کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
11027198 1666321 2019 31 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Preparation of cellulose nanofibers by TEMPO-oxidation of bleached chemi-thermomechanical pulp for cement applications
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Preparation of cellulose nanofibers by TEMPO-oxidation of bleached chemi-thermomechanical pulp for cement applications
چکیده انگلیسی
Hardwood bleached chemi-thermomechanical pulp (BCTMP) was converted to cellulose nanofibers by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) catalyzed oxidization along with mechanical defibrillation process. The TEMPO reaction was evaluated based on the delignification, carboxylate content of cellulose and the yield of the insoluble component. Cellulose nanofibers were characterized by conductometry, Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM), thermogravimetric analysis (TGA) as well as X-ray diffraction (XRD) techniques. Minimum 10 mmol/g NaClO addition was needed to obtain meaningful carboxylate content and easy defibrillation by using high shear mixing. TEMPO-catalyzed oxidization process removed 74% of pentosans and 80% of lignin from bleached chemi-thermomechanical hardwood pulp while 13% of cellulose was also lost. CNF with 1.44 mmol/g carboxylate content resulted high level of water retention (13.4 g/g fiber) Cellulose nanofibers were used in cementitious mixtures. CNF with carboxyl groups resulted in better flow control in wet cement paste and reduced the crack growth in concrete.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Carbohydrate Polymers - Volume 203, 1 January 2019, Pages 238-245
نویسندگان
, , , ,