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PVC characterization

15 May 2012 No Comment

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Playing with PVC

Hello there. I’m Eric Gilvray, an Applications Technologist here at Malvern specialising in Gel Permeation Chromatography (GPC). My job involves the day to day analysis of polymers in order to showcase what exactly Malvern Instrumentation can tell us about a customer’s sample. The variation of samples we receive at Malvern is staggering, with the same polymer very rarely being analysed twice, which keeps the job exciting and challenging.

I find myself working with plastics everyday whether it is on a sample analysis at Malvern, or on the weekend in a nightclub as a DJ with vinyl records (I call this working overtime with plastics). Being the polymer chemist I am, this got me thinking why is this polymer ideal for the production of vinyl records?

This may surprise the older (wiser) generation that I still to this day play with 12” vinyl records. However, vinyls are still extremely useful in music today as they allow the direct physical manipulation of a track, which a CD or digital format cannot replicate. The polymer that makes up a vinyl record is Polyvinyl Chloride (PVC) and is one of the most widely used polymers in the world today.

PVC polymer characterization

The PVC has chlorine atoms which give the polymer flexibility, ease of colouring (allowing the notorious black record colour), scratch resistance, and tensile strength.  The melt viscosity of PVC also makes it suitable to make complex extrusions, this being perfect for making the minute grooves of a record.

The defining characteristic of PVC is in fact the chlorine atom, compared to other plastics which may only contain carbon and hydrogen atoms, which give PVC its useful applications. Unlike hydrocarbon plastics, it is highly resistant to oxidative reactions meaning it can maintain its performance for many years, which is why vinyl records to this day can sound as good as when they were first manufactured.

There are much wider uses of PVC from drainage piping to window frames, to flooring. Understanding the properties of the polymer and how we can manipulate them into new applications is what customers strive to learn from Malvern Instruments. It’s interesting to see how the analysis we carry out at Malvern instruments can affect the applications of polymers in the future. Maybe one day I will be playing with a new type of polymer based record!