Morphological, thermo-mechanical, and thermal conductivity properties of halloysite nanotube-filled polypropylene nanocomposite foam

2016 ◽  
Vol 54 (2) ◽  
pp. 217-233 ◽  
Author(s):  
Renan Demori ◽  
Eveline Bischoff ◽  
Ana P de Azeredo ◽  
Susana A Liberman ◽  
Joao Maia ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Size ◽  
Cell Density ◽  
Void Fraction ◽  
Cell Structure ◽  
Cell Size Distribution ◽  
Halloysite Nanotube ◽  
Dynamic Mechanical ◽  
Foaming Behavior ◽  
Homogeneous Cell

Studies about polypropylene nanocomposite foams are receiving attention because nanoparticles can change physical and mechanical properties, as well as improve foaming behavior in terms of homogeneous cell structure, cell density, and void fraction. In this research, the foaming behavior of polypropylene, polypropylene/long-chain branched polypropylene (LCBPP) 100/20 blend, and polypropylene/LCBPP/halloysite nanocomposites with 0.5 and 3 parts per hundred of resin (phr) is studied. The LCBPP was used to improve the rheological properties of polypropylene/LCBPP blend, namely the degree of strain-hardening. Transmission electron microscopy observation indicated that halloysite nanotube particles are well distributed in the matrix by aggregates. Subsequent foaming experiments were conducted using chemical blowing agent in injection-molding processing. Polypropylene foam exhibited high cell density and cell size as well as a collapsing effect, whereas the polypropylene/LCBPP blend showed a reduction of the void fraction and cell density compared to expanded polypropylene. Also, the blend showed reduction of the collapsing effect and increase of homogeneous cell size distribution. The introduction of a small amount of halloysite nanotube in the polypropylene/LCBPP blend improved the foaming behavior of the polypropylene, with a uniform cell structure distribution in the resultant foams. In addition, the cell density of the composite sample was higher than the polypropylene/LCBPP sample, having increased 82% and 136% for 0.5 and 3 phr of loaded halloysite nanotube, respectively. Furthermore, the presence of halloysite nanotube increased crystallization temperature (Tc) and slightly increased dynamic-mechanical properties measured by dynamic-mechanical thermal analysis. By increasing halloysite nanotube content to 3 phr, the insulating effect increased by 13% compared to polypropylene/LCBPP blend. For comparative purposes, the effect on foaming behavior of polypropylene/LCBPP was also investigated using talc microparticles.

scholarly journals Experimental-numerical studies of the effect of cell structure on the mechanical properties of polypropylene foams

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 713-723
Author(s):  
Wei Gong ◽  
Tuan-Hui Jiang ◽  
Xiang-Bu Zeng ◽  
Li He ◽  
Chun Zhang
Keyword(s):  
Mechanical Properties ◽  
Size Distribution ◽  
Cell Size ◽  
Cell Structure ◽  
Structure Parameters ◽  
Cell Size Distribution ◽  
Numerical Studies ◽  
Polypropylene Foam ◽  
The Impact ◽  
The Relationship

AbstractThe effects of the cell size and distribution on the mechanical properties of polypropylene foam were simulated and analyzed by finite element modeling with ANSYS and supporting experiments. The results show that the reduced cell size and narrow size distribution have beneficial influences on both the tensile and impact strengths. Decreasing the cell size or narrowing the cell size distribution was more effective for increasing the impact strength than the tensile strength in the same case. The relationship between the mechanical properties and cell structure parameters has a good correlation with the theoretical model.

Physico-mechanical properties and cell microstructure of cross-linked PVC/organoclay nanocomposite foams prepared at various processing conditions

2020 ◽  
pp. 089270572097869
Author(s):  
Pezhman Rezaei ◽  
Mostafa Rezaei ◽  
Saeid Talebi ◽  
Amin Babaie
Keyword(s):  
Mechanical Properties ◽  
Size Distribution ◽  
Cell Size ◽  
Cell Density ◽  
Expansion Ratio ◽  
Molding Pressure ◽  
Cell Size Distribution ◽  
Gel Content ◽  
Nanocomposite Foams ◽  
Cloisite 30B

Cross-linked polyvinyl chloride (C-PVC) foams and their nanocomposite foams, containing Cloisite 30B nanoclays were prepared. The effects of compression molding pressure and time on the morphology and mechanical properties of different foams were studied. Increment of molding pressure led to higher apparent density, gel content, cell density, and expansion ratio, and wider cell size distribution, which improved the mechanical properties of the foams. Additionally, with the increasing of molding time, lower cell density and final expansion ratio, narrower cell size distribution, and higher gel content and mechanical properties could be obtained. Moreover, incorporation of Cloisite 30B nanoclay in a PVC matrix not only improved cellular microstructure and mechanical properties but also reduced water uptake ratios of nanocomposite foams.

Cell structure and mechanical properties of microcellular PLA foams prepared via autoclave constrained foaming

2020 ◽  
pp. 026248932093032
Author(s):  
Jinwei Chen ◽  
Ling Yang ◽  
Dahua Chen ◽  
Qunshan Mai ◽  
Meigui Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Size ◽  
Cell Structure ◽  
Saturation Pressure ◽  
Tensile Modulus ◽  
Cell Structures ◽  
Wide Range ◽  
The Mean ◽  
Constrained Foaming ◽  
The Relationship

Microcellular polylactic acid (PLA) foams with various cell size and cell morphologies were prepared using supercritical carbon dioxide (sc-CO2) solid-state foaming to investigate the relationship between the cell structure and mechanical properties. Constrained foaming was used and a wide range of cell structures with a constant porosity of ∼75% by tuning saturation pressure (8–24 MPa) was developed. Experiments varying the saturation pressure while holding other variables’ constant show that the mean cell size and the mean cell wall thickness decreased, while the cell density and the open porosity increased with increase of pressure. Tensile modulus of PLA foams decreased with increasing the saturation pressure, but the specific tensile modulus of PLA foams was still 15–80% higher than that of solid PLA. Tensile strength and elongation at break first increased with increasing saturation pressure up to 16 MPa and then decreased with further increasing saturation pressure (20 MPa and 24 MPa) at which opened-cell structure produced. Compressive modulus, compressive strength, and compressive yield stress also followed the same variation trend. The results indicated that not only cell size plays an important role in properties of PLA foams but also cell morphology can influence these properties significantly.

The Effect of Cell Size on the Physical Properties of Crosslinked Closed Cell Polyethylene Foams Produced by a High Pressure Nitrogen Solution Process

2002 ◽  
Vol 21 (3) ◽  
pp. 165-194 ◽  
Author(s):  
M.A. Rodríguez-Pérez ◽  
J.I. González-Peña ◽  
N. Witten ◽  
J.A. de Saja
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal Expansion ◽  
Cell Size ◽  
Mechanical Response ◽  
Solution Process ◽  
Strain Rates ◽  
Dynamic Mechanical ◽  
Closed Cell

The thermal conductivity, thermal expansion, mechanical properties at low strain rates and dynamic mechanical properties of a collection of crosslinked closed cell polyethylene foams manufactured by a high pressure nitrogen solution process have been studied as a function of the cell size. The main mechanisms that influence each property and the foam microstructure have been considered to rationalise the results. A theoretical model has been used to examine the thermal conductivity values. The results have shown the extent to which reducing the cell size could improve the insulating capabilities of these materials. The effect of cell size on the mechanical properties at low strain rates is very small, as a consequence the thermal expansion does not depend on cell size. Nevertheless, the structural characteristics are seen to influence dynamic mechanical response at temperatures below 15°C.

Effect of Nanoclay on the Physical-Mechanical and Thermal Properties and Microstructure of Extruded Noncross-Linked LDPE Nanocomposite Foams

2011 ◽  
Vol 471-472 ◽  
pp. 751-756 ◽  
Author(s):  
F. Zandi ◽  
M. Rezaei ◽  
A. Kasiri
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Cell Size ◽  
Flame Retardancy ◽  
Image Analyzer ◽  
Mechanical And Thermal Properties ◽  
Average Cell Size ◽  
Cell Size Distribution ◽  
Average Cell ◽  
Nanocomposite Foams

Novel noncross-linked low density polyethylene (LDPE) foams were produced by extrusion process. In this study the effects of Organophilic Montmorillonite (OMMT) nanoclay (DK1) on thermal conductivity, flame retardancy, morphological and mechanical properties of LDPE foams have been investigated. Nanoclay dispersion in LDPE foam structure was examined by X-ray diffraction (XRD), microstructure was observed by an optical microscope and analyzed by Bel View image analyzer, thermal conductivity was studied by a simple transient method, mechanical properties was investigated using a tensile-compression Zwick-Roell machine as well as the flame retardancy of the samples was examined by flammability test. The optimum nanoclay content was determined by comparison of the properties in nanocomposite and neat LDPE foams. Due to the presence of nanoclay in the foam and decreasing the cell nucleation energy around the nanoclay, the average cell size was decreased as well as the cell density and microstructure uniformity was increased. In XRD patterns of LDPE nanocomposite foams, OMMT (DK1) characteristic peak was not observed as evidence of nanoclay intercalation-exfoliation in the polymer matrix, which led to the production of foams with homogenous microstructure. Furthermore, this nanocomposites showed lower thermal conductivity compared to neat LDPE foam, which can be attributed to the cell size reduction as well as narrow cell size distribution in nanocomposite foams. Compression test results demonstrated that LDPE nanocomposite foams with proper clay contents have improved mechanical properties (Young’s modulus, compressive strength). Furthermore due to the presence of DK1 nanoclay, LDPE foam showed a good char formation as an evidence of their flame retardancy.

Synthesis and Properties of Open-Celled Metal Foams

2007 ◽  
Vol 534-536 ◽  
pp. 1005-1008 ◽  
Author(s):  
Peter Quadbeck ◽  
Günther Stephani ◽  
Kerstin Kümmel ◽  
Joerg Adler ◽  
Gisela Standke
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Cell Size ◽  
Significant Influence ◽  
Cell Structure ◽  
Metal Foams ◽  
Compression Tests ◽  
Stainless Steel 316L ◽  
Replication Technique ◽  
Highly Porous

Open-celled metal foams were synthesized using a replication technique. Therefore a reticulated polyurethane template was coated by a slurry and removed thermally, followed by a sintering step. Since the process is feasible for a multiplicity of metals the experiments were performed on the example of stainless steel 316L. Highly porous components were obtained showing adjustable densities between 0.3 and 2.0 g/cm³. The cell structure is exceedingly homogeneous and the cell sizes may be chosen in the range of 10 – 80 ppi. In order to characterise the properties, compression tests and acoustical tests were carried out. A significant influence of the density and the cell size on the acoustical and mechanical properties was noticed.

Morphologies and compression performance of graphene oxide/SiO2 modified phenolic foam

2017 ◽  
Vol 30 (7) ◽  
pp. 803-811 ◽  
Author(s):  
Xia Luo ◽  
Kejing Yu ◽  
Kun Qian
Keyword(s):  
Graphene Oxide ◽  
Cell Size ◽  
Hybrid Materials ◽  
Cell Structure ◽  
Weight Fraction ◽  
Compressive Property ◽  
Cell Size Distribution ◽  
Compression Performance ◽  
In Situ Preparation ◽  
Phenolic Foam

In this study, the graphene oxide/SiO2 hybrid materials with different sizes (GO/SiO2-80, GO/SiO2-170, GO/SiO2-250) were prepared via in situ preparation. Different sizes and weight fraction of GO/SiO2 were added into phenolic resin to prepare phenolic foam composites. The cell properties, morphologies, and mechanism of GO/SiO2 reinforced PF composites were studied. The results showed that the GO/SiO2-80 can improve the cell structure and compressive property obviously than other size nanoparticles. The PF modified with 1 wt% GO/SiO2-80 exhibited most uniform cell structure, and it showed a mean cell size of 117 µm and narrow cell size distribution from 50 µm to 225 µm. The obtained PF/(1 wt% GO/SiO2-80) also showed an excellent compressive strength and modulus of 0.18 and 3.22 MPa, which has increased by 80% and 61%, respectively, compared to the pure PF. This method may make it possible for using GO/SiO2 hybrid materials to enhance the cell structure and compression performance of the phenolic foam composites with broader applications.

A comparative study on effects of layered double hydroxide (LDH) and halloysite nanotube (HNT) on the physical, mechanical and dynamic mechanical properties of reed flour/polyvinyl chloride composites

2021 ◽  
pp. 089270572110517
Author(s):  
Mohammad Dahmardeh Ghalehno ◽  
Behzad Kord ◽  
Laleh Adlnasab
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Layered Double Hydroxide ◽  
Polyvinyl Chloride ◽  
Tensile Modulus ◽  
Dynamic Mechanical Properties ◽  
Halloysite Nanotube ◽  
Clay Nanoparticles ◽  
Dynamic Mechanical ◽  
Double Hydroxide

The objective of this research was to comprehensively compare the effects of two different types of nanoclay, namely layered double hydroxide (LDH) and halloysite nanotube (HNT) on the physical, mechanical, and dynamic mechanical properties of compression-molded composite panels fabricated from reed flour (RF) and polyvinyl chloride (PVC). To achieve the desired properties in the composites, the clay nanoparticles were modified with surfactant (mLDH and mHNT) before usage. The results showed that the composite specimens with mLDH exhibited higher tensile and flexural properties (strength and moduli) than with mHNT at low content. Compared with the maximum flexural strength and tensile modulus of 21.56 MPa and 2186.16 MPa for the specimens made with mHNT, the highest flexural strength and tensile modulus were found in the specimens incorporated with mLDH (23.05 MPa and 2227.44 MPa). Moreover, at high content, the composite specimens with mHNT presented greater hydrophobicity. The comparative analysis exhibited that that the water uptake of the composites including mHNT (5.03%) was approximately 15% lower than that of the mLDH (5.73%) based composite. The DMTA results indicated that the composite specimens with mLDH demonstrated better molecular restriction and larger storage modulus than with mHNT. Besides, the loss-tangent (tan δ) peak was shifted to a higher temperature for the samples including both mLDH and mHNT than without ones. The specimens made with mLDH had the highest glass transition temperature values (70.67°C) compared with 70.12°C for the specimens treated with mHNT. Morphological observations showed that the nanoparticles were predominantly dispersed uniformly within the polymer matrix. Overall, it is found that the addition of 3 phc mLDH clay was the most effective in the composite formulation; it has significantly enhanced the properties of the wood-plastic composites.

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