The Structure and Nonisothermal Crystallization Kinetics of HDPE Nanocomposites Filled with Mg2Al–LDH

2012 ◽  
Vol 20 (8) ◽  
pp. 701-710 ◽  
Author(s):  
Jun Qin ◽  
Xiaolang Chen ◽  
Jie Yu ◽  
Tian Xie ◽  
Yaozhu Tian ◽  
...  
Keyword(s):  
Crystallization Rate ◽  
Random Copolymer ◽  
Nucleating Agent ◽  
Crystallization Behaviour ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Nonisothermal Crystallization ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Master Batch

High-density polyethylene (HDPE)/Mg2Al–layered double hydroxide (Mg2Al–LDH) nanocomposites with an ethylene-acrylic acid random copolymer (EAA)/Mg2Al–LDH master batch were prepared by melt-mixing. The structure of the nanocomposites was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results demonstrate the formation of the nanocomposites with exfoliated/intercalated layered double hydroxides well distributed in the HDPE matrix. The nonisothermal crystallization behaviour of master batch-based HDPE nanocomposites was studied by using differential scanning calorimetry (DSC). The crystallization behaviour of HDPE/Mg2Al–LDH nanocomposites was well defined by the Avrami analysis and Jeziorny method, as well as the combined Avrami and Ozawa analysis (MO's model). The results reveal that a very small amount of Mg2Al–LDH (1%) accelerates the crystallization process in comparison with the neat HDPE, and the high crystallization rate is attributed to the nucleating effect of the exfoliated nanoparticles. Overall, the exfoliated Mg2Al–LDH particles act as the nucleating agent, and therefore distinctly change the type of nucleation, growth and geometry of HDPE crystals.

Nonisothermal crystallization kinetics of polybutene-1 containing nucleating agent with acid amides structure

2014 ◽  
Vol 34 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Yongxian Zhao ◽  
Junyi Chen ◽  
Lei Han ◽  
Le Zhao
Keyword(s):  
Crystallization Process ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Mass Ratio ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Nucleation Effect ◽  
Activation Energy Of Crystallization ◽  
Nonisothermal Crystallization Kinetics ◽  
Kinetics Of

Abstract The nonisothermal crystallization behaviors of virgin isotactic polybutene-1 (iPB-1) and iPBn (iPB-1 containing a nucleating agent that owns acid amides structure; iPB/Mult920=100/0.5, mass ratio) were studied by means of differential scanning calorimetry (DSC). Modified Avrami theories (Ozawa method) and Mo method were used to analyze the DSC date. The results show that both methods are suitable to describe the crystallization process of iPB-1 and iPBn. Addition of 0.5% (mass ratio) nucleating agent can give rise to the nucleation effect, which increases the crystallization temperature (Tc) and the rate of crystallization of iPB-1, decreases the activation energy of crystallization (ΔE), and increases the crystallization rate of iPB-1 under the actual conditions.

Properties and Nonisothermal Crystallization Behavior of Nucleated Polylactide Biodegradable Composite Films

2012 ◽  
Vol 488-489 ◽  
pp. 671-675 ◽  
Author(s):  
Worasak Phetwarotai ◽  
Duangdao Aht-Ong
Keyword(s):  
Tensile Properties ◽  
Cooling Rate ◽  
Crystallization Behavior ◽  
Composite Films ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Precipitated Calcium Carbonate ◽  
Biodegradable Composite

Polylactide biodegradable composite films were prepared via melt extrusion using a twin screw extruder. The effects of type and content of nucleating agent and cooling rate on the thermal and tensile properties of these films were investigated. Two types of nucleating agent, talc and nano precipitated calcium carbonate (NPCC), were studied at various contents from 0 to 2.0 phr. Nonisothermal crystallization behavior of composites was characterized by a differential scanning calorimetry (DSC). The cooling rate was varied from 1 to 10°C/min. The results indicated that the presence of nucleating agent significantly influenced on thermal and tensile properties of the PLA composite films. DSC thermograms revealed that the addition of nucleating agent on the PLA films led to an increase of crystallization temperature (Tc), crystallization rate, and degree of crystallization (χc) compared to the neat PLA. These behaviors could be noticed in both the nucleated PLA films with NPCC and talc. In contrast, the Tc and crystallization half-time (t1/2) of these films significantly decreased when the cooling rate increased from 1 to 10°C/min. However, thermal stability of the films decreased when the nucleating agent content increased, especially that of the composites with NPCC.

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.

Thermal Behavior, Mechanical Property and Microstructure of Low-Density Polyethylene Filled by Diatomite

2014 ◽  
Vol 633-634 ◽  
pp. 413-416
Author(s):  
Kun Yuan Wang ◽  
Qiu Ju Sun ◽  
Yan Liu ◽  
Jie Lu
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Thermal Behavior ◽  
Thermo Gravimetric Analysis ◽  
Crystallization Rate ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Melt Mixing

Diatomite was treated by titanate coupling agent and blended with low-density polyethylene (LDPE) by the method of melt-mixing blend. The performance of the blends, such as thermal behavior, mechanical property and microstructure, were analyzed with differential scanning calorimetry, thermo-gravimetric analysis, tensile strength testing and scanning electron microscopy. The results showed that influenced the crystalline behavior of LDPE phase in the blends and made the crystallization rate of LDPE phase decreased. Moreover, the thermo-decomposing temperature of the blends increased with increasing the diatomite content, diatomite significantly improved the thermal stability of the blends. Tensile strengths of the blends firstly decreased and then increased. When the diatomite content was 30%wt, the tensile strength of the blend reached to 14.6MPa. SEM photographs showed the good dispersion and interaction.

Non-isothermal crystallization kinetics of poly (lactic acid)/graphene nanocomposites

2013 ◽  
Vol 33 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Yanhua Chen ◽  
Xiayin Yao ◽  
Qun Gu ◽  
Zhijuan Pan
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Graphene Nanocomposites ◽  
Solution Blending ◽  
Transmission Electron ◽  
Graphene Nanocomposite

Abstract Poly(lactic acid) (PLA)/graphene nanocomposites were prepared by solution blending and the dispersibility of graphene in the PLA matrix was examined by transmission electron microscopy (TEM). The non-isothermal crystallization behaviors of pure PLA and PLA/graphene nanocomposites from the melt were investigated by differential scanning calorimetry (DSC). The results showed that the graphene could play a role as a heterogeneous nucleating agent during the non-isothermal crystallizing process of PLA, and accelerate the crystallization rate. The non-isothermal crystallizing data were analyzed with the Avrami, Ozawa and Mo et al. models and the crystallization parameters of the samples were obtained. It is demonstrated that the combination of the Avrami and Ozawa models developed by Mo et al. was successful in describing the non-isothermal crystallization process for pure PLA and its nanocomposite. According to the Kissinger equation, the activation energies were found to be -154.3 and -179.5 kJ/mol for pure PLA and PLA/0.1 wt% graphene nanocomposite, respectively. Furthermore, the spherulite growth behavior was investigated by polarized optical microscopy (POM) and the results also supported the DSC data.

scholarly journals Investigation of Polyetherimide Melt-Extruded Fibers Modified by Carbon Nanoparticles

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7251
Author(s):  
Elena Ivan’kova ◽  
Gleb Vaganov ◽  
Andrey Didenko ◽  
Elena Popova ◽  
Vladimir Elokhovskiy ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Fiber Direction ◽  
Scanning Calorimetry ◽  
Orientation Degree ◽  
X Ray ◽  
Orientational Drawing ◽  
X Ray Scattering ◽  
Carbon Nanofiller

The fibers based on thermoplastic partially crystalline polyetherimide R-BAPB modified by vapor grown carbon nanofibers (VGCF) were prepared by melt extrusion, exposed to orientational drawing, and crystallized. All of the samples were examined by scanning electron microscopy, X-ray scattering, and differential scanning calorimetry to study how the carbon nanofiller influences on the internal structure and crystallization behavior of the obtained R-BAPB fibers. The mechanical properties of the composite R-BAPB fibers were also determined. It was found that VGCF nanoparticles introduced into R-BAPB polyimide can act as a nucleating agent that leads, in turn, to significant changes in the composite fibers morphology as well as thermal and mechanical characteristics. VGCF are able to improve an orientation degree of the R-BAPB macromolecules along the fiber direction, accelerate crystallization rate of the polymer, and enhance the fiber stability during crystallization process.

Nucleation versus melting point depression of the polycaprolactone phase in polypropylene/polycaprolactone blends

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Vittoria Balsamo ◽  
Laura Gouveia
Keyword(s):  
Melting Point ◽  
Disperse Phase ◽  
Crystallization Kinetic ◽  
Nucleating Agent ◽  
Melting Point Depression ◽  
Avrami Equation ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Crystallization Conditions ◽  
And Diffusion

AbstractPolypropylene/poly(ε-caprolactone) (PP/PCL) blends were prepared by melt mixing. The thermal behaviour of the blends was investigated using differential scanning calorimetry (DSC) and dynamical rheology in the solid state (RSA). Both non-isothermal and isothermal crystallizations were performed. The Avrami equation was applied to the latter case. DSC and RSA results demonstrated in agreement with morphological observations that PP/PCL blends are immiscible in the whole composition range. PP acts as a nucleating agent for PCL, and when PP forms the disperse phase, it crystallizes in a fractionated fashion. When PCL is the disperse phase, it exhibits an unexpected melting point depression after cooling at 10 °C/min. Such depression was not observed after isothermal crystallizations, indicating that under non-isothermal crystallization kinetic problems show up. Thus, global crystallization is governed by a competition between nucleation and diffusion, which depends on crystallization conditions and composition.

Effect of Poly(D-Lactic Acid)-co-Polyethylene Glycol on the Crystallization of Poly(L-Lactic Acid)

2017 ◽  
Vol 751 ◽  
pp. 283-289 ◽  
Author(s):  
Ployrawee Kaewlamyai ◽  
Amornrat Lertworasirikul
Keyword(s):  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Weight Ratio ◽  
Crystallization Rate ◽  
Heat Stability ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry

Poly (lactic acid) (PLA) is a biopolymer derived from renewable resources and can be disposed of without creating harm to the environment. PLA can be formed by thermoplastic processes and has good mechanical properties. However, its disadvantages are a high crystallization temperature, slow crystallization rate, poor heat stability and low ductility. In the past, it was found that poly (D-lactic acid) (PDLA) can form complexes with poly (L-lactic acid) (PLLA) and the complexes could accelerate the crystallization and increase the degree of crystallinity of the PLA, but decrease the ductility. It is known that polyethylene glycol (PEG) can improve the ductility of PLLA. In this research, PDLA was copolymerized with PEG in an attempt to improve both crystallization behavior and ductility of PLLA. Poly (D-lactic acid)-co-polyethylene glycol (PDEG) was synthesized by ring opening polymerization using D-lactide and PEG at a D-lactide:PEG weight ratio of 10:3. The PDEG was blended with PLLA with a PDEG content of 0wt% to 50wt% by melt blending process. Fourier transform infrared spectrometry (FT-IR) and X-Ray diffractometry (XRD) confirmed the stereocomplex formation between PDEG and PLLA. Characterization by differential scanning calorimetry (DSC) revealed that crystallization temperatures of the blends were decreased in the presence of PDEG. Storage moduli and tan of the blends obtained from dynamic mechanical analysis (DMA) decreased as PDEG content increased. Polarized optical microscopy (POM) micrographs of blends with PDEG content of 1wt% to 5wt% obviously showed that crystallization rate was increased. PDEG has the potential to be an effective nucleating agent and efficient plasticizer for PLLA.

scholarly journals Synthesis and Nonisothermal Crystallization Kinetics of Poly(Butylene Terephthalate-co-Tetramethylene Ether Glycol) Copolyesters

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1897 ◽  
Author(s):  
Hsu-I Mao ◽  
Chin-Wen Chen ◽  
Syang-Peng Rwei
Keyword(s):  
Crystallization Rate ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Excellent Thermal Stability ◽  
Butylene Terephthalate ◽  
Melt Polymerization ◽  
Ft Ir ◽  
Nonisothermal Crystallization Kinetics ◽  
Kinetics Of

Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents.

scholarly journals Effect of Composition on the Crystallization, Water Absorption, and Biodegradation of Poly(ε-caprolactam-co-ε-caprolactone) Copolymers

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2488
Author(s):  
Yuanyuan Dou ◽  
Xinyu Mu ◽  
Yuting Chen ◽  
Zhenbo Ning ◽  
Zhihua Gan ◽  
...  
Keyword(s):  
Water Absorption ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Feed Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Molar Feed Ratio ◽  
Anionic Copolymerization

Poly(ester amide)s have aroused extensive research interest due to the combination of the degradability of polyester and the higher mechanical properties of polyamide. In this work, a series of poly(ε-caprolactam-co-ε-caprolactone) (P(CLA-co-CLO)) copolymers with different compositions were synthesized by anionic copolymerization. The structure, crystallization behavior, water absorption, and biodegradation behavior of these copolymers were investigated by means of nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and polarized optical micrographs (POM). The results indicated that the composition of P(CLA-co-CLO) copolymers can be adjusted by the molar feed ratio. The PCL blocks decreased the crystallization rate of PA6 blocks but had little effect on the melting behavior of PA6, while the crystallized PA6 acted as a heterogeneous nucleating agent and greatly improved the crystallization rate of PCL. Moreover, the introduction of PCL blocks greatly reduced the water absorption of P(CLA-co-CLO) copolymers and endow them a certain degree of degradability.

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