Characterization of volatile compounds, structural, thermal and physico-mechanical properties of cross-linked polyethylene foams degraded thermo-mechanically at variable times

摘要

Waste cross-linked polyethylene foam (wXLPE) was thermo-mechanically degraded at variable time using internal batch mixer. The progress of wXLPE degradation has been investigated by using a simultaneous thermogravimetric/differential scanning calorimetry analyzer coupled with Fourier transform infrared spectroscopy, swelling measurements, tensile tests and scanning electron microscopy. Volatile organic compounds generated during wXLPE degradation were determined using static head-space and gas chromatography-mass spectrometry. It was observed that duration of thermo-mechanical processing of wXLPE has significant impact on content of low molecular degradation products, chemical structure, swelling, thermal and morphological properties of degraded wXLPE, while its impact on physico-mechanical properties was negligible. This indicates complex structural and chemical changes in wXLPE during its thermo-mechanical degradation, which is related to two opposite factors: (ⅰ) decros-slinking efficiency during thermo-mechanical processing of wXLPE and (ⅱ) partial plasticization of polyethylene matrix by volatile degradation products.