scholarly journals Gelation and Crystallization Phenomena in Polyethylene Plastomers Modified with Waxes

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2147
Author(s):  
Markus Gahleitner ◽  
Jingbo Wang ◽  
Floran Prades ◽  
Klaus Bernreitner
Keyword(s):  
Low Molecular Weight ◽  
Low Density ◽  
Optical Performance ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Base Polymer ◽  
Melt Adhesives ◽  
Homogeneous Linear ◽  
Hot Melt

Polyethylene (PE) plastomers, single-site catalyst-based homogeneous linear low-density PEs (LLDPEs), combine low crystallinity, softness, and elasticity, making them ideal candidates for numerous applications such as hot-melt adhesives (HMA). As plastomers crystallize rather slowly, a number of possible low molecular weight polyolefin components were tested to accelerate solidification. An ideal modifier should accelerate solidification while maintaining transparency and softness of the base polymer. A Queo plastomer type was modified with different PE and PP waxes at concentrations of 5 to 25 wt.-%. Next to conventional calorimetry, a rheological technique was applied to study solidification. The resulting morphology was studied by atomic force microscopy, and the final compositions were investigated regarding their mechanical and optical performance. Accelerated solidification was observed in all cases, but a quite different course of structure formation could be concluded. PE waxes dissolve in the melt state, forming a lamellar network during cooling, whereas PP waxes form a heterogeneous blend in the melt for which the wax droplets solidify before the matrix. The particulate-type modification by the PP wax also affects stiffness less while retaining transparency better.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

scholarly journals An Insight into Amorphous Shear Band in Magnetorheological Solid by Atomic Force Microscope

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4384
Author(s):  
Mohd Aidy Faizal Johari ◽  
Asmawan Mohd Sarman ◽  
Saiful Amri Mazlan ◽  
Ubaidillah U ◽  
Nur Azmah Nordin ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Shear Band ◽  
Shear Bands ◽  
Test Duration ◽  
Phase Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Relaxation Stress ◽  
Band Deformation

Micro mechanism consideration is critical for gaining a thorough understanding of amorphous shear band behavior in magnetorheological (MR) solids, particularly those with viscoelastic matrices. Heretofore, the characteristics of shear bands in terms of formation, physical evolution, and response to stress distribution at the localized region have gone largely unnoticed and unexplored. Notwithstanding these limitations, atomic force microscopy (AFM) has been used to explore the nature of shear band deformation in MR materials during stress relaxation. Stress relaxation at a constant low strain of 0.01% and an oscillatory shear of defined test duration played a major role in the creation of the shear band. In this analysis, the localized area of the study defined shear bands as varying in size and dominantly deformed in the matrix with no evidence of inhibition by embedded carbonyl iron particles (CIPs). The association between the shear band and the adjacent zone was further studied using in-phase imaging of AFM tapping mode and demonstrated the presence of localized affected zone around the shear band. Taken together, the results provide important insights into the proposed shear band deformation zone (SBDZ). This study sheds a contemporary light on the contentious issue of amorphous shear band deformation behavior and makes several contributions to the current literature.

Field-Effect Mobility and Morphology Study in Amorphous Films of Symmetric and Unsymmetrical Spiro-Linked Compounds

2002 ◽  
Vol 725 ◽  
Author(s):  
Tobat P. I. Saragi ◽  
Robert Pudzich ◽  
Thomas Fuhrmann ◽  
Josef Salbeck
Keyword(s):  
Field Effect ◽  
Smooth Surface ◽  
Amorphous Materials ◽  
Low Molecular Weight ◽  
Field Effect Mobility ◽  
Amorphous Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Saturation Region ◽  
Microscopy Images

AbstractWe have investigated the field-effect mobility of three kinds of low molecular weight spirolinked compounds, namely 2,2',7,7'-tetrakis (diphenylamino)-9,9'-spirobifluorene (spiro-TAD), 2,2',7,7'-tetrakis(biphenyl-4-yl)-9,9'-spirobifluorene (spiro-6φ) and 2,7-bis-(N,N-diphenylamino)- 2',7'-bis-(biphenyl-4-yl)-9,9'-spirobifluorene (spiro-X2). The field-effect mobilities of these materials in the saturation region are 8 x 10-4 cm2V-1s-1, 5 x 10-5 cm2V-1s-1 and 4 x 10-4 cm2V-1s-1 respectively. The atomic force microscopy images show that films prepared from these materials are amorphous with a very smooth surface and the limited field-effect mobility is due to the intrinsic behaviour of amorphous materials.

Structure and Properties of Hybrid Polyurethane Composites with Carboxyalumoxanes

2008 ◽  
Vol 587-588 ◽  
pp. 212-216 ◽  
Author(s):  
Magdalena Jurczyk-Kowalska ◽  
Joanna Ryszkowska
Keyword(s):  
In Situ Polymerization ◽  
Structure And Properties ◽  
Mechanical Mixing ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Polyurethane Composites ◽  
Polyurethane Matrix

Carboxyalumoxanes have been incorporated into a polyurethane matrix by in situ polymerization. The filler was dispersed in the polyurethane matrix by either both ultrasonic and mechanical mixing or by mechanical mixing alone. The physico-mechanical properties of the composites have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Using ultrasound improves the degree of dispersion of the fillers in the matrix, but it also causes changes in the structure of the polyurethane matrix.

Thermocatalytic Degradation of Low Density Polyethylene Films at Artificial Aging Treatment under Lower Temperature

2014 ◽  
Vol 804 ◽  
pp. 43-46
Author(s):  
Si Zhao Zhang ◽  
Xue Guang Luo ◽  
Feng Ding ◽  
Ke Li ◽  
Xiao Yan Lin ◽  
...  
Keyword(s):  
Artificial Aging ◽  
Aging Treatment ◽  
Degradation Process ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ft Ir ◽  
Lower Temperature ◽  
Chemical Groups

Low density polyethylene (LDPE) films added thermal catalyst were investigated at artificial aging time of 0, 10, 20, and 30 days, respectively. The samples obtained were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), gel permeation chromatograph (GPC) and fourier transform infrared spectroscopy (FT-IR). It shows that the surface of film was destroyed via thermocatalytic reactions at lower temperature. In addition, the changes of chemical groups were also observed in the thermocatalytic degradation process. Thus, the validation to the thermocatalytic route has been confirmed over lower temperature excitation. It is hoped that our work may provide a new insight into the degradation of polymeric films at lower temperature.

Comparison of the Microstructure of AlN Films Grown by MOCVD and by PLD on Sapphire Substrates

1996 ◽  
Vol 449 ◽  
Author(s):  
Yun-Xin Li ◽  
Lourdes Salamanca-Riba ◽  
V. Talyan ◽  
T. Venkatesan ◽  
C. Wongchigul ◽  
...  
Keyword(s):  
Low Density ◽  
Full Width ◽  
High Crystalline Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Film Substrate ◽  
Microscopy Images

ABSTRACT(0001) aluminium nitride thin films were grown epitaxially on (0001) Sapphire substrates by MOCVD at 1200° C and PLD at 800° C. Both films have the same epitaxial growth relationship: (0001)AlN//(0001)Sap, and the same in-plane relationship which shows a 30° rotation between A1N and Sapphire: [ 12 10]AlN//[0 110]Sap and [10 10]AlN //[ 2110]Sap. The full width at half maximum (FWHM) of x-ray rocking curve of the MOCVD A1N film was 0.16° and PLD A1N film was 0.2°. Films grown by both MOCVD and PLD showed high crystalline quality. HRTEM images showed that these films are single crystalline with very low density of defects.Dislocations in the film parallel to the film / substrate interface were observed in both A1N films. Atomic force microscopy images showed that the MOCVD films have flatter and larger terraces than the PLD films. The PLD technique for A1N growth needs to be improved further. But both films have a surface roughness of approximately 100nm.

A Novel Approach to the Functionalisation of Pristine Carbon Fibre Using Azomethine 1,3-Dipolar Cycloaddition

2015 ◽  
Vol 68 (2) ◽  
pp. 335 ◽  
Author(s):  
Linden Servinis ◽  
Thomas R. Gengenbach ◽  
Mickey G. Huson ◽  
Luke C. Henderson ◽  
Bronwyn L. Fox
Keyword(s):  
Carbon Fibre ◽  
Photoelectron Spectroscopy ◽  
Cycloaddition Reaction ◽  
Fibre Surface ◽  
Single Fibre ◽  
Dipolar Cycloaddition ◽  
Force Microscopy ◽  
Atomic Force ◽  
Novel Approach ◽  
The Matrix

We demonstrate the utilisation of an azomethine 1,3-dipolar cycloaddition reaction with carbon fibre to graft complex molecules onto the fibre surface. In an effort to enhance the interfacial interaction of the fibre to the matrix, the functionalised fibres possessed a pendant amine that is able to interact with epoxy resins. Functionalisation was supported by X-ray photoelectron spectroscopy and the grafting process had no detrimental effects on tensile strength compared with the control (untreated) fibres. Also, microscopic roughness (as determined by atomic force microscopy) and fibre topography were unchanged after the described treatment process. This methodology complements existing methodology aimed at enhancing the surface of carbon fibres for advanced material applications while not compromising the desirable strength profile. Single-fibre fragmentation tests show a statistically significant decrease in fragment length compared with the control fibres in addition to transverse cracking within the curing resin, both of which indicate an enhanced interaction between fibre and resin.

Damage Precursors in Individual Microfibers

2016 ◽  
Author(s):  
Daniel P. Cole ◽  
Todd C. Henry ◽  
Frank Gardea ◽  
Robert Haynes
Keyword(s):  
Early Stage ◽  
Force Microscopy ◽  
Atomic Force ◽  
Local Material ◽  
Before And After ◽  
The Matrix ◽  
Local Properties ◽  
Damage Precursor ◽  
The Individual ◽  
Multiscale Composites

Structural health monitoring of composite materials is limited by the lack of fundamental understanding of early stage damage at the local material level. This includes damage precursor formation on fiber surfaces, within the matrix, and at the fiber-matrix interface/interphase. In this effort, we present a micro-/nano-scale technique for characterizing damage precursor formation on individual carbon fibers exposed to cyclic tensile loads. Nanoindentation and atomic force microscopy (AFM) were used to study the local properties of the individual microfibers before and after global loading events. An AFM image analysis was used to track evolution of topography on the fiber surfaces. The work is a first step toward understanding damage precursor formation in individual microfibers; the work is expected to enable multiscale composites modeling efforts as well as enable the development of future self-sensing materials.

Theoretical and experimental investigation of the particle size distribution and magnetic properties of the PP + FE3O4nanocomposites

2019 ◽  
Vol 33 (1) ◽  
pp. 125-137
Author(s):  
Mahammadali A Ramazanov ◽  
Abel M Maharramov ◽  
Rasim A Ali-zada ◽  
Habiba A Shirinova ◽  
Flora V Hajiyeva
Keyword(s):  
Magnetic Properties ◽  
Size Distribution ◽  
Polymer Matrix ◽  
Theoretical Calculations ◽  
Mixing Time ◽  
Magnetic Hysteresis ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Scanning Electron

A detailed study of the dispersion of magnetite (Fe3O4) nanoparticles in the polypropylene (PP) matrix, the degree of coagulation, and the dependence of magnetic properties of PP + Fe3O4nanocomposites on the size of nanoparticles is reported. The size distribution of nanoparticles in polymer matrix and morphology of the nanocomposites were studied by the means of scanning electron microscope (JEOL JSM-7600 F) and atomic force microscopy (NT-MDT). It was found that when the Fe3O4nanoparticles are introduced into the PP matrix, their coagulation takes place. The increase in the size of the Fe3O4nanoparticles depends on their volume content in the polymer matrix, the viscosity of polymer, mixing time, and so on. The magnetic properties of PP + Fe3O4nanocomposites were experimentally and theoretically studied. It was found that the magnetic hysteresis parameters of the nanocomposites directly depend on the size and concentration of the Fe3O4nanoparticles in the matrix. Theoretical calculations were compared with experimental results obtained from M( H) measurements. Discrepancy between theoretical and experimental magnetic values have been explained.

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