New tetrafunctional epoxy resin system with increased shelf life

Abstract

Chlorine-and methyl-substituted aromatic diamines based on diaminodiphenylmethane were epoxidized and characterized. The effect of different substituents on epoxidation was studied. The cure studies of the two new tetrafunctional resins in comparison with unsubstituted resin N,N,NЈ,NЈ-tetraglycidyl-4,4Ј-diaminodiphenylmethane (TGDDM) was carried out by DSC with 3,3Ј-dichloro-4,4Јdiaminodiphenylmethane (o-DCDDM; 30% w/w) as a common curing agent. The mechanical properties such as flexural, Izod impact, heat distortion temperature (HDT), of such cured neat resins were also studied. The results of the cure studies indicate that the substitution of the ␣-hydrogen of the resin by chlorine or methyl group decreases the reactivity of the resin leading to an increase in the shelf life. This study also indicates that the functionality of the resin plays a pivotal role in the reactivity and thus the shelf life of an epoxy resin system. The results of the mechanical properties of the neat resin casts obtained by subjecting to a common cure schedule when compared with the unsubstituted resin showed a decrease in impact strength, which is obvious because of the presence of a bulky pendant group but the impact strength was higher than that of the TGOS30 resin system. Results of flexural strength of the different substituted neat resin casts did not show much of a deviation from that of the unsubstituted resin system. The HDT results indicate no significant difference in the values of the unsubstituted resin vis-a-vis with substituted resin systems.

Subtle variations in the structure of crosslinked epoxy networks and the impact upon mechanical and thermal properties

“…Their benefits are many, and well known, including excellent mechanical properties and corrosion, thermal and chemical resistance to name a few . Another important advantage is their comparative ease of processability, such as low viscosity, long pot life and importantly little to no evolution of volatiles during cure . However, another major factor that has continued to aid their proliferation throughout various industries is the enormous range of available monomers of varying structure, viscosity, and reactivity .…”

Effect of aromatic substitution on the kinetics and properties of epoxy cured tri‐phenylether amines

“…Similar findings on the impact of aromatic substitution patterns have been reported elsewhere 23,24 and used to specifically develop resin systems with improved shelf life. 25,26 Despite electronic and inductive effects being well understood for mono-and bi-aromatic amines, for more complex multi-aromatic amine structures, they are far less studied. To address this, a series of isomeric tri-aromatic ether-linked amines that vary only in their aromatic substitution positions have been cured with the commercially available bifunctional epoxy resin, BisF.…”

Development and study of the thermal and electrical behaviour of TGDDS epoxy nanocomposites for high-performance applications

“…The reaction was continued at this temperature for further period of 1 h. The resulting solution was extracted with chloroform. The organic layer was collected and concentrated at a reduced pressure to get the light brown coloured liquid epoxy product (Shih and Ma 1998;Jagdeesh and Shashikiran 2004). The synthesis of TGDDS is shown in Scheme 1.…”