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Properties and structure of never‐dried cotton fibers. III. Cotton fibers from bolls in early stages of growth
Author(s) -
Tsuji Waichiro,
Nakao Tokie,
Hirai Asako,
Horii Fumitaka
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070450212
Subject(s) - crystallinity , ultimate tensile strength , materials science , composite material , fiber crop , bast fibre , horticulture , malvaceae , biology
Like other kinds of cotton fibers already studied, American cotton fibers taken from cotton bolls immediately before and after opening show high angles of torsional rotation during ambient humidity changes. Cotton fibers taken from cotton bolls at 19 and 24 days postanthesis show remarkably higher angles of rotation and much lower dry and wet tensile strengths than the fibers taken from cotton bolls immediately before and after opening. The wet tensile strength of cotton fibers at 24 days postanthesis is higher than the dry strength like the fibers taken from bolls immediately before and after opening, but fibers at 19 days postanthesis show almost the same tensile strength in the never‐dried, dried, and rewetted states. CP/MAS 13 C NMR spectroscopy reveals that the never‐dried cotton fibers at 19 days or longer postanthesis have high crystallinities. It seems that the degree of crystallinity is somewhat decreased in the dry state and restored by rewetting. The crystallinity increases with the age of growth.