Papers by Keyword: Yellowness Index

Abstract: Ultraviolet aging of B.mori silk fabric was researched under different natural season weathering conditions. Exposed samples were removed periodically and characterized by several analytical techniques. During different natural season weathering, the results showed that the yellowness index of B.mori silk fabric surface appeared obviously rising in natural weathering especially in summer season, reaching 28.78% higher than 25.78% of yellowness index under spring season weathering; The peak intensity of amide I and amide II significantly declined, even disappeared; And the same time, the thermal behavior of B.mori silk changed similarly under different natural season weathering; In addition, breaking strength of B.mori silk fabric decreased approximately 86.27%, 95.11% under spring and summer season weathering, respectively. So, it was obviously shown that during the summer season weathering, the natural aging rate of B.mori silk was more quickly than spring season weathering, which was helpful to understand the aging behavior and measure the correlation aging effect between spring and summer season weathering condition.

Abstract: Ultraviolet aging of B.mori silk fabric was studied under natural and artificial weathering conditions. Exposed samples were removed periodically and characterized by several analytical techniques. During both types of weathering, the results showed that yellowness index presented a rising trend with the extension of aging time; breaking strength of B.mori silk fabric decreased approximately 93.62%, 43.30% under natural aging 150 days and artificial accelerated aging 80 h, respectively; the peak intensity of amide I, and amide II, etc. significantly declined, even disappeared. At the same time, the conformation transition of B.mori silk was from random coil to β–pleated sheet following the prolonging of ultraviolet aging time. What’s more, the content of amino acid obviously declined especially histidine, tyrosine, and lysine etc. In addition, the results evidenced that during natural and artificial weathering, various performances of B.mori silk fabric changed similarly. So artificial weathering can be used to substitute for natural weathering for its weathering evaluation, which is helpful to understand the aging behavior and take measures to avoid aging and elongate its service life.