Planar Large Core Polymer Optical 1x2 and 1x4 Splitters Connectable to Plastic Optical Fiber

We report about new approach to design and fabricate multimode 1 x 2 and 1 x 4 Y optical planar power splitter suitable for low-cost short distance optical network. The splitters were designed by beam propagation method using BeamPROP™ software. The dimensions of the splitters were optimized for connecting standard plastic optical fibre with 1 mm diameter. New Norland Optical Adhesives 1625 glues were used as optical waveguide layers and the design structures were completed by CNC engraving on poly(methyl methacrylate) substrate. The best parameters that were achieved with 1x2 splitter were insertion loss around 4.1dB at 650 nm and the coupling ratio 52:48; the best one of the 1x4 splitters had at 650 nm insertion loss around 17.6 dB

Surface and thermomechanical characterization of polyurethane networks based on poly(dimethylsiloxane) and hyperbranched polyester

Two series of polyurethane (PU) networks based on Boltorn® hyperbranched polyester (HBP) and hydroxyethoxy propyl terminated poly(dimethylsiloxane) (EO-PDMS) or hydroxy propyl terminated poly(dimethylsiloxane) (HPPDMS), were synthesized. The effect of the type of soft PDMS segment on the properties of PUs was investigated by Fourier transform infrared spectroscopy (FTIR), contact angle measurements, surface free energy determination, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). The surface characterization of PUs showed existence of slightly amphiphilic character and it revealed that PUs based on HP-PDMS have lower surface free energy, more hydrophobic surface and better waterproof performances than PUs based on EO-PDMS. PUs based on HPPDMS had higher crosslinking density than PUs based on EO-PDMS. DSC and DMTA results revealed that these newlysynthesized PUs exhibit the glass transition temperatures of the soft and hard segments. DMTA, SEM and AFM results confirmed existence of microphase separated morphology. The results obtained in this work indicate that PU networks based on HBP and PDMS have improved surface and thermomechanical properties

Surface modification of low-density polyethylene with poly(2-ethyl-2- oxazoline) using a low-pressure plasma treatment

Low-density polyethylene (LDPE) is a suitable polymer for biomedical applications due to its good physiochemical properties, but its insufficient biocompatibility is often an issue. Therefore, biocompatible substances such as those based on 2-ethyl-2-oxazoline seem to be a good choice to increase the LDPE biocompatibility. In this work, the surface modification of LDPE with poly(2-ethyl-2-oxazoline) with two different end-groups was investigated. This modification led to the improvement of surface and adhesion properties, which were investigated by several analytical methods. The low-temperature plasma treatment of the LDPE surface was sufficient to create binding sites for the permanent attachment of poly(2ethyl-2-oxazoline) chains. This was confirmed by infrared spectroscopy and X-Ray photoelectron spectroscopy. It was found that the polymer containing the acrylic end-group was well attached to the LDPE surface. 2013 Elsevier Ltd. All rights reserved.This work was supported by the Slovak Grant Agency VEGA for projects Nr. 2/0064/10 , Nr. 2/0151/12 , and Nr. 2/0185/10 ). The Center for Materials, Layers and Systems for Applications and Chemical Processes under Extreme Conditions was supported by the Research & Development Operational Program funded by the ERDF. Electron microscopy at IMC was performed with financial support through grant TACR TE01020118 .Scopu

The effects of the structure and molecular weight of the macrodiol on the properties polyurethane anionic adhesives

Polyurethane anionic adhesives were synthesized as waterborne polyurethane dispersions (PUDs) by modified dispersing procedure, using isophorone diisocyanate, dimethylol propionic acid, ethylenediamine as a chain extender and a range of soft segments with various macrodiols proportions. The soft segment was formed by replacing poly(propylene glycol) (PPG) as polyether polyol with polycarbonate diol (PCD), as polyester polyol. The effect of the macrodiols proportions of soft segment on the thermal properties of polyurethane films was measured by thermogravimetry analyses (TGA) and differential scanning calorimetry (DSC) methods. The infrared spectroscopy (FTIR) was used for evaluating the degree of phase separation. The results showed that phase separation between hard and soft segments of poly(ester-urethane) is more significant than of poly(ether-urethane). The phase separation degree of polyurethane dispersion significantly affected the glass transition temperature (T-g) and film properties. While the phase separation degree increased, T-g proportionally decreased, but the hardness and gloss of the dried films increased, as expected. However, thermal stability was influenced by the molecular weight of used polyols and chemical structure of the polyols, and it was described by the effect of oxygen content, and interaction between the soft and hard segment, and the soft segment composition. The soft segment can be achieved with a proper selection, in order to fine-tune the performance of waterborne polyurethane dispersion, considering certain practical application. (C) 2012 Elsevier Ltd. All rights reserved

Influence of hematite nanorods on the mechanical properties of epoxy resin

The mechanical properties of nanocomposites obtained by incorporation of fairly uniform hematite nanorods (α-Fe2O3 NRs) into epoxy resin were studied as a function of the content of the inorganic phase. A thorough microstructural characterization of the α-Fe2O3 NRs and the nanocomposites was performed using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The TEM measurements revealed rod-like morphology of the nanofiller with a uniform size distribution (8.5 nm×170 nm, diameter×length). High-magnification TEM and AFM measurements indicated agglomeration of α-Fe2O3 NRs embedded in the epoxy resin. Stress at break, strain at break, elastic modulus and tensile toughness of the nanocomposites were compared with the data obtained for pure epoxy resin. Significant influence of nanofiller on the mechanical properties of epoxy resin, as well as on the glass transition temperature, could be noticed for samples with low contents of the inorganic phase (up to 1 wt. %)

Author's personal copy Chromium(IV) ions containing novel silicate glasses

a b s t r a c t Luminescence of approximately 1.3 lm is required in photonics for lasers operating in the near infrared (NIR) region. Luminescent characteristics suitable for this application are exhibited by Cr(IV), but the achievement of chromium in the oxidation state IV in silicate glass appeared to be a rather difficult task. This paper presents our novel approach based on an ion implantation of oxygen ions into specially designed sodium-silicate glasses containing Cr(III) and provides a description of the possible processes involved

Steam cracking of hydrocarbons: 4 analysis of high-boiling products from naphtha in a quartz reactor

Part 3 of this series reported on the steam cracking of straight-run naphtha in a stainless steel and a quartz reactor. High-boiling polynuclear aromatic hydrocarbons were formed in a quartz reactor but were not found as products from a stainless-steel reactor. In this paper the analysis of the polynuclear aromatic hydrocarbons is discussed. The high-boiling fraction was separated by high performance liquid chromatography and by capillary gas chromatography. About 200 of the compounds present were separated by the latter method. Twenty profiling compounds, with boiling points up to 462 OC, were identified by the coelution technique and by combined gas chrmtography/mass spectrometry. The influence of the wall effects on the proceeding of secondary reactions in metal and quartz reactors is discussed