PET vs. PETG: What is the difference?


What’s the difference between PET and PETG plastics? While the acronyms look almost identical with only one letter differentiating the two, their separate chemical properties and laboratory uses truly set these two plastics apart. PET, or ‘polyethylene terephthalate’, is a combination of two monomers. PETG is of the same chemical composition as PET but with the addition of glycol. With just this one addition, the chemical composition is completely changed, creating a whole new plastic.

The addition of glycol to create PETG removes the hazing effect seen during heating and also prevents an undesirable crystallization effect that causes standard PET to become brittle. Additionally, the inclusion of glycol in this plastic will transform the outer walls of a bottle into a softer and more pliable material, making it easier and more comfortable to grip. Despite these advantages, this softer outer wall is easier to scratch, more susceptible to damaging UV light, and cannot be autoclaved. All things considered, these drawbacks are relatively minor when compared to PETG’s superior heat handling, shock resistance, and comfortable grip.

Follow the link below to see the anatomy of a PETG Media Bottle.

PETG Media Bottle Anatomy

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About the Author : Christopher Petrosh

Christopher is a recent graduate of Rutgers University with a bachelor’s in business administration. Chris worked in technology retail while attending college. There he gained experience in providing customers’ solutions which he can translate to helping our customers find the best solution for their application. Chris’ main focus at WHEATON is glass and plastic bottles and closures, instrumentation and cell culture for both research and packaging applications.

1 Comment
  1. Lay Kim Oon June 22, 2016 at 2:34 am

    Hi Chris,
    thank you for the write out on PETG plastic which is very interesting. I understand that PET does not withstand autoclave, disinfectant, dry heat, radiation; can u please kindly advise if PETG withstand any of them besides autoclave that you mentioned ?
    If the answer is yes for all of them, can u please advise what type of disinfectant is suitable to be used on PETG & what’s the max heat/temperature it can stand ?

    thank you.

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