A Carboxyl-Terminated Polybutadiene Liquid Rubber Modified Epoxy Resin with Enhanced Toughness and Excellent Electrical Properties

Abstract

The modification of epoxy (EP) resin with carboxyl-terminated polybutadiene (CTPB) liquid rubber was carried out in this work. The chemical reaction between the oxirane ring of EP and the carboxyl group of CTPB and kinetic parameters were investigated by Fourier transform infrared and differential scanning calorimetry. The resulting pre-polymers were cured with methyl hexahydrophthalic anhydride. Scanning electron microscopic observations indicate that the micro-sized CTPB particles dispersed uniformly in the EP matrix formed a two-phase morphology, mainly contributing to the improved toughness of the modified network. The best overall mechanical performance was achieved with 20 phr CTPB; above it, a fall in the strength and modulus was observed. The storage modulus and loss declined with the CTPB concentration due to its lower modulus and plasticizing effect from dynamic mechanical analysis measurements. Moreover, due to the weak polarity and excellent electrical insulation of CTPB, the CTPB-modified EP presented higher electrical resistivities and breakdown strength, and low dielectric permittivity and loss compared with neat EP.

Heat conductive h‐BN/CTPB/epoxy with enhanced dielectric properties for potential high‐voltage applications

“…We know that similar to the crystal structure of graphite and mica, hBN has molecularly smooth basal plane and no surface functional group which is available for chemical reaction or bonding and interaction. However, at the edge of the hBN platelets, there exits amine and hydroxyl functional groups which are available for chemical bonding or interaction [20] after surface treated with coupler. Therefore, as the hBN loading increases, more number of hydroxyl groups are incorporated into the composites, thereby raising the k [20].…”

Toughened epoxy‐liquid polybutadiene networks cured with anhydride with outstanding thermal and mechanical properties

“…[2][3][4] In this sense, liquid hydroxyl terminated polybutadiene (HTPB) appeared as promising toughening agent for epoxy networks due to its availability at low cost and good flexibility. [5][6][7][8][9][10][11][12][13] Some strategies for improving the compatibility of HTPB with epoxy matrices has been reported in the literature, including the epoxydation of the internal double bonds of HTPB, [14][15] and also the incorporation of more reactive groups at the end on the HTPB chains, such as carboxyl groups, 7,[16][17][18][19] amino groups, [20][21] urea, 22 and isocyanate groups (PBNCO). 6,8,[16][17][23][24] In some procedure, the incorporation of these functionalized rubber into the epoxy matrix was performed by two sequential steps: the first step consisted of the functionalization of HTPB followed by a second step where the functionalized HTPB was reacted with epoxy prepolymer in the presence of a specific catalyst.…”

Improved Dielectric Properties of Thermoplastic Polyurethane Elastomer Filled with Core–Shell Structured PDA@TiC Particles

“…The enhanced interfacial interactions between PDA@TiC−60 and TPU imparted the composites with higher dielectric strength because more electrical energy was needed to destroy the samples as compared with the raw TiC/TPU. E B decreased with further increasing of two kinds of fillers, which was due to an excess of nanoparticles in the composites producing more empty areas and pores, especially in the interface region of inorganic particles and the polymer matrix [ 38 , 39 ].…”