Structure, crystallization behavior, and thermal stability of PP/MCM-41 nanocomposite

2009 ◽  
Vol 49 (12) ◽  
pp. 2459-2466 ◽  
Author(s):  
Na Wang ◽  
Qinghong Fang ◽  
Erfan Chen ◽  
Jing Zhang ◽  
Yawei Shao
Keyword(s):  
Thermal Stability ◽  
Crystallization Behavior ◽  
Thermal Stability Of ◽  
Mcm 41

Thermal stability, crystallization and mechanical properties of nylon11/montmorillonite nanocomposites

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Yingchun Li ◽  
Guosheng Hu ◽  
Bin He
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Avrami Equation ◽  
Melt Compounding ◽  
Izod Impact ◽  
Nylon 11 ◽  
Thermal Stability Of ◽  
Montmorillonite Nanocomposites

AbstractNylon 11 nanocomposites with different montmorillonite loadings were successfully prepared by melt compounding. XRD and TEM show the exfoliated nanocomposites are formed at low montmorillonite concentration (less than 2 wt%) and the intercalated nanocomposites are obtained at higher montmorillonite contents. TGA shows that the thermal stability of the nanocomposites is improved by 27 °C when the montmorillonite content is only 2wt%. At the same time, The crystallization behavior of nylon11/montmorillonite nanocomposites has been studied by means of XRD, DSC.The Avrami equation described well the isothermal crystallization behavior of nylon11 and nylon11/montmorillonite nanocomposites. The results showed that the montmorillonite acted as the nucleating agent and facilitated the crystal growth rate of nylon 11 matrix. The incorporation of montmorillonite did not change the crystal morphology of nylon 11 but increased the crystallization temperature and decreased the crystallization activation energy, which lead to a easy crystallization of nylon11. Mechanical testing shows that the Izod impact strength of all nanocomposites are higher than that of the neat nylon 11, but the tensile strength of the nanocomposites decrease at low nanofiller concentrations (less than 8wt%) and then increased, when the montmorillonite content is 10wt% ,the tensile strength of the nanocomposite is 5% improved than neat nylon 11. This is may be due to the strong interaction between the nylon 11 matrix and the montmorillonite interface.

Thermal stability of Si–MCM-41 in gaseous atmosphere

2003 ◽  
Vol 57 (24-25) ◽  
pp. 3839-3842 ◽  
Author(s):  
Keshu Wan ◽  
Qian Liu ◽  
Cunman Zhang
Keyword(s):  
Thermal Stability ◽  
Gaseous Atmosphere ◽  
Thermal Stability Of ◽  
Mcm 41

Influence of ion exchange and calcination on pore size and thermal stability of MCM-41 with different Si/Al ratios

1998 ◽  
Vol 94 (6) ◽  
pp. 817-820 ◽  
Author(s):  
Heico Koch ◽  
Uwe Böhmer ◽  
Andreas Klemt ◽  
Wladimir Reschetilowski ◽  
Michael Stöcker
Keyword(s):  
Thermal Stability ◽  
Ion Exchange ◽  
Pore Size ◽  
Thermal Stability Of ◽  
Mcm 41

Ion Exchange and Thermal Stability of MCM-41

1995 ◽  
Vol 99 (45) ◽  
pp. 16742-16747 ◽  
Author(s):  
Ji Man Kim ◽  
Ja Hun Kwak ◽  
Shinae Jun ◽  
Ryong Ryoo
Keyword(s):  
Thermal Stability ◽  
Ion Exchange ◽  
Thermal Stability Of ◽  
Mcm 41

Crystallization Behavior and Thermal Stability of Two-Glassy Phase ZR-Based Bulk Metallic Glasses

2010 ◽  
Vol 89-91 ◽  
pp. 562-567
Author(s):  
P.H. Tsai ◽  
I.S. Huang ◽  
T.H. Li ◽  
Jason S.C. Jang ◽  
J.C. Huang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Amorphous Alloy ◽  
Crystallization Behavior ◽  
Heat Of Mixing ◽  
Interface Area ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Thermal Stabilities ◽  
Activation Energy Of Crystallization ◽  
Thermal Stability Of

Based on the thermodynamic calculation, two phase separated Zr-based BMGs (Zr63.8Ni16.2Cu15Al5 and Zr66Cu15.3Ni8.7Al10) which developed by the authors previous study were selected for investigating their crystallization behavior and thermal stabilities by means of differential scanning calorimetry (DSC), and X-ray diffractometry. The results show that the Zr66Cu15.3Ni8.7Al10 amorphous alloy exhibits higher GFA than the Zr63.8Ni16.2Cu15Al5 amorphous alloy. But the Zr63.8Ni16.2Cu15Al5 amorphous alloy presents higher activation energy of crystallization (227 kJ/mole and 188 kJ/mole for Zr63.8Ni16.2Cu15Al5 and Zr66Cu15.3Ni8.7Al10 BMGs, respectively). However, Zr66Cu15.3Ni8.7Al10 amorphous alloy contains less atomic percentage of Cu and Ni elements (with positive heat of mixing) may result in forming less volume phase separation as well less interface area between these separated amorphous phase. Overall, the Zr66Cu15.3Ni8.7Al10 amorphous alloy exhibits longer incubation time at higher annealing temperature in comparison with the Zr63.8Ni16.2Cu15Al5 amorphous alloy, suggesting that the amorphous alloy which contains fewer amounts of Cu and Ni elements would have better thermal stability.

ChemInform Abstract: Ion Exchange and Thermal Stability of MCM-41.

ChemInform ◽  
2010 ◽  
Vol 27 (8) ◽  
pp. no-no
Author(s):  
J. M. KIM ◽  
J. H. KWAK ◽  
S. JUN ◽  
R. RYOO
Keyword(s):  
Thermal Stability ◽  
Ion Exchange ◽  
Thermal Stability Of ◽  
Mcm 41

scholarly journals Effect of Storage Conditions on the Thermal Stability and Crystallization Behaviors of Poly(L-Lactide)/Poly(D-Lactide)

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 238
Author(s):  
Tien-Wei Shyr ◽  
Huan-Chieh Ko ◽  
Tzong-Ming Wu ◽  
Meifang Zhu
Keyword(s):  
Thermal Stability ◽  
Room Temperature ◽  
Crystallization Behavior ◽  
Gel Permeation Chromatography ◽  
Storage Conditions ◽  
Aliphatic Polyester ◽  
X Ray Diffraction ◽  
Melting Points ◽  
X Ray ◽  
Thermal Stability Of

Polylactide (PLA) is a biodegradable thermoplastic aliphatic polyester. The thermal stability and crystallization behavior of PLA are extremely sensitive to storage, processing, and usage conditions. This work systematically studied the thermal stability and crystallization behavior of poly(L-lactide) (PLLA), poly(D-lactide) (PDLA), and a PLLA/PDLA (LD) blend, which were stored under two sets of laboratory storage conditions: (1) stored in a vacuum-free desiccator and (2) stored in vacuum-sealed bags. Both were stored at room temperature for 3 years. Gel permeation chromatography results revealed that the PLLA, PDLA, and LD samples hydrolyzed slowly when stored in vacuum-sealed bags and degraded significantly when stored in a vacuum-free desiccator; this process significantly reduced the thermal stability of the samples stored in the vacuum-free desiccator. Owing to hydrolysis, the levorotation and dextrorotation (L- and D-) molecular chains were shortened; consequently, more nuclei were formed, and this caused the melting points of the PLLA, PDLA, and LD samples to decrease and the melting enthalpy of the crystals in these samples to increase. Wide-angle X-ray diffraction analysis revealed that when the L- and D- molecular chains were packed side by side to form stereocomplex crystals and the randomly arranged L- and D- molecular chains were easy hydrolyzed and degraded, this interfered with the formation of homocrystals in LD. When PLLA, PDLA, and LD samples are stored in a vacuum-free desiccator, they will be significantly hydrolyzed, resulting in the formation of only stereocomplex crystals, and no homocrystals are observed.

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