{'fraction_non_alphanumeric': 0.024407753050969132, 'fraction_numerical': 0.003589375448671931, 'mean_word_length': 5.544600938967136, '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}}
Effect of Plasma Pretreatment on Flame Retardant Modification of Ramie Fabric via Layer-by-layer Assembly

ABSTRACT Polyethylenimine/ammonium polyphosphate (PEI/APP) flame retardant coatings were constructed via layer-by-layer (LbL) assembly method on the surface of ramie fabric treated by plasma pretreatment. The conditions of plasma pretreatment were analyzed according to weight gain rate and the residual char at 600°C in the nitrogen atmosphere of PEI/APP-coated ramie fabric, and the optimum conditions of plasma pretreatment were obtained. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to confirm the effect of plasma pretreatment on PEI/APP flame retardant coating constructed on the surface of ramie fabric by LbL assembly. Flame retardancy of PEI/APP-coated ramie fabrics were analyzed by LOI and UL94 vertical burning tests. These results revealed that PEI/APP-coated ramie fabrics treated by plasma pretreatment exhibited good self-extinguishing and high fire safety. Meanwhile, the treated ramie fabrics still maintained good whiteness and mechanical properties, and plasma pretreatment also was beneficial to improve durability to washing of PEI/APP-coated ramie fabric. These findings have highly significant implications for the application of plasma pretreatment to flame retardant modification of ramie fabric used by LbL assembly.