Structure and Properties of Regenerated Cellulose Filaments Prepared from Cellulose Carbamate–NaOH/ZnO Aqueous Solution

Fu, Feiya; Yang, Quanling; Zhou, Jinping; Hu, Hefei; Jia, Bin; Zhang, Lina

doi:10.1021/sc500559g

Cited by 63 publications

(34 citation statements)

References 45 publications

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“…As illustrated in Figure 10, the chemical shifts of C1 (105.2 ppm), C4 (87.8) ppm, C5 (75.0 ppm) and C6 (62.8 ppm) for the both parts are almost the same as those for regenerated cellulose fibers from CC-NaOH/ ZnO solution. 33,34 In a comparison of the dissolved part, the C4 peak of the insoluble was relatively weak. The previous studies revealed thermal treatment of cellulose would lead to decrease of bands associated with hydroxyl and glycosidic groups, especially in the C4 signal.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Wang

et al. 2015

ACS Sustainable Chem. Eng.

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Cellulose carbamates (CCs) were successfully prepared from cellulose/urea (CU) mixtures based on an easy scale-up method and minimum urea. Urea content and the reaction conditions on the nitrogen content of the reacted CU (RCU) mixtures and CCs were systematically investigated. RCU mixtures and CCs were characterized with elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction, NMR spectrometry and solubility testing. The result indicated that almost all of urea was involved in the derivatization reaction and cellulose was converted into CC with absence of byproducts. The nitrogen content of CCs increased with an increase of the urea content and the reaction temperature, as well as the reaction time. CCs retained the cellulose I crystalline, and the degree of polymerization hardly changed with the reaction conditions. CCs prepared from CU mixtures with the urea content of 3.4−4.6 wt % displayed good solubility in NaOH/ZnO aqueous solutions. Especially, RCU mixtures without washing could be also well dissolved in NaOH/ZnO solutions and its solubility could reach 97%. This work provided a simple, pollution-free and economic pathway for preparing CCs, which is expected to be useful for the CarbaCell process.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Wang

et al. 2015

ACS Sustainable Chem. Eng.

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“…To confirm the successful modification of cellulose, Fourier Transform Infrared Spectroscopy (FTIR) of the original cellulose and CC with different DS were performed, and the results are shown in Figure 2. The obvious absorption peak at 1715 cm −1 for the CC sample was assigned to the stretching vibration of the carbonyl group of the carbamate [32,33]. This indicated that urea had successfully reacted with cellulose to form CC.…”

Section: Confirmation Of Carbamation Of Cellulosementioning

confidence: 94%

Preparation of Microfibrillated Cellulose from Wood Pulp through Carbamate Modification and Colloid Milling

Wei¹,

Zhou

Yao

et al. 2020

Applied Sciences

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This paper studies a new convenient method to prepare microfibrillated cellulose from a bleached eucalyptus kraft pulp. First, the wood pulp was reacted with urea to produce cellulose carbamate (CC), and then the CC was treated with colloid mill in an acidic medium. A feasible preparation process for CC was to soak the pulp with the urea solution, and then the cellulose pulp was dewatered, dried, and reacted with urea at high temperatures above the melting point of urea. The Kjeldahl method, infrared spectroscopy, and solid 13C NMR were used to confirm the effectiveness of the reaction. On the basis of CC with the degree of substitution, DS = 0.123, the aqueous suspension with 2% content of CC at pH values of 1, 3, or 7 was severally ground by a colloid milling. After centrifugation, the nanocellulose carbamate fiber (CCNF) in the supernatant was obtained. X-ray diffraction showed that CC and CCNF had the same crystal form as the cellulose pulp, but the crystallinity decreased successively. The nanometer diameter of the CCNF fiber was observed with scanning electron microscopy. Results showed that when the pH value of the CC suspension decreased during the colloid milling, the crystallinity of the CCNF decreased along with the decrease of fiber diameter, and the zeta potential of the supernatant increased. This indicated that carbamate side groups of CC were protonated at low pHs and the cation repulsion between cellulose molecular chains enhanced the driving force of the pulp separation to CCNF. Interestingly, the thermal stability of CCNF is comparable to that of the original cellulose, and the enhancement effect of CCNF on starch can be clearly observed even at a relatively low loading of CCNF.

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“…8 In addition, these nanoparticles have received a great amount of attention within the scientific community and industry for their electrical, optical, catalytic, antibacterial, and thermal properties. [9][10][11][12][13][14][15][16][17][18] It is generally believed that nanoparticle dispersity is critical to the functionality of nanocomposites, including the UV-blocking capability. 19,20 Therefore, aggregation of nanoparticles may significantly reduce UV-blocking efficiency and functionality.…”

Section: Introductionmentioning

confidence: 99%

Thin Biobased Transparent UV-Blocking Coating Enabled by Nanoparticle Self-Assembly

Olson

Lin

et al. 2019

ACS Appl. Mater. Interfaces

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A waterborne, UV-blocking, and visually transparent nanocomposite coating was formulated with ZnO nanoparticles and 2-hydroxyethyl cellulose (HEC). The coating is highly effective (< 5% UV and ~ 65% visible transmittance) and the film thickness (0.2-2.5 μm) is ~100 times thinner than the conventional coatings of similar UV-blocking performance. The superior properties are due to the fractal structures of ZnO nanoparticles assembled within the HEC matrix, revealed by scanning electron microscopy (SEM) and smallangle x-ray scattering (SAXS). Changing the binder to 2-hydroxyethyl starch (HES) diminishes the UVblocking performance, as ZnO nanoparticles form dense globular aggregates, with an aggregation number measured by SAXS three orders of magnitude larger than the HEC coating. Since HEC and HES share the same same chemical compositionrepeating glucose unit in the polymer backbone, it suggests that the conformational characteristics of the binder polymer have a strong influence on the nanoparticle aggregation, which plays a key role in determining the optical performance. Similar structures were achieved with TiO2 nanoparticles. This study not only offers a cost-effective and readily scalable method to fabricate transparent UV-blocking coating, but also demonstrates that the unique fractal aggregation structures in a nanocomposite material can provide high performance and functionality without fully dispersing the nanoparticles.

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Structure and Properties of Regenerated Cellulose Filaments Prepared from Cellulose Carbamate–NaOH/ZnO Aqueous Solution

Cited by 63 publications

References 45 publications

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Improved Synthesis of Cellulose Carbamates with Minimum Urea Based on an Easy Scale-up Method

Preparation of Microfibrillated Cellulose from Wood Pulp through Carbamate Modification and Colloid Milling

Thin Biobased Transparent UV-Blocking Coating Enabled by Nanoparticle Self-Assembly

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