Optimization of blend toughness by simultaneous measuremnt of heat and work of deformation

摘要

The technique of differential gas pressure calorimtery is used to simultaneously measure heat and work of isothermal deformation of acrylic based latex blend coatings. These coatings comprise of phase separated hard and soft components resulting in a combination of stiffness and toughness. An overall energy balance approach is adopted to study the partition of energy between the two phases in their respective energy-dissipating and energy-absorbing mechanisms. The toughness is maximized by a simultaneous maximization of heat dissipation and energy absorption; a fact often overlooked in the design of commercial rubber toughened systems that focus almost entirely on increasing the energy absorbing capacity of the glassy matrix. It is observed that maximizing both the energy absorption as well as dissipation can result in much higher toughness without a large sacrifice in stiffness.