Influence of phenoxy modifier on mechanical, electrical and morphological properties of epoxy/DDS system

Abstract

The blends of diglycidyl ether of bisphenol-A (DGEBA) and poly (hydroxyl ether of bisphenol-A) or phenoxy were synthesized by melt blending at 120°C. These blends were cured by an aromatic amine hardener, 4,4′-diaminodiphenyl sulphone (DDS). The experiments were performed to study the different amount of phenoxy (10 to 40 parts per hundred resins) on mechanical and electrical properties of the DGEBA/phenoxy blends, such as tensile properties, flexural properties, impact strength, Rockwell hardness, and volume resistivity. The oxirane group of DGEBA epoxy resin reacts with hydroxyl group of phenoxy which provides good toughness to the epoxy resin. The tensile strength, tensile modulus, flexural strength, flexural modulus, heat deflection temperature and volume resistivity of DGEBA/phenoxy blends decreased with increasing the amount of phenoxy from 10 to 40 parts per hundred resins (phr). The opposite trend was observed in impact strength and Rockwell hardness of all DGEBA/phenoxy blends which were increased with increasing the phenoxy content from 10 to 20 phr, but then decreased upto 40 phr. The SEM studies revealed that the DGEBA/phenoxy blends show a multiphase system with an increase in the phenoxy content from 10 to 40 phr. due to inconvenience of mixing of two phases.

Recyclable High-Performance Epoxy-Anhydride Resins with DMP-30 as the Catalyst of Transesterification Reactions

“…Besides, the addition of DEO incorporated a large number of branch and dangling chains, including unreconnected ester bonds and broken irreversible bonds into networks, which made the polymer chains more flexible, resulting in higher elongation at break [ 41 ]. Common epoxy resins are usually rigid and brittle, which greatly limits their industry application [ 74 , 75 ]. The addition of DEO can increase the toughness of epoxy resins, which is of great significance to the modification of epoxy resins.…”

Thermal degradation kinetics of a commercial epoxy resin—Comparative analysis of parameter estimation methods

“…Moreover, modeling on the basis of isothermal conditions neglects the time needed to achieve the reaction temperature for the sample . This is why it is preferable to use a kinetic study under nonisothermal conditions rather than resorting to using isothermal conditions …”

Degradation studies of epoxy coatings on printed circuit boards after pressure cooker test

“…The authors assign band #4 (measured at 1550 cm −1 ) as a C═C–C stretching vibration of conjugated aromatic compounds. [ 65 ] The almost complete disappearance of band #4 demonstrates a modification of the structure and bonding conditions of the components of the polymer network. It attributes to the degradation of the aromatic structure of the polymer.…”

“…Band #1 (916 cm −1 ) is assigned to the C-O-C bending vibration and demonstrates the existence of an epoxide ring. [62][63][64][65][66] The intensity of this band decreases with ongoing exposition time and completely disappeared after 96 h. Band #1 indicates residual, noncompletely cross-linked epoxide groups. The disappearance of this band can be explained by the temperature-induced opening of the three-membered carbon ring (C-O-C) and an additional cross-linking, which would correspond to further curing.…”