ABSTRACT
The capabilities and performance of γ-titanium phosphate (γ-TiP) with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a latent thermal catalyst were investigated by the copolymerization of glycidyl phenyl ether (GPE) and hexahydro-4-methylphthalic anhydride (MHHPA) at different temperatures for a period of one hour. Polymerization was not observed until the reactants were heated to 100 °C. Upon increasing the temperature to 120 °C, the conversion in the presence of γ-TiP·DBU as a catalyst showed 98% conversion in 1 h. The thermal stability of GPE and MHHPA reacted in the presence of γ-TiP·DBU at 40 °C for 144 h resulted in less than 7% conversion of GPE. The conversion of GPE did not show a significant increase at 40 °C.
ABSTRACT
The curing of a mixture of glycidyl phenyl ether (GPE) and hexahydro-4-methylphthalic anhydride (MHHPA) with zeolitic imidazolate frameworks (ZIFs)-ZIF-7, ZIF-8, ZIF-11, and ZIF-14-as latent thermal initiators has been critically evaluated. For ZIF-8 and ZIF-14, the % conversion values for GPE were 92 and 93%, respectively, for curing at 100 °C and for 1 h. With regard to the stability of ZIF-8 and ZIF-14 in the GPE-MHHPA mixture, the % conversion values for GPE were 11 and 12% for storage over 8 days at 25 °C. The ZIF-8 and ZIF-14 initiators exhibited excellent thermal latency for heating at 100 °C and showed good stability for storage at 25 °C. To evaluate the practicality of the resin curing system, the reactions of 2,2-bis(4-glycidyloxyphenyl)propane (DGEBA) and MHHPA with ZIFs were studied by differential scanning calorimetry. Prominent exothermic peaks for ZIF-8 and ZIF-14 were observed at 157 and 162 °C, respectively; by comparison, for the commercially available microencapsulated latent thermal initiators HX-3088 and HX-3722, the respective peak maxima were 177 and 181 °C, respectively. The exothermic peak maxima for ZIF-8 and ZIF-14 were lower than those for HX-3088 and HX-3722. The ZIF-8 and ZIF-14 initiators can be stored in precured epoxy resin at 25 °C and cured by lower temperatures compared with commercially-available initiators HX-3088 and HX-3722.
ABSTRACT
We report a case of diffuse large B-cell lymphoma (DLBCL) in the ampulla of Vater, causing painless obstructive jaundice in a 78-year-old woman. Duodenal endoscopy revealed a mass in the ampulla of Vater and narrowing of the second portion of the duodenum, although diagnosing DLBCL from an endoscopic biopsy was impossible because there were several kinds of leukocytes in the infiltrate. We performed pylorus-preserving pancreatoduodenectomy to establish a histological diagnosis, relieve the obstructive jaundice, and remove the narrowed second portion of the duodenum. Histological and immunohistochemical examination of the surgically resected specimen confirmed a diagnosis of DLBCL. Chemotherapy is the mainstay of treatment for DLBCL; however, surgery still plays an important role when the histological diagnosis cannot be established preoperatively and when complications are not amenable to nonsurgical therapy.
