Plastic Foam In The Classical Nucleation Theory

Plastic foam is used widely in the industrial fields and in daily life.The research work on technical process of making plastic foam, can improve thetechnology. More materials, labor's time and power can be saved New products can beproduced and used in new fields.As the rapid progress has been made on computer technology.it's a very important workto make a reasonable theory model for foaming. The model can help us to emulate the process of foaming by computer and control the producing process.This paper aimed the theory for plastic foaming process.Ordinarily, the process of plastic foam is divided into three basic periods: nucleation,expansion and formation.The nucleation period is the period when the foam is appearing in the plastic where nobubbles exist in the beginning.The most popular theory dealing with plastic foaming is the classical nucleation theory,which has been used by a lot of researchers in their theories and experiments. And the core of the dieory is for explaining the homogeneous nucleation process.Because of the complex conditions for experiments, lack of the ways to watch thenucleation process, and also lack of fitful pertinent dieories such as phase transition dieory,non-equilibrium thermodynamics, the researchers in nucleation dieory for plastic foamcan't make a rapid progress. A lot of scientists have engaged in improving the theory,but the results are not perfectBut a few new chances are appearing when the micro-foam has been made and a newway to watch the nucleation process by optical-electronical instruments has beeninvented.This paper was finished on the background described as above.This paper gives a fine introduction of the classical nucleation dieory A model, called...