MATERIALS BASED ON PHENOLFORMALDEHYDE OLIGOMERS OF RESOL AND NOVOLAC TIPES (review). Part 2

2021 ◽  
pp. 55-65
Author(s):  
O.B. Zastrogina ◽  
◽  
S.D. Sinyakov ◽  
E.А. Serkova ◽  
◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Physicochemical Properties ◽  
Heat Resistance ◽  
Moisture Absorption ◽  
Phenol Formaldehyde ◽  
Friction Materials ◽  
Technological Characteristics

Describes compositions based on a mixture of phenol-formaldehyde oligomers of the resole and novolac types, used to create foams, laminated plastics for electrical purposes, friction materials, press compositions, sealing putties, as well as for vulcanization of rubbers. Detailed information on the composition and physicochemical properties of the compositions and their technological characteristics are given. The main advantages of resole-novolac materials are shown: strength, heat resistance, reduced flammability, low moisture absorption, good dielectric properties.

Synthesis and characterization of divinylbenzene-based cyanate resin and its quartz fiber-reinforced composite

2020 ◽  
Vol 32 (10) ◽  
pp. 1131-1139
Author(s):  
Yunzhao Wei ◽  
Dongliang Shen ◽  
Jianwei Wu ◽  
Yuyu Zhao ◽  
Guan Wang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Bisphenol A ◽  
Heat Resistance ◽  
Moisture Absorption ◽  
Polymeric Materials ◽  
Quartz Fiber ◽  
Fiber Reinforced ◽  
Process Technology ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

Cyanate ester (CE) resins are important polymeric materials with excellent dielectric properties, low moisture absorption, and good heat resistance, which have shown great superiority for use in electronic and aerospace industries. In this article, a novel CE resin was designed and synthesized from divinylbenzene. The proposed structures were characterized with Fourier transform infrared spectroscopy, gel permeation chromatography, and mass spectrometry. The chemical reaction activity, heat resistance, dielectric properties, and water adsorption of the synthesized CE derived from divinylbenzene (DVBCy) were examined and compared with the traditional bisphenol A and bisphenol M (4,4′-[1,3-phenylenebis(1-methyl-ethylidene)]bisphenol)-based CE. The DVBCy resin exhibits a glass transition temperature ( T g) of 162.7°C, a dielectric constant of 2.61, a dielectric loss tangent angle of 0.0035 at about 10 GHz, and a lower water absorption of 0.77%. Compared with the bisphenol M type CE, DVBCy resin provides slightly superior dielectric properties, higher mechanical properties, more favorable process technology for prepreg construction, and lower costing. The DVBCy blend resin modified with bisphenol A-based CE and core–shell particles possesses suitable rheological properties, and the corresponding quartz fiber-reinforced composite exhibits excellent mechanical as well as dielectric properties.

scholarly journals The Effect of Edible Coatings on Selected Physicochemical Properties of Cassava Chips

2021 ◽  
Vol 11 (7) ◽  
pp. 3265
Author(s):  
Diofanor Acevedo-Correa ◽  
José Jaimes-Morales ◽  
Piedad M. Montero-Castillo
Keyword(s):  
Physicochemical Properties ◽  
Whey Protein ◽  
Oil Content ◽  
Moisture Absorption ◽  
Moisture Loss ◽  
Edible Coatings ◽  
Protein Films ◽  
Anova Analysis ◽  
Coating Type ◽  
Sensory Parameters

The objective of this research was to study the effect of edible coatings on the physicochemical properties of cassava chips. The oil and moisture absorption in fried cassava chips that were not coated and in chips that were coated with pectin and whey protein films were determined using a completely randomized experiment design with a 33 factorial arrangement. The multifactorial ANOVA analysis of variance showed that all factors had significant statistical differences for moisture loss and oil absorption (p < 0.05). The coating type, the control, and the whey protein-coated chips presented a 321% greater oil content on average at 180 °C and 180 s than the pectin-coated chips. The density, heat capacity, and thermal diffusivity had statistical differences at all temperatures (p < 0.05). The sensory analysis showed that the coating type affected all sensory parameters, except crispness, as indicated by significant statistical differences (p < 0.05). The temperature only influenced the color of the control chips, with statistical differences (p < 0.05) at all temperatures.

Fertilization state ofAscaris suumdetermined by electrorotation

2006 ◽  
Vol 80 (1) ◽  
pp. 25-31 ◽  
Author(s):  
C. Dalton ◽  
A.D. Goater ◽  
H.V. Smith
Keyword(s):  
Dielectric Properties ◽  
Physicochemical Properties ◽  
Parasitic Nematode ◽  
Invasive Technique ◽  
Non Invasive ◽  
Egg Morphology ◽  
Parasite Biology ◽  
Response Modelling ◽  
Non Destructive ◽  
Insight Into

AbstractElectrorotation is a non-invasive technique that is capable of detecting changes in the morphology and physicochemical properties of microorganisms. The first detailed electrorotation study of the egg (ovum) of a parasitic nematode, namelyAscaris suumis described to show that electrorotation can rapidly differentiate between fertilized and non-fertilized eggs. Support for this conclusion is by optical microscopy of egg morphology, and also from modelling of the electrorotational response. Modelling was used to determine differences in the dielectric properties of the unfertilized and fertilized eggs, and also to investigate specific differences in the spectra of fertilized eggs only, potentially reflecting embryogenesis. The potential of electrorotation as an investigative tool is shown, as undamaged eggs can be subjected to further non-destructive and destructive techniques, which could provide further insight into parasite biology and epidemiology.

scholarly journals Microstructure and Properties of SCE-Al2O3/PES-MBAE Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yufei Chen ◽  
Qiwang Dai ◽  
Xiwang Zhang ◽  
Tao Feng
Keyword(s):  
Dielectric Properties ◽  
Bisphenol A ◽  
Heat Resistance ◽  
Bending Strength ◽  
Sol Gel ◽  
Harmful Effect ◽  
Decomposition Temperature ◽  
Two Phase ◽  
Allyl Compound

SCE-Al2O3was the nano-Al2O3modified by supercritical ethanol and the surface of SCE-Al2O3was coated with active group. 4,4′-diaminodiphenylmethane bismaleimide (MBMI) was used as matrix; 3,3′-diallyl bisphenol A (BBA) and bisphenol-A diallyl ether (BBE) were used as reactive diluent, polyethersulfone (PES) as toughening agent, and SCE-Al2O3as modifier; SCE-Al2O3/PES-MBAE nanocomposite was prepared through in situ sol-gel method. The mechanism of composite toughened by PES was observed and analyzed. FTIR indicated that the reaction between MBMI and allyl compound occurred and SCE-Al2O3had doped into the polymer matrix. SEM showed that PES particle was inlaid in matrix and presented as a two-phase structure in matrix. The heat resistance, dielectric properties, and mechanical properties of SCE-Al2O3/PES-MBAE nanocomposites were evaluated. The results showed that with the incorporation of PES, although the toughness of the material improved, the heat resistance and dielectric properties of material declined, meanwhile. The adulteration of SCE-Al2O3could remedy the harmful effect caused by PES, while the content of SCE-Al2O3was reasonable. The decomposition temperature, dielectric constant, and dielectric loss of composite were 441.23°C, 3.63 (100 Hz), and 1.52 × 10−3(100 Hz); the bending strength and impact strength were 129.22 MPa and 13.19 kJ/mm2, respectively, when the content of SCE-Al2O3was 3 wt% and PES was 5 wt%.

scholarly journals Torrefaction of Almond and Walnut Byproducts

2021 ◽  
Vol 9 ◽  
Author(s):  
Zach McCaffrey ◽  
Lennard Torres ◽  
Bor-Sen Chiou ◽  
Saulo Rocha Ferreira ◽  
Luiz Eduardo Silva ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Moisture Absorption ◽  
Calorific Value ◽  
Dynamic Vapor Sorption ◽  
Energy Applications ◽  
Thermochemical Process ◽  
Heat Treated ◽  
The Us ◽  
Torrefied Biomass ◽  
Different Temperatures

While the US nut industry is growing, markets for nut by-products, particularly nutshells and tree prunings, have not kept pace. Torrefaction is a thermochemical process used to improve physicochemical properties of biomass for energy and other applications. The goal of the paper was to characterize the effects of a range of torrefaction conditions on the properties of nut by-product feedstock. The process consists of thermal treatment of biomass at a temperature between 200 and 300°C in the absence of oxygen, where final material properties of the torrefied biomass depend on the temperature, heating rate, and residence time. In general, torrefied biomass exhibits higher hydrophobicity and calorific value with reduced moisture absorption compared to untreated biomass, making it an ideal fuel source for energy applications compared to raw biomass. In this study, almond shells of soft, semi-soft, and hardshell varieties, as well as walnut shells and almond wood, were torrefied at two different temperatures (230 and 290°C) and three different residence times (20, 40, and 60 min) in order to characterize the physicochemical properties. The thermal behavior of raw and heat-treated biomass was investigated by TGA analysis, elemental analysis, pH, helium pycnometry, FTIR spectroscopy, and dynamic vapor sorption analysis.

scholarly journals Study on Properties of Heat-Resistant Hybrid Resin Containing Silicon and Composites

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Lixin Xuan ◽  
Quan Zhou ◽  
Zhiqiang Wang ◽  
Tao Su
Keyword(s):  
Dielectric Properties ◽  
Flexural Strength ◽  
Heat Resistance ◽  
High Performance ◽  
Dissipation Factor ◽  
Cure Reaction ◽  
Hybrid Resin ◽  
Performance Matrix ◽  
Hot Press Process ◽  
Strength Retention

In recent years, one kind of novel hybrid polymer containing silicon has already been reported in the field of high-temperature resistance polymer. Gradually, it has been a research hotspot in the field of high-performance matrix resins because of excellent heat resistance and dielectric properties. The composite was prepared by M-aminophenylacetylene terminated polymethyldiphenylethynyl silane (MDPES-2) as a matrix and nonalkali glass cloth as reinforced material using a hot press process. The cure reaction of MDPES-2 was characterized. Meanwhile, heat resistance, mechanical properties, and dielectric properties of MDPES-2 composites were systematically studied in this paper. The results showed that flexural strength at room temperature is 321 MPa and flexural strength retention at 240°C was 98.3%. Flexural strength retention after thermal treatment at 500°C for 7 min was 84%. In addition, ε and dielectric dissipation factor ( tan δ ) were 3.9 and 2.0 × 10 − 3 (10 GHz).

scholarly journals Accreditation of Novel Roselle Grafted Fiber Reinforced Bio-Composites

2012 ◽  
Vol 7 (2) ◽  
pp. 155892501200700 ◽  
Author(s):  
Ashish Chauhan ◽  
Balbir Kaith
Keyword(s):  
Moisture Absorption ◽  
Elasticity Modulus ◽  
Phenol Formaldehyde ◽  
Crystallinity Index ◽  
Modulus Of Rupture ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Morphological Transformation ◽  
Physico Chemical ◽  
Uptake Studies

The reaction parameters for the graft co-polymerization of efficient Butyl acrylate (BA) monomer onto Hibiscus sabdariffa (Roselle) stem fiber were optimized and used to further explore the additive effect of methyl acrylate (MA), vinyl acetate (VA) and styrene (Sty) on percentage grafting, properties and the behavior of the fiber, in binary vinyl monomeric mixtures. The graft co-polymers were characterized by XRD, TGA, DTA, SEM and FTIR techniques and evaluated for physico-chemical changes like moisture absorption, swelling behavior, dye uptake studies and chemical resistance against 1N NaOH and 1N HCl. With increase in percentage grafting the percentage crystallinity, crystallinity index, and hydrophylicity were reduced whereas there was an increase in physico-chemico-thermal resistance, hydrophobicity, miscibility with organic solvents as a result of morphological transformation in these fibers. These modified graft copolymers were then used as reinforcement in phenol-formaldehyde polymer matrix as reinforcement and evaluated mechanically for modulus of elasticity, modulus of rupture, stress at the limit of proportionality and hardness. The composites reinforced with grafted fiber had better strength than raw fiber reinforced composites and phenoplast.

The Thermal Stability of Fluorine Doped Silicon Oxide Films Formed by Ecrcvd With SiF4 and O2 Gases

1996 ◽  
Vol 443 ◽  
Author(s):  
Seoghyeong Lee ◽  
Jae-Yoon Yoo ◽  
Jong-Wan Park
Keyword(s):  
Thermal Stability ◽  
Dielectric Properties ◽  
Plasma Treatment ◽  
Exposure Time ◽  
Moisture Absorption ◽  
Silicon Oxide ◽  
Reliability Test ◽  
Air Exposure ◽  
Doped Silicon ◽  
Thermal Stability Of

AbstractThe reliability of SiOF films for intermetal dielectrics in multilevel interconnections of ULSIs is investigated. SiOF films were deposited by ECRCVD using H-free source gases, i.e., SiF4 and O2. The effect of post plasma treatment on the moisture absorption and dielectric properties of SiOF films were carried out in terms of air exposure time. The reliability test of Cu / TiN / SiOF / Si specimen was carried out in terms of temperatures by RTA in N2 ambient. After O2 plasma treatment, no appreciable peak directly related to moisture absorption was detected. The C-V characteristics of the O2 plasma treated SiOF film showed that the film remained to hold the sound dielectric properties even after boiling treatment. The Cu / TiN / SiOF / Si system was found to be reliable up to 600 °C.

The Effect of Fillers on Chrome-Based Wave-Transparent Material Matrix

2012 ◽  
Vol 557-559 ◽  
pp. 357-361 ◽  
Author(s):  
Zheng Hai Liu ◽  
Ji Chuan Huo ◽  
Hai Bin Wang ◽  
Hong Lei ◽  
Yong Lin Lei
Keyword(s):  
Mechanical Properties ◽  
Dielectric Properties ◽  
Absorption Rate ◽  
Moisture Absorption ◽  
Aluminum Phosphate ◽  
Curing Temperature ◽  
Curing Agent ◽  
Matrix Composites ◽  
Transparent Material ◽  
Properties Of Materials

Phosphate of chrome-alumina (PCA) matrix composites were successfully prepared via thermoforming by using chrome-aluminum phosphate as adhesive, ZnO as curing agent and single component or combination of Al2O3, SiO2, SiC and Si3N4as fillers. We have studied the effect of different fillers on the mechanical properties, dielectric properties and moisture absorption rate of composite materials. Results show that, for the PCA-III system, when curing temperature is 180°C, the dielectric properties of materials are the best and the moisture absorption rate is the minimum; When the amount of filler is 35%, the mechanical properties of PCA-III system are the best (i.e. the tensile strength is 94.4MPa and the flexural strength is 134.7MPa).

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