For the first lecture of Polymer Engineering Dr Tong brought a lot of things that are made of polymers like nylon gloves, plastic bottles, paint, polyester scarf, Styrofoam cup, Blutack, shampoo bottle, plastic wrapper and plastic bag. He also tells us briefly about his trip in USA and he went skiing over there so need to wear the think plastic gloves. He also said that his blouse is made of polyester. Of course it helps me to remember that polymers have such wide applications in modern lives that we can’t imagine a life without it.
In the polymer engineering lecture, Dr Tong got demonstrate how to produce a nylon called poly (1,6-diaminohexane sebacide). You mix two solutions of sebacoyl chloride in hexane and 1,6 diaminohexane in water together. I got see this experiment in my secondary school I think. Then interfacial condensation occurs at the interface of hexane and water solution and a thin rubbery substance form in the interface. However, due to his poor pulling techniques he pull out a chunk of nylon instead of a nice string.The advantage is that you don't need to use stoichiometric ratios of sebecoyl chloride and 1,6 diaminohexane for this reaction to produce a high molecular weight polymer because using non stoichiometric ratios in polycondensation reactions does affect the polymer chain length drastically. If you use this method, the reactants will react at the interface in a 1:1 ratio even though you may have slighty more of one of the reactants. This method of production, however will introduce impurities in the form of solvent and you need to heat up to remove them, in order to get a useful nylon plastic.
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