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.

Isothermal and Non-Isothermal Crystallization Behavior of Poly(L-Lactic Acid) with Nucleating Agents

2011 ◽  
Vol 335-336 ◽  
pp. 1299-1302 ◽  
Author(s):  
Xin Qian ◽  
Mi Zhou ◽  
Dong Xu ◽  
Shu Jun Xu ◽  
Yang Fu Jin
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Peak Temperature ◽  
Crystallization Time ◽  
Nucleating Agents ◽  
Scanning Calorimetry ◽  
Crystallization Peak ◽  
Half Crystallization Time

The effects of Amide type nucleating agents SX , talc and nucleating agents SX combination with talc on crystallization behavior of poly (L-lactic acid）(PLLA) were analyzed by means of Differential scanning calorimetry (DSC)．The results of non-isothermal crystallization showed that SX is an efficient nucleating agent. The crystallization peak temperature and degree of crystallization of PLLA sample with 0.6 wt% SX are both higher than that of PLLA sample with 4 wt% Talc，which proved that the nucleating ability of SX is stronger．Nucleating agent SX and talc combination has obvious coordination effects, the sample of PLLA/0.2 wt % SX + 4 wt % talc has the minimal crystallization undercooling temperature, the highest crystallization peak temperature and crystallinity. Isothermal crystallization kinetics of PLA showed that when the four nucleating agents added in are all with the Avrami exponent n between 2.1-2.5, crystallization tended to be heterogeneous nucleation. When the nucleating agents added in are 0.6 wt%, the crystallization time is greatly decreased to 0.75min. Meanwhile, the PLLA crystallinity could be significantly increased by adding SX nucleating agents; besides, with the decrease of the isothermal crystallization temperature, the half crystallization time of the PLLA/0.6 wt% SX sample was decreased.

Study on Non-Isothermal Crystallization Kinetic of Tundish Covering Fluxes

2011 ◽  
Vol 266 ◽  
pp. 102-105
Author(s):  
Li Feng Sun ◽  
Hong Po Wang ◽  
Chun Lai Liu ◽  
Yong Zou ◽  
Mao Fa Jiang
Keyword(s):  
Isothermal Crystallization ◽  
Heat Insulation ◽  
Crystallization Kinetic ◽  
Avrami Equation ◽  
Crystallization Time ◽  
Resistance Furnace ◽  
Crystallization Behaviors ◽  
Good Heat ◽  
Casting Production ◽  
Electrical Resistance Furnace

Basic tundish covering flux is widely used in continuous casting production of high quality steel because of good heat insulation function and the properties of absorbing inclusions. However, there is a serious problem of incrustation caused by basic tundish covering flux in process of pouring and it could be dramatically influenced by the crystallization behaviors of covering flux. In the paper, the crystallization time and ratio of basic tundish covering fluxes were investigated by high temperature electrical resistance furnace and single hot thermocouple apparatus. Based on the crystallization kinetic knowledge and experimental results, Avrami equation was modified, the non-isothermal crystallization equation that could quantitatively describe the crystallization behaviors of basic tundish covering fluxes was established.

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 The effect of isothermal crystallization on mechanical properties of poly(ethylene 2,5-furandicarboxylate)

e-Polymers ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 1-11
Author(s):  
Wei Zhang ◽  
Qingyin Wang ◽  
Gongying Wang ◽  
Shaoying Liu
Keyword(s):  
Mechanical Properties ◽  
Intrinsic Viscosity ◽  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Tensile Modulus ◽  
Optical Microscope ◽  
Crystallization Time ◽  
Scanning Calorimetry ◽  
Crystallization Properties ◽  
Poly Ethylene

Abstract The effects of isothermal crystallization temperature/time on mechanical properties of bio-based polyester poly(ethylene 2,5-furandicarboxylate) (PEF) were investigated. The intrinsic viscosity, crystallization properties, thermal properties, and microstructure of PEF were characterized using ubbelohde viscometer, X-ray diffraction, polarizing optical microscope, differential scanning calorimetry, and scanning electron microscopy. The PEF sample isothermal crystallized at various temperatures for various times was denoted as PEF-T-t. The results showed that the isothermal crystallization temperature affected the mechanical properties of PEF-T-30 by simultaneously affecting its crystallization properties and intrinsic viscosity. The isothermal crystallization time only affected the crystallization properties of PEF-110-t. The crystallinity of PEF-110-40 was 17.1%. With small crystal size, poor regularity, and α′-crystal, PEF-110-40 can absorb the energy generated in the tensile process to the maximum extent. Therefore, the best mechanical properties can be obtained for PEF-110-40 with the tensile strength of 43.55 MPa, the tensile modulus of 1,296 MPa, and the elongation at a break of 13.36%.

Isothermal Crystallization Behavior of Poly (L-lactic Acid)/ Surface-Grafted Silica Nanocomposites

2012 ◽  
Vol 268-270 ◽  
pp. 37-40 ◽  
Author(s):  
Yan Hua Cai
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Melt Blending ◽  
Scanning Calorimetry ◽  
Silica Nanocomposites ◽  
Induction Periods ◽  
Sio2 Nanocomposites ◽  
Different Content

The Poly(L-lactic acid)(PLLA)/surface-grafting silica(g-SiO2) nanocomposites were prepared by melt blending. The isothermal crystallization behavior of PLLA/g-SiO2 nanocomposites with different content of g-SiO2 was investigated by optical depolarizer. In isothermal crystallization from melt, the induction periods and half times for overall PLLA crystallization (95°C Tc 120°C) were affected by the crystallization temperature and the content of g-SiO2 in nanocomposites. The results showed that g-SiO2 as a kind of heterogeneous nucleating agent can reduce induction periods and half times for overall PLLA crystallization. The thermal properties of PLLA/g-SiO2 samples were also investigated by differential scanning calorimetry (DSC), The results showed that the crystalline degree of PLLA was improved as the presence of g-SiO2.

scholarly journals The effect of hydroxyapatite nanoparticles on crystallization and thermomechanical properties of PLLA matrix

2017 ◽  
Vol 89 (1) ◽  
pp. 125-140 ◽  
Author(s):  
Ioanna-Georgia I. Athanasoulia ◽  
Maximos N. Christoforidis ◽  
Dimitrios M. Korres ◽  
Petroula A. Tarantili
Keyword(s):  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Crystallization Kinetic ◽  
Crystallization Rate ◽  
Melting Behavior ◽  
Thermomechanical Properties ◽  
Cold Crystallization ◽  
Crystallization Experiments ◽  
Twin Screw

AbstractIn this study, hydroxyapatite (HA) was incorporated in a poly(L-lactic acid) (PLLA) matrix and the thermal properties and crystallization behavior of the derived composites were investigated. The nanocomposites, containing 0–20 wt% HA, were prepared by melt extrusion employing a twin-screw extruder. XRD experiments verified an increase in the intensity of the characteristic diffraction peak of the α-form crystalline phase of PLLA with increasing HA content. By DSC experiments it was observed that the presence of HA increased the crystallinity during cold crystallization, leading to a shift of cold-crystallization temperature to lower values and to an increase in the melting temperature of the PLLA phase. Isothermal crystallization experiments at 100, 110, 115 and 120°C, revealed a maximum in crystallization kinetic around 100°C after the addition of HA compared to 115°C for pure PLLA. The crystallization rate of PLLA matrix in the nanocomposites decreased with increasing crystallization temperature. By using the Avrami and Lauritzen-Hoffman equations the exponent n was calculated in the range 2–3 and a theoretical approach verified that the HA/PLLA systems belong to Regime II of crystallization behavior. The investigated melting behavior of PLLA was attributed to better organized crystalline structure with increasing isothermal crystallization temperatures and might be related with the longer time necessary for the completion of crystallization.

The Melting Behavior of Poly(Ethylene Terephthalate)/ Attapulgite Nanocomposites

2013 ◽  
Vol 773 ◽  
pp. 530-533
Author(s):  
Chen Liu ◽  
Xiang Hui Lu ◽  
Xue Qi ◽  
Peng Li
Keyword(s):  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Ethylene Terephthalate ◽  
Melting Process ◽  
Melting Behavior ◽  
Crystallization Time ◽  
Scanning Calorimetry ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Crystallization From The Melt

The melting and recrystallization behavior of Poly(ethylene terephthalate) (PET)/ Attapulgite(At)nanocomposites after isothermal crystallization from the melt was studied by Step-scan differential scanning calorimetry (SDSC). The influence of At contents, crystallization temperature and crystallization time on the melting process were examined. Two melting endotherms(in the SDSC CP.A curves, reversible part) and one recrystallization exotherm (in the SDSC CP.IsoK curves, irreversible part)of PET/At nanocomposites after isothermal crystallization were observed during the melt process. This ascribes to the melting-recrystallization mechanism .The low temperature endotherm attributes to the melting of primary crystal formed during the isothermal treating and the high temperature endotherm resulting from the melting of recrystallization materials. The reason why more recrystallization happened with the increase of At content was given and the process of recrystallization was described in detail. The effects of crystal perfection and recrystallization were minimized by increasing of crystallization temperature and time.

Comparative study of the crystallization behavior and morphologies of carbon and glass fiber reinforced poly(ether ether ketone) composites

2020 ◽  
pp. 096739112096510
Author(s):  
Pan Wang ◽  
Qing Lin ◽  
Yaming Wang ◽  
Chuntai Liu ◽  
Changyu Shen
Keyword(s):  
Carbon Fiber ◽  
Glass Fiber ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Unit Cell ◽  
Fiber Reinforced ◽  
Scanning Calorimetry ◽  
Avrami Model ◽  
X Ray ◽  
Glass Fiber Reinforced

This work aims to perform a systematic investigation on the crystallization behavior and morphologies of carbon and glass fiber reinforced PEEK. The nonisothermal and isothermal crystallization behavior was investigated by differential scanning calorimetry (DSC). The resultant morphologies were assessed by wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS), and polarized optical microscopy (POM) to provide details on spherulitic level, crystalline structure at unit cell, and lamellar levels. It was found that the crystallization ability of carbon fiber filled PEEK was better than that of neat PEEK, while the behavior of glass fiber filled PEEK was in an opposite trend. The incorporation of carbon fiber (or glass fiber) led to a looser packing of the unit cell or a less crystal perfection of PEEK but did not change its crystal form as well as its long period of lamellae. The isothermal crystallization kinetics was analyzed by the Avrami model, suggesting that the crystallization mechanism of carbon fiber filled PEEK was different from that of neat PEEK and its glass fiber filled composites. Nevertheless, the POM results showed that fiber-induced transcrystallization in PEEK matrix was not evidenced for either carbon or glass fiber filled PEEK. Finally, the effect of carbon and glass fiber on the crystallization of PEEK matrix was discussed to some extent.

Non-Isothermal Crystallization Behavior of Poly(trimethylene Terephthalate-Co-Isophthalate) Copolyesters

2012 ◽  
Vol 535-537 ◽  
pp. 1413-1416
Author(s):  
Tien Wei Shyr ◽  
Chia Hsin Tung ◽  
Yan Ting Liu
Keyword(s):  
Isothermal Crystallization ◽  
Reaction Rate ◽  
Glassy State ◽  
Exothermic Peak ◽  
Avrami Equation ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
1H Nuclear Magnetic Resonance ◽  
Thermal Nucleation ◽  
Trimethylene Terephthalate

Poly(trimethylene terephthalate-co-isophthalate) (TI) copolyesters were synthesized using different ratios of isophthalic acid (IPA) and Terephthalic acid (TPA) with 1,3-propanediol (1,3-PDO). The compositions of TI copolyesters were analyzed using 1H nuclear magnetic resonance (NMR). Non-isothermal melt- and cold-crystallization and subsequent melting behaviors were investigated using differential scanning calorimetry (DSC). For TI0, TI10, and TI20, non-isothermal crystallization kinetics were analyzed using a modified Avrami equation. The results show that the reaction rate of TPA with 1,3-PDO was similar with that of IPA with 1,3-PDO in TI copolyesters. Crystallization exothermic peak and melting endothermic peak were not observed in DSC traces with an increase of the relative amount of PIP to 41%. The Avrami exponent n is in the range of 3.5-4.2 for melt-crystallized TI copolyesters and between 3.0-3.2 for cold-crystallized copolyesters. It suggests that the crystallization from melt state corresponds to thermal nucleation but the crystallization from glassy state originates from predeterminated nuclei.

Study on the Properties of Polyphenylene Sulfide/Nano-Zinc Oxide Composites

2020 ◽  
Vol 1003 ◽  
pp. 185-190
Author(s):  
Neng Wan ◽  
Wei Hua Yao ◽  
Jui Chen Chen ◽  
Juan Du ◽  
Manuel Reyes De Guzman ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Polyphenylene Sulfide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Comprehensive Properties ◽  
Nano Zinc Oxide ◽  
Nano Zinc ◽  
Internal Mixer ◽  
Oxide Composites

Different proportions of nano-zinc oxide were uniformly dispersed in a polyphenylene sulfide matrix by using an internal mixer. Comprehensive properties were determined through tensile strength test, differential scanning calorimetry, X-ray diffraction, thermogravimetry. The results showed that the sample elongation at break and tensile strength considerably increased with the amount of nano-zinc oxide. Its thermal stability has also improved considerably and crystallization temperature of PPS-NanoZnO composite was increased;while the crystalline phase remained unchanged.

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