S. T. Mhaske

Design and synthesis of bio-based UV curable PU acrylate resin from itaconic acid for coating applications

Abstract UV curable PUA resin was successfully synthesized from polyol based on sustainable resource originated from itaconic acid (IA), isophorone diisocyanate (IPDI) and 2-hydroxyethyl methacrylate (HEMA). A polyol was synthesized by condensation reaction of IA with 16-hexanediol in the presence of p-Toluenesulfonic acid (pTSA). The synthesized PUA resin was characterized for its structural elucidation by using Fourier Transform Infrared Spectrophotometer (FTIR), 1H and 13C NMR spectroscopy. The synthesized UV curable PUA resin was incorporated in varying concentrations in conventional PUA coating system. The effects of varying concentration of synthesized UV curable PUA resin on rheology, crystallinity, thermal and coating properties were evaluated. The rheological behavior of the resins were evaluated at variable stress and result showed decrease in viscosity of resin as concentration of synthesized UV curable PUA resin increases in conventional PUA resin. The cured coatings have been evaluated for glass transition temperature (Tg) and thermal behavior by differential scanning calorimeter and thermogravimetric analysis respectively. The degree of crystallinity of the coatings was determined from X-ray diffraction patterns using the PFM program. It was found that increase in the mass proportion of IA based PUA in coatings, the coating becomes more rigid and crystalline. The synthesized UV curable PUA coatings showed interesting mechanical, chemical, solvent and thermal properties as compared to the conventional PUA. Further, cured coatings were also evaluated for gel content and water absorption.

Polyesteramide resin from PET waste and fatty amide

Purpose – The purpose of this paper is synthesis of polyesteramide resin from jatropha oil and monomer from recycling of poly(ethylene terephthalate) (PET) to get the excellent benefit of individual structure. Along with the synthesis of polyesteramide resin, this research work will also help in recycling of PET waste and help for the conversion of monomer obtained from recycling of PET to value-added application. Design/methodology/approach – Polyesteramide resin was synthesized by conventional method, i.e. by converting jatropha oil to corresponding fatty amide, i.e. hydroxyl ethyl jatropha oil fatty acid amide (HEJA), and treating it with dicarboxylic acid, i.e. sebacic acid but bis(2-hydroxyethyl) terepthalamide (BHETA) is added, i.e. monomer of PET, and then resin synthesis is carried out. Synthesized resin is cured with isocyanate and used for coating application. Coating is characterized for physical, mechanical, thermal and anticorrosive properties. Findings – Coating shows excellent balance of fl...

Synthesis of bio-based epoxy resin from gallic acid with various epoxy equivalent weights and its effects on coating properties

The bio-based epoxy resins for coating application were synthesized from gallic acid (GA) in various molar ratios with epichlorohydrin (ECH). The reaction was carried out in the presence of sodium hydroxide (NaOH) and phase-transfer catalyst tetrabutylammonium bromide. The reaction progress rate at various molar ratios as 1:8, 1:12, and 1:16 with respect to time was monitored by calculating the epoxy content. The epoxy content value increases in the product as the molar ratio of GA to ECH increases. Epoxy equivalent weight of products was evaluated by physiochemical method and structure illustrated by Fourier transform infrared and 1H-nuclear magnetic resonance spectroscopy. This bio-based epoxy resin was cured with polyamide hardener, and the coating properties such as mechanical, chemical, and solvent resistance were studied. The cured films have been evaluated for glass transition temperature (Tg) and thermal behavior by a differential scanning calorimeter and thermogravimetric analysis, respectively. The bio-based epoxy coatings show interesting mechanical, chemical, and thermal properties as compared to the conventional epoxy resin. The gel and water absorption of polyamide-cured coatings has also been evaluated.

Effect of extrusion reprocessing on the mechanical, thermal, rheological and morphological properties of nylon 6/talc nanocomposites

In this study, the preparation of nylon 6/talc nanocomposites was studied by melt blending in a co-rotating twin-screw extruder having length/diameter ratio of 32:1 at a screw rotation speed of 100 r min−1. Concentration of nanotalc was varied from 1 phr to 5 phr in nylon 6. The composite samples were subjected to a series of three extrusion cycles, and the effect of reprocessing on the structural properties of materials was investigated. Properties such as mechanical (tensile flexural and impact), thermal (differential scanning calorimetry), morphological (scanning electron microscopy), rheological (viscosity vs. shear rate), and colour spectrophotometry were investigated. This study would enrich the knowledge about the recycling of nylon 6, with the additional aspect of the use of collected data from more complex system, that is, composite materials, where the nanotalc particles play a role in the interactions initiated by repeated extrusion processing. Mechanical, thermal, rheological and colour properties improved with the increase in nanotalc in nylon 6 and remained nearly unchanged up to second extrusion processing. However, all the properties decreased on third extrusion processing due to the degradation of nylon 6 matrix.

Modification of silane based coating with bisphenol A, isosorbide and resorcinol for anticorrosive application

Abstract(3-glycidoxypropyl) trimethoxysilane (GPTMS) and tetraethyl orthosilicate (TEOS) based coating has been prepared by sol-gel method which has oxirane ring as functionality present in the structure. Since the GPTMS has free oxirane ring hence to modify the sol through this oxirane ring,–OH functional precursor has been added into it. The performance of bisphenol A, isosorbide and resorcinol solely and in combination as bisphenol-isosorbide, bisphenol A-resorcinol and Isosorbide-resorcinol has been compared for such modification. It is observed that in anticorrosive properties, bisphenol A has given the best result. The comparative result has been observed with bisphenol-resorcinol combination. The result has been proven by salt spray and EIS study. In EIS study it is observed that Bisphenol A based coating and Bisphenol AResorcinol combination has shown the impedance value >10 Gohms. In mechanical properties, the hardness of bisphenol A and resorcinol based system observed to be higher. This is due to the aromatic linkage has been introduce in the system which tends to improve the hardness performance of the system.

Rheological analysis of dough prepared with lentil flour at different moistures for production of extruded products

Extruded products like expanded puff product are prepared from lentil (Lens culinaris Medik) at different conditioning moisture (14, 18, 22xa0%) for constant temperatures, range from 100 to 210xa0°C, which was used during extrusion processing. The present study was aimed to investigate the effect of conditioning moisture at different temperature on the rheological behavior of lentil. It was determined that viscosity and yield stress of the lentil dough decreased with increase in conditioning moisture of flour used during extrusion process. Yield stress decreased by 68 and 80xa0% for conditioning moisture at 18 and 22xa0%, respectively as compared to those conditioning moisture at 14xa0%. This was attributed to the changes in the carbohydrates occur due to high extrusion temperature. Increasing the conditioning moisture during extrusion process decreased the fluid consistency index and increased the flow behavior index of the dough, demonstrating a lower viscosity and increased fluidity. All the samples revealed shear thinning behavior. The dough prepared using lentil shows depletion in gelatinization temperature with decreased in conditioning moisture as demonstrated by viscoelastic analysis (loss modulus, storage modulus, Tan δ) of the samples.

Effect of 2-aminobenzothiazole on antimicrobial activity of waterborne polyurethane dispersions (WPUDs)

AbstractAntimicrobial coating, which has myriad applications in food industries,n health authorities, veterinary care,n cleansing, milk parlors, etc., has been produced in this research work. Polyol was synthesized by the condensation reaction of itaconic acid and 1,6-hexanediol. This polyol was then used for the synthesis of waterborne polyurethane dispersion (WPUDs), in which polyol was reacted with dimethylol propionic acid and isophoronediisocyanate to form a prepolymer. The prepolymer obtained was neutralized with triethylamine and 1,4-butanediol was used as a chain extender, followed by the addition of appropriate amount of water, as in a typical acetone process. 2-Aminobenzothiazole (ABT) was incorporated in the backbone along with the chain extender as an antimicrobial agent, and the effect of concentration of ABT on antimicrobial activity of coatings was studied. The obtained WPUDs were analyzed by Fourier transform infrared spectroscopy, particle size and zeta potential. Cured films were characterized for thermal, mechanical and antimicrobial properties. WPUD with 20% ABT content showed increased thermal properties with the highest Tg of 71.48xa0°C and good antimicrobial activity with an approximate 60% inhibition rate.n

Synthesis of polyurethane dispersion from polyesteramide polyol

Purpose To synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion. Design/methodology/approach Polyesteramide polyol has been synthesised from phthalic anhydride and fatty amide of mustard oil.Aminolysis of mustard oil had been carried out with diethanolamine. The novel polyurethane dispersion had been synthesised using a polyesteramide polyol as a precursor.Isophorone diisocyanate (IPDI) was used as an isocyanate component and PUDs had been synthesised by an anionic method where DMPA was introduced to introduce –COOH groups as via grafting to the resin backbone. Triethylamine (TEA) was used for neutralisation and hence for further dispersion in water. Hydroxyl ethyl methacrylate (HEMA) was used for the synthesis to introduce unsaturation in the backbone of polyurethane dispersion (PUDs).The coating was made by an UV curing process. The coating was characterised for mechanical properties, chemical properties, ...

Novel phosphorus-containing epoxy resin from renewable resource for flame-retardant coating applications

A phosphorus-containing epoxy resin has been derived from a renewable resource, sebacic acid (SA), and formulated for flame-retardant applications. The synthesized epoxy resin was characterized by physicochemical and spectral analysis including Fourier-transform infrared (FTIR), 1H and 31P nuclear magnetic resonance spectroscopies. Curing of the epoxy resin mixture was carried out with polyamide hardener at 1:1 stoichiometry on equivalent weight basis. The developed coatings were characterized in terms of their mechanical, solvent, gel content, water absorption, chemical, thermal, and flame-retardant properties, while the glass-transition temperature and thermal stability of the coatings were analyzed by differential scanning calorimetry and thermogravimetric analysis, respectively. The results revealed that the coatings with added SA-based epoxy resin showed good mechanical, chemical, and solvent-resistance properties. The thermal profile of the coatings manifested that the char yield increased with the concentration of the SA-based epoxy resin. Limiting oxygen index (LOI) and UL-94 tests were performed to understand the flame-retardancy behavior of the synthesized coatings, revealing an enhancement as the concentration of phosphorus-containing epoxy resin was increased.

Epoxy-based anticorrosive coating developed with modified poly(o-anisidine) and depolymerized product of PET waste

Poly(o-anisidine) (POA) is used as a modifier in an epoxy system to enhance its anticorrosive properties. The modification of POA is done by aminosilane to introduce amine functionality on the surface. Through this functionality, it becomes part of the coating backbone during curing of an epoxy-polyaminoamide system. The concentration of poly(o-anisidine) has been varied as 1, 3, and 5 wt%. Depolymerized product of polyethylene terephthalate (PET) obtained from aminolysis of PET with ethylamine has amine functionality. Depolymerized product is added at concentrations of only 1 and 3 wt%. The same concentration is used with 5 wt% of silane-modified POA. The synthesized POA and silane-modified POA (Si-POA) have been characterized by FTIR, UV–Visible, and XRD analysis. The coating is characterized by mechanical properties and it is observed that pencil hardness and scratch hardness of the coating were enhanced to 6H and 3.5xa0kg from 2H and 2.5xa0kg of a plain epoxy system. The anticorrosive properties of Si-POA are better as compared to plain POA, but the addition of depolymerized product is unable to improve the anticorrosive performance of the coating. In EIS study, it is observed that 5% Si-POA system shows the highest impedancexa0>xa010 G (Ω) and it has a tendency to retain anticorrosive performance for longer duration.