Abstract The glass transition temperature of polymethylmethacrylate ( MAMA, Perspex) is measured using static and dynamic method while the glass transition temperature of rubber of different size is measured using only dynamic method.
The glass transition temperature Tag of Perspex is found to be ICC using the static method and ICC using the dynamic method. On the other hand, the Tag of rubber is found to be -ICC. Introduction Perspex is a type of amorphous polymer and has the following repeat unit : If the MAMA is heated , the side group of the polymer will start to rotate.As the imperative gradually increase and reach a certain temperature , the polymer would lose its stiffness and becomes elastic like a rubber. This temperature is also known as glass transition temperature ,Tag. The Tag is always lower than melting point of the polymer. By heating and cooling the polymer, and observing the changes in their physical properties we COUld identify Tag.
(For static test method of Perspex) Experimental Tag is determine by observing at which temperature does the coefficient of thermal expansion change. This is done by using a mercury dilapidated which contains about egg of Perspex in the glass bulb.For the heating curve the Tag is found to be ICC and 73. ICC for the cooling curve. This is due to the heat is not being transmitted equally throughout the system, which is cause by the positioning of thermocouple being outside of the bulb.
As such to acquire a reliable value of Tag , we should take the average Tag value which is 81. ICC. (For dynamic test of Perspex) The Perspex is heated from ICC to ICC. At the interval of ICC drop the ball from CACM, the rebound height of mm ball and mm ball is then measured and recorded. Repeat the experiment 3 times to obtain the average value of rebound height to minimize error.