scholarly journals Effect of Microfibrillated Cellulose on Microstructure and Properties of Poly(vinyl alcohol) Foams

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 813 ◽  
Author(s):  
Gennaro Gentile ◽  
Mariacristina Cocca ◽  
Roberto Avolio ◽  
Maria Errico ◽  
Maurizio Avella
Keyword(s):  
Vinyl Alcohol ◽  
Cell Shape ◽  
High Speed ◽  
Microfibrillated Cellulose ◽  
Poly Vinyl Alcohol ◽  
Infrared Analysis ◽  
Cellulose Content ◽  
Scanning Calorimetry ◽  
Hydrogen Bond Interaction ◽  
The Matrix

Poly(vinyl alcohol) foams, containing different amounts of microfibrillated cellulose, were prepared through an eco-friendly procedure based on high-speed mixing and freeze-drying. The effect of filler amount on cell shape and regularity was studied by scanning electron microscopy (SEM) and the evolution of the microstructure was assessed through dynamic cryo-SEM. Fourier Transformed Infrared Analysis and Differential Scanning Calorimetry measurements revealed the presence of hydrogen bond interaction among cellulosic filler and the matrix. The modulus and compression deflection of neat PVA were significantly improved by increasing the amount of microfibrillated cellulose content with respect to foams realised with pulp cellulose fibers.

Characterization of cellulose nanocrystals extracted from El Diss and El Retma local plants and their dispersion in poly(vinyl alcohol-co-ethylene) matrix in the presence of borax

2020 ◽  
pp. 096739112091087
Author(s):  
Lilia Benchikh ◽  
Abdelhafid Merzouki ◽  
Yves Grohens ◽  
Melia Guessoum ◽  
Isabelle Pillin
Keyword(s):  
Water Absorption ◽  
North Africa ◽  
Cellulose Nanocrystals ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
The Matrix ◽  
Dsc Analyses ◽  
Local Plants

This study aims to investigate the potential of two local fibers, namely El Diss and El Retma, which are abundant in the mountains of North Africa (Sétif, Algeria), to provide cellulose nanocrystals (CNCs). Then, the isolated CNCs from El Diss were used as a reinforcement for a poly(vinyl alcohol-co-ethylene) matrix (EVOH) in the absence and in the presence of borax which was added to improve the interactions between the CNCs and the matrix. The extracted CNCs from both El Diss (CNCD) and El Retma (CNCR) were characterized by Zeta-sizer analysis using dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electronic microscopy. Also, untreated EVOH/CNCD nanocomposites and borax-treated EVOH/CNCD/BOR have been characterized using FTIR, differential scanning calorimetry (DSC) analyses, and by the study of their water absorption behavior. The DLS analysis provided the transversal length of the particles and showed that the surface of the obtained CNCs is negatively charged due to the presence of sulfated ions. Also, FTIR results confirmed the elimination of extra cellulosic substances, whereas TGA proved that the degradation of CNCs occurs at relatively lower temperatures compared with the neat fibers. The incorporation of borax to EVOH/CNCD nanocomposites showed its efficiency in improving the interactions at the interface between EVOH and the CNCD, which significantly affected the material’s thermal properties as concluded from DSC results and their water absorption behavior.

Preparation and properties of poly (vinyl alcohol)/sodium caseinate blend films crosslinked with glutaraldehyde and glyoxal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bedriye Ucpinar Durmaz ◽  
Ayse Aytac
Keyword(s):  
Water Vapor ◽  
Vinyl Alcohol ◽  
Sodium Caseinate ◽  
Barrier Properties ◽  
Poly Vinyl Alcohol ◽  
Infrared Analysis ◽  
Crosslinking Reaction ◽  
Water Contact ◽  
Casting Technique ◽  
Water Vapor Barrier

Abstract Bio-based films containing poly (vinyl alcohol)/casein have poor mechanical and water vapor barrier properties that limit their use in packaging application. Some properties such as water resistance and tensile strength can be increased by the cross-linking process. For this reason, poly(vinyl alcohol)/sodium caseinate (PVA/SC) blends were crosslinked by adding glutaraldehyde (GLA) and glyoxal (GL) at different ratios in this work. The films were prepared by solution casting technique. Fourier transform infrared analysis (FTIR) confirmed the crosslinking reaction between the components. As a result of the crosslinking, the thicknesses, water vapor barrier properties and water contact angle values of the films have increased. The total soluble matters (TSM) of PVA/SC film decreased with increasing amounts of crosslinkers and GLA crosslinked films exhibited lower TSM. The addition of GLA and GL resulted in more strengthened films as verified by the tensile test. On the other hand, GLA crosslinked films were more flexible than un-crosslinked and GL crosslinked PVA/SC films. The hydrophilic PVA/SC film became more hydrophobic with the increasing amounts of crosslinkers. With the crosslinking, the PVA/SC film became more thermally stable. In conclusion, the crosslinked PVA/SC films were obtained with suitable properties for packaging applications.

scholarly journals PREPARATION AND CHARACTERIZATION OF POLY (VINYL ALCOHOL)–POLY (VINYL PYRROLIDONE) MUCOADHESIVE BUCCAL PATCHES FOR DELIVERY OF LIDOCAINE HCL

2018 ◽  
Vol 10 (1) ◽  
pp. 115 ◽  
Author(s):  
Napaphak Jaipakdee ◽  
Thaned Pongjanyakul ◽  
Ekapol Limpongsa
Keyword(s):  
Vinyl Alcohol ◽  
Vinyl Pyrrolidone ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Casting Technique ◽  
In Vitro Permeation ◽  
Lidocaine Hcl ◽  
Poly Vinyl Pyrrolidone

Objective: The objectives of this study were to prepare and characterize a buccal mucoadhesive patch using poly (vinyl alcohol) (PVA), poly (vinyl pyrrolidone) (PVP) as a mucoadhesive matrix, Eudragit S100 as a backing layer, and lidocaine HCl as a model drug.Methods: Lidocaine HCl buccal patches were prepared using double casting technique. Molecular interactions in the polymer matrices were studied using attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and X-ray diffractometry. Mechanical and mucoadhesive properties were measured using texture analyzer. In vitro permeation of lidocaine HCl from the patch was conducted using Franz diffusion cell.Results: Both of the free and lidocaine HCl patches were smooth and transparent, with good flexibility and strength. ATR-FTIR, DSC and X-ray diffractometry studies confirmed the interaction of PVA and PVP. Mechanical properties of matrices containing 60% PVP were significantly lower than those containing 20% PVP (*P<0.05). Mucoadhesive properties had a tendency to decrease with the concentration of PVP in the patch. The patch containing 60% PVP had significantly lower muco-adhesiveness than those containing 20% PVP (*P<0.05). In vitro permeation revealed that the pattern of lidocaine HCl permeation started with an initial fast permeation, followed by a slower permeation rate. The initial permeation fluxes follow the zero-order model of which rate was not affected by the PVP concentrations in the PVA/PVP matrix.Conclusion: Mucoadhesive buccal patches fabricated with PVA/PVP were successfully prepared. Incorporation of PVP in PVA/PVP matrix affected the strength of polymeric matrix and mucoadhesive property of patches.

Physical and mechanical investigation for polyionic liquid/poly(vinyl alcohol) blends

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nehad N. Rozik ◽  
Emad Saad Shafik ◽  
Salwa L. Abd-El-Messieh
Keyword(s):  
Mechanical Properties ◽  
Vinyl Alcohol ◽  
Green Manufacturing ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Content Ratio ◽  
Mechanical Investigation ◽  
Manufacturing Techniques ◽  
Polyionic Liquid

Purpose This study aims to polymerize of 1-butyl-3-vinylimidazolium bromide (PIL). PIL was embedded into PVA with a different content ratio by casting method. This research also deals with the effect of adding PIL in different proportions to PVA on the electrical and mechanical properties properties in addition to the morphology of the prepared samples. Design/methodology/approach 1-Butyl-3-vinylimidazolium bromide was synthesized through quaternization and free radical polymerization. The resulting polymer was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis and differential scanning calorimetry. In addition to the morphology of PVA, PVA/PIL was investigated by polarizing microscope. Also, the effect of PIL content on the electrical and mechanical properties was evaluated. Findings The findings of this study might lead to new applications for PVA and PILs in electrical and dielectrics. The mechanical results revealed that the tensile strength increased slightly with increasing polyionic liquid (PIL) content and decreased above 10% PIL. While the elongation at break increased significantly with increasing PIL content and begin to decrease above 10% PIL. Also, the electrical property of the poly(vinyl alcohol) (PVA)/PIL blends was improved because of the strong plasticizing effect of PIL. Also, the electrical conductivity of these polymer electrolytes is greatly increased. This indicates that the imidazolium-based PIL has an effective approach that leads to an increase in the conductivity of the polymer. The PILs/PVA design will not only enrich the chemical structure but also will contribute to green manufacturing techniques and a processing methodology that enables green membrane manufacture. Originality/value This study contributes to green manufacturing techniques and a processing methodology that enables “green” membrane manufacture.

scholarly journals Biocomposites from Rice Straw Nanofibers: Morphology, Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2138 ◽  
Author(s):  
José Carlos Alcántara ◽  
Israel González ◽  
M. Mercè Pareta ◽  
Fabiola Vilaseca
Keyword(s):  
Rice Straw ◽  
Mechanical Performance ◽  
Cellulose Nanofibers ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Nanocomposite Films ◽  
Chemical Extraction ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
The Matrix

Agricultural residues are major potential resources for biomass and for material production. In this work, rice straw residues were used to isolate cellulose nanofibers of different degree of oxidation. Firstly, bleached rice fibers were produced from the rice straw residues following chemical extraction and bleaching processes. Oxidation of rice fibers mediated by radical 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) at pH 10 was then applied to extract rice cellulose nanofibers, with diameters of 3–11 nm from morphological analysis. The strengthening capacity of rice nanofibers was tested by casting nanocomposite films with poly(vinyl alcohol) polymer. The same formulations with eucalyptus nanofibers were produced as comparison. Their thermal and mechanical performance was evaluated using thermogravimetry, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. The glass transition of nanocomposites was shifted to higher temperatures with respect to the pure polymer by the addition of rice cellulose nanofibers. Rice nanofibers also acted as a nucleating agent for the polymer matrix. More flexible eucalyptus nanofibers did not show these two phenomena on the matrix. Instead, both types of nanofibers gave similar stiffening (as Young’s modulus) to the matrix reinforced up to 5 wt.%. The ultimate tensile strength of nanocomposite films revealed significant enhancing capacity for rice nanofibers, although this effect was somehow higher for eucalyptus nanofibers.

Formation of Poly(vinyl alcohol)/SWNTs Fibers with Hierarchical Structure under High-Speed Shear Flow

2020 ◽  
Vol 21 (5) ◽  
pp. 1078-1085
Author(s):  
Xia Wang ◽  
Changcun Wu ◽  
Jun Sun ◽  
Chuanxiang Qin ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Shear Flow ◽  
Hierarchical Structure ◽  
Vinyl Alcohol ◽  
High Speed ◽  
Poly Vinyl Alcohol

Foaming Poly(vinyl alcohol)/Microfibrillated Cellulose Composites with CO2 and Water as Co-blowing Agents

2014 ◽  
Vol 53 (30) ◽  
pp. 11962-11972 ◽  
Author(s):  
Na Zhao ◽  
Lun Howe Mark ◽  
Changwei Zhu ◽  
Chul B. Park ◽  
Qian Li ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Microfibrillated Cellulose ◽  
Poly Vinyl Alcohol ◽  
Blowing Agents ◽  
Cellulose Composites
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