{'fraction_non_alphanumeric': 0.028735632183908046, 'fraction_numerical': 0.0007183908045977011, 'mean_word_length': 5.633333333333334, '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}}
Structure And Properties Of BPDA-PDA Polyimide From Its Poly(Amic Acid) Precursor Complexed With An Aminoalkyl Methacrylate

BPDA-PDA poly(amic acid) precursor was functionalized through its carboxylic acid groups being linked with a crosslinkable aminoalkyl methacrylate, 2-(dimethylamino)ethyl methacrylate (DMAEM), by acid/base complexation. BPDA-PDA polyimide films, which were thermally imidized from the precursors complexed with various amounts of DMAEM, were characterized by means of wide angle x-ray diffraction, stress-strain analysis, and residual stress analysis. The structure and properties of the BPDA-PDA polyimide film were dependent upon the history of the precursor, that is, the complexation of the poly(amic acid) precursor with DMAEM. The molecular packing order was enhanced with the history of DMAEM loading while the molecular order along the chain axis was disrupted. Overall, physical properties, such as mechanical properties and residual stress, were degraded with DMAEM loading. The moisture induced stress relaxation behavior was sensitive to the history of DMAEM loading, whereas the creep induced stress relaxation was varied little due to its high T g . These properties are understood in terms of structure/property relationships, as well as microvoids, which were possibly generated by outgassing the bulky DMAEM pendent groups during thermal imidization.