nonsubstituted是什么意思?化学论文里的.

It was concluded that the two CMCs (两种羧甲基纤维素钠)displayed significant differences in the fraction of nonsubstituted cellulose segments.Furthermore,the CMC with the strongest attractive intermolecular interactions,according to rheometry,also contained the highest fraction of nonsubstituted cellulose segments(未被取代的纤维素残基).