scholarly journals Naphthoxy Bounded Ferrocenium Salts as Cationic Photoinitiators for Epoxy Photopolymerization

2009 ◽  
Vol 2009 ◽  
pp. 1-6
Author(s):  
Zh. Q. Li ◽  
M. Li ◽  
G. L. Li ◽  
Y. Chen ◽  
X. N. Wang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Infrared Spectroscopy ◽  
Cationic Polymerization ◽  
Uv Light ◽  
Good Thermal Stability ◽  
Long Wavelength ◽  
Dsc Studies ◽  
Arene Ligands ◽  
Epoxy Monomer ◽  
Rate Of Polymerization

To improve the absorption and the bulk of arene ligands, two naphthoxy bounded ferrocenium salts as new cationic photoinitiators, (η6-α-naphthoxybenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (NOFC-1) and (η6-β-naphthoxybenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (NOFC-2), were synthesized, characterized, and studied. NOFC-1 and NOFC-2 were prepared by the reaction of nucleophilic substitution (SNAr) with naphthol and chlorobenzene-cyclopentadienyliron salt. Their activity as cationic photoinitiators was studied using real-time infrared spectroscopy. The results obtained showed that NOFC-1 and NOFC-2 are capable of photoinitiating the cationic polymerization of epoxy monomer directly on irradiation with long-wavelength UV light (365 nm). Comparative studies also demonstrated that they exhibited better efficiency than cyclopentadienyl-Fe-cymene hexafluorophosphate (I-261). When NOFC-1 and NOFC-2 were used to efficiently initiate polymerization of epoxide, both rate of polymerization and final conversion increased using benzoyl peroxide (BPO) as sensitizer. DSC studies showed that NOFC-1 and NOFC-2 photoinitiators in epoxides possess good thermal stability in the absence of light.

Synthesis, Photochromism and Optical Recording Properties of a Diarylethene Materials Bearing an Isoxazole Unit

2012 ◽  
Vol 583 ◽  
pp. 125-129 ◽  
Author(s):  
Xiao Ting Li ◽  
Hui Li ◽  
Gang Liu
Keyword(s):  
Thermal Stability ◽  
Uv Light ◽  
Amorphous Film ◽  
Optical Storage ◽  
Optical Recording ◽  
Strong Fluorescence ◽  
Good Thermal Stability ◽  
Closed Ring ◽  
Open Ring ◽  
Hexane Solution

A new unsymmetrical photochromic diarylethene, 1-(3,5-dimethyl-4-isoxazolyl)-2-[2-methyl-5-(4-formylphenyl)-3- thienyl]perfluorocyclopentene(1a) were synthesized, and its properties, such as photochromism and fluorescence properties, were investigated in detail. The results showed that this compound had good thermal stability and exhibited reversible photochromism, changing from colorless to darkred after irradiation with UV light both in solution and in PMMA amorphous film, the maxima absorption of its closed-ring isomer 1b are 529 nm and 541 nm respectively. The open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 492 nm in hexane solution (2 × 10-5 mol/L) when excited at 418 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. This new photochromic system also exhibited remarkable optical storage character.

Research on Photochromic Compounds with Synthesis and Properties of a Novel Unsymmetrical Diarylethene with a Benzothiophene and a Pyrrole Group

2014 ◽  
Vol 1003 ◽  
pp. 23-26
Author(s):  
Hong Jing Jia ◽  
Ying Long Fu ◽  
Cong Bin Fan
Keyword(s):  
Thermal Stability ◽  
Potential Application ◽  
Uv Light ◽  
Optical Storage ◽  
Pmma Film ◽  
Good Thermal Stability ◽  
Photochromic Compounds ◽  
Storage Technology ◽  
Hexane Solution

A new unsymmetrical photochromic diarylethene1o, which is named [1-(2-methyl-benzothiophene)-2-(2-cyano-1,5-dimethyl-4-pyrryl)]perfluorocyclopentene, was synthesized. We used it to accomplish recording by optical storage technology as memory medium. Then its photochromic both in hexane solution and in PMMA film and kinetics experiment were investigated in detail. The result indicated that this diarylethene had good thermal stability and exhibited reversible photochromism, changing the color from colorless to violet in hexane solution upon appropriate irradiation with 297 nm UV light, respectively. What is more, the kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. The results demonstrated that the unsymmetrical diarylethene compound1o, which we have synthesized, had attractive properties for potential application in optical storage.

Synthesis and Properties of a Novel Unsymmetrical Diarylethene with a Benzothiophene and a Thiazole Group

2013 ◽  
Vol 788 ◽  
pp. 190-193
Author(s):  
Hong Jing Jia ◽  
Shou Zhi Pu ◽  
Cong Bin Fan
Keyword(s):  
Thermal Stability ◽  
Fluorescence Intensity ◽  
Potential Application ◽  
Uv Light ◽  
Optical Storage ◽  
Fluorescence Properties ◽  
Good Thermal Stability ◽  
Closed Ring ◽  
Open Ring ◽  
Hexane Solution

A new unsymmetrical photochromic diarylethene1o, which is named 1-(2-methyl-benzothiophene)-2-(2,4-dimethyl-5-thiazoly) perfluorocyclopentene, was synthesized. In the meantime, its photochromic, kinetics and fluorescence properties were investigated in detail. The result indicated that this diarylethene had good thermal stability and exhibited reversible photochromism, changing the color from colorless to orange in hexane solution upon appropriate irradiation with 297 nm UV light, respectively. What is more, the kinetic experiments illustrated that the cyclization/cycloreversion process of this compound was determined to be the zeroth/first reaction. The fluorescence intensity of diarylethene decreased dramatically along with the photochromism from open-ring isomer to closed-ring isomer upon irradiation with UV light in hexane solution. In addition, the results demonstrated that the unsymmetrical diarylethene compound1o, which we have synthesized, had attractive properties for potential application in optical storage.

Optimization of Organic Fibres%[Kevlar/Arobocel/Acrylic] in NAO Brake Pad Application and its Effect on Thermal Stability & Friction Characteristics

2012 ◽  
Vol 531-532 ◽  
pp. 8-12
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Minimum Weight ◽  
Friction Material ◽  
Brake Pad ◽  
Temperature Zone ◽  
Good Thermal Stability ◽  
Friction Testing ◽  
Brake Application ◽  
The Stability

Organic fibres (Kevlar/ Arbocel / Acrylic) have good thermal stability, higher surface area and bulk density. The optimization of organic fibres percentage for thermal behaviour is considered using TGA. The temperature raise during brake application will be between 150-4000 C and this temperature zone is very critical to determine the fade characteristics during friction testing. Hence, three different friction composites are developed with the same formulation varying only the Kevlar, Arbocel and Acrylic fibres which are compensated by the inert filler namely the barites and are designated as NA01, NA02 and NA03 respectively. After the fabrication, the TGA test reveals that the composite NA03 has minimum weight loss. The friction coefficient test rig is then used to test the friction material as per SAE J661a standards. The results prove that the brake pad with minimum weight loss during TGA has higher friction stability. Thus, we can correlate the thermal stability with the stability of friction.

Preparing and Applying of Flame Retardant Microcapsules Containing Magnesium Hydroxide

2013 ◽  
Vol 734-737 ◽  
pp. 2191-2194
Author(s):  
Li Li Wu ◽  
Yuan Lian ◽  
Dan Liu ◽  
Hua Zheng ◽  
Dian Wu Huang
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
Magnesium Hydroxide ◽  
Low Density Polyethylene ◽  
Core Shell ◽  
Low Density ◽  
Melamine Resin ◽  
Shell Material ◽  
Elongation At Break ◽  
Good Thermal Stability

In this study, flame retardant microcapsules were synthesized using magnesium hydroxide as core materials, melamine resin as the shell material. The structure, diameters and thermal properties of prepared microcapsules were investigated by using FTIR, ELS, DSC and TGA. The effects of core/shell ratio on the properties of microcapsules were studied.Flame retardant materials of low-density polyethylene/magnesium hydroxide microcapsules were prepared.The tensile strength and elongation at break tests were performed to determine its mechanical property.Inflammability of the materials was also studied.The results showed the prepared magnesium hydroxide microcapsule shows good thermal stability and it has free compatibility with the polymer.The composites of HDPE/MH microcapsules have good performance．

Effect of Heat Treatment on Mechanical Properties of ECAPed 7075 Aluminum Alloy

2013 ◽  
Vol 829 ◽  
pp. 62-66 ◽  
Author(s):  
Alireza Fallahi ◽  
Hossein Hosseini-Toudeshky ◽  
Seyed Mahmoud Ghalehbandi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Solution Treatment ◽  
7075 Aluminum Alloy ◽  
Ecap Processing ◽  
Good Thermal Stability ◽  
7075 Alloy

It is the objective of this study to investigate the effect of ECAP processing and heat treatment on the mechanical properties of the UFG 7075 alloy. Also the effect of post ECAP heat treatment is investigated. The alloy is processed by ECAP after annealing as well as solution treatment to produce an UFG structure. Furthermore mechanical properties and their variations during annealing and aging are investigated. The hardness of the pre-ECAP annealed and the pre-ECAP solutionised 7075 aluminum alloy has increased significantly compared with that of the CG sample. Also hardness of ECAPed specimen has not experienced significant changes in post-ECAP heat treatment and indicated that the alloy had approximately good thermal stability.

Mechanical and microstructural properties of polystyrene based composites: positron lifetime spectroscopic and DSC studies

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Abdullah Mohammed Ali Mohammed Altaweel ◽  
Jaya Madhu Raj ◽  
Malalvalli Nagarajaiah Chandrashekara ◽  
Puttegowda Ramya ◽  
Parthasarathy Sampathkumaran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Free Volume ◽  
Positron Lifetime ◽  
Tensile Modulus ◽  
Silica Content ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Microstructural Property ◽  
Calcium Aluminosilicate

Abstract Polystyrene (PS) based composites respectively with cenosphere (CS) and calcium aluminosilicate (CAS) as fillers were studied using the positron lifetime technique to reveal the correlation between free volume, a microstructural property, and mechanical properties of the composites (tensile strength and tensile modulus). The thermal stability of the composites was determined using differential scanning calorimetry. The results showed that addition of CAS filler lead to a significant improvement in the mechanical properties of the composite, whereas addition of CS resulted in improvement in tensile modulus only. Both PS/CAS and PS/CS composites showed enhancement in thermal stability compared with that of the pure PS matrix. The positron results showed that the average free volume size for the PS/CAS composite (at 40 phr CAS) was reduced significantly compared with that of the pure PS. These results are understood in terms of the influence of silica content, filler-matrix interaction, and particle size.

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