Key Biomass Energy Laboratory of Henan Province

Zhengzhou, China

Key Biomass Energy Laboratory of Henan Province

Zhengzhou, China
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Ren S.,Key Biomass Energy Laboratory of Henan Province | Dong L.,Key Biomass Energy Laboratory of Henan Province | Zhang X.,Key Biomass Energy Laboratory of Henan Province | Lei T.,Key Biomass Energy Laboratory of Henan Province | And 5 more authors.
Materials | Year: 2017

Nanofibers with excellent activities in surface-enhanced Raman scattering (SERS) were developed through electrospinning precursor suspensions consisting of polyacrylonitrile (PAN), silver nanoparticles (AgNPs), silicon nanoparticles (SiNPs), and cellulose nanocrystals (CNCs). Rheology of the precursor suspensions, and morphology, thermal properties, chemical structures, and SERS sensitivity of the nanofibers were investigated. The electrospun nanofibers showed uniform diameters with a smooth surface. Hydrofluoric (HF) acid treatment of the PAN/CNC/Ag composite nanofibers (defined as p-PAN/CNC/Ag) led to rougher fiber surfaces with certain pores and increased mean fiber diameters. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results confirmed the existence of AgNPs that were formed during heat and HF acid treatment processes. In addition, thermal stability of the electrospun nanofibers increased due to the incorporation of CNCs and AgNPs. The p-PAN/CNC/Ag nanofibers were used as a SERS substrate to detect p-aminothiophenol (p-ATP) probe molecule. The results show that this substrate exhibited high sensitivity for the p-ATP probe detection. © 2017 by the authors.

Zhang X.,Key Biomass Energy Laboratory of Henan Province | Zhang J.,Louisiana State University | Dong L.,Key Biomass Energy Laboratory of Henan Province | Ren S.,Key Biomass Energy Laboratory of Henan Province | And 2 more authors.
Cellulose | Year: 2017

We report a series of thermoresponsive cellulose nanocrystals (CNCs) decorated with poly(poly(ethylene glycol) methylacrylate) copolymers (poly(PEGMA)-g-CNCs) synthesized by surface initiated-atom transfer radical polymerization (SI-ATRP). The chemical structures and surface morphologies were subsequently confirmed by FT-IR, XPS, and AFM measurements. With regard to thermally responsive behavior, poly(PEGMA)-g-CNCs show tunable lower critical solution temperature (LCST) values in the range of 34–66 °C by varying the feeding ratios of comonomers. The reversible morphological transformation from individual nano-rod structures to larger globule aggregates was further verified by AFM during the LCST transition. These functionalized CNCs have potential as smart film filters and biosensors. © 2017 Springer Science+Business Media B.V.

Zhang J.,Louisiana State University | Wu Q.,Louisiana State University | Li M.-C.,Louisiana State University | Song K.,Louisiana State University | And 3 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2017

A novel thermoresponsive copolymer poly(N-vinylcaprolactam) grafted cellulose nanocrystals (PVCL-g-CNCs) was synthesized using surface-initiated atom transfer radical polymerization, and its temperature responsive behavior was studied in this work. The chemical structure characterization by Fourier transform infrared spectroscopy, solid-state CP/MAS 13C NMR spectroscopy, and X-ray photoelectron spectroscopy confirmed the presence of covalently grafting PVCL chains on the CNC surface. The crystalline structure and nanorod-shaped morphology of CNCs were well preserved after polymerization. Transmission electron microscope results indicated that the surface of CNCs was covered with grafted PVCL brushes. The viscoelastic properties of PVCL-g-CNC aqueous suspensions (1.0 wt %) by dynamic rheology measurements confirmed the thermally induced phase transition behavior. The work presented herein paves the way to design CNC-based advanced functional materials benefiting both from the intrinsic characteristics of CNCs and the new properties imparted by the temperature sensitive grafted polymer chains. © 2017 American Chemical Society.

Song K.,Louisiana State University | Zhang H.,Henan Agricultural University | Wu Q.,Louisiana State University | Zhang Z.,Louisiana State University | And 3 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

This study was carried out to elucidate chemical composition and thermal decomposition behavior of bio-tar from the gasification of agricultural crop residue, facilitating its further processing and utilization. Structural characterization by gas chromatography mass spectroscopy (GC-MS), Fourier transform infrared spectroscopy, and elemental analysis indicated that the bio-tar was mainly composed of phenols and polycyclic aromatic hydrocarbons. It contained more oxygenated and less aromatic compounds compared with fossil pitches. Thermogravimetric measurements demonstrated that the tar decomposed rapidly within the temperature range of 183-252 °C under nitrogen atmosphere. The apparent activation energy values obtained from the Friedman method and distributed activation energy model showed the same trend. The activation energy values from both methods nearly unchanged within the conversion rate of 0.1-0.6, with average values of 107 and 85 kJ mol-1, respectively. The activation energy increased quickly when the conversion rate was larger than 0.6. The change of reaction mechanism from parallel single reactions or uniform multiple reactions at lower conversion rates to multiple-step reactions at higher conversion rates indicated the complex nature of the bio-tar. The developed chemical and thermal degradation data of the tar can facilitate the design and manufacture of tar-containing polymeric composites. © 2014 Akadémiai Kiadó, Budapest, Hungary.

Song K.,Louisiana State University | Wu Q.,Louisiana State University | Zhang Z.,Louisiana State University | Ren S.,Key Biomass Energy Laboratory of Henan Province | And 4 more authors.
Fuel | Year: 2015

Biomass pyrolysis and gasification are used to efficiently convert lignocellulosic materials to a variety of products that can substitute for petrochemical-derived energy and chemicals. Tar (heavy hydrocarbons) is inevitably produced from the thermochemical processes, and is often disposed as an industrial waste, leading to environmental pollution. To utilize the tar, a facile route to fabricate porous fibrous composite with antimicrobial capability was demonstrated by electrospinning tar and polyacrylonitrile (PAN) blends. Continuous fibers with an average diameter ranging from 422 to 948 nm without beads were prepared from tar and PAN blends. The electrospun Tar/PAN nanofibers exhibited a high porosity of 51-63% with an average pore diameter ranging from 5.6 to 7.1 nm, indicating a mesoporous structure. The Tar/PAN nanofibers showed higher antimicrobial activities (up to 39%) against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) in comparison with the neat PAN nanofibers, due to the presence of phenolic compounds in the tar. Aside from their antimicrobial capability, the electrospun nanofibers can also be applied in the manufacture of low-cost adsorption materials and carbon nanofibers. © 2015 Elsevier Ltd.

Ren S.,Key Biomass Energy Laboratory of Henan Province | Sun X.,Louisiana State University | Lei T.,Key Biomass Energy Laboratory of Henan Province | Wu Q.,Louisiana State University
Journal of Nanomaterials | Year: 2014

Cellulose nanoparticles were fabricated from microcrystalline cellulose (MCC) through combined acid hydrolysis with sulfuric and hydrochloric acids and high-pressure homogenization. The effect of acid type, acid-to-MCC ratio, reaction time, and numbers of high-pressure homogenization passes on morphology and thermal stability of the nanoparticles was studied. An aggressive acid hydrolysis was shown to lead to rod-like cellulose nanocrystals with diameter about 10 nm and lengths in the range of 50-200 nm. Increased acid-to-MCC ratio and number of homogenization treatments reduced the dimension of the nanocrystals produced. Weak acid hydrolysis treatment led to a network of cellulose nanofiber bundles having diameters in the range of 20-100 nm and lengths of a few thousands of nanometers. The high-pressure homogenization treatment helped separate the nanofiber bundles. The thermal degradation behaviors characterized by thermogravimetric analysis at nitrogen atmosphere indicated that the degradation of cellulose nanocrystals from sulfuric acid hydrolysis started at a lower temperature and had two remarkable pyrolysis processes. The thermal stability of cellulose nanofibers produced from hydrochloric acid hydrolysis improved significantly. © 2014 Suxia Ren et al.

Li M.-C.,Louisiana State University | Wu Q.,Louisiana State University | Song K.,Louisiana State University | Lee S.,Korea forest Research Institute | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite-water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications. © 2015 American Chemical Society.

Zhang Z.,Louisiana State University | Wu Q.,Louisiana State University | Song K.,Louisiana State University | Lei T.,Key Biomass Energy Laboratory of Henan Province | Wu Y.,Central South University of forestry and Technology
Cellulose | Year: 2015

Cellulose nanocrystals (CNCs) were used to improve the performance of poly(vinylidene fluoride) (PVDF), and the composite properties were characterized. The results showed that the prepared nanocomposites displayed the increases in mechanical properties. In particular, with the incorporation of 6 wt% CNCs, increases in tensile strength and dynamic storage modulus were observed. For hydrophilicity, the water contact angle decreased from 90° to 77° with the incorporation of only 3 wt% CNCs, indicating improved hydrophilicity. Addition of CNCs to PVDF also helped improve its thermal stability and crystallinity. It was suggested that CNCs played a nucleating role in the crystallization of PVDF, which was supported by the smaller size of PVDF spherulite observed from scanning electron microscopy analysis. Rheological results indicated that incorporation of CNCs also increased both melt storage modulus and shear viscosity of composites. Overall, our present work demonstrates that CNCs can provide PVDF with simultaneously improved properties. © 2015, Springer Science+Business Media Dordrecht.

Sun X.,Louisiana State University | Wu Q.,Louisiana State University | Ren S.,Key Biomass Energy Laboratory of Henan Province | Lei T.,Key Biomass Energy Laboratory of Henan Province
Cellulose | Year: 2015

Transparent cellulose films from 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized cellulose nanocrystals (TOCNs) and 64 wt% sulfuric acid treated cellulose nanocrystals (SACNs) were prepared from bleached wood pulp. Film morphology, optical, mechanical, thermal, and surface wettability properties were characterized and compared. The results showed that TOCNs and SACNs had different average length (200.7 vs. 163.0 nm), diameter (5.8 vs. 15.6 nm), and aspect ratio (34.4 vs. 10.4). Compared with the SACN film, TOCN films exhibited higher optical transmittance (98.4 % at 900 nm) and larger tensile strength (236.5 MPa). SACN films exhibited better thermal stability (Tonset = 239 °C), higher crystallinity (73.4 %) and lower coefficient of thermal expansion (CTE = 8.38 ppm/k). Additionally, both films demonstrated good surface wettability. The results indicate that the TOCN and SACN films could be considered as a substrate material to replace traditional glass and plastic substrates for the next generation “Green” electronics. © 2015, Springer Science+Business Media Dordrecht.

Zhang Z.,Louisiana State University | Wu Q.,Louisiana State University | Song K.,Louisiana State University | Ren S.,Key Biomass Energy Laboratory of Henan Province | And 2 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2015

The aim of this study is to use cellulose nanocrystals (CNCs) as a sustainable additive for improving hydrophilicity, mechanical and thermal properties of poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blends. A casting-evaporation method was used to prepare the nanocomposites, and their surface wettability, mechanical, thermal and morphological properties were characterized. With the addition of only 3 wt% CNCs, tensile strength, tensile modulus, dynamic storage modulus at 45 °C, and onset thermal decomposition temperature of the ternary composite exhibited 32%, 70%, 36% and 4.0 °C increase, respectively, while the static water angle decreased by 6°. As the CNC content increased to 6 wt %, further improvement was observed in all above properties except tensile strength. The observed performance enhancement is attributed to a considerably increased crystallinity of PVDF (e.g., from 28.5% for the binary blend to 43.3% for ternary composite at the 3 wt % CNC level). Our present work demonstrates the importance of using sustainable CNCs to achieve synergetic improvement in physical and mechanical performance of PVDF/PMMA blend, suggesting a facile way to prepare nanocomposites for potential membrane-based separation applications. © 2015 American Chemical Society.

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