Pigment & Resin Technology

Purpose – The purpose of this paper is to investigate in situ modification of cyclohexanone-formaldehyde resins (CFR) by 4-vinyl aniline (Van). The roles of the reaction temperature, the conductivity, thermal properties, and molecular weight of the product were investigated. CFR was in situ modified with VAn in the presence of sodium hydroxide. Ketonic resin-bound 4-vinyl aniline was synthesised with a one-step method of in situ modification of ketonic resin. The roles of the reaction temperature and the conductivity of the product were investigated.

Design/methodology/approach – Ketone, formalin (37% aqueous solution), vinyl aniline were mixed and then 20% aqueous NaOH solution was added to produce the resin. The solubility, molecular weight and thermal properties of the products were investigated.

Findings – The 4-vinyl aniline modified cyclohexanone-formaldehyde resins were found to have conductivity values of 10^-4 and 10^-2?S/cm and may be considered as conductive ketonic resin. Soluble and processable conductive ketonic resins were developed.

Research limitations/implications – The reaction mixture of CFR must be stirred continuously at low temperature. Subsequently, 37% formalin was added dropwise in equal portions while refluxing. Temperature should be controlled to prevent the thermal polymerisation of vinyl group and higher branching of amino groups. The amount of vinyl aniline used in reaction mixture is limited since the formed resin may become insoluble in common organic solvents.

Practical implications – This study provides technical information for the synthesis of conducting resins. The modified resins contain vinyl groups. The chemical redox or radical system can be used to polymerise these vinyl groups and resins with much higher molecular weight may be produced. The resins may also promote the adhesive strength of a coating and corrosion inhibition to metal surfaces of a coating.

Originality/value – Vinyl aniline modified cyclohexanone formaldehyde resins have been synthesised in the presence of a basice catalyst. These soluble and conductive resins may overcome difficulties in the applications of conducting polymers and open new application areas. Therefore, the vinyl aniline modified resin may find a number of new application areas, as well as existing conducting resin and polymer applications.