Flourier Transform Infrared Spectroscopy Research Articles

Ionic liquid-like inimer mediated RAFT polymerization of N-isopropylacrylamide

Inimer bears a polymerizable vinyl group and a reactable group, and thus has great potentials in the synthesis of branched and functional polymers. Herein, a strategy was developed for the synthesis of ionic liquid (IL)-like inimer containing a trithiocarbonate moiety and a styryl group. The newly-developed IL-like inimer could be facilely achieved via the neutralization reaction using a carboxyl-contained chain transfer agent (CTA) and an alkaline IL monomer. The IL-like inimer was characterized through proton and carbon nuclear magnetic resonance spectroscopy (1H and 13C NMR), Flourier transform infrared spectroscopy (FT-IR) and Mass spectroscopy. Moreover, the reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) mediated by the as-prepared IL-like inimer was investigated. The results revealed that branched PNIPAM with tunable molecular weight and degree of branching (DB) could be prepared. Additionally, lower critical solution temperature (LCST) of branched PNIPAM could be adjusted through the feed ratio of IL-like inimer and the monomer in the polymerization process. As a result, our study offers a new technique for the design of functional inimer, as well as broadens the application of ILs in the polymer field.

Starch-Assisted Synthesis and Characterization of Layered Calcium Hydroxide Particles

The presented study aims at synthesizing layered calcium hydroxide particles by precipitating method in aqueous media. Prepared layered particles were characterized by different experimental methods including powder X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and flourier transform infrared spectroscopy (FT-IR). It is observed by the XRD analysis that the layered Ca(OH)2 particles exhibit high crystallininty structure and layered particles preferentially orientate in (001) and (101) reflection plane. The FT-IR result shows that the starch molecules exist in interlayer of Ca(OH)2 crystals after removing washing step which confirms that the starch molecules are involved in the growth process of the Ca(OH)2 crystal. Starch modified Ca(OH)2 particles are observed in irregular shape with layers assembled given in SEM images. When pr-dissolving the starch in alkaline solution, only irregular thin plates are observed in SEM images. Based on the results, the formation mechanism of layered calcium hydroxide could be summarized as that monolayer calcium hydroxide is assembled by starch molecules. Starch-assisted synthetic layered calcium hydroxide particle method was first proposed and synthetic particles can be used to control the cement hydration process.

Synthesis and characterization of shale stabilizer based on polyethylene glycol grafted nano-silica composite in water-based drilling fluids

In order to solve wellbore instability problems in the drilling process, high-performance shale stabilizers in water-based drilling fluids are essential. In this paper, a novel shale stabilizer based on polyethylene glycol grafted nano-silica composite (PEG-NS) was successfully synthesized. Conventional techniques were used to characterize PEG-NS including Flourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), particle size distribution (PSD) and thermogravimetric analysis (TGA). The results showed that the structure of PEG-NS was in agreement with the design objective. The particle size of PEG-NS ranged from 110 to 434 nm, and PEG-NS had good thermal stability. Pressure transmission test, pore structure characterization of shale, rolling recovery test were applied to evaluate the comprehensive performance of PEG-NS as a novel shale stabilizer. The experimental data indicated that PEG-NS could effectively retard the pore pressure transmission and reduce the permeability of shale sample. PEG-NS could adsorb onto the shale surface and a dense plugging film could finally coat on it. Moreover, PEG-NS also exhibited better inhibition performance compared with that of potassium chloride (KCl) and polymeric alcohol (JHC) at the same concentration. Hence, PEG-NS could be a good shale stabilizer in water-based drilling fluids for drilling reactive shale formations.

English

Bone tissue engineering with cells and synthetic extracellular matrix represents a new approach for the regeneration of mineralized tissue compared with the transplantation of bone. Hydroxyapatite (HA) and its composite with biopolymer are extensively developed and applied in bone tissue regeneration. The main aim of this study was to fabricate and characterize of HA apatite based biocompatible scaffold for bone tissue engineering. Scaffolds with different ratio of polymers (chitosan & alginate), and fixed amount of synthetic HA were prepared using in situ co precipitation method and mineral to polymer ratio was 1:1 to 1: 2 . A cross linker agent, 2-Hydroxylmethacrylate (HEMA) was added at different percentage (0.5-2%) into the selected composition and irradiated at 5- 25 kGy to optimize the proper mixing of components at the presence of HEMA. Fabricated scaffolds were analyzed to determine porosity, density, biodegradability, morphology and structural properties. Porosity and density of the prepared scaffold were 75 to 92% and 0.21 to 0.42 g/cm3 respectively. However, the swelling ratio of the fabricated scaffolds was ranged from 133 to 197%. Nonetheless, there had a reasonable in-vitro degradation of prepared scaffolds. Flourier transform infrared spectroscopy (FTIR) analysis showed intermolecular interaction between components in the scaffold. Pore size of scaffold was measured by scanning electron microscope and the value was 162-510 μm. It could be proposed that this scaffold fulfills all the main requirements to be considered as a bone substitute for biomedical application in near future.

Greatly enhanced hydrolytic degradation ability of poly(L-lactide) achieved by adding poly(ethylene glycol)

Plasticized poly(L-lactide) (PLLA) materials have been applied in many fields and the microstructure performance of such materials attracts much attention of researchers. However, few reports declared the hydrolytic degradation ability of the plasticized PLLA materials. In this article, a small quantity of poly(ethylene glycol) (PEG) was introduced into PLLA, which aimed to understand the hydrolytic degradation behavior of the plasticized PLLA materials. The microstructures of the plasticized samples were comparatively investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and Flourier transform infrared spectroscopy (FTIR), etc. The results demonstrated that PEG improved the hydrophilicity of sample surface, and the relatively high content of PEG enhanced the crystallization ability of PLLA matrix. The hydrolytic degradation measurement was carried out at 60 °C in an alkaline solution of pH = 12. The results demonstrated that the plasticized PLLA samples exhibited accelerated hydrolytic degradation compared with the pure PLLA sample, and the hydrolytic degradation was also dependent on the PEG content. Further results demonstrated that PEG induced the change of hydrolytic degradation mechanism possibly due to the good dissolution ability of PEG in water, which provided more paths for the penetration of water. Furthermore, the microstructure evolution of the plasticized PLLA during the hydrolytic degradation process was also investigated, and the results demonstrated the occurrence of PLLA crystallization, which was possibly contributed to the decreased hydrolytic degradation rate observed at relatively long hydrolytic degradation time. This work is of great significance and may open a new way for promoting the reclamation of PLLA waste material.

Photocatalytic TiO 2 /porous BNNSs composites for simultaneous LR2B and Cr (VI) removal in wool dyeing bath

Abstract Titanium dioxide/porous boron nitride nanosheets (TiO 2 /P-BNNSs) were prepared to remove dyes (Lanaset Red 2B, LR2B) and heavy metals (hexavalent chromium, Cr (VI)) simultaneously in a simulated wool dyeing bath where pollutants (LR2B or Cr (VI)) and auxiliaries were simultaneously presented. Characterisations of TiO 2 /P-BNNSs were carried out by X-ray diffraction (XRD), Flourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM) and N 2 adsorption desorption equilibrium. Application of TiO 2 /P-BNNSs for the treatment of LR2B alone, Cr (VI) alone and their mixture in the simulated wool dyeing bath was discussed. Both LR2B and Cr (VI) removal were decreased in the ternary system (LR2B/Cr (VI)/(TiO 2 /P-BNNSs)) compared with those in their respective binary systems (LR2B/(TiO 2 /P-BNNSs) or Cr (VI)/(TiO 2 /P-BNNSs)) in the simulated wool dyeing bath. In spite of these decreases, simultaneous LR2B and Cr (VI) removal was achieved after 5 successive cycles of use of TiO 2 /P-BNNSs, which particularly maintained the durability for LR2B removal, implicating their potential for real wool dyeing effluent treatment.

Preparation of a novel porous adsorption material from coal slag and its adsorption properties of phenol from aqueous solution

A new porous adsorption material (PAM) was successfully prepared from raw coal slag and characterized by several techniques, including N2 adsorption–desorption isotherm, thermogravimetric analysis (TGA), flourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Transmission electron microscope (TEM) and X-ray diffraction (XRD) measurement. The preparation procedure of PAM involved two steps: (1) SiO32− chemical leaching from coal slag, and (2) preparation of the PAM. The optimum SiO32− leaching condition was confirmed at 30mL HCl for the pretreated processes, 200mesh particle size of coal slag, leaching temperature of 100°C, reaction time of 2h, NaOH initial concentration of 30wt.%, and the ratio of alkaline to slag of 2:1. Under this condition, SiO32− leaching yield arrived at 39.42wt.%, which accounted for 80.78wt.% of the total content of SiO32 in coal slag. The PAM was then easily prepared with the yield of 99.20wt.% at 90°C for 4h with Ca/Si mole ratio of 0.75:1. According to Langmuir model, the adsorption capability of phenol on the PAM with a maximum uptake was 63.78mg/g. According to adsorption thermodynamic results, the process was exothermic, thermodynamically feasible, spontaneous and chemically controlled.

Dendritic macromolecules as nano-scale drug carriers: Phase solubility, in vitro drug release, hemolysis and cytotoxicity study

Potential of nanoscale triazine based dendritic macromolecules G1, G2 and G3 as solubility enhancers of drug was investigated. Effect of pH, concentration and generation of synthesized dendritic macromolecules on solubility of ketoprofen was studied. G3 dendrimer was further exploited as carrier for sustained release. Ketoprofen was encapsulated by inclusion complex method and also characterized by Flourier Transform Infrared spectroscopy. Sustained release study of ketoprofen from ketoprofen loaded dendrimer was carried out and compared with free ketoprofen. Hemolytic potential and Cytotoxicity assay using A-549 lung cancer cell lines revealed that synthesized triazine based dendritic macromolecules having more potential that commercially available PAMAM dendrimer.

Properties of a Solid–Solid Phase Change Material PAN/SA-LA/ZMS

In this study, novel solid–solid phase change materials (PCM) composed of polyacrylonitrile, binary of fatty acids ((blending of stearic acid (SA) and lauric acid (LA)) and zeolite molecular sieve (ZMS) were prepared by solution blending process. The structure and properties of the PCM were characterized using flourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG), respectively. DSC analysis indicated that the crystallization latent heat of the PCM was 125.22 J/g and its phase transition temperature was about 17 °C. The temperature curve for step cooling of the PCM showed that it’s holding time achieved 1 480 s, which explains that the PCM had excellent heat-insulating properties. Based on all results it can be concluded that the novel PCM can be considered as potential PCM for thermal energy storage.

Bio-based core–shell casein-based silica nano-composite latex by double-in situ polymerization: Synthesis, characterization and mechanism

Casein-based silica nano-composite latex as bio-based film-forming material was synthesized from casein, caprolactam, acrylate, tetraethoxysilane and silane coupling agent via double-in situ emulsion polymerization. The objective of this study was to solve the problem of casein film deficiencies, such as hard, brittle and poorer water resistance. To investigate the influences of silica on properties of the latexes and films, the resultant nano-composite and the control system (without silica) were both characterized by flourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry (TG), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), separately. FT-IR spectra suggested the successful incorporation of nano-silica particles with the matrix as well as the expected grafting of polyacrylate onto casein chains. Morphology of resultant composite latex exhibited evident core–shell structure with the average size of around 80nm, and the improved shell thickness indicated the encapsulation of silica on the outer layer of the particle, which was verified by TEM results. TG analysis demonstrated the enhanced thermostability of casein-based silica nano-composite, in comparison with the control system (without nano-silica). SEM, AFM and XPS results confirmed that the substantial silica dispersed uniformly near the outer layer of the films, and showed good compatibility between the inorganic and organic phases in the casein-based silica composite. Additionally, compared with the latex film without silica, the hybrid latex film containing silica showed higher hydrophobicity, lower water absorption, enhanced tensile strength and decreased flexibility.

Preparation of ZnO thin films by MO-CVD using fibrous bis (acetylacetonato) zinc (II) and ozone

The fibrous bis (acetylacetonato) zinc (II) (Zn(C5H7O2)2·xH2O) was prepared with novel apparatus involved the vaporization and the recrystallization, and was investigated by differential thermal analysis (DTA), flourier transform infrared spectroscopy (FT-IR) with attenuated total reflection (ATR), and the inductively coupled plasma optical emission spectroscopy (ICP-OES). The zinc oxide (ZnO) films were prepared by the low-pressure CVD (LP-CVD) using the fibrous Zn(C5H7O2)2·xH2O and ozone(O3). The DTA curve of the fibrous material with a wide-ranging endothermic peak under 100°C according to desorption of the hydrated water separated to two peaks decreasing in the evaporation temperature. The resistivity of the ZnO films has changed widely from 104 to 108 Ωcm by the fibrous material with a different preparation condition.

Preparation and characterization of three-dimensional chrysanthemun flower-like calcium carbonate

Calcium carbonate with three-dimensional chrysanthemun flower-like structure was successfully prepared from calcium chloride and sodium carbonate ethanol/water mixed solution by a simple precipitation method, using trisodium citrate as crystal modifier. The experimental results show that the three-dimensional structure of chrysanthemun flower-like calcium carbonate is built up with several symmetrical micrometer multi-layer petals arranged around the multi-layer pancake-liked center, and the micrometer center and petals are assemblied by a large number of nanometer spherical particles with size 10–20 nm. It is found that the amount of trisodium citrate, the ethanol volume content has an important influence on the formation of this morphology. A possible mechanism is proposed to explain the formation of three-dimensional chrysanthemun flower-like calcium carbonate according the results. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), flourier transform infrared spectroscopy (FT-IR), thermogravimety analysis (TG), transmission electron microscopy (TEM) equipped with energy-dispersive X-ray (EDX), and selected area electron diffraction (SAED) were used to characterize the crystals.

Thermal properties and flame retardancy of polycarbonate/hydroxyapatite nanocomposite

AbstractThe thermal degradation of polycarbonate (PC) and polycarbonate/hydroxyapatite (PC/HAP) composite was investigated by the thermogravimetric analysis (TGA) and the decomposition activation energy was calculated by Kissinger method. It was found that the first step decomposition activation energy (Ea1) was higher than that of pure PC while the second step decomposition (Ea2) decreased a little. The limiting oxygen index (LOI) of PC/HAP composite with 0.5 wt % HAP reached 34. The carbon char of PC and PC/HAP composite after combustion was analyzed by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and flourier transform infrared spectroscopy (FTIR) and similar morphology, components, and the same functional groups were found in the char residues. Based on these results, it can be concluded that a low content of HAP in PC matrix can significantly improve the thermal properties and flame retardancy of the composite. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Crystallization Behavior of Polypropylene Filled with Modified Carbon Black

A novel method was employed to modify the surface of carbon black (CB) by organic small molecules in a Haake Rheomix mixer. The investigations of Thermo Gravimetric Analysis (TGA), transmission electron microscopy (TEM), Flourier Transform Infrared spectroscopy (FT-IR) and X-ray Photoelectronic Spectroscopy (XPS) indicated that organic small molecules were grafted onto the surface of MCB and the particle size of MCB was reduced notably. Then the crystallization behavior of polypropylene (PP)/MCB composite as well as pure PP and PP/CB composite were investigated via differential scanning calorimeter (DSC), wide angle X-ray diffraction (WAXD) and optical polarizing microscope (POM). It was found that both CB and MCB can influence the crystallization behavior of PP and provide nucleation sites to the matrix. However, MCB accelerated the crystallization rate and increased the crystallization peak temperature of PP more evidently than CB did. In the case of non-isothermal crystallization, Jeziorny and Mo Equations were used to analyze the data of DSC and both could describe these systems. Finally, the nucleation activity of MCB was evaluated. It was proved that the nucleation activity of MCB was higher than that of CB at the same concentration.