Elucidating the Relationship Between Structure and Property of Waterborne Polyurethane-Cellulose Nanocrystals Nanocomposite Films

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.

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2279
Author(s):  
Darrel S. Naidu ◽  
Maya J. John

In this study, xylan–alginate-based films were reinforced with nanoclays (bentonite or halloysite) by the solvent casting technique. The effect of the nanoclay loadings (1–5 wt %) on various properties—mechanical, optical, thermal, solubility, water sorption, and water vapor permeability (WVP)—of the xylan–alginate films were examined for their application as food packaging materials. A 5 wt % loading of either bentonite or halloysite resulted in a 49% decrease of the WVP due to the impermeable nature of the silicate layers that make up both bentonite and halloysite. Thermal stability and solubility of the nanocomposite films were not significantly influenced by the presence of the nanoclays, whereas the optical properties were significantly improved when compared to neat xylan–alginate blend. In general, films reinforced with bentonite exhibited superior mechanical and optical properties when compared to both halloysite-based nanocomposite and neat films.


2013 ◽  
Vol 469 ◽  
pp. 156-161 ◽  
Author(s):  
Hong Pan ◽  
Dan Xu ◽  
Qin Liu ◽  
Hui Qing Ren ◽  
Min Zhou

Starch-based nanocomposite films were fabricated by the incorporation of different amounts of nanodiamond (ND) particles. These films were characterized by SEM, FT-IR, TGA, tensile testing and water vapor permeability measurement. It was observed that at low loadings, ND dispersed well in starch matrix. However, as the loading amount increased, aggregates as large as several micrometers appeared. The physical blending of ND with starch didnt change the thermal degradation mechanisms of starch films, only increased the char residues. As the ND loading increased, the tensile strength of composite films increased but the elongation at break decreased. However, the water vapor permeability increased as the loading of ND increased due to the increased microspores in films. With further modifications, ND may be considered as a novel of biocompatible nanofillers for reinforcement of biopolymers for food packaging applications.


2021 ◽  
Author(s):  
Josemar Gonçalves de Oliveira Filho ◽  
Beatriz Regina Albiero ◽  
Lavínia Cipriano ◽  
Carmen Cris de Oliveira Nobre Bezerra ◽  
Fernanda Campos Alencar Oldoni ◽  
...  

Abstract Arrowroot starch (AA)-based films incorporated with a carnauba wax nanoemulsion (CWN), cellulose nanocrystals (CNCs), and essential oils (EOs) from Mentha spicata (MEO) and Cymbopogon martinii (CEO) were produced using the casting technique and then characterized in terms of their water barrier, tensile, thermal, optical, and microstructural properties and in vitro antifungal activity against Rhizopus stolonifer and Botrytis cinerea. Whereas the incorporation of CNCs decreased the moisture content and water vapor permeability of the AA/CWN/CNC film, the additional incorporation of either EO decreased the transparency and affected the microstructure of the AA/CWN/CNC/EO nanocomposites. MEO and CEO incorporation improved the thermal stability of the films and provided excellent protection against fruit-spoiling fungi. Because of their excellent barrier properties against fungal growth, water vapor permeability, and ultraviolet and visible light, these AA/CWN/CNC/EO films have promising potential for application as active food packaging or coating materials.


2021 ◽  
Author(s):  
Ya-Yu Li ◽  
Yan-Ru Bai ◽  
Xin-Qian Zhang ◽  
Xin Liu ◽  
Zhen Dai ◽  
...  

Abstract Three kinds of cellulose nanocrystals (CNCs) were added into waterborne polyurethane (WPU), and nanocomposite films were prepared by solution casting method. The influence of different ionic function groups on microstructure and properties of composite films was investigated, and interaction mechanism between these two components was analyzed. Results show that thermal stability of these composite films are improved by 15℃. Compared with sulfated CNCs (SCNCs) and TEMPO oxidized CNCs (TOCNCs), FE-SEM results prove that cationized CNCs (CaCNCs) have better dispersion in composite films. In addition, fracture surface did not display large cavities, which indicates the interface binding force between WPU and CaCNCs is stronger. The tensile strength and fracture work of CaCNC/WPU composite film increase by 11.9% and by 8.4%, respectively. The oxygen permeability of CaCNC/WPU composite film is the lowest in these composite films, which is 5.00 cm3•cm (cm2•s•Pa)-1. Water vapor permeability of composite films may have a close positive correlation with their hygroscopicity. In all, composite film with CaCNCs has optimal strength, toughness, light transmittance and oxygen barrier properties. There may be opposite ion attraction superimposed hydrogen bond between CaCNCs and WPU in the composite film. The composite films are expected to have applications in food packaging, furniture coatings and biomedical applications.


2021 ◽  
Vol 1021 ◽  
pp. 280-289
Author(s):  
Abdulkader M. Alakrach ◽  
Awad A. Al-Rashdi ◽  
Mohamed Khalid Al-Omar ◽  
Taha M. Jassam ◽  
Sam Sung Ting ◽  
...  

In this study, PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites films were fabricated via solution casting method. By testing the film density, solubility, water contact angle and water vapor permeability, the PLA nanocomposite films, the comprehensive performances of the nanocomposites were analysed. The outcomes demonstrated that maximum film density of PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites films increased gradually with the increasing of nanofiller loadings. Moreover, the incorporation of TiO2 and HNTs-TiO2 significantly decreased the water vapor transmittance rate of the nanocomposite films with a slight priority to the addition of HNTs-TiO2, the water solubility was significantly improved with the addition of both nanofillers. Furthermore, the barrier properties were developed with the addition of both TiO2 and HNTs-TiO2 especially after the addition of low nanofiller loadings. Overall, the performance of the PLA/HNTs-TiO2 nanocomposite films was better than that PLA/TiO2 film. Nevertheless, both of the PLA nanocomposite samples achieved the requests of food packaging applications.


10.5219/1177 ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 854-862 ◽  
Author(s):  
Usman Amin ◽  
Muhammad Azam Khan ◽  
Muhammad Ehtasham Akram ◽  
Abdel Rahman Mohammad Said Al-Tawaha ◽  
Alexey Laishevtcev ◽  
...  

Environmental consciousness as well as individual’s demand for ready to eat food, recently, has changed the trends in food packaging leading to the development of biodegradable and edible packaging. Emulsified edible films have better transparency, superior mechanical properties and provide barriers to water and other atmospheric gases. Edible films if not consumed, biodegrad chemically. In present study, edible films were, initially, prepared using Chitosan and Aloe vera at different concentrations. Films were then subjected to physical and mechanical testing. Films with 20% Aloe vera had low thickness as compared to films with no Aloe vera. These films also had superior mechanical properties and lower water vapor permeability. Films with 20% Aloe vera were, then, selected and beeswax was dispersed in Chitosan-Aloe vera solution at concentration upto 2.0% followed by film preparation through casting technique. Thickness and water vapor permeability were observed to be improved with increase in concentration of beeswax. Tensile strength of edible films was also improved 1.3 times when concentration of beeswax increased from 0.5 to 2.0%. Percentage elongation decreased with increase in beeswax concentration in the emulsified films. No change in particle size was observed with change in concentration of beeswax. Emulsions were also stable at room temperatures. Decrease in transparency of emulsified edible films was observed with increase in beeswax content in the emulsified films. In addition, cost analysis of the films proved them reasonable to be used as an alternate of synthetic packaging materials.


Author(s):  
Grégoire David ◽  
Laurent Heux ◽  
Stéphanie Pradeau ◽  
Nathalie Gontard ◽  
Hélène Angellier-Coussy

Abstract This paper aims at investigating the potential of vine shoots (ViSh) upcycling as fillers in novel poly(3-hydroxybutyrate-3-hydroxyvalerate) (PHBV) based biocomposites. ViSh particles of around 50 µm (apparent median diameter) were obtained combining dry grinding processes, and mixed with PHBV using melt extrusion. Thermal stability and elongation at break of biocomposites were reduced with increasing contents of ViSh particles (10, 20 and 30 wt%), while Young’s modulus and water vapor permeability were increased. It was shown that a surface gas-phase esterification allowed to significantly increase the hydrophobicity of ViSh particles (increase of water contact angles from 59° to 114°), leading to a reduction of 27% in the water vapor permeability of the biocomposite filled with 30 wt% of ViSh. The overall mechanical performance was not impacted by gas-phase esterification, demonstrating that the interfacial adhesion between the virgin ViSh particles and the PHBV matrix was already good and that such filler surface treatment was not required in that case. It was concluded that ViSh particles can be interestingly used as low cost fillers in PHBV-based biocomposites to decrease the overall cost of materials.


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


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 158
Author(s):  
Yao Dou ◽  
Liguang Zhang ◽  
Buning Zhang ◽  
Ming He ◽  
Weimei Shi ◽  
...  

The development of edible films based on the natural biopolymer feather keratin (FK) from poultry feathers is of great interest to food packaging. Edible dialdehyde carboxymethyl cellulose (DCMC) crosslinked FK films plasticized with glycerol were prepared by a casting method. The effect of DCMC crosslinking on the microstructure, light transmission, aggregate structure, tensile properties, water resistance and water vapor barrier were investigated. The results indicated the formation of both covalent and hydrogen bonding between FK and DCMC to form amorphous FK/DCMC films with good UV-barrier properties and transmittance. However, with increasing DCMC content, a decrease in tensile strength of the FK films indicated that plasticization, induced by hydrophilic properties of the DCMC, partly offset the crosslinking effect. Reduction in the moisture content, solubility and water vapor permeability indicated that DCMC crosslinking slightly reduced the moisture sensitivity of the FK films. Thus, DCMC crosslinking increased the potential viability of the FK films for food packaging applications, offering a value-added product.


Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 618 ◽  
Author(s):  
Hynek Beneš ◽  
Jana Kredatusová ◽  
Jakub Peter ◽  
Sébastien Livi ◽  
Sonia Bujok ◽  
...  

Currently, highly demanded biodegradable or bio-sourced plastics exhibit inherent drawbacks due to their limited processability and end-use properties (barrier, mechanical, etc.). To overcome all of these shortcomings, the incorporation of lamellar inorganic particles, such as layered double hydroxides (LDH) seems to be appropriate. However, LDH delamination and homogenous dispersion in a polymer matrix without use of harmful solvents, remains a challenging issue, which explains why LDH-based polymer nanocomposites have not been scaled-up yet. In this work, LDH with intercalated ionic liquid (IL) anions were synthesized by a direct co-precipitation method in the presence of phosphonium IL and subsequently used as functional nanofillers for in-situ preparation of poly (butylene adipate-co-terephthalate) (PBAT) nanocomposites. The intercalated IL-anions promoted LDH swelling in monomers and LDH delamination during the course of in-situ polycondensation, which led to the production of PBAT/LDH nanocomposites with intercalated and exfoliated morphology containing well-dispersed LDH nanoplatelets. The prepared nanocomposite films showed improved water vapor permeability and mechanical properties and slightly increased crystallization degree and therefore can be considered excellent candidates for food packaging applications.


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