Improving coating properties of shellac–epoxidised-novolac blends with melamine formaldehyde resin

Purpose The purpose of this study is to improve the coating properties of shellac–epoxidised novolac blends by treatment with melamine formaldehyde resin (MF) at ambient temperature for its use as a coating material. Design/methodology/approach Epoxidised-novolac resin was synthesised by epoxidation of novolac resin with epichlorohydrin. Novolac resin was synthesised by reaction of phenol with formaldehyde in acidic medium. Shellac was blended with the epoxidised-novolac resin in solution in varying ratios and treated the blends with MF resin in fixed ratio. Coating properties of the treated compositions were studied using a standard procedure. The compositions were characterised with Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopic (SEM) spectroscopy. Findings Treatment of shellac–epoxidised-novolac blends with MF resin improved water and alkali resistance of the blends, besides enhancing gloss. Gloss in all the blends was uniformly increased on treatment with MF resin. Water resistance of the blends tremendously improved after treatment with MF resin. Contact angle of the blends against water increased while decreased against ethylene glycol and dioxane. The compositions were more resistant to polar solvent than non-polar ones, suggesting that the compositions shifted to hydrophobic (lipophilic) nature on treatment with the MF resin. Research limitations/implications A specified concentration of MF resin was used in the study. Different concentrations of the MF resin can also be tried for treatment of shellac–epoxidised-novolac blends to see the effect of the resin on the blends. Practical implications Treatment of shellac–epoxidised-novolac blend with MF resin improved the coating properties of the blends. The formulation SeNB-64 is the best with high gloss, good impact, scratch hardness and water resistance, and hence can be used as coating material for metal surfaces. Originality/value Blending of shellac with epoxidised-novolac resin and treatment of the blends with the MF resin was done for the first time. The formulation SeNB-64 can be used as coating material for metal surfaces.

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Coating properties of shellac modified with synthesised epoxidised-novolac resin

Pigment & Resin Technology ◽

10.1108/prt-06-2013-0111 ◽

2014 ◽

Vol 43 (5) ◽

pp. 314-322 ◽

Cited By ~ 2

Author(s):

Mohammad Fahim Ansari ◽

Gautam Sarkhel ◽

Dipendra Nath Goswami ◽

Bangali Baboo

Keyword(s):

Metal Surfaces ◽

Standard Procedure ◽

Impact Resistance ◽

Contact Angle Measurement ◽

Angle Measurement ◽

Coating Material ◽

Formaldehyde Resin ◽

Coating Properties ◽

Novolac Resin ◽

Content Type

Purpose – The purpose of this paper is to improve the properties of shellac by blending with epoxidised novolac resin for its use as coating material for metal surfaces. Design/methodology/approach – Epoxidised-novolac resin was synthesised by epoxidation of novolac resin, which in turn was synthesised by reaction of phenol with formaldehyde. The epoxidised-novolac resin was blended with different weight ratios of shellac ranging 10-50 weight per cent with an interval of 10 weight per cent. Films of the blends were studied for different coating properties using standard procedure. Findings – Significant improvement in coating properties of shellac such as gloss, scratch hardness and impact resistance was observed on blending with epoxidised novolac resin. Resistance towards water and alkali increased, while acid resistance decreased, with the increase in concentration of epoxidised novolac resin in the blends. Contact angle measurement revealed that blends showed more resistance towards polar solvent than non-polar ones. Research limitations/implications – Epoxidised-novolac resin used in the study was synthesised of epoxy equivalent of 187. Epoxidised-novolac resin of different epoxy equivalent can also be synthesised and used for blending and studying the properties. Practical implications – Blending of shellac with epoxidised-novolac resin improved the coating properties of shellac, which was further enhanced with the treatment of butylated melamine formaldehyde resin. The formulation can be used as coating material for metal surfaces. Originality/value – Blending of shellac with epoxidised-novolac resin was done for the first time. The formulation can be utilised for developing coating material for metal surfaces.

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The influence of urea on composition, microstructure and electrochemical properties of nitrogen-enriched carbon based on polyvinylpyrrolidone/melamine formaldehyde resin

Pigment & Resin Technology ◽

10.1108/prt-02-2015-0017 ◽

2015 ◽

Vol 44 (5) ◽

pp. 257-265 ◽

Cited By ~ 1

Author(s):

Qiang Li ◽

Jiahuan Du ◽

Xugang Zhang ◽

Chuanli Qin ◽

Zheng Jin ◽

...

Keyword(s):

Electrochemical Properties ◽

Electrode Material ◽

Nitrogen Concentration ◽

Negative Electrode ◽

Formaldehyde Resin ◽

Melamine Formaldehyde ◽

High Nitrogen ◽

Content Type ◽

Melamine Formaldehyde Resin ◽

High Nitrogen Concentration

Purpose – The purpose of this paper is to develop porous nitrogen-enriched carbon (NC-U) with high nitrogen concentration and high specific capacitance (Cpe) as the electrode material for supercapacitors. Design/methodology/approach – NC-U was obtained by carbonization of polyvinylpyrrolidone/melamine formaldehyde resin (PVP/MF) with different contents of urea. In comparison, NC-K was also prepared by the KOH activation method. A series of asymmetric supercapacitors with NC as a negative electrode was assembled. The composition, microstructure and electrochemical properties of NC and their supercapacitors were studied. Findings – The results show that NC-U shows irregular particles with a porous honeycomb structure. High Cpe was obtained for urea-treated NC-U because of the improvement of nitrogen, conductivity and specific surface area (S BET ). NC-U50 with 13.15 per cent at nitrogen has the highest Cpe of 148.53 F/g because of the highest concentration of N-6 and N-5. NC-K with higher S BET has lower Cpe than NC-U50 because of its lower nitrogen concentration. When the specific power of the supercapacitor with NC-U50 as a negative electrode is 1,565.56 W/kg, its specific energy is still 4.35 Wh/kg. There is only 5.9 per cent decay in Cpe over 1,000 cycles. Research limitations/implications – NC-U is a suitable electrode material for supercapacitors, which can be used in the field of electric vehicles to solve the problems of energy shortage and environmental pollutions. Originality/value – Porous NC-U based on PVP/MF/urea composites with high nitrogen concentration and Cpe is novel, and it owns good electrochemical properties.

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