Cellulose is rich in wheat straw,but it is hard to be modified because of its high crystallinity.Using wheat straw as a raw material,we pretreated cellulose from wheat straw by NaOH/thiourea/urea aqueous solution method and ethylenediamine method,respectively.Moreover,we optimized two chemical pretreatment methods by orthogonal experiment,and compared their effects on cellulose from wheat straw by determination of FTIR spectrum,crystallinity,and crystal form with FTIR and XRD.Results indicated that,for optimized NaOH/thiourea/urea aqueous solution method,mass fraction of NaOH,thiourea,and urea were 8％,7％,and 6 ％,respectively,the crystallinity of cellulose decreased 51％,meanwhile the crystal form turned from cellulose Ⅰ to cellulose Ⅱ;for optimized ethylenediamine method,mass fraction of ethylenediamine was 70 ％,liquid-solid ratio was 16 ∶ 1(mL ∶ g),treatment temperature was 40 ℃,treatment time was 4 h,the crystallinity of cellulose only decreased 36％,the crystal form was still remained cellulose Ⅰ.%纤维素在小麦秸秆中含量丰富,但因其结晶度高而不易改性.以小麦秸秆为原料,采用NaOH/硫脲/尿素水溶液法和乙二胺法分别对小麦秸秆纤维素进行预处理,采用正交实验对2种化学预处理方法进行优化,通过FTIR、XRD对红外光谱、结晶度、晶型的测定,比较了2种化学预处理方法对小麦秸秆纤维素的影响.结果表明,采用优化的NaOH/硫脲/尿素水溶液法(NaOH、硫脲、尿素的质量分数分别为8％、7％、6％),能使纤维素结晶度降低51％,晶型由纤维素Ⅰ变为纤维素Ⅱ;而采用优化的乙二胺法[乙二胺质量分数70％、液固比16∶ 1(mL∶g)、处理温度40℃、处理时间4 h],纤维素结晶度仅降低36％,且晶型未变,仍为纤维素Ⅰ.
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