The influence of bamboo fiber content on the non-isothermal crystallization kinetics of bamboo fiber-reinforced polypropylene composites (BPCs)

Holzforschung ◽  
2018 ◽  
Vol 72 (4) ◽  
pp. 329-336 ◽  
Author(s):  
Chin-Yin Hsu ◽  
Teng-Chun Yang ◽  
Tung-Lin Wu ◽  
Ke-Chang Hung ◽  
Jyh-Horng Wu
Keyword(s):  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Bamboo Fiber ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Relative Crystallinity ◽  
Crystallinity Degree ◽  
Polypropylene Composites ◽  
Time Period ◽  
Crystal Growth Mechanism

AbstractBamboo fiber (BF)-reinforced polypropylene (PP) composites (BPCs) have been investigated and it was shown by differential scanning calorimetry (DSC) that BF is a nucleation agent and accelerates the crystallization rate of the PP matrix. Numerical analyses according to Avrami, Avrami-Ozawa, and Friedman described well the nucleation mechanism, the crystallization rate and the activation energy for the non-isothermal crystallization behavior of BPCs, respectively. The Avrami approach indicated that BF as a reinforcement significantly changed the crystal growth mechanism of PP matrix during the cooling process. Based on the Avrami-Ozawa method, a lower cooling rate can achieve a certain relative crystallinity degree within a time period. According to the Friedman method, the activation energies of BPCs were lower than that of neat PP below a relative crystallinity of 35%, when the BF content was more than 60%.

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 Effects of Boric Acid Ester Modified Magnesium Borate Whisker on the Mechanical Properties and Crystallization Kinetics of Polypropylene Composites

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1698 ◽  
Author(s):  
Jin-Hua Luo ◽  
Shi-Hu Han ◽  
Juan Wang ◽  
Hui Liu ◽  
Xiao-Dong Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boric Acid ◽  
Isothermal Crystallization ◽  
Acid Ester ◽  
Crystallization Rate ◽  
Scanning Calorimetry ◽  
Magnesium Borate ◽  
Crystallization Property ◽  
Polypropylene Composites ◽  
Boric Acid Ester

Polypropylene (PP) is notch sensitive and brittle under severe conditions of deformation, limiting wider range of its usage as a structural load-bearing polymer. Hence, in this work the magnesium borate whisker (MBw), with similar mechanical properties to carbon fiber but much less expensive than polycrystalline silicon carbide, was modified by boric acid ester (BAE) and then used to fabricate PP composites. The mechanical properties, morphology, and non-isothermal crystallization property of virgin PP, PP/MBw, and PP/BAE-MBw composites were studied through mechanical testing, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC), respectively. The non-isothermal crystallization data was analyzed via Mo, Kissinger, and Dobreva methods. The results reveal that the incorporation of BAE-MBw into PP matrix results in higher tensile strength and impact strength than those of virgin PP and PP/MBw composite. The activation energies based on Kissinger were 190.20 kJ/mol for virgin PP, 206.59 kJ/mol for PP/MBw, and 218.98 kJ/mol for PP/BAE-MBw. The nucleation activities of whiskers determined by the Dobreva model were 0.86 for PP/MBw and 0.75 for PP/BAE-MBw. As a result, the whiskers, especially the modified whiskers, act as active substrates to facilitate heterogeneous nucleation, which leads to an increase in crystallization rate.

CRYSTALLINE STRUCTURES AND α → β AND γ POLYMORPHS TRANSFORMATION INDUCED BY NANOCLAY IN PVDF-BASED NANOCOMPOSITE

NANO ◽  
2014 ◽  
Vol 09 (06) ◽  
pp. 1450065 ◽  
Author(s):  
MOHAMMAD MAHDI ABOLHASANI ◽  
MINOO NAEBE ◽  
AZAM JALALI-ARANI ◽  
QIPENG GUO
Keyword(s):  
Electron Microscopy ◽  
Isothermal Crystallization ◽  
Vinylidene Fluoride ◽  
Crystallization Rate ◽  
Avrami Exponent ◽  
Degree Of Crystallinity ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Clay Platelets

Poly(vinylidene fluoride) (PVDF) nanocomposites were prepared by melt-mixing. The dispersion of clay platelets and rheology of nanocomposites were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and rheometric mechanical spectrometer (RMS). The transformation of α to β and γ phase in PVDF was induced by the addition of nanoclay and subsequently the isothermal crystallization kinetics of neat PVDF and its nanocomposite have been investigated. The interaction between clay nanofillers and PVDF macromolecular chains induced the change of conformation from trans-gauche to all-trans crystal structure in PVDF segment. The isothermal crystallization of PVDF/clay nanocomposites was carried out by Differential Scanning Calorimetry (DSC) technique. The influence of clay platelets on nucleation crystallization rate and Avrami exponent were studied. PVDF/clay nanocomposite showed higher crystallization rate indicating that nanoclay has acted as an effective nucleation agent. This nucleation effect of nanoclay increased the Avrami exponent and decreased the degree of crystallinity.

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.

Non-isothermal crystallization behavior of polypropylene/zinc oxide composites

2016 ◽  
Vol 23 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Jianqiang Fang ◽  
Minghua Lang ◽  
Xuchu Ye ◽  
Wei Zhang ◽  
Kongjun Zhu
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Crystallization Kinetic ◽  
Exothermic Peak ◽  
Crystallization Time ◽  
Scanning Calorimetry ◽  
Relative Crystallinity ◽  
Oxide Composites

AbstractThe non-isothermal crystallization behavior of polypropylene (PP)/zinc oxide composites with various mass ratios was investigated by differential scanning calorimetry. The Jeziorny and Mo models were applied to calculate the non-isothermal crystallization kinetic parameters of the composites. During non-isothermal crystallization, the width of the exothermic peak increased from 7°C to 12°C with increasing cooling rate. The exothermic peak position at 10°C shifted to a lower temperature, and the half crystallization time t1/2 decreased from 2.86 min to 0.51 min. The Friedman model was used to determine the variation of activation energy at each stage of crystallization. The crystallization activation energies obtained varied significantly at each stage of crystallization. The crystallization activation energy of PP was -126.8 kJ/mol at 70% relative crystallinity but reached -232.8 kJ/mol at 10% relative crystallinity.

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.

Crystal Morphology and Thermal Properties of PTT/POE/OMMT Nanocomposites

2011 ◽  
Vol 181-182 ◽  
pp. 39-42
Author(s):  
Ming Tao Run ◽  
Qing Chang Zhang ◽  
Wen Zhou ◽  
Yu Zhong
Keyword(s):  
Crystal Morphology ◽  
Testing Machine ◽  
Crystallization Rate ◽  
Material Testing ◽  
Melt Crystallization ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Lower Melting Point ◽  
Universal Material Testing Machine ◽  
Material Testing Machine

The crystal morphology, melt-crystallization and mechanical properties of poly (trimethylene terephthalate)/maleinized poly (octene-ethylene)/organo-montmorillonite nanocomposites were investigated by using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and universal material testing machine, respectively. The results suggest that the nanocomposites form smaller or imperfect microcrystallites with lower melting point due to the influence of OMMT components and the nanocomposites have increased crystallization rate because OMMT is an effective nucleation agent. However, the crystallinity decreases because of the thickening effect of OMMT in the composites. The nanocomposite with 2%OMMT has the largest tensile and impact strength.

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.

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.

Synergistic effects of intumescent flame retardant and nano-CaCO3 on foamability and flame-retardant property of polypropylene composites foams

2017 ◽  
Vol 54 (3) ◽  
pp. 615-631 ◽  
Author(s):  
Li Depeng ◽  
Li Chixiang ◽  
Jiang Xiulei ◽  
Liu Tao ◽  
Zhao Ling
Keyword(s):  
Mechanical Properties ◽  
Stress Concentration ◽  
Flame Retardant ◽  
Synergistic Effects ◽  
Crystallization Rate ◽  
Intumescent Flame Retardant ◽  
Limit Oxygen Index ◽  
Scanning Calorimetry ◽  
Polypropylene Composites ◽  
Flame Retardant Property

Synergistic effects of intumescent flame retardant and nano-CaCO3 on foamability and flame retardant property of polypropylene composites and their foams were carefully investigated. The differential scanning calorimetry results showed that the intumescent flame retardant played a plasticizing effect on the polypropylene/intumescent flame-retardant composites and accelerated the crystallization rate. The rheological properties and supercritical CO2-assisted molding foaming behaviors of the polypropylene/intumescent flame retardant/nano-CaCO3 composites showed that the nano-CaCO3 could enhance their foamability. Scanning electron microscopy pictures and mechanical properties of the polypropylene/intumescent flame-retardant composites foams indicated that the agglomeration of intumescent flame retardant would reduce the cell uniformity and even cause the cell collapse. Furthermore, the stress concentration, caused by the agglomeration, could reduce the mechanical properties of the PP composites foams. The synergistic effect of the nano-CaCO3 could improve the cell uniformity and reduce the stress concentration so that the mechanical properties of the polypropylene/intumescent flame retardant /nano-CaCO3 composites foams were improved. Moreover, the polypropylene/intumescent flame retardant/nano-CaCO3 composites foams had the higher limit oxygen index values than the polypropylene/intumescent flame-retardant foams. TGA results also showed that the nano-CaCO3 could improve the thermal stability of the polypropylene composites foams by forming compact carbon layer. The experimental results indicated that the foamability of the polypropylene composites and the flame-retardant property of their foams could be improved by the synergistic effects of intumescent flame retardant and nano-CaCO3.

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