Electrical-thermal aging characteristic research of polymer materials by infrared spectroscopy,

2014 ◽  
Vol 25 (12) ◽  
pp. 1396-1405 ◽  
Author(s):  
Wei Wang ◽  
Dongxin He ◽  
Jiefeng Gu ◽  
Jian Lu ◽  
Jiazhen Du
Keyword(s):  
Infrared Spectroscopy ◽  
Thermal Aging ◽  
Polymer Materials ◽  
Aging Characteristic

Investigation into the Differences Chemical Properties of Laser Sintering Polymer Powders Using Fourier Transform Infrared Spectroscopy

2014 ◽  
Vol 548-549 ◽  
pp. 133-136
Author(s):  
Yusoff Way ◽  
Hadi Puwanto ◽  
Farizahani ◽  
P.T. Pham
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Chemical Composition ◽  
Fourier Transform Infrared Spectroscopy ◽  
Surface Finish ◽  
Chemical Properties ◽  
Fourier Transform Infrared ◽  
Laser Sintering ◽  
Polymer Materials ◽  
Powder Materials

Selective Laser Sintering (SLS) or Laser Sintering (LS) allows functional parts to be produced in a wide range of powdered materials using a dedicated machine, and is thus gaining popularity within the field of Rapid Prototyping (RP). One of the advantages of employing LS is that the loose powder of the building chamber can be recycled. The properties of polymer powder significantly influence the melt viscosity and sintering mechanism during Laser Sintering (LS) processes which results in a good surface finish. The objective of this research is to investigate the chemical composition of fresh polymer materials used in Laser Sintering. There are seven virgin SLS materials which are PA2200, GF3200, Alumide, PrimeCast, PrimePart, Duraflex and CastForm. Fourier Transform Infrared Spectroscopy (FTIR) was used to analyze the chemical composition of the materials by using infrared radiation and absorbed frequency. The spectra show that similar functional groups were found in the materials apart from PrimePart and Duraflex. Obtained data from this analysis could be used to investigate on how the fresh and recycled powder materials with different chemical properties would affect the part surface finish.

scholarly journals Research on the Thermal Aging Behaviors of LDPE/TiO2 Nanocomposites

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Jun Liu ◽  
Youyuan Wang ◽  
Kun Xiao ◽  
Zhanxi Zhang
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Thermal Aging ◽  
Oxygen Diffusion ◽  
Crystallization Behavior ◽  
Dissipation Factor ◽  
Sem Images ◽  
Dispersion Of Nanoparticles ◽  
Aging Characteristic

The ability of antithermal aging of LDPE/TiO2 nanocomposites was investigated through SEM, FTIR, DSC, and dielectric properties in this paper. The results of SEM images showed that the thermal aging had a significant influence on the structure of Pure-LDPE and LDPE/TiO2 samples. The measurement of FTIR showed that the content of hydroxyl and carboxyl increased with thermal aging, but the time of emerging aging characteristic peaks for the LDPE/TiO2 samples was delayed. The DSC measurement indicated that filling TiO2 nanoparticles changed the crystallization behavior of LDPE, played a role of heterogeneous nucleation during the process of recrystallization, and improved the crystallinity of LDPE/TiO2. Similarly, the aged LDPE/TiO2 samples had lower permittivity and dissipation factor compared to the aged Pure-LDPE samples. All the results had indicated the LDPE/TiO2 samples had the significant ability of antithermal aging, especially the LDPE/TiO2-0.5 samples with good dispersion of nanoparticles. A new model was proposed to illustrate the antithermal aging behaviors of LDPE/TiO2 samples, which shows that the TiO2 nanoparticles play a role of “crosslinking points” between LDPE molecular chains, increasing the density of crystal structure and reducing oxygen diffusion into materials to break molecular structure.

scholarly journals THERMAL AGING STUDY OF BIODEGRADABLE POLYMER MATERIALS BY DIELECTRIC THERMAL ANALYSIS

2018 ◽  
Vol 4 (7) ◽  
Author(s):  
Aleksandra Porjazoska Kujundziski ◽  
Dragica Chamovska
Keyword(s):  
Lactic Acid ◽  
Thermal Aging ◽  
Polymer Materials ◽  
Dielectric Losses ◽  
Phase Lag ◽  
Heating Rates ◽  
Vacuum Oven ◽  
Molecular Weights ◽  
Aging Study ◽  
Dielectric Thermal Analysis

Two different studies of the thermal aging of polyesters based on lactic and glycolic acidswere compared. Thermal degradation of poly(L-lactic acid) (PLLA), poly(L-lactic acid-co-glycolicacid) (PLLGA) and poly(DL-lactic acid-co-glycolic acid) (PDLGA) was studied by the dielectricthermal analysis (DETA). The aging was performed at 37C in vacuum oven. The dielectric featuresi.e., dielectric permittivity,, dielectric losses,, and phase lag, tg , were determined by PL-DETAcontaining a parallel plate capacitance cell, from the room temperature to 80, 150, and 180  C,at the heating rates of 2 and 3 Cmin-1. Dielectric scans were obtained at a frequency of 1 kHz anda.c. signal of 200 mV. Different behavior of PLLA, PLLGA, and PDLGA during degradation wasobserved. As the aging of PDLGA proceeds, dielectric losses shift to the lower temperatures,indicating existence of lower molecular weights.  - T, and tg  - T dependences of PLLGA, as wellas those for PLLA show two simultaneous processes occurring, crystallization and degradation.

Electron-diffraction studies in synthetic polymer materials

1983 ◽  
Vol 41 ◽  
pp. 362-365
Author(s):  
D.T. Grubb
Keyword(s):  
Electron Diffraction ◽  
Synthetic Polymer ◽  
Polymer Materials ◽  
Crystallographic Structure ◽  
High Dose ◽  
Electron Dose ◽  
Dose Rates ◽  
First Case ◽  
Diffraction Patterns ◽  
The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

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