▎ 摘　　要

NOVELTY - Preparing natural hair dye comprises mixing madder herb extracting solution, and graphene-chitooligosaccharide gel to obtain dye of different proportions including hair pattern (i) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 5:1, hair pattern (ii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 4:1, hair pattern (iii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 3:1, hair pattern (iv) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 2:1, hair pattern (v) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:1, hair pattern (vi) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:2, hair pattern (vii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:3, and hair pattern (viii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:4. USE - The method is useful for preparing natural hair dye. DETAILED DESCRIPTION - Preparing natural hair dye comprises mixing madder herb extracting solution, graphene-chitooligosaccharide gel to obtain dye of different proportions including hair pattern (i) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 5:1, hair pattern (ii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 4:1, hair pattern (iii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 3:1, hair pattern (iv) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 2:1, hair pattern (v) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:1, hair pattern (vi) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:2, hair pattern (vii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:3, hair pattern (viii) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:4, and hair pattern (ix) ratio of madder extracting solution and graphene-chitooligosaccharide gel is 1:5. An INDEPENDENT CLAIM is also included for preparing the reduced graphene-chitosan, comprising (i) measuring 50 ml graphene oxide solution (10 mg/ml) in a 250 ml round bottom flask, then accurately measure 50 ml ascorbic acid solution (50 mg/ml), stirring and heating at 90 degrees C for 1 hour, centrifuging at speed of 10,000 rpm for 5 minutes, washing for 3 times with deionized water to obtain black product reduced graphene, (ii) measuring 2.5 mg/ml ascorbic acid solution (300 ml) in a 500 ml beaker, then taking 0.75 g chitosan, mixing the weighed chitosan and ascorbic acid solution in a 60 degrees C water bath to obtain chitosan gel, and(iii) measuring 200 ml chitosan gel, add uniformly mixing the reduced graphene obtained in the step (i) to obtain graphene-chitosan gel.