The invention discloses a modified
polylactic acid fiber and a preparation method thereof. The preparation method comprises the following steps: providing polybasic hydroxyl-terminated D-
polylactic acid; the method comprises the following steps: respectively providing
betaine-grafted D-
polylactic acid and a poly (butylene
adipate terephthalate)-
epoxy-polyether co-modified organic
silicon-D-polylactic acid
copolymer by taking the multi-hydroxyl-terminated D-polylactic acid as a main
raw material, wherein the poly (butylene
adipate terephthalate)-
epoxy-polyether co-modified organic
silicon-D-polylactic acid
copolymer; and carrying out Haake blending and
melt spinning on the
betaine-grafted D-polylactic acid, a poly (butylene
adipate-co-modified
organosilicon-D-polylactic acid)
copolymer, L-polylactic acid, an
antioxidant and an anti-
hydrolysis agent, so as to obtain the modified polylactic acid
fiber. The preparation method comprises the following steps: carrying out Haake blending and
melt spinning on the
betaine-grafted D-polylactic acid, poly (butylene adipate-co-modified
organosilicon-D-polylactic acid copolymer, L-polylactic acid, the
antioxidant and the anti-
hydrolysis agent. The modified polylactic acid
fiber prepared by the method has the characteristics of easy decontamination, hydrophilicity, high
temperature resistance and high
toughness, and can effectively avoid
water washing shedding, and the comprehensive performance is obviously improved.