Measurement Of Crosslinking Degree For Electron Beam Irradiated Block Copolymers

Introduction

Recently a lot of block copolymers are applied as useful composite systems or
adhesives because of their excellent mechanical properties such as modulus, elongation and
breaking energy. However, since these copolymers are essentially thermoplastic, once
heated up, the mechanical characteristics mentioned above will be easily lost. In order to
give them excellent properties at high temperature, crosslinking by the electron beam
irradiation is commonly used, because it does not need initiator. In addition, the
crosslinking reaction by electron beam proceeds at lower temperature than that by thermal or
ultraviolet light. Due to these reasons, the crosslinldng with electron beam is very popular to
improve their thermal properties for industrial applications. On the other hand, to measure
crosslinking degree of. highly crosslinked polymers is tough work, because of the low
solubility in the. In order to measure it, same theoretical or experimental
equations have been applied for the relationship between the crosslinking degree and the
mechanical modulus, Tg or swelling.
The rubber theory shows the relationship betw en the mechanical modulus and Mc
at higher temperature than theTg.