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polyvinyl acetate/poly(amide-12-b-ethylene oxide) blend membranes for carbon dioxide separation

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Journal of Energy Chemistry 2013年第6期22卷 837-844页

作者： Shichao Feng Jizhong Ren Hui Li Kaisheng Hua Xinxue Li Maicun Deng National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences

In this paper,blend membranes from polyvinyl acetate(PVAc)and block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074)are prepared by solution casting and solvent evaporation *** they are homogeneous on a macro-scale,the observations from DSC and SEM indicate micro-phase separation for PVAc/Pebax1074 blend *** the increase of Pebax1074 content,gas permeabilities of CO2,H2,N2and CH4all increase ***/Pebax1074 blend membranes with high PVAc content are appropriate for CO2/*** temperature dependence of gas permeability is divided into rubbery region and glassy *** activation energies of permeation in rubbery region are smaller than those in glassy region,and they all decrease with increasing Pebax1074 *** N2,H2and CH4,their gas permeation properties are mainly influenced by the dual-mode sorption and hydrostatic pressure *** for CO2,its permeability increases with the increase of pressure due to CO2-induced plasticization effect,which is more obvious for PVAc/Pebax1074 blend membranes with high PVAc content.

关键词： polyvinyl acetate poly(amide-12-b-ethylene oxide) blend membrane carbon dioxide separation

Effects of Vibration Technology and polyvinyl acetate Emulsion on Microstructure and Properties of Expanded Polystyrene Lightweight Concrete

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Transactions of Tianjin University 2009年第2期15卷 145-149页

作者：赵晓艳田稳苓姜忻良张雪松 School of Civil Engineering Tianjin University Civil Engineering Institute Hebei University of Technology China Academy of Building Research

To prevent expanded polystyrene （EPS） beads from rising up to the surface in the molding process of EPS lightweight concrete, vibration with pressure was applied and the polyvinyl acetate （PVA） emulsion was adopted to improve its mechanical properties. The mechanical properties, thermal properties and durability of EPS lightweight concrete were tested. The microstruetures of EPS lightweight concrete were observed by scanning electron microscope （SEM）. Vibration with pressure reduces the number of small cracks. The 180 d compressive strength and flexural strength increase obviously as a large amount of PVA was added. The mixed amount of PVA has no obvious influence on the thermal performance when it is not more than 10% of the cement. Vibration with pressure and surface modification of EPS beads by PVA improve the combination of EPS beads with cement stone and the mechanical properties of EPS lightweight concrete.

关键词： expanded polystyrene(EPS) lightweight concrete vibration with pressure polyvinyl acetate microstructure mechanical properties thermal properties

Synthesis of Microcrystalline Cellulose—polyvinyl Alcohol Stabilized polyvinyl acetate Emulsion

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Green and Sustainable Chemistry 2023年第1期13卷 23-33页

作者： Ravindra V. Gadhave S. K. Vineeth Department of Polymer and Surface Engineering Institute of Chemical Technology Mumbai India

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.

关键词： Wood Adhesive polyvinyl acetate Microcrystalline Cellulose Bio-Based Emulsion

Importance of Dynamic Mechanical Analysis to Predict Performance of the polyvinyl acetate Wood Adhesives in Summer Season

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Open Journal of Polymer Chemistry 2022年第3期12卷 93-100页

作者： Ravindra V. Gadhave Department of Polymer and Surface Engineering Institute of Chemical Technology Mumbai India

Conventionally available polyvinyl acetate (PVAc) wood glues are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor strength at high humidity, poor strength at high temperature and workability at low-temperature. PVAc is non-resistant to high humidity, and if such adhesive bonds are exploited in a highly humid environment, its strength substantially decreases. Sufficiently water-resistant adhesive bonds are achieved by modifying PVAc dispersion with special chemicals like acrylic acid (AA) and N-methylol acrylamide (NMA) as a co-monomer, Silanes, and ethylene modified PVA. The Lewis acids like aluminium chloride and aluminium nitrate are used as cross-linkers. So PVAc adhesives are classified as reactive and non-reactive glue. Application of non-reactive D1 (as per EN 204-205) and reactive D2 and D3 (as per EN 204-205) adhesives for bonding laminate on plywood is a regular practice in the Indian market. In summer time, Crack formation was seen in laminate bonded with reactive D2 and D3 adhesives in regions where the room temperature was above 45°C. However, if the same laminate substrates were bonded with non-reactive D1, no cracks were seen. To analyse the above phenomenon, we have done Dynamic mechanical analysis of non-reactive D1, reactive D2 and D3 adhesive.

关键词： polyvinyl acetate Wood Adhesive Cracking Dynamic Mechanical Analysis

Starch Grafted Water Resistant polyvinyl acetate-Based Wood Adhesive: A Review

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Open Journal of Organic Polymer Materials 2022年第2期12卷 17-30页

作者： Ravindra Vilas Indubai Gadhave Department of Polymer and Surface Engineering Institute of Chemical Technology Mumbai India

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.

关键词： Starch Water Resistance Grafting polyvinyl acetate N-Methylol Acrylamide

Comparative Study of Effect of Addition of Calcium Carbonate and Clay on the Performance Properties of polyvinyl acetate Wood Glue

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Open Journal of Polymer Chemistry 2023年第1期13卷 1-13页

作者： Ravindra V. Gadhave Department of Polymer and Surface Engineering Institute of Chemical Technology Mumbai India

polyvinyl alcohol (PVA) stabilized polyvinyl acetate (PVAc) dispersions-based wood adhesive has poor water and heat resistance. Recently, the addition of fillers in the wood adhesive is one of the most effective ways to enhance the performance of PVAc wood adhesive. Inorganic fillers have unique characteristics to improve the performance of adhesive, such as small size, high surface energy and surface hardness. Hence, the present work investigates the applicability of calcium carbonate and clay incorporated 3% in situ emulsion polymerization PVAc wood adhesive. 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 3% calcium carbonate and 3% clay were prepared and the shear strength of the applied adhesive on wood was measured. The viscosity of the adhesives was reduced in the case of the addition of calcium carbonate and increased in the case of clay. The mechanical properties like tensile strength of adhesives with calcium carbonate and clay were measured by a universal tensile machine (UTM). Thermal stability was studied by differential scanning calorimetry (DSC). The tensile shear strength demonstrates that clay can improve bonding strength as compared to calcium carbonate of PVAc adhesive in wet conditions. The hardness of PVAc films was also changed positively by the addition of calcium carbonate and clay. Thermal stability of PVAc was significantly improved as calcium carbonate and clay were added to PVAc. Here, we did a comparative study of the effect of the addition of calcium carbonate and clay filler materials in situ polymerization of PVAc on their different properties.

关键词： polyvinyl acetate Clay Calcium Carbonate polyvinyl Alcohol Wood Adhesive

Cellulose Stabilized polyvinyl acetate Emulsion: Review

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Open Journal of Organic Polymer Materials 2021年第2期11卷 51-66页

作者： Pritam V. Dhawale S. K. Vineeth Ravindra V. Gadhave Prakash A. Mahanwar Department of Polymer and Surface Engineering Institute of Chemical Technology Mumbai India

The global energy crisis and overconsumption of non-renewable resources have depleted natural resources, climatic changes with global warming, and rise in sea level. The research on alternate sources and chemicals has resulted in the usage of green materials. These biomaterials are sustainable sources, biodegradable, and are abundant in nature. The replacement of petrochemicals with biopolymers has gained much importance in this aspect. Conventionally, polyvinyl alcohol is employed as a protective colloid in polyvinyl acetate adhesive. polyvinyl alcohol has the limitation of petroleum origin, is replaced by biopolymers. Starch being a biopolymer, has gained interest in replacing polyvinyl alcohol as a stabilizer. Cellulose has a low cost, and the most abundant biomaterial finds application as a reinforcing agent in conventional adhesives. Exploring cellulose as a stabilizer for polyvinyl acetate emulsion polymerization with reinforcement has created potential applicability of cellulose in adhesives. Surface hydroxyl groups in cellulose act as sites for functionalization, making it material for the adhesive sector. This review paper aims to showcase biomaterials, namely starch, and cellulose, in the adhesive field. A detailed review of cellulose as functional filler for polyvinyl acetate emulsion adhesives has been explained.

关键词： Cellulose Nanocellulose polyvinyl acetate Wood Adhesive Renewable Material

Strength performance of mortise and loose-tenon furniture joints under uniaxial bending moment

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Journal of Forestry Research 2014年第2期25卷 483-486页

作者： Mohammad Derikvand Ghanbar Ebrahimi Department of Wood and Paper Science and Technology College of Natural ResourcesUniversity of Tehran

We determined the effects of adhesive type and loose tenon dimensions （length and thickness） on bending strength of T-shaped mor- tise and loose-tenon joints. polyvinyl acetate （PVAc） and two-component polyurethane （PU） adhesives were used to construct joint specimens. The bending moment capacity of joints increased significantly with increased length and thickness of the loose tenon. Bending moment capacity of joints constructed with PU adhesive was approximately 13% higher than for joints constructed with PVAc adhesive. We developed a predictive equation as a function of adhesive type and loose tenon dimensions to estimate the strength of the joints constructed of oriental beech （Fagus orientalis L.） under uniaxial bending load.

关键词： bending moment capacity mortise and loose tenon loose tenon dimensions polyvinyl acetate two-component polyurethane

Radio Frequency Gluing Technique for Wood-to-Wood Bonding: Review

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Open Journal of Polymer Chemistry 2023年第2期13卷 15-26页

作者： Ravindra V. Gadhave Super Bond Adhesives Private Limited Thane India

White glues, also referred to as polyvinyl acetate (PVAc) adhesives, are thermoplastics that soften when heated to a specific degree and re-harden when cooled. For general assembly tasks in the joinery business, such as edge gluing, wood veneer, and edge bonding, white glues have been used. White glue requires a prolonged setting time to achieve adequate handling strength as it solidifies through evaporation or absorption of water by the wood. Cold press and hot press techniques are used to bond wood substrates. Recently, white glue is frequently used as a wood adhesive with dielectric heating systems to prevent this and enhance production speeds. Radio frequency (RF) curing is merely a technique for heating glue lines in wood-to-wood joints. It considered a source of heat, like steam and electricity. In order to bond wood substrates with the least amount of clamping time, the RF produces a very rapid, uniform rise in temperature. In this review paper, we discussed the radio frequency curing technique, their mechanism and troubleshooting to achieve perfect wood bond in joinery segment.

关键词： Radio Frequency Curing Wood Adhesive polyvinyl acetate