A Mechanistic Study of the Interaction of Ultraviolet Laser Radiation with Low Density Polymers

1986 ◽  
Vol 75 ◽  
Author(s):  
Philip J. Hargis
Keyword(s):  
Laser Radiation ◽  
Laser Fluence ◽  
Emission Spectra ◽  
Mechanistic Study ◽  
Etch Depth ◽  
Low Density ◽  
Foam Density ◽  
Absorption Mechanism ◽  
Linear Absorption ◽  
Ultraviolet Laser

AbstractUltraviolet laser radiation at 248 nm and 266 nm was used to ablate low density (0.04 to 0.14 g/cm3) microcellular polystyrene and TPX foams at laser fluences between 0.1 and 1000 J/cm2, The dependence of the etch rate on laser fluence and foam density is consistent with a linear absorption mechanism for the initial stages of polystyrene ablation. Studies of the morphology and chemical composition of the ablated foams as a function of laser fluence and foam density show that the degree of melting increases at the higher foam densities. Blackbody and radical specie contributions to optical emission from the ablated foam were readily resolved for correlation with laser fluence, foam density, absorption spectra, and etch depth. Temperatures in excess of 3000 °K are calculated from emission spectra observed during the ablation of polystyrene foams. From this data we conclude that chemical and thermal changes in the ablated foam are influenced by the absorption spectrum as well as the density of the foam.

scholarly journals Kinked Bisamides as Efficient Supramolecular Foam Cell Nucleating Agents for Low-Density Polystyrene Foams with Homogeneous Microcellular Morphology

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1094
Author(s):  
Bastian Klose ◽  
Daniel Kremer ◽  
Merve Aksit ◽  
Kasper P. van der Zwan ◽  
Klaus Kreger ◽  
...  
Keyword(s):  
Cell Size ◽  
Self Assembly ◽  
Large Scale ◽  
Elevated Temperatures ◽  
Foam Cell ◽  
Cell Structure ◽  
Expansion Ratio ◽  
Low Density ◽  
Nucleating Agents ◽  
Foam Density

Polystyrene foams have become more and more important owing to their lightweight potential and their insulation properties. Progress in this field is expected to be realized by foams featuring a microcellular morphology. However, large-scale processing of low-density foams with a closed-cell structure and volume expansion ratio of larger than 10, exhibiting a homogenous morphology with a mean cell size of approximately 10 µm, remains challenging. Here, we report on a series of 4,4′-diphenylmethane substituted bisamides, which we refer to as kinked bisamides, acting as efficient supramolecular foam cell nucleating agents for polystyrene. Self-assembly experiments from solution showed that these bisamides form supramolecular fibrillary or ribbon-like nanoobjects. These kinked bisamides can be dissolved at elevated temperatures in a large concentration range, forming dispersed nano-objects upon cooling. Batch foaming experiments using 1.0 wt.% of a selected kinked bisamide revealed that the mean cell size can be as low as 3.5 µm. To demonstrate the applicability of kinked bisamides in a high-throughput continuous foam process, we performed foam extrusion. Using 0.5 wt.% of a kinked bisamide yielded polymer foams with a foam density of 71 kg/m3 and a homogeneous microcellular morphology with cell sizes of ≈10 µm, which is two orders of magnitude lower compared to the neat polystyrene reference foam with a comparable foam density.

Effect of UV Treatment on Optical Properties of Low-Density Polyethylene Films Doped with Eu(TTA)3phen Complex

2014 ◽  
Vol 895 ◽  
pp. 155-161
Author(s):  
M.I. Khairuldin ◽  
N.M.A. Aziz ◽  
N.M. Nashaain ◽  
S. Wedianti ◽  
I. Farehah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Low Density Polyethylene ◽  
Rare Earth Complex ◽  
Low Density ◽  
Uv Treatment ◽  
Uv Spectrum ◽  
Light Manipulation ◽  
Emission Transition ◽  
Ft Ir

Low-Density Polyethylene (LDPE) films doped with Eu (TTA)3phen complex (TTA=2-thenoyltrifluoroacetone, phen=1,10-phenanthroline) were fabricated by hot-blowing technique for thickness of 100 μm. The films were doped with 0.1 % of Eu (TTA)3phen to the total weight of LDPE and exposed to UV irradiation from deuterium lamp for 5, 10, 20, 40 and 60 hours to investigate the effect of its optical properties. The films were characterized by Spectrofluorometer, UV/VIS Spectrophotometer and FT-IR Spectrometer to measure their emission spectra, lifetimes, transmission transparency and chemical bonding. Photoluminescence of the room-temperature Eu (TTA)3phen doped films consist of typical Eu3+emission transition lines with hypersensitive5D07F2emission band at 610 nm. After 20 hours UV treatment, the peak intensity dropped by 90 % and shortened the luminescent lifetimes from 0.654 ms to 0.305 ms. Longer UV treatment also has accelerated degradation in doped LDPE films shown by significant reducing in absorption peak of FTIR at 3395, 3186 and 1645 cm-1. The results would provide a mechanism to improve the lifetime of the LDPE by utilizing the light-manipulation property of Eu (TTA)3phen complex to absorb UV spectrum and covert into red emission.Keywords: LDPE, rare-earth complex, photoluminescence

Photoablation Studies of Polymers, Quartz, and Semiconductors with Vacuum Ultraviolet Laser Radiation

1991 ◽  
Vol 236 ◽  
Author(s):  
Peter R. Herman ◽  
Boyi Chen ◽  
David J. Moore ◽  
Mark Canaga-Retnam
Keyword(s):  
Laser Radiation ◽  
Polymethyl Methacrylate ◽  
Thermal Damage ◽  
Vacuum Ultraviolet ◽  
Medical Industry ◽  
Surface Melting ◽  
Excimer Lasers ◽  
Ultraviolet Laser ◽  
Low Threshold ◽  
Microelectronics Industry

AbstractExcimer lasers sources of 193nm and 157 nm wavelength were used to obtain new photoablation etching rates for several materials of interest to the microelectronics industry. The harder 157nm radiation provided lower ablation rates and smaller threshold fluences for Polyimide and Polymethyl Methacrylate (PMMA) than with 193nm. For normally robust materials like quartz and Teflon (PTFE), the 157nm laser produced clean and smooth ablation sites with low threshold fluences of 620mJ/cm2 and 68mJ/cm2, respectively, features impossible to obtain with conventional excimer lasers at longer wavelengths. The data should help define new micromachining applications of these two materials for the electronic, optical or medical industry. Results are also reported for GaAs and InP based materials which are found to undergo moderate etch rates of 30-80nm/pulse at fluences of ∼3J/cm2, but suffer thermal damage and material segregation due to surface melting.

Deep Ultraviolet Laser Radiation Causes Brittle Fracture of C α ‐C β Bonds in Neurotransmitters

2019 ◽  
Vol 4 (18) ◽  
pp. 5235-5239
Author(s):  
Guanhua Yang ◽  
Haiming Wu ◽  
Anthony M. S. Pembere ◽  
Zhixun Luo
Keyword(s):  
Laser Radiation ◽  
Brittle Fracture ◽  
Ultraviolet Laser ◽  
Deep Ultraviolet

Laser-radiation volume absorber and x-ray converter based on low-density beryllium

2001 ◽  
Author(s):  
N. G. Borisenko ◽  
Vladimir V. Gorlevsky ◽  
A. I. Gromov ◽  
Sergei Y. Gus'kov ◽  
Valeriy M. Dorogotovtsev ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Low Density ◽  
X Ray

Interaction of ultraviolet laser radiation with a XeCl laser

1985 ◽  
Vol 2 (6) ◽  
pp. 925 ◽  
Author(s):  
D. B. Geohegan ◽  
A. W. McCown ◽  
J. G. Eden
Keyword(s):  
Laser Radiation ◽  
Xecl Laser ◽  
Ultraviolet Laser

Optical emission of a plasma from low-density targets irradiated with coherence-controllable laser radiation

2017 ◽  
Vol 47 (2) ◽  
pp. 101-105 ◽  
Author(s):  
A A Fronya ◽  
N G Borisenko ◽  
V N Puzyrev ◽  
A T Sahakyan ◽  
A N Starodub ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Optical Emission ◽  
Low Density

Interaction of laser radiation with a low-density structured absorber

2016 ◽  
Vol 122 (2) ◽  
pp. 256-276 ◽  
Author(s):  
V. B. Rozanov ◽  
D. V. Barishpol’tsev ◽  
G. A. Vergunova ◽  
N. N. Demchenko ◽  
E. M. Ivanov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Low Density
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