Preparation of poly(L-lactide)/poly(ethylene glycol)/organo-modified montmorillonite nanocomposites via melt intercalation under continuous elongation flow

2018 ◽  
Vol 38 (5) ◽  
pp. 449-460 ◽  
Author(s):  
Ting Wu ◽  
Ding Yuan ◽  
Jin-Ping Qu
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Nucleation Density ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Modified Montmorillonite ◽  
Elongation Flow ◽  
Poly Ethylene

AbstractAn innovative eccentric rotor extruder (ERE), which can generate continuous elongation flow, was used to prepare the poly(L-lactide) (PLLA)/poly(ethylene glycol) (PEG)/organo-modified montmorillonite (OMMT) nanocomposites. The morphology was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and showed that the OMMT nanoparticles were uniformly dispersed in the matrix and mainly existed in intercalation mode. The influence of OMMT on the rheological behavior of plasticized PLLA was investigated by dynamic rheological measurements, showing greater improvement of rheological properties compared to that of PLLA/PEG blend. The crystallization behavior and crystalline structures were studied by differential scanning calorimetry (DSC) and XRD, respectively, and showed that the presence of OMMT further speeds up the crystallization rate of plasticized PLLA. However, the crystallization rate and crystallinity had a slight downward trend at high OMMT content because of the inhibition effect of the OMMT percolation network structure. Polarizing optical microscopy (POM) was further carried out and proved that the OMMT nanoparticles as a heterogeneous nucleating agent can increase the spherulite growth rate and nucleation density. The thermal stability was investigated by thermogravimetric analysis and indicated that the addition of OMMT at low concentration can improve the thermal stability of plasticized PLLA more effectively.

Gelation Crystallization of Poly(L-Lactide) in Solvents of Varying Molecular Size

2007 ◽  
Vol 15 (5) ◽  
pp. 389-393
Author(s):  
Hong Hao ◽  
Guozheng Liang ◽  
Junmin Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ethylene Glycol ◽  
Crystallization Rate ◽  
Molecular Size ◽  
Large Molecule ◽  
X Ray Diffraction ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Poly Ethylene

The crystallization behaviour of poly(L-lactide) (PLLA) samples prepared in large-molecule solvents, such as poly(ethylene glycol) (PEG), was studied by differential scanning calorimetry (DSC) and X-ray diffraction. The results indicate that those samples recovered from large-molecule solvents exhibit higher crystallinity, non-isothermal crystallization temperature and faster crystallization rate than the ones crystallized in a small-molecule solvent. The crystallinity of samples from PLLA/PEG gel is about 73% measured by the DSC. The molar size of the solvent has a large influence on the formation of helical conformations and, thereby on the crystallization rate of PLLA in solution.

scholarly journals Tailoring Atomoxetine Release Rate from DLP 3D-Printed Tablets Using Artificial Neural Networks: Influence of Tablet Thickness and Drug Loading

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 111
Author(s):  
Gordana Stanojević ◽  
Djordje Medarević ◽  
Ivana Adamov ◽  
Nikola Pešić ◽  
Jovana Kovačević ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Release Rate ◽  
Drug Loading ◽  
Prolonged Release ◽  
Cylindrical Shape ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Artificial Neural ◽  
Poly Ethylene

Various three-dimensional printing (3DP) technologies have been investigated so far in relation to their potential to produce customizable medicines and medical devices. The aim of this study was to examine the possibility of tailoring drug release rates from immediate to prolonged release by varying the tablet thickness and the drug loading, as well as to develop artificial neural network (ANN) predictive models for atomoxetine (ATH) release rate from DLP 3D-printed tablets. Photoreactive mixtures were comprised of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) 400 in a constant ratio of 3:1, water, photoinitiator and ATH as a model drug whose content was varied from 5% to 20% (w/w). Designed 3D models of cylindrical shape tablets were of constant diameter, but different thickness. A series of tablets with doses ranging from 2.06 mg to 37.48 mg, exhibiting immediate- and modified-release profiles were successfully fabricated, confirming the potential of this technology in manufacturing dosage forms on demand, with the possibility to adjust the dose and release behavior by varying drug loading and dimensions of tablets. DSC (differential scanning calorimetry), XRPD (X-ray powder diffraction) and microscopic analysis showed that ATH remained in a crystalline form in tablets, while FTIR spectroscopy confirmed that no interactions occurred between ATH and polymers.

scholarly journals Sizing and Thermal Stability of Prepared Tetraaminophthalocyaninatocopper(II) Derivatives-grafted Polymers

2016 ◽  
Vol 13 (2) ◽  
pp. 221-234
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Group Analysis ◽  
Condensation Polymerization ◽  
Grafted Polymers ◽  
Poly Ethylene Glycol ◽  
Molecular Weights ◽  
Poly Ethylene ◽  
Thermal Stability Of ◽  
End Group

Different polymers were prepared by condensation polymerization of sebacic anhydride and adipic anhydride with ethylene glycol and poly(ethylene glycol). Their number average molecular weights were determined by end group analysis. Then, they were grafted on the prepared phthalocyaninatocopper(II) compounds with the general formula (NH2)4PcCu(II) having amino groups of 3,3',3'',3'''- or 4,4',4'',4'''- positions. All prepared polymers, compounds, and phthalocyaninatocopper(II)-grafted polymers were characterized by FTIR. The sizing measurements were carried out in 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) compounds with and without grafting polymers. The results showed that the grafting process led to decreasing in particle size and increasing in surface area. The grafting process was reflected positively on the thermal degradation of 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) grafted polymers. They had higher thermal stability accompanied with higher char residue and T50% weight loss with 3,3',3'',3'''-(NH2)4PcCu(II) and their grafted polymers being the best.

Encapsulation of Lanthanide β-diketone Hybrids in Organic Oligomer Poly(ethylene glycol) 400

2015 ◽  
Vol 1102 ◽  
pp. 125-128
Author(s):  
Hua Ti Li ◽  
Dong Liu ◽  
Ying Li ◽  
Jie Lin Wang ◽  
Xia Wang
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Hybrid Materials ◽  
Mesoporous Material ◽  
Organic Ligand ◽  
Poly Ethylene Glycol ◽  
Characteristic Emission ◽  
Hybrid Precursor ◽  
Poly Ethylene ◽  
The Eu

The organic ligand 2-Thenoyltrifluoroacetone (TTA) which was selected as molecular bridge for sensitization of europium and terbium ions were modified by 3-(triethoxysilyl)-propylisocyanate (TEPIC) to obtain the hybrid precursor TTA-Si. Then the solution of Eu(NO3)3 and Tb(NO3)3 were added in the presence of tetraethylorthosilicate (TEOS). The binary lanthanide organic/inorganic hybrid material were obtained. The ternary hybrid materials were obtained by adding the solution of Eu(NO3)3 and Tb(NO3)3 and Poly (ethylene glycol) (PEG400). We investigated the thermal stability and luminescence properties of hybrids and found that the ternary hybrid materials exhibit better thermal stability and stronger emission intensity. Furthermore, compared with the binary mesoporous material Eu-(TTA-Si)3 and Tb-(TTA-Si)3, the ternary mesoporous material Eu-(TTA-Si)3-PEG and Tb-(TTA-Si)3-PEG exhibits the characteristic emission of the Eu3+ and Tb3+ ion with a higher luminescence intensity, suggesting that the introduction of PEG is of benefit for the sensitization of Eu3+ and Tb3+ luminescence, by replacing H2O groups that can quench the luminescence of Eu3+ and Tb3+ ions.

Mechanical properties and hydrolytic degradation of methoxy poly(ethylene glycol)-b-poly(DL-lactide-coglycolide- co-ε-caprolactone) diblock copolymer films

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Nongnit Morakot ◽  
Jirasak Threeprom ◽  
Yodthong Baimark
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Ethylene Glycol ◽  
Diblock Copolymers ◽  
Hydrolytic Degradation ◽  
Size Exclusion ◽  
Block Length ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Poly Ethylene

AbstractBiodegradable films of methoxy poly(ethylene glycol)-b-poly(DL-lactideco- glycolide-co-ε-caprolactone) diblock copolymers (MPEG-b-PDLLGCL) were prepared by solution casting method. Effects of MPEG block length and DLL:G:CL ratio of the MPEG-b-PDLLGCL films on their mechanical properties and hydrolytic degradation were studied and discussed. It was found that the mechanical properties of films were strongly dependent on glass transition temperatures (Tg) of the diblock copolymers. The hydrolytic degradation was investigated in phosphatebuffered solution at 37°C. The degraded films were characterized using gravimetry (%water uptake and %weight loss), 1H-NMR spectroscopy, differential scanning calorimetry and size exclusion chromatography. The %weight loss of the degraded films increased and molecular weight decreased on increasing the MPEG block length and incorporating the G and CL units, according to their %water uptakes. The MPEG content of the degraded film decreased and the Tg increased with hydrolytic degradation time.

PP/MWCNTs composites: Effects of length of MWCNTs on isothermal crystallization behaviors, crystalline structure, and thermal stability

2017 ◽  
Vol 52 (4) ◽  
pp. 503-517 ◽  
Author(s):  
Zheng-Ian Lin ◽  
Ching-Wen Lou ◽  
Yi-Jun Pan ◽  
Chien-Teng Hsieh ◽  
Chien-Lin Huang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Crystalline Structure ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Scanning Calorimetry ◽  
Crystallization Behaviors ◽  
Walled Carbon Nanotubes ◽  
Thermal Stability Of

This study adopts the melt compounding method to prepare /mutli-walled carbon nanotubes composites. The effects of different lengths of the mutli-walled carbon nanotubes on the isothermal crystallization behaviors, crystalline structure, and thermal stability of the polypropylene/mutli-walled carbon nanotubes composites are examined. The PLM results show that the combination of mutli-walled carbon nanotubes prevents the growth of polypropylene spherulites, and thus results in a small size of spherulites. The differential scanning calorimetry results show that the short (S-) or long (L-) mutli-walled carbon nanotubes can function as the nucleating agent of polypropylene, which accelerates the crystallization rate of polypropylene. Avrami theory analyses indicate that the addition of short-mutli-walled carbon nanotubes particularly provides polypropylene/mutli-walled carbon nanotubes composites with a high crystallization rate. The X-ray diffraction results show that the combination of mutli-walled carbon nanotubes does not pertain to the crystal structure. The TGA test results show that long-mutli-walled carbon nanotubes outperform short -mutli-walled carbon nanotubes in improving the thermal stability of polypropylene, and both can significantly improve it.

scholarly journals Polymer Electrolytes Based on Borane/Poly(ethylene glycol) Methyl Ether for Lithium Batteries

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Ali Murat Soydan ◽  
Recep Akdeniz
Keyword(s):  
Ethylene Glycol ◽  
Methyl Ether ◽  
Polymer Electrolytes ◽  
Lithium Ion ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Molar Ratios ◽  
Poly Ethylene ◽  
Chain Lengths ◽  
Glycol Methyl Ether

This work presents a different approach to preparing polymer electrolytes having borate ester groups for lithium ion batteries. The polymers were synthesized by reaction between poly(ethylene glycol) methyl ether (PEGME) and BH3-THF complex. Molecular weight of PEGMEs was changed with different chain lengths. Then the polymer electrolytes comprising boron were prepared by doping of the matrices with CF3SO3Li at various molar ratios with respect to EO to Li and they are abbreviated as PEGMEX-B-Y. The identification of the PEGME-borate esters was carried out by FTIR and 1H NMR spectroscopy. Thermal properties of these electrolytes were investigated via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The ionic conductivity of these novel polymer electrolytes was studied by dielectric-impedance spectroscopy. Lithium ion conductivity of these electrolytes was changed by the length of PEGME as well as the doping ratios. They exhibit approximate conductivities of 10−4 S·cm−1 at 30°C and 10−3 S·cm−1 at 100°C.

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