Effect of accelerated weathering on the creep behaviour of additively manufactured Polyethylene Terephthalate Glycol (PETG)

As additively manufactured components move away from short-term usability, such as single-use prototypes, towards commercial products used for longer periods of time, the long-term material properties, such as ageing and creep, are becoming increasingly important design considerations. Moreover, when additively manufactured components are designed for outdoor use, environmental stressors affect these long-term material properties in a process known as 'weathering'. In this research paper, an initial set of experiments assessed the flexural creep behaviour of pellet-printed PETG after exposure to three accelerated environmental stressors: UV radiation, temperature and humidity. The outcomes thereof indicated that UV exposure was the only stressor to increase the creep compliance. A subsequent set of experiments increase the UV exposure duration from 100 to 200 h and excluded the effects of ageing on creep behaviour during creep tests. The outcome of this second series of experiments showed that the increase in creep compliance can be attributed to the effects of UV alone.