Effect of thermal treatment on the mechanical and viscoelastic response of polypropylenes incorporating a β nucleating agent

2018 ◽  
Vol 51 (6) ◽  
pp. 562-579 ◽  
Author(s):  
K Belkouicem ◽  
A Benarab ◽  
R Krache ◽  
R Benavente ◽  
E Pérez ◽  
...  
Keyword(s):  
Young Modulus ◽  
Nucleating Agent ◽  
Thermal Treatments ◽  
Mechanical Parameters ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Good Balance ◽  
X Ray ◽  
Structure Morphology ◽  
Ultimate Properties

The influence of two thermal treatments on the structure, morphology, and ultimate properties exhibited by isotactic polypropylene (iPP), synthesized by conventional Ziegler–Natta iPP (Z-iPP) or metallocene iPP (m-iPP) catalysts, has been investigated in the present work. Novelty of this research consisted in the incorporation of a β nucleating agent in two different contents to the m-iPP. Results attained are compared with those found in the Z-iPP and important differences are observed. Differential scanning calorimetry and X-ray diffraction experiments revealed that coexistence of different crystalline lattices took place depending on the type of iPP: β and α forms were found in the β nucleated Z-iPP specimens, whereas α, β, and γ polymorphs could be developed in the m-iPP with nucleating agent. On the other hand, the iPP glass transition temperature ( Tg) did not exhibit a significant change because of the addition of β nucleant, as deduced from Dynamic Mechanical Thermal Analysis (DMTA) analysis. Moreover, the size and shape of the iPP spherulites was totally changed by the presence of the β agent. This nucleant promoted the formation of smaller spherulites in a greater amount, as demonstrated by optical microscopy. Concerning the mechanical parameters, microhardness, MH, and Young modulus, E, values were in the fast crystallized samples lower than those presented by their slowly cooled counterparts. A good balance in properties was seen for the slowly crystallized m-iPP that incorporated a 5 wt% content in β nucleating agent, this fact being ascribed to the coexistence of the three α, β, and γ polymorphs.

Synthesis and Properties of Thermotropic Liquid Crystalline Polyesters with Flexible Polymethylene Spacer

2010 ◽  
Vol 428-429 ◽  
pp. 126-131
Author(s):  
Wei Zhong Lu ◽  
Chun Wei ◽  
Qui Shan Gao
Keyword(s):  
Optical Microscopy ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Structure Morphology ◽  
Temperature Ranges ◽  
Ft Ir ◽  
Diffraction Peaks ◽  
Ubbelohde Viscometer

Polymethylene bis(p-hydroxybenzoates) were prepared from methyl p-hydroxybenzoate and different diols by melted transesterification reaction. Three liquid crystalline polyesters were synthesized from terephthaloyl dichloride and polymethylene bis(p-hydroxybenzoates). Its structure, morphology and properties were characterized by Ubbelohde viscometer, Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), polarized optical microscopy (POM) with a hot stage, and wide-angle X-ray diffraction (WAXD). Results indicated that the intrinsic viscosities were between 0.088 and 0.210 dL/g. Optical microscopy showed that the TLCP has a highly threaded liquid crystalline texture and a high birefringent schlieren texture character of nematic phase and has wider mesophase temperature ranges for all polyesters. DSC analysis were found that the melting point (Tm), isotropic temperature (Ti) of TLCPs decreased and the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyester. The WAXD results showed that TLCPs owned two strong diffraction peaks at 2θ near 19° and 23°.

Synthesis of Spherical LiFePO4/C Composites as Cathode Material of Lithium-Ion Batteries by a Novel Glucose Assisted Hydrothermal Method

2013 ◽  
Vol 787 ◽  
pp. 58-64 ◽  
Author(s):  
Xiang Feng Li ◽  
Zhao Zhang ◽  
Fang Liu ◽  
Shu Ping Zheng
Keyword(s):  
Hydrothermal Method ◽  
Raw Materials ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Discharge ◽  
X Ray ◽  
High Discharge Capacity ◽  
Optimal Sample ◽  
Structure Morphology

The LiFePO4/C composites with different morphology are synthesized by a novel glucose assisted hydrothermal method at various glucose concentrations (from 0 to 0.25mol/L) and the insoluble lithium source Li2CO3, (NH4)2Fe (SO4)2·6H2O and (NH4)2HPO4(n (Li):n (Fe):n (P)=1:1:1) are used as raw materials. The structure, morphology, thermal performance and electrochemical properties of the synthesized composites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry/differential scanning calorimetry (TG-DSC), galvanostatic charge/discharge tests and cyclic voltammetry (CV). The results show that the LiFePO4/C synthesized with 0.125mol/L glucose has the relatively small particles size (0.1~0.5μm) and the well spherical morphology. The optimal sample exhibits a high discharge capacity of 160.0mAh/g at the first cycle and exhibits a good reversibility and stability in CV tests.

Synthesis of La2NiO4+δ Nanofibers by Electrospinning Method and their Application

2018 ◽  
Vol 281 ◽  
pp. 859-864
Author(s):  
Yan Xing ◽  
Meng Fei Zhang ◽  
Tian Jun Li ◽  
Wei Pan
Keyword(s):  
Electron Microscopy ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Mixed Conductivity ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Electrospinning Method

La2NiO4+σ nanofibers exhibiting typical Ruddlesden–Popper structure (K2NiO4) were fabricated by a facile electrospinning method. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to analyze the structure, morphology and crystal process of the La2NiO4+σ nanofibers. For electrical properties measurement, uniaxially aligned nanofibers were directly collected and assembled into electrode. In our research, La2NiO4+σ phase forms above 873K with no impurity phase emerges during the thermal treatments. The nanofibers are smooth and uniform throughout the entire length and the grain is growing as calcination temperature increases. Furthmore, the La2NiO4+σ nanofibers own high mixed conductivity at 773K, laying good foundation for intermediate temperature solid oxide fuel cells application.

Investigation on β-Polypropylene/Talc Composites

2012 ◽  
Vol 182-183 ◽  
pp. 259-264
Author(s):  
Jia Wei Duan ◽  
Qiang Dou
Keyword(s):  
Polarized Light ◽  
Nucleating Agent ◽  
Mechanical Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Melt Compounding ◽  
Β Phase ◽  
Α Phase ◽  
Melting And Crystallization

In this study polypropylene (PP) composites containing β-nucleating agent (NT-C) and talc filler were prepared by melt compounding. The melting and crystallization behavior, morphology and mechanical properties of the composites were studied by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), polarized light microscopy (PLM) and mechanical tests. The results indicate that talc suppresses the formation of β phase, but promotes the formation of α phase. The Izod notched impact strength and tensile strength of β-PP/talc composites are superior to those of PP/talc composites, indicating an outstanding balance of stiffness and toughness of β-PP/talc composites.

Crystallization Properties of Nucleated Poly(lactic acid)

2012 ◽  
Vol 549 ◽  
pp. 322-326 ◽  
Author(s):  
Yong Chen ◽  
Qiang Dou
Keyword(s):  
Lactic Acid ◽  
Crystallization Behavior ◽  
Polarized Light ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystallization Properties ◽  
Melting And Crystallization

The effect of a nucleating agent (NT-C) on the crystallization behavior of poly(lactic acid) (PLA) was studied. The melting and crystallization behavior and spherulitic morphology of the nucleated PLA were investigated by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarized light microscopy (PLM). It is found that the crystallization temperature and crystallinity increase, the spherulitic size decrease for the nucleated PLA. But the crystal structure of the nucleated PLA is not changed.

Effect of Molybdenum and Ruthenium on the Crystallization Tendency of a New Nuclear Glass Containing High Rare-earth Concentration

2010 ◽  
Vol 1265 ◽  
Author(s):  
Daniel Caurant ◽  
Nolwenn Chouard ◽  
Odile Majerus ◽  
Jean-Luc Dussossoy ◽  
Aurelien Ledieu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Nucleating Agent ◽  
High Level Waste ◽  
Optical Absorption Spectroscopy ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Level ◽  
The Impact ◽  
Crystallization Tendency

AbstractThe impact of Nd2O3, MoO3 and RuO2 addition on the competition between the crystallization of apatite Ca2Nd8(SiO4)6O2 and powellite CaMoO4 phases which both may appear in High Level Waste nuclear glass (under certain specific conditions of cooling and glass composition) has been studied on a simplified composition belonging to the system SiO2-Na2O-CaO-Al2O3-B2O3. X-ray diffraction (at room temperature and high temperature) and scanning electron microscopy measurements have been performed on five glasses under two different thermal treatments. We show that RuO2 acts as a nucleating agent for apatite. Moreover, neodymium and molybdenum cations seem to be very close in the glassy network as Nd2O3 addition stops the phase separation of molybdates and inhibits the crystallization of CaMoO4. On the contrary, MoO3 seems to favor the crystallization of apatite. For several samples, the evolution of the distribution of Nd3+ cations after crystallization was followed by optical absorption spectroscopy.

scholarly journals Thermal and Nanoindentation Behaviours of Layered Silicate Reinforced Recycled GF-12 Nanocomposites

2016 ◽  
Vol 5 (4) ◽  
pp. 10
Author(s):  
A. Shalwan ◽  
A. I. Alateyah ◽  
B. Aldousiri ◽  
M. Alajmi
Keyword(s):  
Layered Silicate ◽  
Nucleating Agent ◽  
Slight Improvement ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Polyamide 12 ◽  
Recycled Glass ◽  
Base Polymer ◽  
Positive Effect

<p class="1Body">This work is an attempt to improve the thermal and nanoindentation behaviours of recycled Glass-Filled Polyamide-12 (GF-12) by adding layered Silicate (Nanoclay) as a reinforced filler. Differential Scanning Calorimetry (DSC) and Nanoindentation tests were conducted to study the effect of various loading levels (0-7 wt. %) of Nano-layered silicate on the thermal and nanohardness behaviours of GF-12 and its nanocomposites. Wide Angle X-ray Diffraction (WAXD) was employed to characterise the nanostructure of material and determine the intercalation/exfoliation for layered silicate in a GF-12 matrix. This study reveals that the layer silicate has a positive effect on the hardness results. Nanoindentation results showed remarkable improvement when layered silicate was added to recycled GF-12. The Glass transition (T<sub>g</sub>) and crystallization (T<sub>c</sub>) temperatures showed a slight improvement over the base polymer by the incorporation of layered silicate. Moreover, the enhancement of crystallization was obvious with the addition of clay loading, which functioned as a nucleating agent that could increase the rate of crystallization.</p>

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.

Crystalline form transformation of isotactic polypropylene induced by N,N’-diphenyl glutaramide

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Quliang Lu ◽  
Qiang Dou
Keyword(s):  
Polarized Light ◽  
Nucleating Agent ◽  
Maximum Amount ◽  
Crystalline Form ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Cell Parameters ◽  
Form Transformation

AbstractN,N’-Diphenyl glutaramide (DPG) is found to be an effective nucleating agent to induce the β-form of iPP. The results of wide angle X-ray diffraction, differential scanning calorimetry and polarized light microscopy indicate that 0.2 wt% of DPG can induce the maximum amount of β-form iPP, and the favorable crystallization temperature for the growth of β-form is 120 ˚C in this study. Analysis of the misfit factor between the cell parameters of DPG and β-iPP shows β-iPP can epitaxially crystallize on the bc face of DPG crystal well.

scholarly journals Composites of a Polypropylene Random Copolymer and Date Stone Flour: Crystalline Details and Mechanical Response

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2957
Author(s):  
Amina Benarab ◽  
Enrique Blázquez-Blázquez ◽  
Rachida Krache ◽  
Rosario Benavente ◽  
María L. Cerrada ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Random Copolymer ◽  
Nucleating Agent ◽  
Particle Dispersion ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mechanical Responses ◽  
Widespread Availability ◽  
Polypropylene Random Copolymer

Several composites were prepared based on a polypropylene random copolymer (PPR) and different amounts of date stone flour (DSF). This cellulosic fiber was silanized beforehand in order to reduce its hydrophilicity and improve the interfacial adhesion with the polymer. Other composites were also obtained, including a sorbitol derivative as an effective nucleant. Films made from these composites were prepared using two different thermal treatments, involving slow crystallization and rapid cooling from the melt. Scanning electron microscopy was used to evaluate the morphological features and the DSF particle dispersion within the PPR matrix. X-ray diffraction experiments and differential scanning calorimetry tests were employed to assess the crystalline characteristics and for the phase transitions, paying especial attention to the effects of the DSF and nucleating agent on PPR crystallization. An important nucleation ability was found for DSF, and evidently for the sorbitol derivative. The peak crystallization temperature upon cooling was considerably increased by the incorporation of either the nucleant or DSF. Additionally, a much higher proportion of orthorhombic crystals developed in relation to the monoclinic ones. Moreover, the mechanical responses were estimated from the microhardness experiments and significant improvements were found with increasing DSF contents. All of these findings indicate that the use of silanized DSF is a fairly good approach for the preparation of polymeric eco-composites, taking advantage of the widespread availability of this lignocellulosic material, which is otherwise wasted.

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