Preparation and Characterization of Polylactic Acid Fiber Enhanced Hydroxyapatite/Chitosan Composites

2011 ◽  
Vol 368-373 ◽  
pp. 321-325
Author(s):  
Hai Rong Yin ◽  
Quan Xian Zu ◽  
Yang Wu
Keyword(s):  
Polylactic Acid ◽  
Composite Plate ◽  
Influence Factors ◽  
Orthogonal Test ◽  
Pecking Order ◽  
Bending Modulus ◽  
Chitosan Matrix ◽  
Ft Ir ◽  
And Performance ◽  
Chitosan Composite

A novel hydroxyapatite/chitosan composite plate enhanced by polylactic acid fiber is prepared via in–situ hybridization in the semipermeable mold. The influence factors of the composites are evaluated by orthogonal test; FT–IR, XRD and SEM are also used to determine the relevance between the composition and performance. Analyses show that: hydroxyapatite with weak crystalline state is generated in the composites; there is hydrogen bonding associating existing in the complex system; preferable interface junction is created between the fiber and hydroxyapatite /chitosan matrix, which is able to play benign potentiation to the mechanical strength. Orthogonal test finds that the pecking order of the influencing factors to physical properties is: fiber content > fiber length > hydroxyapatite content. HA/CS composite plate enhanced by PLA–fiber can get a significantly increase on flexural strength and bending modulus, therefore, it will be a kind of potential orthopaedic materials which possesses the ability of completely degraded.

Formulation and performance of slow-setting cement-based grouting paste (SCGP) for capsule grouting technology using orthogonal test

2021 ◽  
Vol 302 ◽  
pp. 124204
Author(s):  
Gang Zheng ◽  
Jianyou Huang ◽  
Yu Diao ◽  
Aoyang Ma ◽  
Yiming Su ◽  
...  
Keyword(s):  
Orthogonal Test ◽  
And Performance

scholarly journals Effect of Intercalation Structure of Organo-Modified Montmorillonite/Polylactic Acid on Wheat Straw Fiber/Polylactic Acid Composites

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 896 ◽  
Author(s):  
Qiqi Fan ◽  
Guangping Han ◽  
Wanli Cheng ◽  
Huafeng Tian ◽  
Dong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermogravimetric Analysis ◽  
Wheat Straw ◽  
Polylactic Acid ◽  
Low Cost ◽  
Interlayer Spacing ◽  
Positive Influence ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Ir Analysis

In this work, an easy way to prepare the polylactic acid (PLA)/wheat straw fiber (WSF) composite was proposed. The method involved uses either the dopamine-treated WSF or the two-step montmorillonite (MMT)-modified WSF as the filler material. In order to achieve the dispersibility and exfoliation of MMT, it was modified by 12-aminododecanoic acid using a two-step route. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to characterize the modified MMT and the coated WSF. As for the properties of PLA/WSF composites, some thermal (using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis) and mechanical properties (flexural, tensile, and impact) were analyzed. The results showed that the dopamine was successfully coated onto the WSF. Furthermore, Na-MMT was successfully transformed to organo-montmorillonite (OMMT) and formed an exfoliated structure. In addition, a better dispersion of MMT was obtained using the two-step treatment. The interlayer spacing of modified MMT was 4.06 nm, which was 123% higher than that of the unmodified MMT. Additionally, FT-IR analysis suggested that OMMT diffused into the PLA matrix. The thermogravimetric analysis (TGA) showed that a higher thermal stability of PLA/WSF composites was obtained for the modified MMT and dopamine. The results also showed that both the dopamine treated WSF and the two-step-treated MMT exhibited a positive influence on the mechanical properties of PLA/WSF composites, especially on the tensile strength, which increased by 367% compared to the unmodified precursors. This route offers researchers a potential scheme to improve the thermal and mechanical properties of PLA/WSF composites in a low-cost way.

Financing Decisions and Performance of Italian SMEs in the Hotel Industry

2018 ◽  
Vol 60 (4) ◽  
pp. 335-354 ◽  
Author(s):  
Marco Botta
Keyword(s):  
Capital Structure ◽  
Financial Performance ◽  
Optimal Level ◽  
Pecking Order ◽  
Optimal Capital Structure ◽  
Financing Decisions ◽  
Medium Enterprise ◽  
Optimal Capital ◽  
And Performance ◽  
The Relationship

This study investigates the existence of an optimal capital structure for small and medium enterprise (SME) hotels through the analysis of the relationship between financing decisions and financial performance in a large sample of Italian hotel SMEs. The results show that hotel SMEs face an optimal capital structure that allows them to maximize returns to investors, while instead having both too little and too much debt reduces their financial performance. This notwithstanding, we show that hotel SMEs are not particularly concerned with optimizing their capital structure, and their funding behavior is deeply connected with the availability of internally available funds, a typical pecking order behavior, and they result extremely slow in converging toward their optimal level of leverage so that they could improve their performance by adopting a more sophisticated financial strategy.

scholarly journals Preparation of Microcrystalline Cellulose from Water Hyacinth Reinforced Polylactic Acid Biocomposite

2018 ◽  
Vol 187 ◽  
pp. 02003
Author(s):  
Teerapa Semachai ◽  
Panitnad Chandranupap ◽  
Pravitra Chandranupap
Keyword(s):  
Polylactic Acid ◽  
Microcrystalline Cellulose ◽  
Water Hyacinth ◽  
Morphological Analysis ◽  
X Rays ◽  
Elongation At Break ◽  
Internal Mixing ◽  
Ft Ir ◽  
Treated Fiber ◽  
Ft Ir Spectroscopy

In this work, we successfully mixed polylactic acid (PLA) with microcrystalline cellulose (MCC) from water hyacinth. The MCC was prepared by treating water hyacinth fiber (WHF). Then hydrochloric acid was used to hydrolyze treated fiber to MCC. X-rays diffraction (XRD) showed that the MCC produced has 73.28 per cent crystallinity. Internal mixing was used to combine composites between MCC and PLA. Percentages of MCC were 1, 5, 10 and 15, respectively. Fourier transform infrared (FT-IR) spectroscopy indicated that the interaction between MCC and PLA are only mechanically interaction. Tensile testing of this composite (ASTM D638) revealed that tensile strength and percentage of elongation at break decreased but the increase of young's modulus. The morphological analysis was observed thru composites fractured surface by Scanning Electron Microscope (SEM). They showed a void between cellulosic fiber and PLA when high amount of MCC conformed with tensile results.

scholarly journals A novel silver-loaded chitosan composite sponge with sustained silver release as a long-lasting antimicrobial dressing

RSC Advances ◽  
2017 ◽  
Vol 7 (55) ◽  
pp. 34655-34663 ◽  
Author(s):  
Xiaofei Huang ◽  
Xiaojiong Bao ◽  
Zhengke Wang ◽  
Qiaoling Hu
Keyword(s):  
Wound Healing ◽  
Potential Candidate ◽  
Chitosan Matrix ◽  
Silver Release ◽  
Chitosan Composite

A new kind of chitosan-based sponge with sustained silver release was prepared by loading CCS-AgNPs into chitosan matrix through interaction between catechol and chitosan, which is considered as a potential candidate for wound healing dressings.

Studies of Iron-Doped Carbon Material from Carbonization of Soy Protein/Polyaniline Composite and its Electrical Capacitance

2020 ◽  
Vol 999 ◽  
pp. 13-20
Author(s):  
Qing Wu Zhang ◽  
Tian Fang ◽  
Hao Lu ◽  
Wei Wang ◽  
Qing Qing Zhang ◽  
...  
Keyword(s):  
Carbon Material ◽  
Nitrogen Atmosphere ◽  
Electrical Capacitance ◽  
Protein Gel ◽  
Solution Energy ◽  
Iron Doped ◽  
Good Potential ◽  
Ft Ir ◽  
And Performance ◽  
A Current

Protein gel of soy was formed immediately during polymerization of aniline initiated by certain amount of FeCl3. In order to obtain iron-doped carbon material, this composite was then carbonized at 700°C under nitrogen atmosphere for 5h. SEM, FT-IR, XRD, and isothermal desorption/adsorption technologies were employed to characterize morphology and structure of the material. Electrical capacitance of iron-doped carbon materials and performance of a prototype supercapacitor based on the material as its electrodes were measured by cyclic voltammetry, chronopotentiometry, and A.C. impedance respectively. Results show that morphology of as-obtained material is porous and hierachical, specific surface area of the material is 232.1m2/g, and specific capacitance of the material can reach 475.2F/g in 6 M KOH aqueous solution. Energy density and power density of the cell is 2.1Wh/kg and 2.0kW/kg, respectively. Capacity retention of the device is 100% after 5000 cycles at a current density of 2A/g. The above studies imply that this original iron-doped carbon material will have a good potential application in field of energy storage.

scholarly journals Demethylation of Alkali Lignin with Halogen Acids and Its Application to Phenolic Resins

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1771 ◽  
Author(s):  
Hao Wang ◽  
Thomas L. Eberhardt ◽  
Chunpeng Wang ◽  
Shishuai Gao ◽  
Hui Pan
Keyword(s):  
1H Nmr ◽  
Nucleophilic Reagent ◽  
2D Nmr ◽  
Hydroxyl Groups ◽  
Chemical Processing ◽  
Hydroxyl Content ◽  
Phenolic Resins ◽  
Alkali Lignin ◽  
Ft Ir ◽  
And Performance

Lignin, a byproduct from the chemical processing of lignocellulosic biomass, is a polyphenolic compound that has potential as a partial phenol substitute in phenolic adhesive formulations. In this study, HBr and HI were used as reagents to demethylate an alkali lignin (AL) to increase its hydroxyl content and thereby enhance its reactivity for the preparation of phenolic resins. Analyses by FT-IR, 1H-NMR and 2D-NMR(HSQC) demonstrated both a decrease in methoxyl groups and an increase in hydroxyl groups for each demethylated lignin (DL). In addition, the molar amounts of phenolic hydroxyls, determined by 1H-NMR, increased to 0.67 mmol/g for the HI-DL, and 0.64 mmol/g for the HBr-DL, from 0.52 mmol/g for the AL. These results showed that HI, a stronger nucleophilic reagent than HBr, provided a higher degree of AL demethylation. Lignin-containing resins, prepared by copolymerization, met the bonding strength standard for exterior plywood with DL used to replace as much as 50 wt.% of phenol. The increased hydroxyl contents resulting from the lignin demethylations also imparted faster cure times for the lignin-containing resins and lower formaldehyde emissions. Altogether, the stronger nucleophilicity of HI, compared to HBr, impacted the degree of lignin demethylation, and carried through to measurable differences the thermal properties and performance of the lignin-containing PF resins.

scholarly journals Preparation, Characterization, and Performance Analysis of S-Doped Bi2MoO6 Nanosheets

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1341 ◽  
Author(s):  
Ruiqi Wang ◽  
Duanyang Li ◽  
Hailong Wang ◽  
Chenglun Liu ◽  
Longjun Xu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Degradation Rate ◽  
X Ray Diffraction ◽  
Photo Degradation ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Performance ◽  
Adsorption Desorption ◽  
Excellent Stability

S-doped Bi2MoO6 nanosheets were successfully synthesized by a simple hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), elemental mapping spectroscopy, photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectra (UV-vis DRS). The photo-electrochemical performance of the samples was investigated via an electrochemical workstation. The S-doped Bi2MoO6 nanosheets exhibited enhanced photocatalytic activity under visible light irradiation. The photo-degradation rate of Rhodamine B (RhB) by S-doped Bi2MoO6 (1 wt%) reached 97% after 60 min, which was higher than that of the pure Bi2MoO6 and other S-doped products. The degradation rate of the recovered S-doped Bi2MoO6 (1 wt%) was still nearly 90% in the third cycle, indicating an excellent stability of the catalyst. The radical-capture experiments confirmed that superoxide radicals (·O2−) and holes (h+) were the main active substances in the photocatalytic degradation of RhB by S-doped Bi2MoO6.

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