Polyvinyl Acetate Emulsion Research Articles

Polyvinyl acetate wood adhesive stabilized with hydroxyethyl cellulose: synthesis and characterizations

Specifically, the conventional wood adhesive uses polyvinyl alcohol (PVA) as colloid to stabilise the polyvinyl acetate (PVAc) emulsion. Green materials are being used as a result of recent study on chemicals and alternative sources. This factor has made the substitution of sustainable biopolymers for petrochemicals considerably more important. An emulsifier, sodium lauryl sulphate (SLS), was used during the addition polymerization process to produce a hydroxyethyl cellulose-grafted-poly (vinyl acetate) (HEC-g-P(VAc)) emulsion from HEC and VAc. The purpose of the study was to increase the content of renewable materials in the emulsion. The adhesive films glass transition temperatures (Tg) have been identified via Differential Scanning Calorimetry (DSC). The performance of the PVAc emulsion-based adhesive in accordance with EN 204 and EN 205 standards was evaluated by measuring the tensile shear strength of wood joints under both dry and wet conditions. The viscosity of the adhesives significantly increased along with the addition of HEC. The application of HEC led to an increase in PVAc film hardness, which was confirmed by the film’s glass transition temperature. In an environment that was wet, after 24 h, the tensile strength of the sample containing HEC increased by 54% compared to a pristine sample, as per EN 204 and EN 205. Water resistance significantly increased in sample with HEC, as was found by measuring the water contact angle which is in line with wet strength. The overall study conclusion emphasises the superior water resistance and increased adhesion capabilities of PVAc emulsion-based wood adhesives stabilised by HEC.

Glycidyl methacrylate co-polymer emulsion-based heat and water-resistant wood adhesive

This work aims to add an epoxy-ended co-monomer to polyvinyl acetate (PVAc) emulsion adhesive-based wood adhesive to improve its resistance to heat and moisture. Here, glycidyl methacrylate (GMA), vinyl neodecanoate (VeoVa), and vinyl acetate (VAc) emulsion copolymers have been created and evaluated as wood adhesives. To prepare the emulsion-based adhesive samples, a polyvinyl alcohol (PVA) solution, aluminium chloride solution, preservatives, and a plasticizer are added. Following that, the poly(VAc–VeoVa–GMA) based adhesive sample is compared with the VAc, VeoVa, and methyl methacrylate (MMA) (poly(VAc-VeoVa-MMA)) co-polymer-based adhesive. Tensile shear strength of wood joints under dry and wet conditions was tested in compliance with EN 204-205 standard to assess the adhesives’ performance. The EN 14257 standard, which defines the shear stress of wood joints at 80 °C, was used to assess the heat resistance of the wood adhesives. Tests on the hardness of films confirmed the results of differential scanning calorimetry, which indicated that the glass transition temperature in the GMA-based adhesive was significantly higher than in the MMA-based adhesive. After 6 h of bonding, EN 204 shows that the tensile shear strength of a GMA-based adhesive increased by 15.56% in a dry environment, by 16.67% in a wet environment and 37.84% heat resistance when compared to a co-polymer-based adhesive based on MMA. The approach that was developed provides a simple and useful way of developing adhesives with enhanced heat, water, and bonding strength resistance.

Adhesive Strength in the Structure of Composite Materials Based on Organic Raw Materials

This article discusses issues related to correcting the adhesive properties of composite materials based on organic waste and expanded polystyrene. The theoretical prerequisites for the formation of the structure of materials based on organic raw materials are determined. An average series of binders has been established as the adhesive strength with vegetable filler increases. The results of determining the adhesive strength of polystyrene foam in the structure of the composite material are presented. In order to increase the hydrophilicity of polystyrene foam, such binders as polyvinyl acetate emulsion, liquid glass, and acrylic latex were used in research. Analysis of the results obtained allows us to evaluate the effectiveness of the binder and determine the optimal type of filler in the composition of the composite material, based on the values of the shear strength. As a result, it was found that the introduction of expanded polystyrene into the composition of a composite material based on organic raw materials makes it possible to reduce the consumption of the binder by 82–87% due to its treatment with an aqueous solution of dimethyl ketone and providing it with adhesive ability. Thus, it is possible to significantly increase the share of organic waste used in the production of building materials, increasing the efficiency of their processing and disposal.

A facile strategy to fabricate low viscosity and high cold tack soy protein-based adhesive for particleboard production

The utilization of soy protein as a wood adhesive has been successfully implemented in the industrial production of plywood. However, it is still a significant challenge to directly utilize soy protein-based adhesive for the fabrication of particleboard owing to its high viscosity and low cold tack. In this study, polyvinyl acetate (PVAc) emulsion was used to modify soy protein-based adhesive to reduce its viscosity and enhance its cold tack. By incorporating a content of 30% PVAc emulsion, the viscosity of the adhesive was reduced to 880 mPa·s, which was much lower than the pure soy protein-based adhesive value. Simultaneously, the cold tack was significantly increased by nearly 500 times after the addition of PVAc. The obtained adhesives met the requirements for particleboard production. In addition, the internal bonding strength of the produced particleboard reached 0.7 MPa, significantly exceeding the requirements for P6-grade particleboards (≥ 0.40 MPa, GB/T4897–2015). Moreover, it exhibited no formaldehyde emissions, making it a high-quality particleboard suitable for furniture applications. This study successfully presents a soy protein-based adhesive suitable for particleboard production using a simple blending modification approach, thereby expanding the application scope of soy protein-based adhesives.

Improving the adhesion strength and moisture resistance of poly(vinyl acetate) latex as wood adhesive via blending with gelatin

Gelatin can act as wood adhesive for fabrication of numerous structures. Polyvinyl acetate (PVAc) is also used as wood adhesive because it provides excellent adhesion. Unfortunately, its bonds are sensitive to humid atmospheres especially at elevated temperatures. The current work explores hybridization of PVAc emulsion with finite amounts of gelatin and the resulting latex was fully characterized using different techniques, where it was found that gelatin insertion caused densification of the latex structure without affecting its stability while the viscosity increased without visual phase separation, indicating strong interactions emerged between both. Dynamic light scattering (DLS) and transmission electron microscope (TEM) confirmed a mean size of the latex particles increasing from 265 nm to 290 nm in presence of elevated doses of gelatin, with the surface charge decreasing from −42 mV to −33 mV. Turbidity measurements revealed the latex particles became more likely to coagulate in presence of increasing amounts of gelatin and formation of a more compact film that provides higher resistance to water permeation and stronger adhesion as supported by shear strength evaluations. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) proved strong interactions between PVAc with gelatin, causing higher thermal stability and possibility of use at relatively higher temperatures. X-ray diffraction (XRD) showed broadening of the peak at 2θ = 21° indicating partial destruction of the triple helical structure of gelatin, which can be correlated with the spectra of Fourier transform infrared (FTIR) that showed obvious shifts of the main peaks of PVAc due to effective insertion of gelatin.

Enhanced curing process of eco-friendly oxidized cornstarch adhesive with Nano-CeO2

ABSTRACT This paper investigates the development of an eco-friendly adhesive fortified with cerium dioxide nanoparticles (nano-CeO2), incorporating oxidized corn starch (OCS) and a Polyvinyl acetate (PVAc) emulsion. Initially, OCS was prepared through an oxidation reaction, and its chemical structural attributes were explored using FT-IR, XRD, DSC, viscosity, and carboxyl value analysis. Subsequently, the adhesive formulation (OCS-PVAc-CeO2) was synthesized, demonstrating substantial improvements in both strength and curing kinetics due to the inclusion of nano-CeO2, as confirmed by SEM surface morphology analysis. Laboratory-scale evaluations of this adhesive confirmed its suitability for the packaging industry due to its rapid curing process and enhanced mechanical properties.

Development and formulation of a novel plasticizer-free polyvinyl acetate-based wood adhesive

Amongst water-based emulsion adhesives, polyvinyl acetate (PVAc) emulsion is majorly employed in the non-structural bonding of interior or exterior furniture and joinery industries. However, PVAc emulsion requires plasticizers, which inherently have challenges resulting in deteriorating thermal and mechanical properties. Hence, the present work focuses on formulating a plasticizer-free adhesive by copolymerizing vinyl acetate with butyl acrylate (BA). The physical, thermal, and mechanical properties of BA-incorporated adhesives were analyzed by viscosity, pH, water contact angle, pencil hardness test of films, and differential scanning calorimetry. Optimizing strategy by varying the content of BA was evaluated. The shear strength of the samples on the wood specimen was verified in dry conditions at various intervals, and in wet conditions as per EN 204 standard. The viscosity of the adhesives exhibited a positive shift, as the concentration BA increased. The hardness of PVAc films was also altered positively by the addition of BA. Water contact angle measurement unveiled the hydrophobic nature of BA incorporation. The performance of the newly formulated adhesive tested on dry conditions showed enhanced tensile shear strength, and the values were maximum for 1 wt. % BA sample. Tensile shear strength value measured at dry conditions after 7 d of drying displayed an increment of ∼5.5% on 1 wt. % BA sample, compared to pristine adhesive. Analysis at wet conditions also corroborated enhanced performance with BA incorporation. Hence by optimizing the content of BA, a new concept of PVAc emulsion adhesive without any plasticizer can be formulated, with enhanced water resistance and performance.

Gluing characteristics of Papua New Guinea timber species for various non-structural applications

Papua New Guinea (PNG) has abundant natural forest resources but there are many constraints which need to be addressed to support the development of competitive value-added wood industries. There is a need to develop knowledge and capacity in wood science and processing technologies which support successful domestic value-adding wood processing enterprises. A comprehensive testing program has been developed to assess the glue‐bond strength and performance of selected commercial PNG timber species in various climatic conditions to simulate service conditions in potential market destinations. Two criteria namely shear strength and wood failure have been used to determine if a species can meet the minimum requirements for either dry use or wet use applications. The performance of 24 different PNG commercial timber species has been assessed using a one-component cross-linking polyvinyl acetate emulsion adhesive. The bondability of the selected species has been carefully estimated considering the wood density and wood moisture content for the strength and durability in dry- and wet-use conditions. The testing results show that as the wood density as a wood property factor and moisture content as a service condition factor increase, high shear strength with high wood failure become more difficult to achieve consistently. The highest shear strength and wood failure results were achieved by softwood plantation species and low-density hardwood species. Based on the testing results, the selected species have been classified into bondability classes (bond very well, bond well, bond with difficulty, very difficult to bond).

СПОСОБ ФОРМООБРАЗОВАНИЯ ДЕТАЛЕЙ ОДЕЖДЫ ПОЛИМЕРНОЙ КОМПОЗИЦИЕЙ

This study analyzes a new composition used in textile and finishing production in order to determine the possibility of its use to provide the required shape of parts in clothing production conditions. Various methods of imparting stability to the shape of a polymer composition on fabric samples are considered, and the modes of sizing and wet-heat treatment when changing the concentration of the polymer composition are determined. By adjusting the concentration of polyvinyl acetate emulsion (PVA), dimensional stability parameters were studied depending on the opening angle of the fabric after treatment. Diagrams of changes in shape stability of tissue samples depending on the concentration of the emulsion are presented. The obtained results of shape stability allow us to conclude that it is possible to use a PVA-based mold fixer in the clothing industry to obtain structures of a given volumetric shape.

Hydrophilic matrix system coated by polyvinyl acetate emulsion versus calcium alginate for sustained acetylsalicylic acid release

Hydrophilic matrix system coated by polyvinyl acetate emulsion versus calcium alginate for sustained acetylsalicylic acid release

Improvement of Core–Shell Lightweight Aggregate by Modifying the Cement–EPS Interface

To improve the interfacial compatibility between cement matrix and expanded polystyrene (EPS) in core-shell lightweight aggregates (CSLA), the effects of sodium silicate, polyvinyl acetate (PVA) emulsion, vinyl acetate-ethylene (VAE) emulsion, acrylic acid, and acetic acid on the cement-EPS interface were investigated. The density of the interface was studied by scanning electron microscopy (SEM), and the effect of interfacial agents on the hydration process of cement was studied by the heat of hydration and induction resistivity. The macroscopic properties of the interface of the CSLA were characterized by the "leak-white" rate, drop resistance, and numerical crushing strength. The results show that the sodium silicate densifies the interface by generating hydration products on the EPS surface. At the same time, organic acid enhances the interfacial properties of EPS and cement by increasing the surface roughness, and allowing hydration products to grow in the surface micropores. In terms of the cement hydration process, both interfacial agents delay the cement hydration. Above all, with comprehensive interface properties, "leak-white" rate, and mechanical properties, VAE emulsion and sodium silicate can achieve the best performance with a final crushing resistance of 5.7 MPa, which had a 46% increase compared with the reference group.

Thermal runaway evaluation on batch polyvinyl acetate emulsion polymerization from calorimetric measurement.

Emulsion polymerization is the most applied method in the vinyl acetate monomer (VAM)-polyvinyl acetate (PVAc) process. However, the flammable property and unexpected bulk polymerization for the reactant and product may occur in the batch reactor or storage tank. VAM is reactive enough to decompose readily into free radicals and then, initiate the polymerization, which may contribute to heat accumulation due to the monomer, initiator, and solvent mixtures. This study attempts to analyze the exothermic reaction and compare the thermal runaway potential for various VAM solutions during PVAc polymerizations. Summarily, 50%, 70%, and 100% of VAM solutions reacting with 2,2'-azobis(2-methylpropionitrile) readily increase the self-heating rate with their concentration from adiabatic calorimetric tests. Furthermore, kinetic parameters of 50, 70, and 100 mass% VAM solutions were evaluated to elucidate the self-heating model associated with thermal analysis and to determine heat production mechanisms that are practical to proactive safety protocol for the PVAc emulsion process.

Preparation and Characterization of Cellulose Nanoparticles from Agricultural Wastes and Their Application in Polymer Composites

, Page no - | ABSTRACT | PDF | FULL TEXT | e-PUB Background: The development of innovative eco-sustainable bio-nano-composites materials based on cellulose nanomaterials obtained from agricultural waste such as rapeseed plant straw and polymeric materials with improved properties. At first, cellulose was extracted from rapeseed plant straw and cellulosic and no cellulosic materials were estimated. It was found that the rapeseed plant straw contained about 43.48 wt.% cellulosic materials and 56.52 wt.% no cellulosic materials. It was also found that the rapeseed plant straw content about 34.84 wt.% α- cellulose. Then, nano-cellulose was prepared by acid hydrolysis of α -cellulose obtained from rapeseed plant straw. Poly vinyl acetate (PVAc) was prepared by soap free emulsion polymerization of vinyl monomer. Natural rubber (NR) collected as latex was oxidized by KMnO4. Blends of NR and oxidized NR with PVAc of different compositions such as NR60/PVAc40, NR40/PVAc60, ONR60/PVAc40, ONR40/PVAc60 were prepared by mixing NR latex and PVAc emulsion and followed by drying in an oven at 60°C. Composites of NR60/PVAc40 and ONR60/PVAc40 reinforced nano-cellulose (NC) were also prepared in similar way. The blends and composites were then characterized by FTIR, SEM, and Tensile test (TS). FTIR analysis confirmed the oxidation of NR and shown the variation of the functional groups in the blends and composites compared with the FTIR spectrum of NR, ONR and PVAc. SEM study exhibited that the nano-cellulose were dispersed within NR/PVAc and ONR/PVAc blends matrices with a little agglomeration. The tensile test results showed that the strength in composites was increased due to the reinforcing effect of nano-cellulose (NC). Objectives: The aim of this study is to assess the Preparation and characterization of binary blends of NR and oxidized NR with PVAc. Methods: This is an observational study. The study used to be carried out in the admitted patient’s Department of Applied Chemistry and Chemical Engineering, Islamic University, Kushtia-7003, Bangladesh. The duration of the period from Data was entered in MS Excel and Statistical analysis was done using SPSS trial version. Results: This study shows that the according to Constituent, Cellulose was 43.4822%, Alpha-Cellulose were 34.8427% and Cellulose were 8.6395%. And according to Source, Rice Straw were 32.15% %, Sugarcane were 41-43%, Rye Straw were 31.8-42.64%, Corn Stalks were 29.80% and Wheat Straw were 34-40%. Conclusion: Novel eco-friendly bio-nano-composites substances primarily based on renewable and sustainable assets namely natural rubber (NR) and nano-cellulose received from rapeseed plant straw as properly as poly vinyl acetate (PVAc) have been developed. In order to enhance the interfacial interactions amongst the composite factors such as NR, PVAc and NC, oxidation of the NR latex was once carried out by way of KMnO4 before blending mixing with PVAc emulsion and NC suspension.

Reinforcement Mechanism and Erosion Resistance of Loess Slope Using Enzyme Induced Calcite Precipitation Technique

The disaster of loess slope seriously threatened the safety of people and property. Enzyme Induced Calcite Precipitation (EICP) was demonstrated as an environmentally friendly soil improvement method. However, few studies have focused on the improvement effect of EICP on loess slopes. In this study, a series of tests were conducted to investigate the effect of EICP and added either basalt fiber (BF) to the loess or polyvinyl acetate emulsion (PVAC) to the solution on the erosion resistance of loess slopes. The results showed that all of the EICP, EICP-BF, and EICP-PVAC treatments could improve surface strength (SS). The addition of 50 g/L PVAC achieved high SS because the network structure formed by PVAC promoted the affixation of CaCO3. The thickness of the crust layer decreased with the increasing BF content or PVAC concentration. With the increasing number of EICP treatment cycles, the CaCO3 content increased progressively, but the increase rate decreased. For rainfall erosion, the time until erosion occurred was delayed and the stability was improved for loess slopes treated with EICP, EICP-BF, and EICP-PVAC. The high erosion resistance of loess slopes treated with EICP-0.5% BF, EICP-30 g/L PVAC, and EICP-50 g/L PVAC was attributed to the stable spatial structure formed by CaCO3 precipitation and the additional cementation provided by high BF content and PVAC concentration. The addition of 0.5% BF effectively inhibited the development of surface cracks in loess slope after dry–wet cycles. With the increasing number of dry–wet cycles, the accumulative loess loss weight of slopes treated with various methods increased gradually. Among all treatment methods, the number of dry–wet cycles had less effect on EICP-30 g/L PVAC treated loess slopes. This study provided guidance for loess slopes prevention.

Synthesis of Microcrystalline Cellulose—Polyvinyl Alcohol Stabilized Polyvinyl Acetate Emulsion

Polyvinyl alcohol (PVA) colloid stabilized Polyvinyl acetate (PVAc) based wood adhesive has poor performance in highly humid conditions. Currently, the addition of natural fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive in highly moist conditions. Microcrystalline cellulose (MCC) are strong renewable, bio-based material and has great potential in a reinforcement of the polymeric matrix. Hence, the present work investigates the applicability of microcrystalline cellulose incorporated 3% and 5% in situ emulsion polymerization PVAc wood adhesives. Effect on physical, thermal and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC) and pencil hardness test of films. Emulsions with different proportions of MCC were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was increased by increasing the concentration of MCC. The mechanical properties like tensile strength of adhesives with MCC were measured by universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that MCC can improve bonding strength as compared to PVAc Homo based adhesive in the wet condition which was validated through a contact angle study. The hardness of PVAc films were also changed positively by the addition of MCC. Here, we studied the effect of the addition of different concentrations of MCC materials in situ polymerization of PVAc on their performance properties.

Effect of Curing Condition on the Compressive Mechanical Behavior of Clayey Soil Stabilized with Liquid Polymer

This study investigates the potential use of polyvinyl acetate emulsion in soil strengthening with emphasis on curing condition. Molded clay specimens treated with three polymer contents of 1%, 2%, and 3% (by the weight of dry soil) are cured in dry and humid environment, respectively. Unconfined compression tests are performed on the specimens after 1, 3, and 9 days of curing, and the results are compared with that for the untreated clay specimens. This comparison shows that polyvinyl acetate polymer can enhance soil mechanical properties. It was found that the compressive strength of soil-polymer composite increases significantly with the increase of polymer content and curing time in air-drying condition, which is 24% higher than that of plain soil after 9-day curing. The role of polymer treatment is to provide soil interparticle binding, which becomes particularly important in humid environments. In curing environments of high moisture, polymer-treated soils always have greater strength, but the effectiveness of polymer treatment decreases with polymer content. The scanning electron microscopies indicate that soil structure is reinforced mostly by three-dimensional interparticle polymeric bridges. The tension in polymeric threads and textiles provides the interparticle bonding that prevents the development of cracks.

Starch Grafted Water Resistant Polyvinyl Acetate-Based Wood Adhesive: A Review

Global energy issues and the reliance on hydrocarbon resources have resulted in the reduction of petroleum sources, and the focus of the chemical industries has shifted to substitute raw material sources. The major raw materials used in wood adhesives, such as hydrocarbons like polyvinyl acetate, would be gradually replaced by renewable natural polymers. Currently, polyvinyl alcohol has the limitation of petroleum origin, which is non-economical and it will be replaced by biopolymers. Conventionally available wood adhesive emulsions are colloid-like polyvinyl alcohol stabilized. Starch, being a naturally available polymer, has gained interest from researchers for replacing polyvinyl alcohol as a stabilizer. New research on sustainable, economical, biodegradable, renewable, and environmentally friendly starch grafted polyvinyl acetate emulsion that was synthesized by the graft polymerization of vinyl acetate monomer onto starch. However, starch grafted polyvinyl acetate emulsion-based adhesive’s properties, such as poor water resistance, weak adhesion, delayed drying rate and delayed setting speed, have resulted in limitations in its application as a wood adhesive. A detailed review of starch grafting on vinyl acetate and comonomers like acrylamides, and acrylic acid, and the addition of nano-fillers to enhance the water resistance and performance properties of sustainable adhesives has been explained.

Technology of Production of Binder Modifying Nanoadditives

The article deals with the issue concerning production of a dry nanoadditive. In order to achieve this goal, an aqueous solution of polyvinyl acetate dispersion (PVAD) and nanotubes, or lime slaking nanoparticles is used. As a result of the hydration process heat is released, the polyvinyl acetate emulsion forms particles with nanotubes in their composition. During the study performed an optimal ratio of all components was established: quicklime + PVAD-CNT – 71-73% and 0.01-0.018 CNT; “Megalith” – 21-25%; ammonium salt – 4-6%, as well as the optimal amount of the complex additive, which is in the range of 1-1.5% by weight of calcium sulfate hemihydrate. Later on the resulting nanoadditive can be used to modify binders or other materials

Conversion Enhancement of Vinyl Acetate Monomer to Polyvinyl Acetate Emulsion through Emulsion Polymerization Method

Synthesis of Polyvinyl Acetate (PVAc) through the conversion of Vinyl Acetate Monomer (VAM) was carried out by emulsion polymerization method assisted by thermal initiator Ammonium persulfate (APS) under reaction temperature was kept at 70 °C – 80 °C with 5 hours of reaction time and agitation speed at 300 rpm. The polymerization reaction was running used batch process technique where is all components were mixed all together simultaneously. A set of polymerization reactions was conducted when the absence of surfactant and cationic and amphoteric surfactant presence. The monomer chain's double bond was found at 1645 cm-1 was measured by FTIR Spectrophotometer did not disappear after polymerization reaction was utterly done. The spectrum FTIR of Polyvinyl acetate did not explicitly found at 1644 cm-1. During the reaction, characterization was conducted by measuring the solid content value where the maximum solid content was achieved was 6,1 % when using Amphoteric surfactant while the lowest solid content was obtained when the absence of surfactant. Other parameters were conducted to observe the acidity value by pH Meter.

Handsheet Coated by Polyvinyl Acetate as a Drug Release System

The present work aims to prepare a controlled release matrix, using biodegradable materials containing different active ingredients (AI) in order to deliver only the necessary dose for a specific time and a well-defined target. The matrix is a manual sheet, composed of lignocellulosic fibers. The membrane, which regulates the release, is obtained by immersing the sheet in an emulsion of polyvinyl acetate. Different thicknesses were deposited by varying the concentration of the emulsion. Five AIs, which differ in volume and solubility, were used as probes: salicylic acid (SA), acetylsalicylic acid (ASA), metoclopramide (MCP), ketoprofen (KP), and thiocolchicoside (TCC). Kinetic studies have shown that the release of these substances is strongly related to the pH, the solubility of the AI, the thickness, and the permeability of the polymer membrane. The kinetics of release of AI are zero order in an acidic medium and complex in a basic medium. The images taken by scanning electron microscopy (SEM) show the variation in thickness with the number of layers of emulsion deposited. Our system, paper coated with a polyvinyl-acetate (PVAc) emulsion film without a coalescing agent has proven to be a promising matrix for achieving the controlled release of different IAs. It suffices only to adjust the thickness of the membrane. The process is simple and easy compared with other recently developed extended release matrices.