Preparation and Optimization of Starch/Poly Vinyl Alcohol/ZnO Nanocomposite Films Applicable for Food Packaging

Pollution and destruction of the environment due to the accumulation of non-degradable plastics are some of the most important concerns in the world. A significant amount of this waste is related to the polymers used in food packaging. Therefore, experts in the food industry have been looking for suitable biodegradable alternatives to synthetic polymers. Preparing biocompatible and biodegradable films based on starch is a good choice. In this study, various factors affecting films of starch/polyvinyl alcohol (PVA)/containing ZnO nanoparticles such as the amount of starch, PVA, glycerol, and ZnO were evaluated by response surface methodology (RSM). Film formation by solvent casting method, mechanical properties, swelling, solubility, and water vapor permeability (WVP) were selected as responses of RSM. The results showed that hydrogen bonding interactions between polyvinyl alcohol and starch improved the film formation. The effect of glycerol and PVA content on the mechanical strength was contrary to each other. As the amount of PVA increased, the tensile strength first decreased and then increased. The value of WVP was for all Runs from 0 to 6.77?×?10^??8 g m^??1 s^??1 Pa^??1. Finally, films with high film formation, maximum tensile strength, and high elongation at break, minimum solubility, permeability, and swelling were optimized.

     

Biodegradation Behavior of Composite Films with Poly (Vinyl Alcohol) Matrix

The main objective of this study was to develop biodegradable, composite materials, based on poly (vinyl alcohol), bacterial cellulose and chitosan for possible application in packaging industry. Two composite materials were prepared, one containing poly (vinyl alcohol) (PVA) and bacterial cellulose (BC), named PVA/BC, and the other containing PVA, BC but also chitosan (CTS), named PVA/BC/CTS. The biodegradation behavior was studied in a fed-batch bioreactor, in aerobic and anaerobic conditions, using activated sludge. Biodegradation tests were based on weight loss measurements. Structural changes were confirmed by Fourier transform infrared spectroscopy (FTIR) and the morphological ones by scanning electron microscopy (SEM). After 4?weeks, the biodegradation experiments have shown a relative high degradation of the PVA/BC/CTS film compared with the PVA/BC one. These results were confirmed by spectral analysis and also by SEM images. Besides, the SEM images revealed that biodegradation occurs also inside the composite materials, not only on the surface.     

Effects of Starch Moisture on Properties of Wheat Starch/Poly(Lactic Acid) Blend Containing Methylenediphenyl Diisocyanate

Methylenediphenyl diisocyanate was found to improve the interfacial interaction between poly(lactic acid)(PLA) and granular starch. The objective of this research was to study the effect of starch moisture content on the interfacial interaction of an equal-weight blend of wheat starch and PLA containing 0.5% methylenediphenyl diisocyanate by weight. Starch moisture (10% to 20%) had a negative effect on the interfacial binding between starch and PLA. The tensile strength and elongation of the blend both decreased as starch moisture content increased. At 20% moisture level, the starch granules embedded in the PLA matrix were observed to be swollen, resulting in poor strength properties and high water absorption by the blend.     

Properties of Starch/PVA Blend Films Containing Citric Acid as Additive

Starch/polyvinyl alcohol (PVA) blend films were prepared successfully by using starch, polyvinyl alcohol (PVA), glycerol (GL) sorbitol (SO) and citric acid (CA) for the mixing process. The influence of mixing time, additional materials and drying temperature of films on the properties of the films was investigated. With increase in mixing time, the tensile strength (TS), elongation (%E), degree of swelling (DS) and solubility (S) of the film were equilibrated. The equilibrium for TS, %E, DS and S value was 20.12 MPa, 36.98%, 2.4 and 0.19, respectively. The mixing time of equilibrium was 50 min. TS, %E, DS and S of starch/PVA blend film were examined adding glycerol (GL), sorbitol (SO) and citric acid (CA) as additives. At all measurement results, except for DS, the film adding CA was better than GL or SO because hydrogen bonding at the presence of CA with hydroxyl group and carboxyl group increased the inter/intramolecular interaction between starch, PVA and additives. Citric acid improves the properties of starch/PVA blend film compared to glycerol and sobitol. When the film was dried at low temperature, the properties of the films were clearly improved because the hydrogen bonding was activated at low temperature.     

Characterization of Biodegradable Composite Films Prepared from Blends of Poly(Vinyl Alcohol), Cornstarch,and Lignocellulosic Fiber

Several composite blends of poly(vinyl alcohol) (PVA) and lignocellulosic fibers were prepared and characterized. Cohesive and flexible cast films were obtained by blending lignocellulosic fibers derived from orange waste and PVA with or without cornstarch. Films were evaluated for their thermal stability, water permeability and biodegradation properties. Thermogravimetric analysis (TGA) indicated the suitability of formulations for melt processing, and for application as mulch films in fields at much higher temperatures. Composite films were permeable to water, but at the same time able to maintain consistency and composition upon drying. Chemical crosslinking of starch, fiber and PVA, all hydroxyl functionalized polymers, by hexamethoxymethylmelamine (HMMM) improved water resistance in films. Films generally biodegraded within 30 days in soil, achieving between 50–80% mineralization. Both starch and lignocellulosic fiber degraded much more rapidly than PVA. Interestingly, addition of fiber to formulations enhanced the PVA degradation.     

Evaluation of Biodegradable Films Made of Waste Mycelium and Poly (Vinyl Alcohol) on the Yield of Pak-Choi

Novel biodegradable films were prepared via blending of poly (vinyl alcohol) and waste mycelium from sauce residue and citric acid fermentation residue, respectively. The performance of these two types of films when used as alternative covers for pak-choi growth under semi-arid climatic conditions was evaluated via field test towards their abilities for water retention and biodegradation, together with the impact on the yield and nutritional quality of pak-choi. Experimental results showed that the use of these films could result in 50% higher water retention than a blank control film after 96-h treatment at 40?°C. Films were biodegraded within 14?weeks under natural conditions, leading to a significant mineralization, progressively releasing over 56% of K⁺, NO₃ ^?, Mg²⁺ and organics, beneficial for plant growth as fertilizer. The yield of pak-choi was increased by 80% in weight when using these films compared with the unmulched control. Compared to those treated with traditional LDPE mulching film, the average contents of chlorophyll, crude protein and soluble sugar in pak-choi were increased by 52.9, 7.2, 80.7% (blends of sauce residue) and 26.7, 11.4, 10.8% (blends of citric acid fermentation residue), respectively.     

Physicochemical and Antibacterial Evaluation of Poly (Vinyl Alcohol)/Guar Gum/Silver Nanocomposite Films for Food Packaging Applications

Journal of Polymers and the Environment - In this study, we prepared Poly (vinyl alcohol) (PVA)/Guar gum (GG) based nanocomposite films with a different weight ratio of silver nanoparticles (AgNPs)...     

A Study of Physicomechanical and Morphological Properties of Starch/Poly(vinylalcohol) Based Films

Starch/Poly(vinylalcohol) blends in two different ratios (60:40 and 50:50) were prepared with glycerol as a plasticizer. Films were cast by a solution casting method. One set of films were filled with 10 wt% of unmodified bentonite clay and another set of films were crosslinked with epichlorohydrin in an alkaline medium. The prepared film samples were subjected to X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), mechanical characterization and scanning electron microscope (SEM). Significant changes in the tensile properties were observed depending on the different chemical constituents of the films. The presence of clay and crosslinking with epichlorohydrin were both found to have considerable effect on the morphology and mechanical property of the films. The SEM investigations, XRD analysis and FTIR studies revealed the interaction between the various chemical components of the films.     

Biodegradability and Mechanical Properties of Poly(vinyl alcohol)-Based Blend Plastics Prepared Through Extrusion Method

Plastic blend materials consisting of poly(vinyl alcohol), glycerol and xanthan or gellan were prepared through laboratory extrusion. Their base mechanical properties were compared with the properties of poly(vinyl alcohol) foil and their biodegradability in soil, compost and both activated and anaerobic sludge were assessed. In samples with lower polysaccharide content (10–21 %w/w) the tensile strength of 15–20 MPa was found; the elongation at break of all blends was relatively close to the parameter of poly(vinyl alcohol) foil. The biodegradability levels of the blends tested corresponded to the content of natural components, and the mineralization of the samples with the highest carbohydrate proportion (42 %) reached 50–78 %, depending on the type of the environment. Complete biodegradation of all samples occurred in activated sludge.     

Biodegradable Films Based on Blends of Gelatin and Poly (Vinyl Alcohol): Effect of PVA Type or Concentration on Some Physical Properties of Films

The aim of this work was to develop biodegradable films based on blends of gelatin and poly (vinyl alcohol) (PVA), without a plasticizer. Firstly, the effect of five types of PVA with different degree of hydrolysis (DH) on the physical properties of films elaborated with blends containing 23.1% PVA was studied. One PVA type was then chosen for the study of the effect of the PVA concentration on the mechanical properties, color, opacity, gloss, and water solubility of the films. The five types of PVA studied allowed for films with different characteristics, but with no direct relationship with the DH of the PVA. Therefore, the PVA Celvol^®418 with a DH = 91.8% was chosen for the second part, because they produced films with greater tensile strength. The PVA concentration affected all studied properties of films. These results could be explained by the results of the DSC and FTIR analyses, which showed that some interactions between the gelatin and the PVA occurred depending on the PVA concentration, affecting the crystallinity of the films.     

Biodegradable Green Glove Containing Ascorbic Acid from Maleated Epoxidized Natural Rubber/Poly(vinyl alcohol) Blend: Preparation and Physical Properties

Journal of Polymers and the Environment - The objective of this work was to prepare a maleate epoxidized natural rubber (MENR) and poly(vinyl alcohol) (PVA) (MENR/PVA) blend in the presence of...     

Preparation and Biodegradation of Starch/Polycaprolactone Films

Starch granules were modified with trisodium trimetaphosphate (TSTP) and characterized by P³¹-NMR, FTIR and DSC. Seventy-micron films were prepared from modified starch and polycaprolactone blends by solvent casting technique. Three different types of films—PCL (100% polycaprolactone), MOD-ST/PCL (50% modified starch and 50% polycaprolactone blend) and NONMOD-ST/PCL (50% nonmodified starch and 50% polycaprolactone blends)—were prepared, and their thermal, mechanical, and morphologic properties were investigated to show the increased performance of PCL with the addition of starch and also the effect of modification. It was observed that with the addition of starch the Young's modulus of polycaprolactone was increased and became less ductile, whereas tensile strength and elongation at break values decreased. Biodegradation of these films was inspected under different aerobic environments with the presence of Pseudomonas putida, activated sludge, and compost. It was observed that whereas P. putida had almost no effect on degradation during 90 days, with the presence of activated sludge, considerable deformation of films was observed even in the first 7 days of degradation. In a compost environment, degradation was even faster, and all polymer films were broken into pieces within first 7 days of degradation and no film remained after 15 days.     

A Study of Dynamic Mechanical and Thermal Behavior of Starch/Poly(vinylalcohol) Based Films

Starch/Poly(vinylalcohol) blends in two different ratios (60:40 and 50:50) were prepared with glycerol as a plasticizer. Films were cast by a solution casting method. One set of films were filled with 10 wt% of bentonite clay and another set of films were crosslinked with epichlorohydrin in an alkaline medium. The prepared film samples were characterized with dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The presence of clay and crosslinking with epichlorohydrin was found to have considerable effect on the dynamic mechanical properties and thermal stability of the films. Intercomponent H-bonding between starch, Poly(vinylalcohol) and glycerol enhanced the thermal stability of the films. But incorporation of clay and crosslinking with epichlorohydrin enhanced the steric crowding and lowered the thermal stability of the films.     

Influence of pH and C/N Ratio on Poly(Vinyl Alcohol) Biodegradation in Mixed Bacterial Culture

Cultivation conditions affecting poly(vinyl alcohol) (PVA) degradation by a mixed bacterial culture of Bacillus sp. and Curtobacterium sp. were investigated. Bacterial strains used in this study were isolated from the watercourse and the sewage sludge of vinylonfibre mill by enrichments on PVA as the sole carbon source. The results showed that PVA was greatly degraded under the following conditions: 0.5% PVA as a substrate at the initial medium pH of 8 with 0.15% glucose and urea at C/U ratio 1.5:1 and 1% bacterial inoculum, at a temperature of 35 °C and a shaking speed of 110 rpm. The analysis of FTIR and ¹H NMR spectra before and after biodegradation indicate fission of the PVA molecular chain during the incubation.     

Effect of Poly(Vinyl Alcohol) and Polyethylene on the Growth of Red Pepper and Tomato

Poly(vinyl alcohol) (PVA) and polyethylene (PE) were blended with a soil for cultivation, and their effects were investigated on the growth behavior of red pepper and tomato by examining the stems, the leaves, and the roots. PVA retarded the growth of red pepper significantly even at a concentration as low as 0.05%. The roots were depauperated more than the stems and the leaves. Tomato was also affected by PVA but to a lesser extent than red pepper. In contrast, the presence of both round pieces (10 mm diameter) of PE film and powdery PE influenced negligibly the growth of red pepper as well as that of tomato up to 35 wt% in soil.     

Properties of Poly(Vinyl Alcohol)/Chitosan Nanocomposite Films Reinforced with Oil Palm Empty Fruit Bunch Amorphous Lignocellulose Nanofibers

The objective of this study was to investigate the properties of poly(vinyl alcohol)/chitosan nanocomposite films reinforced with different concentration of amorphous LCNFs. The properties analyzed were morphological, physical, chemical, thermal, biological, and mechanical characteristics. Oil palm empty fruit bunch LCNFs obtained from multi-mechanical stages were more dominated by amorphous region than crystalline part. Varied film thickness, swelling degree, and transparency of PVA/chitosan nanocomposite films reinforced with amorphous part were produced. Aggregated LCNFs, which reinforced PVA/chitosan polymer blends, resulted in irregular, rough, and uneven external surfaces as well as protrusions. Based on XRD analysis, there were two or three imperative peaks that indicated the presence of crystalline states. The increase in LCNFs concentration above 0.5% to PVA/chitosan polymer blends led to the decrease in crystallinity index of the films. A noticeable alteration of FTIR spectra, which included wavenumber and intensity, was obviously observed along with the inclusion of amorphous LCNFs. That indicated that a good miscibility between amorphous LCNFs and PVA/chitosan polymer blend generated chemical interaction of those polymers during physical blending. Reinforcement of PVA/chitosan polymer blends with amorphous LCNFs influenced the changes of T_g (glass transition temperature), T_m (melting point temperature), and T_max (maximum degradation temperature). Three thermal phases of PVA/chitosan/LCNFs nanocomposite films were also observed, including absorbed moisture evaporation, PVA and chitosan polymer backbone structural degradation and LCNFs pyrolysis, and by-products degradation of these polymers. The addition of LCNFs 0.5% had the highest tensile strength and the addition of LCNFs above 0.5% decreased the strength. The incorporation of OPEFB LCNFs did not show anti-microbial and anti-fungal properties of the films. The addition of amorphous LCNFs 0.5% into PVA/chitosan polymer blends resulted in regular and smooth external surfaces, enhanced tensile strength, increased crystallinity index, and enhanced thermal stability of the films.     

Dielectric and Material Properties of Poly (Vinyl Alcohol): Based Modified Red Mud Polymer Nanocomposites

Red mud emerges as the major waste material during production of alumina from bauxite by the Bayer??s process. Based on economics as well as environmental related issues, enormous efforts have been directed worldwide towards red mud management issues i.e. of utilization, storage and disposal. The present research work has been undertaken with an objective to explore the use of red mud as a reinforcing material in the polymer matrix as a low cost option. The silicate layered red mud was organophilized by aniline formaldehyde and to know the effect of various filler loading on the material properties of PVA-organophilized red mud composites, prepared by a conventional solvent casting technique and comparison of the same with that of the virgin poly (vinyl alcohol) (PVA), various characterizations was done. The modified red mud was typically characterized by X-ray diffraction. The X-ray diffraction pattern of the composite materials was also studied. The morphological image of the composite materials was studied by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) was used to characterize the dispersion of the red mud within the composite materials. The surface topography of the composite materials was studied by Atomic Force Microscopy (AFM). The dielectric properties of composite materials were investigated in wide frequency ranges from 1?MHz to 1?GHz.     

Poly(lactic acid)-Based Composites Containing Natural Fillers: Thermal,Mechanical and Barrier Properties

Natural filler/poly(lactic acid)-Based composites have been prepared by melt blending in order to investigate the resulting thermal, mechanical, and oxygen permeability properties. To this aim, several wastes or by-products (namely, cellulose fibers, wood sawdust, hazelnut shells, flax fibers, corn cob and starch) have been used, ranging from 10 to 30 wt%. The presence of these fillers is responsible of a slight reduction of the polymer degradation temperature in nitrogen as well as of a significant increase of the storage modulus as a function of the filler content. The experimental data obtained by dynamic mechanical analysis have been mathematically fitted, employing three micromechanical models (namely, Voigt, Reuss and Halpin–Tsai). Furthermore, the presence of cellulose or starch has turned out to significantly reduce the polymer oxygen permeability. Finally, in order to fully assess the feasibility of such materials, an economic analysis has been carried out and discussed.     

Role of Crosslinker on the Biodegradation Behavior of Starch/Polyvinylalcohol Blend Films

The effect of crosslinkers on the biodegradation behavior of starch/polyvinyl alcohol (PVA) blend films was investigated by weight loss study, Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Starch/PVA films were prepared by solution casting method and 5 weight% of four different crosslinking agents like epichlorohydrin, formaldehyde, zinc oxide and borax were used in four different sets to crosslink the films. These crosslinked starch/PVA films were biodegraded in compost. Weight loss study showed that crosslinking retarded the biodegradation of the films in the first 15?days, but after that, there was a significant increase in weight loss. The DSC analysis revealed that the consumption of starch and consequent rearrangement of the PVA molecules were distinctly different in the crosslinked films due to the effect of different crosslinking agents.