%. The hydrolysis degree of materials increased markedly by adding mixed strains.

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.

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