Effects of β -nucleating agent and crystallization conditions on the crystallization behavior and polymorphic composition of isotactic polypropylene/multi-walled carbon nanotubes composites

2014 ◽  
Vol 26 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Jian Kang ◽  
Jinghan He ◽  
Zhengfang Chen ◽  
Feng Yang ◽  
Jinyao Chen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Isotactic Polypropylene ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Multi Walled Carbon Nanotubes ◽  
Crystallization Conditions ◽  
Polymorphic Composition ◽  
Walled Carbon Nanotubes

scholarly journals Structure and Mechanical Properties of Multi-Walled Carbon Nanotubes-Filled Isotactic Polypropylene Composites Treated by Pressurization at Different Rates

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1294 ◽  
Author(s):  
Xiaoting Li ◽  
Wenxia Jia ◽  
Beibei Dong ◽  
Huan Yuan ◽  
Fengmei Su ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Isotactic Polypropylene ◽  
Mechanical Tests ◽  
High Yield ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Polypropylene Composites ◽  
Pressurization Rate ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Isotactic polypropylene filled with 1 wt.% multi-walled carbon nanotubes (iPP/MWCNTs) were prepared, and their crystallization behavior induced by pressurizing to 2.0 GPa with adjustable rates from 2.5 to 1.3 × 104 MPa/s was studied. The obtained samples were characterized by combining wide angle X-ray diffraction, small angle X-ray scattering, differential scanning calorimetry, transmission electron microscopy and atomic force microscopy techniques. It was found that pressurization is a simple way to prepare iPP/MWCNTs composites in mesophase, γ-phase, or their blends. Two threshold pressurization rates marked as R1 and R2 were identified, while R1 corresponds to the onset of mesomorphic iPP formation. When the pressurization rate is lower than R1 only γ-phase generates, with its increasing mesophase begins to generate and coexist with γ-phase, and if it exceeds R2 only mesophase can generate. When iPP/MWCNTs crystallized in γ-phase, compared with the neat iPP, the existence of MWCNTs can promote the nucleation of γ-phase, leading to the formation of γ-crystal with thicker lamellae. If iPP/MWCNTs solidified in mesophase, MWCNTs can decrease the growth rate of the nodular structure, leading to the formation of mesophase with smaller nodular domains (about 9.4 nm). Mechanical tests reveal that, γ-iPP/MWCNTs composites prepared by slow pressurization display high Young’s modulus, high yield strength and high elongation at break, and meso-iPP/MWCNTs samples have excellent deformability because of the existence of nodular morphology. In this sense, the pressurization method is proved to be an efficient approach to regulate the crystalline structure and the properties of iPP/MWCNTs composites.

Functionalization of multi-walled carbon nanotubes (MWCNTs) with pimelic acid molecules: effect of linkage on β-crystal formation in an isotactic polypropylene (iPP) matrix

2014 ◽  
Vol 50 (3) ◽  
pp. 1457-1468 ◽  
Author(s):  
J. A. Gonzalez-Calderon ◽  
E. O. Castrejon-Gonzalez ◽  
F. J. Medellin-Rodriguez ◽  
Norbert Stribeck ◽  
A. Almendarez-Camarillo
Keyword(s):  
Carbon Nanotubes ◽  
Isotactic Polypropylene ◽  
Crystal Formation ◽  
Pimelic Acid ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Functionalization of Multiwalled Carbon Nanotubes by Poly (Ethlylene Glycol) and Non-Isothermal Crystallization Kinetic Study

2011 ◽  
Vol 688 ◽  
pp. 127-134
Author(s):  
Song Gao ◽  
Kun Yan Sui ◽  
Zhi Ming Wu ◽  
Wen Wen Wu ◽  
Yan Zhi Xia
Keyword(s):  
Carbon Nanotubes ◽  
Crystallization Behavior ◽  
Crystallization Kinetic ◽  
Crystallization Rate ◽  
Avrami Equation ◽  
Nonisothermal Crystallization ◽  
Multiwalled Carbon ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Kinetics Of

Multi-walled carbon nanotubes (MWNT) were successfully chemically modified (MWNT-COOH) and reacted with polyethylene glycol (PEG) to prepare nanocomposites. As- prepared kinds of functionalized MWNT (MWNT-g-PEG) were characterized with FTIR, TGA and TEM. Nonisothermal crystallization kinetics of MWNT-g-PEG composites was investigated by differential scanning calorimeter (DSC). The kinetics was analyzed using the Ozawa and Avrami equation modified by Jeziorny. The results showed that the Ozawa approach failed to describe the crystallization behavior of nanocomposites, whereas the modified Avrami analysis could explain the behavior of MWNT-g-PEG nanocomposite only. It is observed that the presence of MWNT hindered the mobility of PEG chains and decreased the overall crystallization rate. It was found that the crystallization behavior of MWNT-g-PEG nanocomposite was strongly affected by the incorporation of MWNT. The data for the nonisothermal crystallization could be analyzed properly by the Avrami equation modified by Jeziorny. The results showed that the presence of MWNT decreased the overall nonisothermal crystallization rate of the PEG chains which were grafted onto the MWNT due to MWNT might act as physical hindrances retarding the mobility of PEG chains and decreased the crystallinity.

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