{'fraction_non_alphanumeric': 0.027210884353741496, 'fraction_numerical': 0.0, 'mean_word_length': 5.844961240310077, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
NEXAFS Spectroscopic Study of Surface Modification on Poly(butylene terephthalate) Induced by UV Irradiation

Surface modification of poly(butylene terephthalate) (PBT) induced by ultraviolet (UV) irradiation was investigated using near-edge X-ray absorption fine structure spectroscopy (NEXAFS). UV irradiation drastically altered carbon and oxygen K-edge NEXAFS spectra of PBT. NEXAFS spectra obtained after UV irradiation were compared with those of various molecules containing carbonyl, carboxylic, ester, and anhydride groups. UV-irradiated PBT surfaces had spectral features similar to those of pyromellitic dianhydride, which contains anhydride groups. These results indicate that UV irradiation removes alkyl chains and ester bonds in PBT and forms anhydride groups on PBT surfaces. It was also suggested that anhydrides might be formed near PBT surfaces by UV irradiation.