Epoxy-modified properties

Adherent films would not necessarily require formation of covalent bonds at the Interface, since localized lntermolecul u dispersion forces that u e operative In the adsorption of coatings (with good wetting properties) should provide stable interfacial bond conditions. Among candidate materials which could fulfill the requirements of good adhesion and substrate protection from moisture are epoxy-modified polyurethanes and epoxy-siloxane polymers. 

Cement hydration and epoxy polymerization occur simultaneously to form a structure that is similar to the latex-modified cementitious system. Epoxy systems develop high strength, adhesion and have low permeability, good water resistance and chemical resistance. A major advantage of this system is that it can be cured under moist or wet conditions. According to a recent study, the epoxy-modified mortars can be made without the hardeners with superior properties to those obtained with conventional epoxy mortars [89, 90]. 

Auad, M.L. Zhao, L.H. Shen, H.B. Flammability properties and mechanical performance of epoxy modified phenolic foams. J. Appl. Polym. Sci. 2007,104, 1399-1407. 

Fig. 13 is a TTT cure diagram of three systems a neat epoxy resin and the same epoxy modified with two reactive rubbers at the same concentration level. The times to the cloud point, gelation and vitrification are shown for each system. The cloud point is the point of incipient phase separation, as detected by light transmission. The modified system with the longer times to the cloud point and gelation, and the greater depression of Tg, contains the more compatible of the two rubbers. The difference in compatibility could then be used to account for differences in the volume fractions of the phase separated rubber-rich domains and in the mechanical properties of the neat and the two rubber-modified systems. 

Morton International (undated b) ELP-3 Epoxy Modifier, product properties, Morton International Ltd, Coventry, UK. 

In this paper, we report the preliminary results on the synthesis and properties of epoxy-modified ZrP. These materials show classical graded characteristics in composition, microstructure, and properties. The microstructure-property relationships in these novel FGMs are discussed. 

The presence of infiltrated epoxy has imparted significant increases in strength, hardness, elastic modulus, and toughness. The improvement in these properties can be attributed to the pore-filling effect and the concomitant reduction in the overall residual porosity. Porosity has been established by various workers to have a profound influence on hardness, strength, and elastic modulus [10]. This identical strengthening mechanism has also been observed for epoxy-modified HTSC materials [7],... 

Uses Epoxy hardener, curing agent for powd. coatings containing 2% accelerator and 2.5% flow modifier Properties Gardner 1 max. solid vise. 290-470 cps (150 C)... 

Uses Cocuring agent, modifier for epoxy and hot-melt adhesives, coatings, corrosion inhibitors, epoxy curing adhesives/coatings, hydrophilic polymers, isocyanate precursors, epoxy resins Properties M.w. 2000 Jeffamine EDR-148 [Huntsman]... 

Uses Epoxy modifier esp. suited for use in wh. and pastel coatings, and in hot-melt, hot-melt pressure-sensitive, and pressure-sensitive adhesives diluent for low-vise, epoxy systems pigment wetting agent plasticizer for epoxy system injections provides impermeable membrane between asphaltic surfs, and concrete bridge decks Properties Gardner 1 resin sol. in alcohols, chlorinated hydrocarbons, esters, ethers, ketones (except acetone), aromatic, naphthenic, and terpene hydrocarbons partially sol. in paraffinic hydrocarbons m.w. 225 vise. 1.75 poises hyd. no. 50 Toxicology TSCA listed Nevoxy EPX-L5 [Neville]... 

Epoxies modified with butadiene acrylonitrile copolymers with (32) amine or carboxy end groups have disadvantages. They are susceptible to thermal and oxidative degradation and also have poor hot/wet properties, i.e., they soften when exposed to heat and moisture for long periods. Polysiloxane rubbers such as polydimethylsiloxane have been considered as a possible alternative. 

Table 8. Mechanical properties of a tetrafunctional epoxy modified with a polysulfone. ...

Mix property HRA with epoxy-modified bitumen HRA with conventional bitumen... 

S. Dutta, N. Karak, J. P. Saikia and B. Konwar, Biocompatible epoxy modified bio-based polyurethane nanocomposites mechanical property, cytotoxicity and biodegradation , Bioresour Technol, 2009,100, 6391-7. 

The presence of reactive sites such as double bonds, hydroxyl and carboxyl groups and phenyl rings in aromatic anhydride and ester linkages all provide tremendous potential for the modification of oil-modified polyester. Epoxy resins are considered to be polyols, which react with the carboxylic functions of polyester resin. The modification of oil-modified polyesters with epoxy resins results in products with excellent adhesion properties and improved water and chemical resistance. Epoxy modified polyesters are less expensive than epoxy resins. 

Two types of environmentally friendly jute fibre reinforced green composites have been studied. These are based on Mesua ferrea L. seed oil-based poly(urethane ester) and poly(urethane amide) resin blends with commercially available partially butylated melamine-formaldehyde and epoxy resins by solution impregnation and hot-curing methods. The composites were cured at a temperature of about 130-140°C under a pressure of 35.5 kg cm for around 2 h.The physical, mechanical and chemical properties of the epoxy-modified polyurethane composites were better than those of the MF-modified composites. They also possessed excellent chemical resistance and hydrolytic stability in water, acid and salt solutions, making them useful for low load-bearing applications. 

Epoxy-modified Mesua ferrea L. seed oil-based polyurethane/clay nanocomposites at different loadings (1-5 wt%) have been studied as biocompatible biomaterials. The partially exfoliated nanocomposites were prepared by an ex situ solution technique under high mechanical shearing and adequate ultrasonication at room temperature. The nanocomposites exhibited enhanced mechanical properties such as tensile strength (twofold) and scratch hardness (five-fold), thermostability (to about 40°C), and an increase in the rate of biodegradation between five- and ten-fold. All the nanocomposites showed RBC haemolysis inhibition observed by anti-hemolytic assay carried out on the sterilised films. 

Nano-clay incorporated polymer coatings are important for modifying properties of surfaces. Nano-clay incorporated thermoset polymer nanocoatings exhibit superior properties such as super-hydrophobicity, improved wettability, excellent resistance to chemicals, corrosion resistance, improved weather resistance, better abrasion resistance, improved barrier properties and resistance to impact, scratches, etc. [116]. The parameters such as dipping time, temperature, nature of surfactant, and purity of nanomaterials decides the coating thickness. Clay-epoxy coating... 

Ohama, V., Demura, K., and Endo, T. (1992) Strength properties of epoxy-modified mortars without hardener, m. Proceedings 9th ICCC, New Delhi, Vol. 5, pp. 512-511. 

Property Epoxy Modified phenolic Polyurethane Modified acrylic ... 

Reactive flexibilizers such as polysulfldes, urethanes, polybutadienes, and polyesters are copolymerized with epoxies to increase flexibihty, improve adhesion, modify electrical properties, and improve resistance to chemicals. Nonreactive extenders such as thermoplastics, asphaltums, and waxes are used to modify properties and reduce the cost of the compounds. Polyarylene ether sulfone as an extender in epoxy resins increases the fracture toughness fivefold with only a slight drop in Tg. 

An epoxy modified vinyl ester polyester offering excellent mechanical properties and good chemical-corrosion resistance, low shrinkage, higher tensile and elongation properties. Suitable for hand-lay and filament winding. 

The viscoelastic and thermal properties of fully and partially cured DGEBA epoxy resin composites were smdied modified with montmorillonite nanoclay exposed to UV radiation. Samples were fabricated and cured to 80 % conversion (partially cured) based on isothermal cure kinetic smdies. Influence of 1-3 wt% loading of montmorillonite nanoclay on the cure behavior and development of physical properties of these composites were evaluated. Results of the smdy revealed that for optimization of modified epoxy composite properties, a different curing cycle was necessary due to interaction of different amounts of nanoclay and epoxy molecules. Addition of nanoclay increased the viscoelastic properties, storage modulus and activation energy of decomposition of partially cured samples evolved over exposure time, while fuUy cured samples degraded over the same period. 

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