Crystallization Kinetics in Isotactic Polypropylene Films with Carbon Nanotubes

2011 ◽  
Vol 1312 ◽  
Author(s):  
Georgi Georgiev ◽  
Scott Schoen ◽  
Devin Ivy ◽  
Lauren Wielgus ◽  
Yaniel Cabrera ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Crystallization Kinetics ◽  
Isotactic Polypropylene ◽  
Crystallization Rate ◽  
Crystal Nucleation ◽  
Commercial Application ◽  
Peak Time ◽  
Slight Variation ◽  
Scanning Calorimetry ◽  
Avrami Analysis

ABSTRACTPolymer nanocomposites are the largest commercial application for carbon nanotubes (CNTs) which determines the interest in their effect on crystallization processes of polymers. We chose Isotactic Polypropylene (iPP) as one of the most widely used polymers. Nanocomposites with multiwall carbon nanotubes (MWCNTs) 0-5% by weight were studied, using differential scanning Calorimetry to measure the crystal nucleation and kinetics effects of MWCNTs. Isothermal crystallization at 138°C was performed and the data were analyzed using Avrami analysis. We obtained results for the effect of MWCNTs on the crystallization kinetics. The Avrami analysis showed a dramatic increase in the crystallization rate constant and constancy of the Avrami exponent with increase of the CNTs concentration. The full width at half maximum (FWHM) of the heat flow exotherm and the peak time for crystallization (tp) change dramatically. The crystallinity shows a slight variation with the CNTs concentration dipping at 2% CNTs which can be explored further at higher concentrations.

Carbon Nanotube-Induced Changes of Crystal Growth In Polymer Films

2008 ◽  
Vol 1150 ◽  
Author(s):  
Georgi Yordanov Georgiev ◽  
Yaniel Cabrera ◽  
Lauren Wielgus ◽  
Zarnab Iftikhar ◽  
Michael Mattera ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Crystallization Rate ◽  
Peak Time ◽  
Scanning Calorimetry ◽  
Avrami Analysis ◽  
Low Concentrations ◽  
Nucleation Agents ◽  
Speed Up ◽  
Induced Changes

AbstractIsotactic Polypropylene (iPP) nanocomposites with low concentrations of multiwall carbon nanotubes (CNTs) 0-1% were studied, using differential scanning calorimetry and Avrami analysis. The nanocomposites were isothermally crystallized at 135°C, in order to measure the effect of nanotubes on the kinetics of crystallization. In our study there is a great effect of the CNTs on the iPP crystallization kinetics. The Avrami analysis shows increase in the crystallization rate constant and constancy the Avrami exponent with increase of the CNTs concentration. The full width at half maximum (FWHM) of the heat flow exotherm and the peak time for crystallization (tp) change dramatically. For iPP, the carbon nanotubes serve as nucleation agents to speed up the crystallization process.

Effect of Hyperbranched Polymer on Crystallization Kinetics of Isotactic Polypropylene

2012 ◽  
Vol 535-537 ◽  
pp. 1142-1145
Author(s):  
Guang Tian Liu ◽  
Jing Lei
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Isotactic Polypropylene ◽  
Isothermal Crystallization ◽  
Hyperbranched Polymer ◽  
Crystallization Rate ◽  
Crystallization Activation Energy ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Kinetics Of

In this paper, the isothermal crystallization kinetics of isotactic polypropylene (iPP) and iPP with 5% hyperbranched polymer (HBP) added had been investigated by differential scanning calorimetry (DSC). The results show that a small addition of HBP affects the crystallization behavior of iPP. During isothermal crystallization, the crystallization rate of the blend is higher than those of iPP remarkably. An increase in the Avrami exponent may be attributed to the fractal structure of hyperbranched polymer. The crystallization activation energy is estimated by the Friedman equation, the results show that the activation energy decreases remarkably by addition of HBP and the crystallization rate of the blend is more sensitive to temperature than that of iPP.

scholarly journals New Insights into Crystallization of Heterophasic Isotactic Polypropylene by Fast Scanning Chip Calorimetry

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1683
Author(s):  
Daniela Mileva ◽  
Jingbo Wang ◽  
Markus Gahleitner ◽  
Katalee Jariyavidyanont ◽  
René Androsch
Keyword(s):  
Crystallization Kinetics ◽  
Isotactic Polypropylene ◽  
Crystallization Rate ◽  
Crystal Nucleation ◽  
Crystallization Time ◽  
Chip Calorimetry ◽  
The Matrix ◽  
Homogeneous Crystal ◽  
Kinetics Of ◽  
Fast Scanning Chip Calorimetry

The crystallization kinetics of metallocene-catalyzed heterophasic isotactic polypropylene composed of a matrix of isotactic polypropylene (iPP) and rubbery particles made of random ethylene–propylene copolymers (EPC), often denoted as heterophasic iPP copolymers, was analyzed as a function of the cooling rate and supercooling in nonisothermal and isothermal crystallization experiments, respectively. Fast scanning chip calorimetry (FSC) allowed assessing crystallization at processing-relevant conditions, and variation of the content (0–39 wt %) and composition (0–35 wt % propylene counits) of the EPC particles revealed qualitatively new insight about mechanisms of heterogeneous crystal nucleation. For neat iPP homopolymer, the characteristic bimodal temperature dependence of the crystallization rate due to predominance of heterogeneous and homogeneous crystal nucleation at high and low temperatures, respectively, is reconfirmed. At high temperatures, in heterophasic iPP, the here studied ethylene-(C2)-rich EPC particles accelerate crystallization of the iPP-matrix, with the acceleration or nucleation efficacy correlating with the EPC-particle content. The crystallization time reduces by more than half in presence of 39 wt % EPC particles. An additional nucleating effect of the EPC particles on iPP-matrix crystallization is detected after their crystallization, suggesting that liquid/rubbery particles are less effective than solid/semicrystalline particles in affecting crystallization of the surrounding iPP-matrix. At low temperature, homogeneous crystal nucleation in the iPP-matrix outpaces all heterogeneous nucleation effects, and the matrix-crystallization rate is independent of the sample composition. The obtained results lead to the conclusion that the crystallization kinetics of iPP can be affected significantly by the content and composition of EPC particles, even towards superfast crystallizing iPP grades.

Non-Isothermal Crystallization Kinetics of Graphene Oxide-Carbon Nanotubes Hybrids / Polyamide 6 Composites

2019 ◽  
Vol 41 (3) ◽  
pp. 394-394
Author(s):  
Zhi Qiang Wang Zhi Qiang Wang ◽  
Yong Ke Zhao and Xiang Feng Wu Yong Ke Zhao and Xiang Feng Wu
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Cooling Rate ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Polyamide 6 ◽  
Degree Of Crystallinity ◽  
Isothermal Crystallization Kinetics ◽  
Kinetics Of

The hybrids combined by nano-materials with different dimensions usually possess much better enhancement effects than single one. Graphene oxide-carbon nanotubes hybrids / polyamide 6 composites has been fabricated. The non-isothermal crystallization kinetics of the as-prepared samples was discussed. Research results showed that increasing the cooling rate was in favor of increasing the crystallization rate and the degree of crystallinity for the as-prepared samples. Moreover, the crystallization rate was first decreased and then increased with increasing the hybrids loading. Furthermore, the crystallization mechanism was changed with increasing the crystallization temperature and the cooling rate. The nucleation and growth modes of the non-isothermal crystallization could be classified into three different types, according to the Ozawa’s theory. These complicated results could be attributed to the important role of crystallization rate as well as the simultaneous hindering and promoting effects of the as-prepared hybrids. This work has reference values for understanding the crystallization kinetics of the polyamide 6-based composites.

The non-isothermal crystallization behavior of polyamide 6 and polyamide 6/HDPE/MAH/L-101 composites

2019 ◽  
Vol 39 (2) ◽  
pp. 124-133 ◽  
Author(s):  
Bingxiao Liu ◽  
Guosheng Hu ◽  
Jingting Zhang ◽  
Zhongqiang Wang
Keyword(s):  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Isothermal Condition ◽  
Crystallization Rate ◽  
Polyamide 6 ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Analysis And Design ◽  
Processing Techniques

AbstractStudy of the crystallization kinetics is particularly necessary for the analysis and design of processing operations, especially the non-isothermal crystallization behavior, which is due to the fact that most practical processing techniques are carried out under non-isothermal conditions. The non-isothermal crystallization behaviors of polyamide 6 (PA6) and PA6/high-density polyethylene/maleic anhydride/2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (PA6/HDPE/MAH/L-101) composites were investigated by differential scanning calorimetry (DSC). The crystallization kinetics under non-isothermal condition was analyzed by the Jeziorny and Mo equations, and the activation energy was determined by the Kissinger and Takhor methods. The crystal structure and morphology were analyzed by wide-angle X-ray diffraction (WXRD) and polarized optical microscopy (POM). The results indicate that PA6/HDPE/MAH/L-101 has higher crystallization temperature and crystallization rate, which is explained as due to its heterogeneous nuclei.

scholarly journals Non-Isothermal Crystallization Kinetics of Injection Grade PHBV and PHBV/Carbon Nanotubes Nanocomposites Using Isoconversional Method

2020 ◽  
Vol 4 (2) ◽  
pp. 52
Author(s):  
Thaís Larissa do Amaral Montanheiro ◽  
Beatriz Rossi Canuto de Menezes ◽  
Larissa Stieven Montagna ◽  
Cesar Augusto Gonçalves Beatrice ◽  
Juliano Marini ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Model Fitting ◽  
Polarized Light ◽  
Isoconversional Method ◽  
Degree Of Crystallinity ◽  
Gamma Aminobutyric Acid ◽  
Scanning Calorimetry ◽  
Kinetics Of

Carbon nanotubes (CNT)-reinforced polymeric composites are being studied as promising materials due to their enhanced properties. However, understanding the behavior of polymers during non-isothermal crystallization is important once the degree of crystallinity and crystallization processes are affected when nanoparticles are added to matrices. Usually, crystallization kinetics studies are performed using a model-fitting method, though the isoconversional method allows to obtain the kinetics parameter without assuming a crystallization model. Therefore, in this work, CNTs were oxidized (CNT-Ox) and functionalized with gamma-aminobutyric acid (GABA) (CNT-GB) and incorporated into a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) matrix. The influence of the addition and functionalization of CNT in the crystallization kinetics of PHBV was evaluated using the isoconversional method with differential scanning calorimetry (DSC), and by polarized light optical microscopy (PLOM) and Shore D hardness. The incorporation and functionalization of CNT into PHBV matrix did not change the Šesták and Berggren crystallization model; however, the lowest activation energy was obtained for the composite produced with CNT-GB, suggesting a better dispersion into the PHBV matrix. PLOM and Shore D hardness confirmed the results obtained in the kinetics study, showing the smallest crystallite size for CNT-containing nanocomposites and the highest hardness value for the composite produced with CNT-GB.

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.

More Dominant Shear Flow Effect Assisted by Added Carbon Nanotubes on Crystallization Kinetics of Isotactic Polypropylene in Nanocomposites

2015 ◽  
Vol 7 (2) ◽  
pp. 1364-1375 ◽  
Author(s):  
Junyang Wang ◽  
Jingjing Yang ◽  
Liang Deng ◽  
Huagao Fang ◽  
Yaqiong Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Shear Flow ◽  
Crystallization Kinetics ◽  
Isotactic Polypropylene ◽  
Flow Effect ◽  
Kinetics Of

scholarly journals Combined Effects of Cellulose Nanofiber Nucleation and Maleated Polylactic Acid Compatibilization on the Crystallization Kinetic and Mechanical Properties of Polylactic Acid Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3226
Author(s):  
Siti Shazra Shazleen ◽  
Lawrence Yee Foong Ng ◽  
Nor Azowa Ibrahim ◽  
Mohd Ali Hassan ◽  
Hidayah Ariffin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polylactic Acid ◽  
Crystallization Kinetics ◽  
Crystallization Kinetic ◽  
Crystallization Rate ◽  
Combined Effects ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics

This work investigated the combined effects of CNF nucleation (3 wt.%) and PLA-g-MA compatibilization at different loadings (1–4 wt.%) on the crystallization kinetics and mechanical properties of polylactic acid (PLA). A crystallization kinetics study was done through isothermal and non-isothermal crystallization kinetics using differential scanning calorimetry (DSC) analysis. It was shown that PLA-g-MA had some effect on nucleation as exhibited by the value of crystallization half time and crystallization rate of the PLA/PLA-g-MA, which were increased by 180% and 172%, respectively, as compared to neat PLA when isothermally melt crystallized at 100 °C. Nevertheless, the presence of PLA-g-MA in PLA/PLA-g-MA/CNF3 nanocomposites did not improve the crystallization rate compared to that of uncompatibilized PLA/CNF3. Tensile strength was reduced with the increased amount of PLA-g-MA. Contrarily, Young’s modulus values showed drastic increment compared to the neat PLA, showing that the addition of the PLA-g-MA contributed to the rigidity of the PLA nanocomposites. Overall, it can be concluded that PLA/CNF nanocomposite has good performance, whereby the addition of PLA-g-MA in PLA/CNF may not be necessary for improving both the crystallization kinetics and tensile strength. The addition of PLA-g-MA may be needed to produce rigid nanocomposites; nevertheless, in this case, the crystallization rate of the material needs to be compromised.

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.

Sign in / Sign up

Export Citation Format

Share Document