Article
Chemistry, Physical
Oriana M. Vanderfleet, Francesco D'Acierno, Akira Isogai, Mark J. MacLachlan, Carl A. Michal, Emily D. Cranston
Summary: This study investigated the thermal performance of carboxylated cellulose nanocrystals (CNCs) with varying physicochemical properties and found that they are more thermally stable in acid form than in sodium form. The content of sulfate groups had a greater effect on CNC thermal stability. The catalytic effect of sodium in highly charged carboxylated CNCs and the formation of sodium carbonate in moderately charged, esterified CNCs led to more structural degradation of cellulose in sodium form.
CHEMISTRY OF MATERIALS
(2022)
Article
Agronomy
Vyacheslav Polyakov, Evgeny Abakumov, Evgeny Lodygin, Roman Vasilevich, Alla Lapidus
Summary: The accumulation of low-molecular-weight humic acid fractions in the soil of boreal forests indicates the process of organic matter stabilization, which is correlated with the increase in aromaticity. The content of aromatic compounds and carboxyl structural fragments are important factors contributing to the resistance of the soil organic matter to biodegradation in Chernevaya taiga.
Article
Materials Science, Paper & Wood
Shichen Yuan, Maksim Tyufekchiev, Michael T. Timko, Klaus Schmidt-Rohr
Summary: The quantification of reducing chain ends in hydrolyzed cellulose samples using solid-state C-13 NMR was demonstrated. This method can serve as a primary standard to calibrate other methods for molar-mass determination in hydrolyzed cellulose.
Article
Polymer Science
Mei Hong, Wei Liu, Runxiang Gao, Rui Li, Yonggang Liu, Xuemin Dai, Yu Kang, Xuepeng Qiu, Yanxiong Pan, Xiangling Ji
Summary: In this study, the stability of PAA solution under different temperatures and concentrations was systematically investigated. The results showed that high temperature accelerated the hydrolysis reaction of concentrated PAA solution, while the degradation rate was faster for dilute solution. Furthermore, it was found that the degradation mechanism of PAA in this study differed from the chain length equilibration mechanism reported in literature.
Article
Polymer Science
Edyta Malachowska, Dominika Pawcenis, Jacek Danczak, Joanna Paczkowska, Kamila Przybysz
Summary: The degradation of cellulose significantly impacts the mechanical, optical, physical, and chemical properties of paper, affecting its longevity. Analytical techniques such as size-exclusion chromatography and spectroscopy are used to evaluate the degradation processes, particularly in papers containing lignin. Humidity was found to alter cellulose chain lengths, with high lignin content suppressing some degradation pathways. This knowledge can guide the development of strategies and chemical treatments to prevent paper aging.
Article
Chemistry, Multidisciplinary
Xiaoxiao Wu, Xushuo Yuan, Jiaxin Zhao, Decai Ji, Haiyang Guo, Wentao Yao, Xiaoping Li, Lianpeng Zhang
Summary: This study aimed to prepare nanocellulose by pretreating microcrystalline cellulose (MCC) with heating and stirring + pectinase/cellulase + ultrasonic treatment (HSt - P/C - Ultr). The optimal conditions were determined as a pectinase:cellulase ratio of 1:1, a hydrolysis time of 90 min, and a temperature of 50 °C, resulting in a nanocellulose yield of approximately 32.0%. The nanocellulose obtained maintained the cellulose I crystalline form with a high crystallinity of 73.5% and exhibited a width of 20-50 nm, high aspect ratio, and winding network structure, making it a promising toughening material for composite materials.
Review
Environmental Sciences
Nisha Yadav, Minna Hakkarainen
Summary: Biodegradable and/or biobased plastics are seen as potential solutions to the plastic waste problem, but achieving complete degradation in natural environments remains challenging, with the interactions between chemical structure, composition, and degradation environment playing a crucial role.
Article
Chemistry, Multidisciplinary
Richard Whitfield, Nghia P. Truong, Athina Anastasaki
Summary: The study presents a simplified approach where mixing two polymers can achieve any intermediate dispersity value with unparalleled precision. This method not only controls the shape of molecular weight distributions but also enables the generation of block copolymers with high dispersity accuracy.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemical Research Methods
Hooman Torabi, Farhad Javi, Ted W. Deisenroth, Toan V. Pho, Victoria Barbright, Alireza Abbaspourrad
Summary: Generalized shrinking particle (SPM) and shrinking core (SCM) models were developed to describe the kinetics of heterogeneous enzymatic degradation of polymer microparticles in a continuous microflow system. Time-resolved measurements of the physical changes of the particles during degradation were made using image processing. The proposed models were able to predict the degradation of different types of polymer microparticles.
Article
Biochemical Research Methods
Hooman Torabi, Farhad Javi, Ted W. Deisenroth, Toan V. Pho, Victoria Barbright, Alireza Abbaspourrad
Summary: Generalized shrinking particle (SPM) and shrinking core (SCM) models were developed to describe the kinetics of heterogenous enzymatic degradation of polymer microparticles in a continuous microflow system. Time-resolved measurements using image processing were used to predict the degradation process. Experimental results confirmed the accuracy and wide applicability of the models.
Article
Biochemistry & Molecular Biology
Zhengyong Liang, Xing Li, Meng Li, Yulu Hong
Summary: In this study, a cellulose membrane was prepared using microwave-assisted acidic hydrolysis and a mixture of N-methylmorpholine-N-oxide and water as a solvent. The mechanical strength and separation performance of the membrane were influenced by the content of microcrystalline cellulose in the casting liquid. The study provides guidance for the preparation of high-performance microcrystalline cellulose membranes.
Article
Polymer Science
Yan-Yan Tu, Xue-Ting Wan, Jie Huan, Xiang Zhu, Xiao-Hong Li, Ying-Feng Tu
Summary: This study investigates the effect of trifluoroacetic acid on the hydroxyl end-groups of polyesters when used as a co-solvent, revealing esterification reactions that impact molecular weight determination. The results suggest that NMR measurements must be conducted within 1.3 hours of solution preparation at 25 degrees C in the mixture solvent to achieve a relative error of 5%. The findings provide insights for the characterization of polyesters and polyethers with alcohol functionalized groups.
CHINESE JOURNAL OF POLYMER SCIENCE
(2021)
Review
Polymer Science
Cleidiane Goncalves, Nelson Ferreira, Lucia Lourenco
Summary: Chitosan's molecular weight can be regulated through different hydrolysis methods, with acid hydrolysis being the most commonly used method, but may cause environmental impacts. Combining different hydrolysis methods may be the most effective approach, although it could increase costs. Enzymatic hydrolysis is widely studied due to its environmental advantages and high specificity, but factors such as hydrolysis time and cost still limit its industrial application.
Article
Chemistry, Applied
Yan Zhou, Xiaocheng Zhang, Yaohui Cheng, Jinming Zhang, Qinyong Mi, Chunchun Yin, Jin Wu, Jun Zhang
Summary: In this study, a rapid benzoylation reaction of cellulose was achieved in an ionic liquid, with a newly discovered anion-tunnel transfer effect. The resulting cellulose tribenzoates showed excellent solubility, allowing accurate determination of the molecular weight parameters by gel permeation chromatography.
CARBOHYDRATE POLYMERS
(2022)
Article
Polymer Science
David Seelinger, Markus Biesalski
Summary: A novel polymer gel system based on oxidized hydroxypropyl cellulose (keto-HPC) cross-linked with polyamines was investigated to develop sustainable wet strength agents for paper. The wet strength system significantly increased the paper's wet strength with low amounts of polymer, comparable to traditional wet strength agents based on fossil resources. The wet strength mechanism was analyzed, showing that the polymer distribution and molecular weight dependence play important roles in altering the paper's wet tensile strength.
