Repositori URV

Identificador: TDX:781

Handle: https://hdl.handle.net/20.500.11797/TDX781

Autors:
Cervellera Piñol, Roser

Resum:
Epoxy resins are among the most important thermosetting materials used as electric and electronic packaging applications. They are used like insulators in conductive materials and in construction of turbines and commutators due to good mechanical, electrical and thermal properties. In addition, they have a low cost and they are easy to apply. One of their more important uses is as coatings, underfills and encapsulants in microelectronics. The protection of delicate chips against atmospheric agents, dust, humidity and mechanical erosion must be done with a material able to cure without producing a great contraction and with a coefficient of thermal expansion similar to the ones of the components of the chip.Due to these requirements sometimes the epoxy resins have limited their use due to a series of disadvantages that display as their persistence once their utility life is over, their fragility and the contraction that experiments during curing. With the aim to solve these problems the diglycidyl ether of bisphenol A (DGEBA) has been copolymerized with expanding monomers such as spiroorthocarbonates (SOCs) and five and six membered cyclic carbonates. In addition, we choose the ring-opening polymerization mechanism because it leads to a smaller contraction.Spiroorthocarbonates are considered expandable monomers because there are changes in the linking distances in the monomer, when it transforms into the polymer. By each covalent linkage that forms on polymerizing, two covalent linkages transform into Van der Waals distances, reducing the contraction. In the cyclic carbonates the expansion is due to the change of interactions that experiments on polymerizing, which transform a strong interactions between monomers to a weaker interaction between polymeric chains. The copo