On the Nature of Epoxy Resin Post-Curing

Post-curing is intended to improve strength, elevate glass transition, and reduce residual stress and outgassing in thermosets. Also, experiments indicate post-curing temperatures lead to ether crosslinks and backbone dehydration. These results informed molecular dynamics methods to represent them and compare the resulting thermomechanical effects. Diglycidyl ether of bisphenol A (DGEBA)-diamino diphenyl sulfone (DDS) systems were examined. Independent variables were resin length, stoichiometry, and reaction type (i.e., amine addition, etherification, and dehydration). Etherification affected excess epoxide systems most. These were strengthened and became strain hardening. Systems which were both etherified and dehydrated were most consistent with results of post-curing experiments. Dehydration stiffened and strengthened systems with the longer resin molecules due to their intermediate hydroxyl groups for crosslinking. Changes in the concavity of functions fit to the specific volume versus temperature were used to detect thermal transitions. Etherification generally increased transition temperatures. Dehydration resulted in more transitions.

Research on Performance of Flame-Retardant Epoxy Resin Electronic Packaging Materials

In this article, a new flame-retardant epoxy electronic packaging materials was synthesized through the reaction of matrix resin (E-51), flame retardant (neopentyl glycol phosphate melamine sale, NPM), toughening agent (nitrile rubber, CTBN), curing agent (4, 4-diamino diphenyl sulfone, DDS) and curing catalyst (dosage of benzoyl peroxide, BPO). The results showed that: when the flame retardant was added in an amount of 5wt%, ultimate index (LOI) value of the EPNPM system was increased 2 than that of the EPAl (OH)3 system. When the NPM was added in an amount of 5wt%, the tensile shear strength of the composite was increased 18.27% than that of pure composite. Consequently, the EPNPM system prepared showed betterflame retardance and the mechanical properties.

Clinical Relevance of Autoantibodies in Patients with Autoimmune Bullous Dermatosis

The authors present their experience related to the diagnosis, treatment, and followup of 431 patients with bullous pemphigoid, 14 patients with juvenile bullous pemphigoid, and 273 patients with pemphigus. The detection of autoantibodies plays an outstanding role in the diagnosis and differential diagnosis. Paraneoplastic pemphigoid is suggested to be a distinct entity from the group of bullous pemphigoid in view of the linear C3 deposits along the basement membrane of the perilesional skin and the “ladder” configuration of autoantibodies demonstrated by western blot analysis. It is proposed that IgA pemphigoid should be differentiated from the linear IgA dermatoses. Immunosuppressive therapy is recommended in which the maintenance dose of corticosteroid is administered every second day, thereby reducing the side effects of the corticosteroids. Following the detection of IgA antibodies (IgA pemphigoid, linear IgA bullous dermatosis, and IgA pemphigus), diamino diphenyl sulfone (dapsone) therapy is preferred alone or in combination. The clinical relevance of autoantibodies in patients with autoimmune bullous dermatosis is stressed.