Kinetics of crystallization for polypropylene/polyethylene/halloysite nanotube nanocomposites

2018 ◽  
Vol 33 (4) ◽  
pp. 451-463 ◽  
Author(s):  
MY Ong ◽  
WS Chow
Keyword(s):  
Crystallization Rate ◽  
Avrami Equation ◽  
Crystallization Time ◽  
Halloysite Nanotube ◽  
Kissinger Equation ◽  
Polyethylene Blends ◽  
Instantaneous Nucleation ◽  
Half Crystallization Time ◽  
T Values ◽  
Kinetics Of

The aim of this study is to investigate the kinetics of non-isothermal crystallization of polypropylene/high-density polyethylene/halloysite nanotube (PP/HDPE/HNT) nanocomposites using three methods, that is, Avrami equation, combined Ozawa–Avrami method (hereafter called Mo model), and Kissinger equation. The Avrami exponent ( n) is in the range of 1–2 for all the PP/HDPE/HNT nanocomposites indicating instantaneous nucleation while the crystallization rate constant ( Zt) values of PP/HDPE increased with the addition of HNT. This proved that addition of HNT increases the crystallization rate. The reduction of half crystallization time ( t 1/2) for PP/HDPE as the increasing HNT loading indicates faster crystallization rate. In the Mo model, the cooling rate chosen at unit crystallization time F( T) values for PP/HDPE decreases with the addition of HNT. Kissinger equation showed that the activation energy ( E a) of crystallization for the PP/HDPE decreases with the addition of HNT. All the results demonstrated that HNT can accelerate the crystallization rate for the PP/polyethylene blends.

Isothermal Crystallization Kinetics of Polypropylene and Hyperbranched Polyester Blends

2011 ◽  
Vol 396-398 ◽  
pp. 1688-1691
Author(s):  
Qing Chun Fan ◽  
Fei Hong Duan ◽  
Huai Bing Guo ◽  
Tian Wu
Keyword(s):  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Interfacial Free Energy ◽  
Crystallization Time ◽  
Hyperbranched Polyester ◽  
Isothermal Crystallization Kinetics ◽  
Half Crystallization Time ◽  
Kinetics Of

The isothermal crystallization kinetics of PP with different contents of AB2 hyperbranched polyester(HBP) added has been investigated. The results show that HBP acts as a nucleating agent for PP, and the hyperbranched polyester can decrease the half crystallization time (t1/2) and increase the crystallization rate of PP greatly. The Avrami exponents of PP and nucleated PP are all close to 2.5. Hoffman theory was adopted to calculate the interfacial free energy per unit area perpendicular to PP chains σe of PP and PP/HBP blends.

Crystallization and Melting Behaviors of Polylactic Acid/Thermoplastic Polyurethane Blends

2012 ◽  
Vol 627 ◽  
pp. 156-159 ◽  
Author(s):  
Tien Wei Shyr ◽  
Jung Yang ◽  
Chun Chieh Hu ◽  
Jian Ren Wang ◽  
Chia Hsin Tung
Keyword(s):  
Polylactic Acid ◽  
Thermoplastic Polyurethane ◽  
Crosslinking Agent ◽  
Crystallization Rate ◽  
Optical Microscope ◽  
Avrami Equation ◽  
Isothermal Crystallization Kinetics ◽  
X Ray ◽  
Structure Morphology ◽  
Kinetics Of

A series of blends were prepared by different ratios of polylactic acid (PLA) and thermoplastic polyurethane (TPU) with a crosslinking agent of dicumyl peroxide (DCP). This study focused on the crystal structure, morphology, crystallization, and melting behaviors of PLA/TPU blends using a wide angle x-ray diffractometer (WAXD), a polarizing optical microscope (POM) and a differential scanning calorimeter (DSC). A Modified Avrami equation was applied to analyze non-isothermal crystallization kinetics of PLA/TPU blends. Results show that the nucleation of PLA was enhanced by the added TPU. The spherulitic growth rate, crystallization rate, and crystallinity of the PLA/TPU blends increased with an increase of TPU content. WAXD results show that all of the crystal reflections of PLA/TPU blends related to those of PLA.

Kinetic Study on Phosphate Enrichment Behavior in CaO–SiO2–FeO–Fe2O3–P2O5 Steelmaking Slags

2018 ◽  
Vol 37 (5) ◽  
pp. 477-486
Author(s):  
Jin-yan Li ◽  
Mei Zhang ◽  
Min Guo ◽  
Xue-min Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Avrami Equation ◽  
One Dimensional ◽  
Thermal Crystallization ◽  
Steelmaking Slags ◽  
Cooling Schedules ◽  
Kinetics Of

AbstractThe iso-thermal crystallization behavior of phosphate-enriched phase has been experimentally investigated in the rapidly quenched CaO–SiO2–FeO–Fe2O3–P2O5 steelmaking slags under different cooling schedules. The experimental results indicate that increasing endpoint temperature from 1453 to 1533 K and prolonging holding time from 2 to 60 min can result in an increasing tendency of the size of phosphate-enriched phase in the shape of one-dimensional rod. The crystallization kinetics of phosphate-enriched phase in steelmaking slags has been described by Avrami equation. The Avrami constant $$n$$ was obtained to be 0.472, while the crystallization rate constant $$k$$ was recommended as $$\ln k{\rm{= 57}}{\rm{. 40 + 12,273}}{\rm{. 96}}/T - {\rm{8}}{\rm{. 25}}\,\ln T - {\rm{5}}{\rm{. 5}\times{\rm 10}^{- 3}}T$$. Thus, the apparent activation energy $$E$$ of crystallization is recommended as $$E{\rm{= 537}}{\rm{. 60}} - {\rm{206}}{\rm{. 015}}T$$ kJ/mol.

scholarly journals Isothermal Crystallization Kinetics of Poly(ethylene terephthalate) Copolymerized with Various Amounts of Isosorbide

2020 ◽  
Vol 10 (3) ◽  
pp. 1046 ◽  
Author(s):  
Nicolas Descamps ◽  
Florian Fernandez ◽  
Pierre Heijboer ◽  
René Saint-Loup ◽  
Nicolas Jacquel
Keyword(s):  
Isothermal Crystallization ◽  
Ethylene Terephthalate ◽  
Systematic Investigation ◽  
Crystallization Time ◽  
Isothermal Crystallization Kinetics ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Half Crystallization Time ◽  
First Time ◽  
Kinetics Of

Poly(ethylene-co-isosorbide terephthalate) (PEIT) copolyesters could be used in various applications depending on their ability to crystallize. Moreover, the possibility to carry out solid-state post-condensation (SSP) is conditioned by its ability to sufficiently crystallize. The present study, thus, gives a systematic investigation of isothermal crystallization of these statistical copolyesters with isosorbide contents ranging from 4.8 to 20.8 mol.%. For each copolyester composition, the lowest isothermal half crystallization times and the highest Avrami constant (K) were obtained around 170 °C. Over the range of composition that was studied, both melting points and melting enthalpies decreased with increasing amounts of isosorbide (from 250 to 207 °C and from 55 to 28 J/g, respectively). On the contrary, half crystallization time displayed an exponential increase when increasing isosorbide contents in the studied range. Finally, structural and thermal analysis of PIT homopolyester are reported for the first time, showing that only ET moieties crystallized when PEIT was subjected to isothermal crystallization at 170 °C.

Crystallization behavior of poly(ε-caprolactone) grafted on silicon surface

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Xi Wang ◽  
Juping Yang ◽  
Jianjun Zhou
Keyword(s):  
Film Thickness ◽  
Silicon Wafer ◽  
Crystallization Rate ◽  
Crystallization Time ◽  
Chain Entanglement ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nodular Structure ◽  
Half Crystallization Time ◽  
Different Thickness

AbstractPoly(ε-caprolactone) (PCL) grafted on silicon wafer with different thickness (10 to 100 nm) were prepared by surface-initiated ring-opening polymerization (ROP). The morphologies, crystallinity, and crystallization rate of different thickness thin films have been investigated by atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The nascent morphology of the as polymerized 15 nm film was found to be nodular structure form. As the film thickness increased, the nodular structures gradually aggregated to form flat-on lamellae. When the film thickness reached 100 nm, the surface of silicon wafer was covered with a whole layer of flat-on lamellae. The isothermal crystallization study on 100 nm film had shown that the tethered PCL chains could only crystallize in the form of flat-on lamellae. FTIR study had showed that the crystallinity decreased significantly with the film thickness decreasing, while the half-crystallization time increased as the film became thicker. The halfcrystallization time increase of thicker film was supposed to relate with the degree of chain entanglement in the tethered brushes.

Parameters characterizing the kinetics of the non-isothermal crystallization of polyamide 5,6 determined by differential scanning calorimetry

2014 ◽  
Vol 34 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Yassir A. Eltahir ◽  
Haroon A.M. Saeed ◽  
Chen Yuejun ◽  
Yumin Xia ◽  
Wang Yimin
Keyword(s):  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Degree Of Crystallinity ◽  
Avrami Equation ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Ozawa Model ◽  
Kinetic Crystallization ◽  
Kinetics Of

Abstract The non-isothermal crystallization behavior of polyamide 5,6 (PA56) was investigated by differential scanning calorimeter (DSC), and the non-isothermal crystallization kinetics were analyzed using the modified Avrami equation, the Ozawa model, and the method combining the Avrami and Ozawa equations. It was found that the Avrami method modified by Jeziorny could only describe the primary stage of non-isothermal crystallization kinetics of PA56, the Ozawa model failed to describe the non-isothermal crystallization of PA56, while the combined approach could successfully describe the non-isothermal crystallization process much more effectively. Kinetic parameters, such as the Avrami exponent, kinetic crystallization rate constant, relative degree of crystallinity, the crystallization enthalpy, and activation energy, were also determined for PA56.

scholarly journals Nonisothermal Crystallization Kinetics of Acetylated Bamboo Fiber-Reinforced Polypropylene Composites

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1078 ◽  
Author(s):  
Yu-Shan Jhu ◽  
Teng-Chun Yang ◽  
Ke-Chang Hung ◽  
Jin-Wei Xu ◽  
Tung-Lin Wu ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Crystallization Rate ◽  
Bamboo Fiber ◽  
Crystallization Time ◽  
Nucleation Agent ◽  
Relative Crystallinity ◽  
Crystallinity Degree ◽  
Friedman Method ◽  
Kinetics Of

The crystallization behavior of bamboo fiber (BF) reinforced polypropylene (PP) composites (BPCs) was investigated using a differential scanning calorimeter (DSC). The results showed that unmodified BF as a nucleation agent accelerated the crystallization rate of the PP matrix during cooling whereas there is no significant effect on the improved crystallization rate in BPCs with acetylated BFs. Based on the Avrami method, Avrami–Ozawa method, and Friedman method, the corresponding crystallization kinetics of PP reinforced with different acetylation levels of BFs were further analyzed. The results demonstrated that the crystal growth mechanism of the PP matrix for BPCs with unmodified and various acetylated BFs exhibited tabular crystal growth with heterogeneous nucleation. A higher cooling rate is required to achieve a certain relative crystallinity degree at the unit crystallization time for BPCs with a higher weight percent gain (WPG) of acetylated BFs (WPG >13%). Furthermore, based on the Friedman method, the lowest crystallization activation energy was observed for the BPCs with 19% WPG of acetylated BFs.

scholarly journals Isothermal Crystallization Kinetics Study of Fully Aliphatic PA6 Copolyamides: Effect of Novel Long-Chain Polyamide Salt as a Comonomer

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 472 ◽  
Author(s):  
Syang-Peng Rwei ◽  
Palraj Ranganathan ◽  
Yi-Huan Lee
Keyword(s):  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Three Dimensional ◽  
Sebacic Acid ◽  
Crystallization Rate ◽  
Polyamide 6 ◽  
Crystallization Time ◽  
Structure Property ◽  
Isothermal Crystallization Kinetics ◽  
Half Crystallization Time

N1, N6-bis (4-aminobutyl) adipamide (BABA) diamine and sebacic acid (SA), also called BABA/SA polyamide salt, were used in a typical melt polymerization processes of polyamide 6 (PA6) to form a series of PA6-BABA/SA copolyamides. The effects of BABA/SA on the isothermal crystallization kinetics of PA6-BABA/SA were studied for the first time. An isothermal crystallization analysis demonstrates that the PA6-BABA/SA matrix provided a higher crystallization rate and shorter half-crystallization time than virgin PA6 did. The degree of crystallization of the PA6-BABA/SA30 matrix was also the lowest among all of the samples considered herein. This result is attributed to the high nucleation efficacy of a small amount of BABA/SA in the crystallization of PA6. Values of the Avrami exponent (n) from 1.84 to 3.91 were observed for all of the polyamide samples, suggesting that the crystallization was involved via a two- to three-dimensional growth mechanism. These findings deepen our understanding of the structure–property relationship of PA6-BABA/SA copolyamides, favoring their practical application.

Isothermal Crystallization Kinetics of Poly(phenylene Sulfide)/ZnO Composites

2012 ◽  
Vol 535-537 ◽  
pp. 243-246 ◽  
Author(s):  
Zhong Hou Zhang ◽  
Wen Xin Zhou ◽  
Ya Dong Li ◽  
Chun Mian Yan
Keyword(s):  
Heterogeneous Nucleation ◽  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Nucleating Agent ◽  
Avrami Equation ◽  
Crystallization Time ◽  
Nano Zno ◽  
Kinetics Of ◽  
Phenylene Sulfide

Poly (phenylene sulfide) (PPS)/nano-ZnO composites were prepared by DAKA miniature blending instrument. Isothermal crystallization behavior of PPS composites at 245°C, 250°C, 255°C and 260°C were investigated by means of DSC. The crystallization time of PPS composites is shorter than which of neat PPS at the same crystallization temperature. The Avrami equation was used to analyze DSC data. Results showed that neat PPS is homogeneous nucleation at lower crystallization temperature, which is heterogeneous nucleation at higher crystallization temperature contrarily. PPS/nano-ZnO composites are heterogeneous nucleation at various crystallization temperature, nano-ZnO particles play a role of nucleating agent.

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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