High-Temperature Adhesives Based on Alder-ene Reaction of Diallyl Bisphenol a Novolac and Bismaleimide: Effect of BMI Structure and Novolac Molar Mass

2003 ◽  
Vol 11 (4) ◽  
pp. 311-320 ◽  
Author(s):  
C. Gouri ◽  
C.P. Reghunadhan Nair ◽  
R. Ramaswamy
Keyword(s):  
Bisphenol A ◽  
High Temperatures ◽  
Molar Mass ◽  
Adhesion Properties ◽  
Ene Reaction ◽  
Network Polymers ◽  
Lap Shear ◽  
Higher Temperature ◽  
Stable Network ◽  
Good Retention

Diallyl bisphenol A formaldehyde novolac (ABPF) resin was cured with four structurally different bismaleimides (BMIs) at high temperatures through an Alder-ene reaction which resulted in thermally stable network polymers. The adhesive characteristics of the different BMI-ABPF systems were evaluated in terms of the lap shear strength (LSS) on aluminium substrates at varying temperatures up to 250°C. The LSS properties were not significantly affected by the structure of the BMI. Although the LSS of BMI-ABPF systems per se were not particularly high due to the brittle nature of the cross-linked structures, all the systems exhibited remarkably good retention of LSS at high temperatures. Replacing ABPF with its monomeric analogue i.e. o,o′- diallyl bisphenol A (DABA) resulted in better adhesion, but in a poorer thermo-adhesive profile. Comparison of DMA and thermo-adhesive profiles implied that in the majority of the cases molecular relaxations at higher temperature are conducive to matrix toughening which results in enhanced adhesion properties.

Organic solvent-free synthesis of phosphorus-containing polymers

2007 ◽  
Vol 79 (11) ◽  
pp. 1879-1884 ◽  
Author(s):  
Smaranda Iliescu ◽  
Gheorghe Ilia ◽  
Aurelia Pascariu ◽  
Adriana Popa ◽  
Nicoleta Plesu
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Bisphenol A ◽  
Organic Solvent ◽  
Molar Mass ◽  
Interfacial Polycondensation ◽  
H Nmr ◽  
Phosphorus Containing ◽  
Solvent Free Synthesis ◽  
Thermal Stability Of

Direct, efficient, organic solvent- and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas-liquid interfacial polycondensation between arylphosphoric dichlorides and bisphenol A. The polyphosphates were characterized by IR, 1H NMR, 31P NMR, inherent viscosity, thermal analysis, and molar mass. Yields in the range 70-90 % and inherent viscosities in the range 0.30-0.40 dl/g were obtained. The thermal stability of the polyphosphates was investigated by using thermogravimetry.

scholarly journals Hard Quasicrystalline Coatings Deposited by HVOF Thermal Spray to Reduce Ice Accretion in Aero-Structures Components

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 290
Author(s):  
J. Mora ◽  
P. García ◽  
R. Muelas ◽  
A. Agüero
Keyword(s):  
Thermal Spray ◽  
Surface Engineering ◽  
High Hardness ◽  
Ceramic Materials ◽  
Ice Accretion ◽  
Adhesion Properties ◽  
Wetting Properties ◽  
Lap Shear ◽  
Hvof Thermal Spray ◽  
Ice Adhesion

Weather hazards, in particular icing conditions, are an important contributing factor in aviation accidents and incidents worldwide. Many different anti-icing strategies are currently being explored to find suitable long-lasting solutions, such as surface engineering, which can contribute to reduce ice accumulation. Quasicrystals (QCs) are metallic materials, but with similar properties to those of ceramic materials, such as low thermal and electrical conductivities, and high hardness. In particular, QCs that have low surface energy are commercially used as coatings to replace polytetrafluoroethylene (PTFE), also known as Teflon, on frying pans, as they do not scratch easily. PTFE exhibits excellent anti-wetting and anti-icing properties and therefore QCs appear as good candidates to be employed as ice-phobic coatings. Al-based QCs have been applied by High Velocity Oxyfuel (HVOF) thermal spray on typically used aeronautic materials, such as Ti and Al alloys, as well as steels. The coatings have been characterized and evaluated, including the measurement of hardness, roughness, wetting properties, ice accretion behavior in an icing wind tunnel (IWT), and ice adhesion by a double lap shear test. The coatings were studied, both as-deposited, as well as after grinding, in order to study the effect of the surface roughness and morphology on the ice accretion and adhesion properties. The QC coating was compared with PTFE and two polyurethane (PU)-based commercial paints, one of them known to have anti-icing properties, and the results indicate an ice accretion reduction relative to these two materials, and ice adhesion lower than bare AA6061-T6, or the PU paint in the ground version of one of the two QCs. Since the QC coatings are hard (GPa Vickers hardness > 5), a durable behavior is expected.

scholarly journals Temporal Patterns of Flowering and Pod Set of Determinate Soybean in Response to High Temperature

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 414 ◽  
Author(s):  
Yean-Uk Kim ◽  
Doug-Hwan Choi ◽  
Ho-Young Ban ◽  
Beom-Seok Seo ◽  
Junhwan Kim ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Temporal Distribution ◽  
Temporal Patterns ◽  
Bimodal Distribution ◽  
Flowering Duration ◽  
Sowing Dates ◽  
Glycine Max L ◽  
Higher Temperature ◽  
Pod Number

Global warming is expected to affect yield-determining factors of soybean (Glycine max (L.) Merr.), including the number of flowers and pods. However, little is known about the effects of high temperature on the temporal patterns of flowering and pod set. Experiments in the temperature-controlled greenhouses were conducted to examine the temporal pattern of flowering in determinate soybean cultivar “Sinpaldalkong” and to assess the effects of high temperature on the flower number, pod-set ratio, and pod number of the early- and late-opened-flowers and their contributions to overall pod number. The experiment comprised five sowing dates in 2013–2015 and four temperature treatments, namely ambient temperature (AT), AT + 1.5 °C, AT + 3.0 °C, and AT + 5.0 °C. Flowering duration (i.e., days between the first flowering and the last flowering) was extended by higher temperature and earlier sowing. The temporal distribution of flowering showed a bimodal distribution except for the experiment with the shortest flowering duration, i.e., second sowing in 2014. More flowers were produced in the late flowering period at high temperatures; however, most of these late-opened-flowers failed to reproduce, regardless of temperature conditions, resulting in a negligible contribution to the overall pod number. For the early-opened-flowers, the number of flowers was not significantly affected by temperature, while the pod-set ratio and pod number decreased with high temperatures resulting in a decrease in the overall pod number at temperatures above 29.4 °C.

Preparation of Butadiene

1928 ◽  
Vol 1 (2) ◽  
pp. 208-210
Author(s):  
Stanley Francis Birch
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Liquid Phase ◽  
High Temperatures ◽  
Vapor Phase ◽  
Complex Mixture ◽  
Higher Temperature ◽  
Oil Gas

Abstract OF THE numerous methods available for the preparation of butadiene in the laboratory, those described by Thiele and by Ostromuislenskii are probably the most convenient. Both, however, suffer from the disadvantages which usually characterize operations at comparatively high temperatures; the exact conditions are difficult to find, the process is long and tedious, and finally involves the separation of the required material from a complex mixture. It has long been known that butadiene occurs in the various products obtained when oils are heated to a high temperature. Caventou first isolated butadiene in the form of its tetrabromide from illuminating gas, and Armstrong and Miller definitely established the presence of butadiene in the liquid obtained by compressing oil gas. The work of numerous later investigators has confirmed their results and has shown that the more drastic the heat treatment to which the oil is submitted the greater is the tendency for butadiene to be formed. For this reason vapor-phase cracking of petroleum, which is carried out at a much higher temperature than liquid-phase cracking, yields products specially rich in butadiene.

scholarly journals Synthesis and Characterization of Polyesteramide Hot Melt Adhesive from Low Purity Dimer Acid, Ethylenediamine, and Ethanolamine

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Pravin G. Kadam ◽  
Parth Vaidya ◽  
Shashank T. Mhaske
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Acid Value ◽  
Peel Strength ◽  
Partial Replacement ◽  
Adhesion Properties ◽  
Dimer Acid ◽  
Lap Shear ◽  
Hot Melt

Polyesteramide hot melt adhesive (HMA) was synthesized using low purity dimer acid (composition: 3% linoleic acid, 75% dimer acid, and 22% trimer acid), ethanolamine, and ethylenediamine. Ethanolamine was added as a partial replacement (10, 20, and 30%) of ethylenediamine. Prepared HMAs were characterized for acid value, amine value, hydroxyl value, Fourier transform infrared spectroscopy, mechanical (tensile strength, percentage strain at brea, and shore D hardness), thermal (glass transition temperature, melting temperature, enthalpy of melting, crystallization temperature, and enthalpy of crystallization), rheological (viscosity versus shear rate and viscosity versus time), and adhesion properties (T-peel strength and lap shear strength). Replacement of ethylenediamine by ethanolamine replaced certain amide linkages by ester linkages, decreasing the intermolecular hydrogen bonding, leading to decrease in the crystallinity of the material, and thus the mechanical, thermal, adhesion, and rheological properties. However, HMAs prepared using ethanolamine will have better low temperature flexibility due to low glass transition temperature and better adhesion process due to the lower viscosity.

scholarly journals THE DYNAMIC NATURE OF THERMOPHILY

1950 ◽  
Vol 33 (3) ◽  
pp. 205-214 ◽  
Author(s):  
Mary Belle Allen
Keyword(s):  
Temperature Coefficient ◽  
High Temperatures ◽  
Thermophilic Bacteria ◽  
Close Relation ◽  
Enzyme Synthesis ◽  
Dynamic Nature ◽  
Mesophilic Bacteria ◽  
Enzyme Systems ◽  
Higher Temperature ◽  
Synthetic Capacity

1. Evidence for a close relation between thermophilic and mesophilic bacteria is discussed. 2. It is shown that in the absence of nutrients thermophilic bacteria at 55°C. die as rapidly as mesophilic bacteria, and that enzyme systems of the thermophils are rapidly inactivated at this temperature. 3. It is concluded that the thermophils can live at high temperatures because they can synthesize enzymes and other cellular constituents faster than these are destroyed by heat. 4. In order to account for this great synthetic capacity at high temperatures, and for the high minimum temperatures observed for many thermophils, it is postulated that these organisms have a higher temperature coefficient of enzyme synthesis than mesophils.

scholarly journals On a new register-pyrometer, for measuring the expansions of solids, and determining the higher degrees of temperature upon the common thermometric scale

1833 ◽  
Vol 2 ◽  
pp. 404-406
Keyword(s):  
Melting Point ◽  
High Temperatures ◽  
The Other ◽  
Royal Institution ◽  
Guyton De Morveau ◽  
Higher Temperature ◽  
The Subject ◽  
The Common ◽  
The One ◽  
Universal Application

In the year 1821, the author published in the Journal of the Royal Institution an account of a new pyrometer, and of some determinations of high temperatures, in connexion with the scale of the mercurial thermometer, obtained by its means. The use of the instrument then described was, however, limited; and the author was subsequently led to the invention of a pyrometer of a more universal application, both to scientific researches and to various purposes of art. Fie introduces the subject by an account of the late attempt of M. Guyton de Morveau, to employ the expansions of platina for the admeasurement of high temperatures, and for connecting the indications of Wedgwood’s pyrometer with the mercurial scale, and verifying its regularity. The experiments of that philosopher were by the contraction of porcelain, and by actual comparison with those of the platina pyrometer, at no higher temperature than the melting point of antimony; but they are sufficient to establish the existence of a great error in Wedgwood’s original estimation of his degrees up to that point. This he carries on by calculation, on the hypothesis of uniform progression of expansion, up to the melting point of iron; the construction of his instrument not admitting of its application to higher temperatures than a red heat, in which platina becomes soft and ductile. Mr. Daniell shows, by an examination of M. Guyton’s results, that he has failed in establishing the point he laboured to prove; namely, the regularity of the contraction of the clay pieces. The pyrometer of the author consists of two distinct parts; the one designated the register , the other the scale .

Welding Consumables for 2.25Cr-1Mo-V Refining Reactors

2017 ◽  
Author(s):  
Hideaki Takauchi ◽  
Tomoaki Nakanishi ◽  
Hidenori Nako
Keyword(s):  
High Temperatures ◽  
Temper Embrittlement ◽  
Pressure Vessels ◽  
Creep Rupture ◽  
Hydrogen Attack ◽  
Fine Carbide ◽  
Higher Temperature ◽  
Welding Consumables ◽  
Segregation Of Impurities ◽  
Welding Materials

Owing to the demands for larger-capacity reactor vessels in petroleum plants and higher temperature processes for the upgrade of heavy oil, enhanced 2.25Cr-1Mo, 2.25Cr-1Mo-V and 3Cr-1Mo-V steels, which suit both high temperatures and pressure operations, have been developed and used for heavy-wall pressure vessels since the 1990s. 2.25Cr-1Mo-V steel, which has very special mechanical properties, resistant to both hydrogen attack and embrittlement under high temperatures and pressure environments in particular, has been used since 2000. The specifications for 2.25Cr-1Mo-V steel pressure vessels, such as ASME Sec. VIII and API RP 934-A, have been established and reviewed to enhance the contents [1–2]. In this report, the transition of materials, the welding techniques for hydrocracking reactors and 2.25Cr-1Mo-V welding materials are introduced. Particularly, for these welding materials, in order to improve the creep rupture and temper embrittlement properties, the effectiveness of precipitates is discussed. It was found that fine carbide (MC) in crystal grains improves creep rupture lifetime and MC at the prior austenite (γ) grain boundaries inhibits temper embrittlement caused by the segregation of impurities.

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