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Xanthan Gum—Bio-Based Raw Material for Wood Adhesive

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Green and Sustainable Chemistry 2023年第2期13卷 153-161页

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

Due to their lower environmental impact, ease of accessibility, low cost, and biodegradability, bio-renewable sources have been used extensively in the last several decades to synthesize adhesives, substituting petrochemical-based adhesive. Vegetable oils (including palm, castor, jatropha, and soybean oils), lactic acid, potato starch, and other bio-renewable sources are all excellent sources for the synthesis of adhesives that are being taken into consideration for the synthesis of “eco-friendly” adhesives. Due to their widespread use, accessibility, affordability, and biodegradability, biobased raw materials like carbohydrates used to synthesize wood and wood composite adhesive have gradually replaced petrochemical-based adhesive. Recently, xanthan gum, a naturally occurring polymer, has drawn the interest of scientists as a potentially petroleum source replacement. It possesses specific rheological characteristics, excellent water solubility, and stability to heat, and can be used as a binder, thickener, suspending agent, and stabilizer. Xanthan gum increases the adhesive strength in addition to increasing the viscosity of water-soluble adhesives. This article discusses xanthan gum as a potential substitute for traditional raw materials derived from petroleum that is used as a raw material for adhesives.

关键词： Xanthan Gum Bio-Polymer Adhesive Wood Carbohydrates

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

The clinical outcomes of laser with suction device in mini-percutaneous nephrolithotomy

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Asian Journal of Urology 2022年第1期9卷 63-68页

作者： Abhishek Gajendra Singh Sundaram Palaniappan Shrikant Jai Gopal Tak Arvind Ganpule ravindra Sabnis Mahesh Desai Department of Urology Muljibhai Patel Urological HospitalVirendradesai MargNadiadGujaratIndia

Objective:To evaluate the safety,efficacy and feasibility of laser with suction device in mini-percutaneous nephrolithotomy(mini-PCNL).Methods:A retrospective study was conducted including 200 patients who underwent mini-PCNL for renal *** patients underwent PCNL using Electro-Medical Systems *** addition to the laser in 100 patients,a suction device was used(laser with suction[LWS]).In the other 100,suction device was not used(laser with no additional suction[LOS]).Mini-PCNL was performed using standard technique and Karl Storz minimally invasive PCNL-medium system was *** end point was stone ***:Both the groups were comparable in terms of demographic *** stone size was 15.24±5.90 mm and 16.16±5.53 mm in LWS and LOS,*** Hounsfield unit of stone was 1285.64 and 1206.79 in LWS and LOS,*** time was less in LWS group(56.89±19.65 min)as compared to LOS(62.01±28.81 min).At one-month follow-up,radiological complete clearance was 96%in LWS and 92%in *** subgroup analysis of stones larger than 18 mm,the clearance rate was in favour of LWS(85.7%vs.100%)and also the need for nephrostomy placement was less in LWS ***:LWS device is safe and efficacious when used with *** stones greater than 18 mm,it has a better stone free rate as compared to using no suction.

关键词： Mini-percutaneous nephrolithotomy Laser with suction Stone clearance

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

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

Lactic Acid-Sustainable Raw Material for Biodegradable Hot Melt Adhesive: Review

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Open Journal of Organic Polymer Materials 2022年第3期12卷 31-45页

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

Currently, due to scarcity of hydrocarbon resources and the extensive use of water based, solvent based and hot melt adhesives in wood bonding in furniture industries and packaging industries that demand recyclability, compostability and bio-degradability, recently attention has been concentrated to making these formulations completely bio-based, sustainable and biodegradable. Biodegradable hot melt adhesives (HMAs) prepared from natural sources have a potential for use in furniture and packaging industries because of an increase in awareness of environmental issues, the replacement of conventional petroleum-derived hydrocarbon raw materials by renewable, biodegradable and sustainable materials has developed. In terms of environmental issues, such as climate crisis due to an increase of carbon dioxide emission, attempts have been made to produce HMAs using non-hydrocarbon resins, such as polylactic acid (PLA)-based resins, containing no petroleum as a raw material. Polylactic acid was prepared by self-condensation reactions of lactic acid or by lactide ring opening polymerisation, and used for packaging materials, sanitary pads, diapers etc., especially adhesives owing to its excellent processability and the excellent mechanical properties of its HMAs products. Therefore, recently the use of PLA materials as a substitute for non-biodegradable hydrocarbon-based polymers can be considered to be environmentally favourable. Here, we discussed the various uses of PLA as a sustainable and bio-degradable and sustainable hot melt adhesive.

关键词： Lactic Acid Hot Melt Sustainable Bio-Degradable Adhesive

Application of RP-HPLC method in dissolution testing and statistical evaluation by NASSAM for simultaneous estimation of tertiary combined dosages forms

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Journal of Pharmaceutical Analysis 2015年第5期5卷 307-315页

作者： Yogesh Upadhyay Nitin Sharma G.S.Sarma ravindra K.Rawal Department of Pharmaceutical Analysis Indo-Soviet Friendship College of Pharmacy

A dissolution method with robust high performance liquid chromatographic （HPLC） analysis for im- mediate release tablet formulation was developed and validated to meet the requirement as per Inter- national Conference on Harmonization （ICH） and United States Food and Drug Administration （USFDA） guidelines. The method involved the use of Agilent ZORBAX Eclipse XDB C18 column, and temperature was maintained at 30 ℃. After optimization, the mobile phase was selected as phosphate buffer （KH2PO4, 30 mM）： ACN （60：40, v/v） with pH 3.0, and retention time Rt was found as 3.24, 4.16, and 2.55 min for paracetamol （PCM）, chlorpheniramine maleate （CPM） and phenylephrine hydrochloride （PH） respec- tively at 265 nm and at a flow rate of 1 mL/min. The relative standard deviation （%RSD） for 6 replicate measurements was found to be less than 2%. Furthermore net analyte signal standard addition method （NASSAM） with spectrophotometer was performed for standard and liquid oral suspension. On the basis of selectivity, sensitivity and accuracy analysis, it was confirmed that this novel method could be useful for simultaneous estimation of the given drug combinations. Two-way analysis of variance （ANOVA） was applied for evaluating the statistical difference between the assay results obtained via both NASSAM and RP-HPLC methods and ultimately no significant difference was found between both the methods. All the methods and results were acceptable and confirmed that the method was suitable for intended use.

关键词： DissolutionRP-HPLCNet analyte signal standard addition meth-odTwo-way ANOVA

Zeeman-Like Topologies in Special and General Theory of Relativity

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Journal of Modern Physics 2016年第7期7卷 627-641页

作者： ravindra Saraykar Sujatha Janardhan Department of Mathematics R T M Nagpur University Nagpur India Department of Mathematics St. Francis De Sales College Nagpur India

This is a short review article in which we discuss and summarize the works of various researchers over past four decades on Zeeman topology and Zeeman-like topologies, which occur in special and general theory of rela... 详细信息

关键词： Zeeman Topology Fine Topologies on Minkowski Space Zeeman-Like Topologies in General Relativity Homeomorphism Group Lorentz Group Conformal Group Topological Properties

Hyperparasitism of Homona coffearia Nietn. (Lepidoptera: Tortricidae), the Tea Tortrix of Sri Lanka: Implications for Biological Control

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Advances in Entomology 2015年第2期3卷 33-43页

作者： ravindra S. Walgama Division of Entomology Tea Research Institute Talawakelle Sri Lanka

Tea tortrix, Homona coffearia Nietner (Lepidoptera: Tortricidae), is a seasonal pest of tea in Sri Lanka. Though it is active in dry weather, it is observed that populations do occur in wet weather causing serious damage to tea. The parasite, Macrocentrus homonae Nixon (Hymenoptera: Braconidae), controls the tortrix populations, but the efficiency of Macrocentrus has been reduced on account of hyperparasites in recent times. Level of hyperparasitism was studied in some tea tortrix prone areas in the up country region to study how this affected the tortrix populations during wet weather. The hyperparasitism varied during the study period of which average values observed ranged from 35% to 52% in the plantations studied. A negative linear relationship was observed between the average number of parasite cocoons in a cocoon mass and the percentage hyperparasitism. Three generations of tortrix were evident during the study period of May to November 2005. It is observed that tortrix populations do occur in dry and wet weather, and that hyperparasitism has been identified as the major cause affecting the efficient control of tortrix by the parasite. Possibilities of tea tortrix control in wet weather are discussed.

关键词： Control Hyperparasitism Homona coffearia Lepidoptera Macrocentrus homonae Parasites Tea Tortrix Tea Plantation