Preparation and characterization of waterborne polyurethane/clay nanocomposite: Effect on water vapor permeability

2008 ◽  
Vol 110 (6) ◽  
pp. 3697-3705 ◽  
Author(s):  
Mohammad Mizanur Rahman ◽  
Han-Do Kim ◽  
Won-Ki Lee
Author(s):  
Nan Chen ◽  
Yanchun Li ◽  
Jianbo Qu ◽  
Jian-Yong Wang

The traditional thick coating on split leather does not have the ability to breathe like full grain leather.  The air and water vapor permeabilities of full grain leather are well known properties due to its fiber woven structure. Simulating the fiber morphology and weaving structure of the dermis or grain layer is very important to construct a top surface layer for split leather. In this paper, a PU (polyurethane) foam layer is put first on the split to enhance the adhesion of a second application of a superfine fibrous PU resin. This foam uses well-known waterborne polyurethane foaming technology. This dried foam has good breathability because of high porosity. A superfine fiber membrane is next put atop of the foam layer by using an electro-spun polyurethane resin. This second resin imitates collagen fibers in the network structure of the leathers’ grain layer. Thus, this resultant electrospun fiber biomimetics membrane simulated the grain layer of natural leather. SEM showed the morphology and structure of this electrospun fiber biomimetic membrane to be like that of the grain layer of natural leather. The porosity and apparent density were basically the same as the grain of leather, which were 63.65% and 583.878 kg/m3 respectively. The air and water vapor permeability of the biomimetics membrane were also as high as 2250 mL·cm-2·h-1 and 8753.02 μg·cm-2·h-1 respectively. Therefore, the biomimetics membrane largely restored the ability to breathe of split leather. Thus, this method simulates the performance and structure of full grain leather and is a novel method for industrial production


Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 384
Author(s):  
Juan Tirado-Gallegos ◽  
Paul Zamudio-Flores ◽  
José Ornelas-Paz ◽  
Claudio Rios-Velasco ◽  
Guadalupe Olivas Orozco ◽  
...  

Apple starch films were obtained from apples harvested at 60, 70, 80 and 90 days after full bloom (DAFB). Mechanical properties and water vapor permeability (WVP) were evaluated. The apple starch films at 70 DAFB presented higher values in the variables of tensile strength (8.12 MPa), elastic modulus (3.10 MPa) and lower values of water vapor permeability (6.77 × 10−11 g m−1 s−1 Pa−1) than apple starch films from apples harvested at 60, 80 and 90 DAFB. Therefore, these films were chosen to continue the study incorporating ellagic acid (EA). The EA was added at three concentrations [0.02% (FILM-EA0.02%), 0.05% (FILM-EA0.05%) and 0.1% (FILM-EA0.1%) w/w] and compared with the apple starch films without EA (FILM-Control). The films were characterized by their physicochemical, optical, morphological and mechanical properties. Their thermal stability and antioxidant capacity were also evaluated. The FILM-Control and FILM-EA0.02% showed a uniform surface, while FILM-EA0.05% and FILM-EA0.1% showed a rough surface and insoluble EA particles. Compared to FILM-Control, EA modified the values of tensile strength, elasticity modulus and elongation at break. The antioxidant capacity increased as EA concentration did. EA incorporation allowed obtaining films with higher antioxidant capacity, capable of blocking UV light with better mechanical properties than film without EA.


2014 ◽  
Vol 1051 ◽  
pp. 117-120
Author(s):  
Wei Ling Wang ◽  
Wei Dong Yu

Waterborne polyurethane and chitosan were mixed in different volume ratio, and finished on the cotton of plasma pre-treatment and non-plasma pre-treatment to discuss the influence of plasma pretreatment on the properties of the fabric. Firstly, the mixed aqueous emulsion was made into film and analyzed by FTIR. Secondly, the relationship between the properties of whiteness, wrinkle recovery performance and water vapor permeability of the fabric that finished by the only blended solution and the mixed ratio was studied. Finally, the property changes between the pretreatment with and without plasma was compared. The results showed that, the blended film not only had both polyurethane and chitosan characteristic peaks, but also generated the new characteristic peaks; the three properties of the fabric that finished by the only blended solution changed with the mixed ratio; the plasma pre-treatment would increase the fabric’s whiteness, decrease wrinkle recovery performance, but the water vapor permeability would improve obviously.


2021 ◽  
Author(s):  
Aritra Sinha

Abstract This study focuses on the development and characterization of a novel biodegradable edible film made from soy protein isolate enriched with alginate-glycyrrhizin nanogel(GL-ALG NGP). Nanoparticles of particle sizes below 100 nm were synthesized using glycyrrhizin(GL), calcium chloride and, sodium alginate(SA) through the reverse micro-emulsion/internal gelation method. Soy protein isolate (SPI) based films were prepared by a simple casting procedure by incorporating GL-ALG NGPs in SPI solution in different ratios of (SPI: GL-ALG NGPs) 5:0, 5:1, 2:1, 1:1, and 1:1.5. Glycerol was used as a plasticizer in the film-forming solution. The effects of the proportions of GL-ALG NGPs addition on the thickness, mechanical properties, water vapor permeability, UV barrier performance, antioxidant activity, and antimicrobial property of the obtained films were studied. The GL-ALG NGPs were analyzed using Dynamic Light Scattering. Microstructural studies of obtained films were performed using Scanning Electron microscopy. Results show incorporation of GL-ALG NGPs in soy protein-alginate complex produced smoother, compact, and more continuous matrices as compared to pure SPI films. The test results indicated that blending of SPI with GL-ALG NGPs in the ratio 1:1 increased tensile strength of obtained films by 185%, reduced water solubility to 23.59%, and water vapor permeability to 0.3087 g-mm/m2-d-kPa. Obtained films exhibited good UV barrier performance, antioxidant activity and inhibited the growth of E. coli, S. aureus, Enterobacter sakazakii, and A. niger. So, soy protein isolate-based films enriched with GL-ALG NGPs are active biodegradable edible films that can be used to extend the shelf life of food products.


2020 ◽  
Vol 12 (8) ◽  
pp. 1213-1224
Author(s):  
Ya-Yu Li ◽  
Wei-Wen Jing ◽  
Jian-Hua Wang ◽  
Jun-Fang Li

Cellulose nanocrystals (CNCs) are promising polymer reinforcements owning to their biocompatibility and high elastic modulus, low density, nano size, and inherent biocompatibility. The waterborne polyurethane-cellulose nanocrystals (WPU-CNCs) nanocomposite films were prepared using the conventional solvent casting technique over a whole composition. The mechanical performance, optical transmittance, amphiphilicity, water vapor permeability (WVP), and oxygen permeability (OP) of these WPU-CNCs films were evaluated. The incorporation of CNCs into WPU resulted in a significant enhancement of Young's modulus and tensile strength. The WVP of nanocomposite films had a lowest value at CNCs content of 50 wt.%. Upon the increase of CNCs content from 0 to 90 wt.%, the transmission path of oxygen molecular through the nanocomposite films became more tortuous, leading to drastic decrease in the OP. These WPU-CNCs nanocomposite films with high strength, optical transparency, water vapor and oxygen barrier properties have the potential applications in biomedical, furniture coating, and food packaging fields.


2020 ◽  
Vol 25 (2) ◽  
pp. 81
Author(s):  
Eti Indarti ◽  
Arisa Sri Marlita ◽  
Zaidiyah Zaidiyah

Production of Polylactic acid (PLA)/Polycaprolactone (PCL) bionanocomposite films with various ratios was done by adding nanocrystalline celullose (NCC) from oil palm empty fruit bunches (OPEFB) as a filler. The aim of the research was to find out the effect of PLA/PCL ratio on film thickness, transparency of bionanocomposite films and water vapor permeability or WVP of the film bionanocomposite with addition of the 3% NCC.  The PLA/PCL ratio are 1.0/0.0; 0.8/0.2; 0.6/0.4; 0.5/0.5; 0.4/0.6; 0.2/0.8; and 0.0/1.0, prepared with solvent casting method. Characterization of PLA/PCL bionanocomposites film performed was thickness, transparency test and water vapor permeability (WVP) test. The thickness of bionanocomposites film produced were around are about 0.036-0.053 mm, results show that the lower PLA/PCL ratio the thicker film obtained. The highest value of film transparency was obtained at a ratio of 1.0 / 0.0 (81.4% at a wavelength of 550 nm), the smaller the PLA / PCL ratio, the lower the value of transparency. The WVP value of PLA/PCL bionanocomposite films gives a lower value than the WVP value of pure PLA film and pure PCL film. The best WVP was obtained at a PLA/PCL ratio of 0.8/0.2 which was 1.49x10-16kg.m/(m2.s.Pa).  


Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1339
Author(s):  
Enrica Musella ◽  
Ismael Chahed el Ouazzani ◽  
Ana Rita Mendes ◽  
Cesare Rovera ◽  
Stefano Farris ◽  
...  

Chitosan films with olive leaf extract (OLE) incorporated at different concentrations were characterized regarding their antimicrobial, antioxidant and some relevant physical properties (i.e., solubility, water vapor permeability, and tensile properties). Results indicate that the active films have substantial antimicrobial activity against Listeria monocytogenes and Campylobacter jejuni mostly extending the microorganisms lag phase. A lower level of inhibition was found in the case of Escherichia coli. However, the OLE seems not to improve the intrinsic antimicrobial properties of the chitosan itself, except for C. jejuni. These results were confirmed with in situ testing using chicken. The chitosan films with OLE exhibited antioxidant activity, increasing with the OLE concentration, from 0.04 to 0.15 g/L ascorbic acid equivalents, corresponding to films with 10%–30% OLE relative to the chitosan. Chitosan films loaded with OLE exhibited a higher solubility in food simulants and a reduced permeability against water vapor. Overall, the combination of OLE and chitosan allows to obtain a promising active bio-based packaging solution for addressing safety and quality issues.


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