scholarly journals Crystalline Modification of Isotactic Polypropylene with a Rare Earth Nucleating Agent Based on Ultrasonic Vibration

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1777 ◽  
Author(s):  
Li ◽  
Xin ◽  
Song ◽  
Dong ◽  
Ben ◽  
...  
Keyword(s):  
Rare Earth ◽  
Isotactic Polypropylene ◽  
Nucleating Agent ◽  
Relative Content ◽  
Water Cooling ◽  
Crystalline Modification ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Agent Based ◽  
The Relationship

In this paper, the crystalline modification of isotactic polypropylene (PP) with a rare earth β nucleating agent (WBG) with different ultrasound conditions was investigated by scanning electron microscopy (SEM), wide-angle X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The relationship between the ultrasound conditions and the crystalline structure, as well as the mechanism for the behavior, were revealed. SEM showed that the dispersion of the nucleating agent in the PP matrix was better at shorter ultrasound distances. In addition, the higher the water cooling temperature, the better the nucleating agent was dispersed in the PP matrix. The results of XRD and DSC showed that the crystallinity and the relative content of the β-crystal were increased with nearer ultrasound distance, as well as increased in higher water cooling temperatures. In particular, under the same conditions, the crystallinity and the relative content of the β-crystal after ultrasonic treatment were much higher than those without ultrasound.

scholarly journals Crystalline modification of a rare earth nucleating agent for isotactic polypropylene based on its self-assembly

2018 ◽  
Vol 5 (5) ◽  
pp. 180247 ◽  
Author(s):  
Yuanming Zhang ◽  
Tingting Sun ◽  
Wei Jiang ◽  
Guangting Han
Keyword(s):  
Hydrogen Bond ◽  
Rare Earth ◽  
Isotactic Polypropylene ◽  
Self Assembly ◽  
Dendritic Structure ◽  
Nucleating Agent ◽  
The Self ◽  
Structure Evolution ◽  
Crystalline Modification ◽  
Assembly Structure

In this paper, the crystalline modification of a rare earth nucleating agent (WBG) for isotactic polypropylene (PP) based on its supramolecular self-assembly was investigated by differential scanning calorimetry, wide-angle X-ray diffraction and polarized optical microscopy. In addition, the relationship between the self-assembly structure of the nucleating agent and the crystalline structure, as well as the possible reason for the self-assembly behaviour, was further studied. The structure evolution of WBG showed that the self-assembly structure changed from a needle-like structure to a dendritic structure with increase in the content of WBG. When the content of WBG exceeded a critical value (0.4 wt%), it self-assembled into a strip structure. This revealed that the structure evolution of WBG contributed to the K β and the crystallization morphology of PP with different content of WBG. In addition, further studies implied that the behaviour of self-assembly was a liquid–solid transformation of WBG, followed by a liquid–liquid phase separation of molten isotactic PP and WBG. The formation of the self-assembly structure was based on the free molecules by hydrogen bond dissociation while being heated, followed by aggregation into another structure by hydrogen bond association while being cooled. Furthermore, self-assembly behaviour depends largely on the interaction between WBG themselves.

scholarly journals Thermal Effect of Different Laying Modes on Cross-Linked Polyethylene (XLPE) Insulation and a New Estimation on Cable Ampacity

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2994 ◽  
Author(s):  
Zhu ◽  
Zhao ◽  
Han ◽  
Wang ◽  
Wang ◽  
...  
Keyword(s):  
Thermal Effect ◽  
Thermal Parameter ◽  
Thermal Parameters ◽  
Breakdown Field ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Modeling Software ◽  
The Relationship ◽  
Insulation Condition ◽  
Xlpe Insulation

This paper verifies the fluctuation on thermal parameters and ampacity of the high-voltage cross-linked polyethylene (XLPE) cables with different insulation conditions and describes the results of a thermal aging experiment on the XLPE insulation with different operating years in different laying modes guided by Comsol Multiphysics modeling software. The thermal parameters of the cables applied on the models are detected by thermal parameter detection control platform and differential scanning calorimetry (DSC) measurement to assure the effectivity of the simulation. Several diagnostic measurements including Fourier infrared spectroscopy (FTIR), DSC, X-ray diffraction (XRD), and breakdown field strength were conducted on the treated and untreated specimens in order to reveal the changes of properties and the relationship between the thermal effect and the cable ampacity. Moreover, a new estimation on cable ampacity from the perspective on XLPE insulation itself has been proposed in this paper, which is also a possible way to judge the insulation condition of the cable with specific aging degree in specific laying mode for a period of time.

PREPARATION AND CHARACTERIZATION OF BIOACTIVE COMPOSITES OF PCL/BIOACTIVE FILLERS

2010 ◽  
Vol 24 (01n02) ◽  
pp. 128-135 ◽  
Author(s):  
YING LI ◽  
CHI MUN CHEAH ◽  
HENGKY CHANG ◽  
LEONARD LOH ◽  
ADELINE KUM
Keyword(s):  
Material Design ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Composition Structure ◽  
Co Precipitation ◽  
Bioactive Composites ◽  
The Relationship ◽  
Substitute Materials

A variety of bioactive composites have been invested over the last two decades as substitute materials for diseased or damaged tissues in the human body. In this paper, bioactive composites were prepared using polycaprolactone ( PCL ) and hydroxyapatite ( HA ). The influence of micro-sized and nano-sized HA on composite properties was investigated. The nano- HA was prepared by wet chemical co-precipitation reaction method. Studies of biocomposite specimen morphology were performed by Field-emission scanning electron microscopy (SEM). XRD (X-Ray Diffraction) and DSC (Differential scanning calorimetry) were used to assess the crystal structure of HA and thermal properties of the composites, respectively. The synthesized nano- HA is found to be of high purity HA structure. The relationship between composition, structure and properties was studied. Different methods to prepare uniform composites were tried, and the outcome of this work suggests that by proper manipulation of biodegradable polymers and bioactive ceramics through material design, bioactive composites with controlled properties might be achievable.

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.

The Relationship between Phase Structure and Melting Characteristics of High Cesium Content KF-CsF-AlF3 Aluminum Flux

2013 ◽  
Vol 634-638 ◽  
pp. 2909-2915 ◽  
Author(s):  
Fang Jie Cheng ◽  
Jun Xiang Yang ◽  
Hai Wei Zhao ◽  
Guan Xing Zhang ◽  
Jun Lan Huang ◽  
...  
Keyword(s):  
Solid Phase ◽  
Chemical Elements ◽  
Eutectic Reaction ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Decomposition Products ◽  
Melting Characteristics ◽  
The Common ◽  
The Relationship

The melting curves of high cesium content KF-CsF-AlF3 flux samples prepared by the wetting synthesis method were measured by differential scanning calorimetry (DSC), and the effect of the flux compositions on the melting characteristics was analyzed and summarized. Existing phases of every representation sample was identified by X-ray diffraction (XRD), meanwhile, the morphology and chemical elements of the typical flux samples were analyzed by scanning electron microscope (SEM) and energy spectrum analysis (EDS), respectively. The results indicated that solid phase decomposition first occurred in the common phase Cs2AlF5 for all the flux samples at 420°C; one of the decomposition products, Cs3AlF6 take the eutectic reaction with the Cs2KAlF6 at about 450°C; the flux samples containing phase CsAl2F7 or Cs2KAl3F12 have the e5 and e1 eutectic reaction at 471°C and 525°C, respectively, and their liquidus increased correspondingly. The liquidus for regionⅠflux samples is about 450°C and with a narrow melting range, which would make them good substrates for aluminum alloy middle temperature brazing.

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.

N,N′-Bis(benzoyl) adipic acid dihydrazide and talc: nucleating agents for poly(l-lactic acid)

2016 ◽  
Vol 36 (4) ◽  
pp. 381-390 ◽  
Author(s):  
Bai Xue ◽  
Dan Guo ◽  
Jianjun Bao
Keyword(s):  
Lactic Acid ◽  
Adipic Acid ◽  
Polymeric Composite ◽  
Weight Fraction ◽  
Nucleating Agent ◽  
High Heat ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Heat Distortion Temperature ◽  
Composite Samples

Abstract In this paper, high-heat-resistant polymeric composite products were prepared via the traditional melt blending process by incorporating N,N′-bis(benzoyl) adipic acid dihydrazide (BAAD) into poly(l-lactic acid) (PLLA), which acted as an organic nucleating agent. The heat distortion temperature (HDT) of the PLLA/BAAD composite samples was measured by an HDT apparatus, and a high value of 96.2°C was achieved at a BAAD loading fraction of 0.5 wt.%, whereas, at the same processing conditions, the HDT of PLLA/talc specimens reached a similar value at a talc content of 20 wt.%, which was much higher than the BAAD content. Differential scanning calorimetry and X-ray diffraction analyses were applied to determine the melting and crystallization behavior of the PLLA/BAAD blends. Polarized optical microscopy was used to observe the crystalline morphologies. Thermogravimetric analysis was employed to study the effect of BAAD on the thermal stability of PLLA. Measurement of the mechanical property confirmed that the addition of BAAD was beneficial to the enhancement of the mechanical properties of the resulting blends. However, the tensile strength of the PLLA/talc composites decreased with increasing weight fraction of talc.

Structure and Performance of PP Porous Membrane Prepared with Adipic Acid and NA-40 as Nucleating Agent via TIPS

2016 ◽  
Vol 848 ◽  
pp. 733-737
Author(s):  
Hui Xia Xuan ◽  
Chun Ju He
Keyword(s):  
Adipic Acid ◽  
Water Flux ◽  
Nucleating Agent ◽  
Porous Membrane ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Thermally Induced ◽  
Cooling Temperature ◽  
And Performance

Polypropylene (PP) membranes were respectively prepared using adipic acid (APA) and Sorbitol (NA-40) as nucleating agent via thermally induced phase separation (TIPS) method. The effects of nucleating agent content and cooling temperature on the structure and performance of membrane were investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). WAXD spectrogram indicates that three kinds of α, β and γ-form crystal were formed in this preparation process and the relative content of β-form crystal in membrane prepared by NA-40 system is higher than that of membrane formed by adipic acid. SEM images show that porous structure and cellular structure were observed on the surface and cross-section of membrane. The water flux, tensile strength and elongation increase with the addition of nucleating agent content and decrease with cooling temperature rising. This paper aims to choose proper nucleating agent NA-40 and coagulation temperature to improve the properties of PP membranes.

Sign in / Sign up

Export Citation Format

Share Document