Mixing epoxy-modified

Table 7,1 Typical Mix Proportions of Epoxy-Modified Concrete. ( 1987, American Concrete Institute, reprinted with permission.)...

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

Considering epoxy resin filled with potassium titanate whisker as an example, the specific operation is as follows. Mix bisphe-nol A-glycidyl methacrylate (bis-GMA) and triethylene-glycol dimethacrylate at a mass ratio of 1 1 as a resin matrix add initiator benzoyl peroxide (BPO) and the polymerization inhibitor butylated hydroxytoluene (BHT, 264) and blend uniformly. Then mix surface-modified potassium titanate whisker into the resin, fill into the mold, and cure in an oven at 120°C for 30 minutes. 

After the mixed epoxy resin was degassed, the samples for volumetric measurements were prepared by placing pristine and modified epoxy systems in 2.5-cc disposable aluminum cups (see Figure 18.1). The initial mass of epoxy resin was recorded and monitored between consecutive volumetric measurements. Finally, resin samples were cured in a convection oven at 60 °C for 2 h followed by postcuring at 94 °C for 4 h. 

Epoxy resin has superior properties such as high adhesion and anticorrosion, and has widely been used as adhesives and anticorrosives in the construction industry in the world. Provided the incorporation of the epoxy resin into cement mortar can give its superior properties to the mortar, it is possible to produce a highly polymer-modified cement mortar. The first patent of an epoxy-modified cement system was taken by Donnelly in 1965 [1]. Since the patent, 30 or more papers on the epoxy resin modification of the cement mortar and concrete have already been published [2]. Most epoxy resin-based cement modifiers dealt with in the papers are specially compounded by the manufacturers, and the procedures for mixing them to fresh mortar and... 

This paper consists of two parts as follows (1) The selection of the optimum mix proportions of the epoxy-modified mortars prepared without the use of specially compounded epoxy resin-based cement modifiers in the same manner as conventional cement mortar, and (2) The investigation concerning the properties of the epoxy-modified mortars with the optimum mix proportions. 

From the above test results, the optimum mix proportions of epoxy-modified mortars are recommended as shown in Table 2. ... 

Preparation of specimens According to JIS A 1171, epoxy-modified mortars were prepared with the mix proportions as shown in Table 2. Mortar specimens with the geometry indicated in Table 3 were molded, and then given a 2-day-20°C-80%R.H.-moist plus 5-day-20 C-water plus 21-day-20 °C-50%R.H.-dry cure. 

Epoxy-modified mortars which are prepared by mixing most popular bisphenol A-type epoxy resin with commercial modified polyamide-amine hardener, polyalkyl aryl sulfonate-type water-reducing agent, polyoxyethylene nonylphenol ether-type nonionic surfactant and silicone emulsion-type antifoamer into cement mortar have excellent properties comparable to ordinary polymer-modified mortars using latex-type cement modifiers[5]. The optimum mix proportions of the epoxy-modified mortars are shown in Table 2. Their disadvantage is a need of much higher polymer-cement ratio than the ordinary polymer-modified mortars. Therefore, the development of low-cost, effective dispersants is expected in the near future. 

A variety of materials has been proposed to modify the properties of asphaltic binders to enhance the properties of the mix (112), including fillers and fibers to reinforce the asphalt—aggregate mixture (114), sulfur to strengthen or harden the binder (115,116), polymers (98,117—121), mbber (122), epoxy—resin composites (123), antistripping agents (124), metal complexes (125,126), and lime (127,128). AH of these additives serve to improve the properties of the binder and, ultimately, the properties of the asphalt—aggregate mix. 

S02-cured epoxy resin. Modified epoxy/acrylic resins (1.2 to 1.4% of sand weight) are mixed with organic peroxide (26 to 60% of resin weight), the mixture is blown into the core box and a hardening mechanism similar to the S02 process takes place. 

Of the several types of the polymer-modified mortars and concretes used for various construction applications, latex-modified mortar and concrete are by far the most widely used materials. Latex-modified mortar and concrete are prepared by mixing a latex, either in a dispersed liquid or as a redispersible powder form with fresh cement mortar and concrete mixtures. The polymers are usually added to the mixing water just as other chemical admixtures, at a dosage of 5-20% by weight of cement. Polymer latexes are stable dispersions of very small (0.05-5 pm in diameter) polymer particles in water and are produced by emulsion polymerization. Natural rubber latex and epoxy latex are exceptions in that the former is tapped from rubber trees and the latter is produced by emulsifying an epoxy resin in water by the use of surfactants [87]. 

In Table 2 are tabulated the Tg values for resins modified with the siloxane copolymers described in Table 1. Transition temperatures for samples modified with oligomers containing primarily dimethyl siloxane units give little indication of intimate mixing beween epoxy and rubber. Evidence for partial miscibility with increasing... 

Li and Netravali [121] modified an UHSPE fiber surface using allylamine plasma deposition to improve its adhesion to epoxy resin. The shear strength of the modified surface increased by a factor of 2-3 when measured by pull-out test using a U-shaped epoxy resin. The epoxy resin and a curing agent were mixed and molded into U-shaped form without disturbing the fiber (see Fig. 8). 

The fabrication of the material that forms when linear polyimides are mixed or coupled with epoxy resins to form three dimensional interpenetrating networks (IPN) is wrought with problems. These can be viewed from a polymer science aspect, where chemically modifying the structure of the components will result in their compatibility or from an engineering viewpoint where modifying existing fabrication methods and formulations will result in the desired composite materials. The following is a summary of research of epoxy and polyimide combinations to date. 

Because the components must initially form miscible solutions or swollen networks a degree of affinity between the reacting components is needed. Therefore, most of the investigations into epoxy IPNs have involved the use of partially miscible components such as thermoplastic urethanes (TPU) with polystyrenes [57], acrylates [58-61] or esters which form loose hydrogen-bound mixtures during fabrication [62-71 ]. Epoxy has also been modified with polyetherketones [72],polyether sulfones [5] and even polyetherimides [66] to help improve fracture behavior. These systems, due to immiscibility, tend to be polymer blends with distinct macromolecular phase morphologies and not molecularly mixed compounds. 

Oligophenylethoxysiloxanes are used as modifiers for various polymers to improve their weather resistance and other technical characteristics, as well as to increase the heat resistance of coatings. E.g., PES-50 is used to modify polyethers, aciylic and epoxy polymers PES-80 is used to modify alkyd and urea-formaldehyde resins. Besides, PES-80 is used as an additive in paints and enamels (to improve their flow properties, gloss and colour), as well as in concrete mixes (to improve the water resistance and durability of concrete works). 

From container 9 the flushed hydrolysate is sent to partially distil the solvent into tank 77 to produce modified polymethylphenylsiloxane varnishes, it is first mixed with polyester or epoxy polymer in apparatus 7 0, and then sent into the tank. From the tank, the hydrolysate is sent to condensation into three-sectioned apparatus 12. In the first section the solvent is additionally distilled and the product of the hydrolytic cocondensation is partially condensed in the second section it is further condensed at 125-... 

Molar excess of epoxynovolak resin was reacted with DDS highly branched aminoepoxide resin was thus obtained. The resin was then mixed with a non-modified epoxide resin, BPA/DC-BMI copolymer, benzoyl peroxide and /V-(3,4-dichloro-phenyI)-Ar, Ar -dimethyIurea (curing agent for the epoxy component) [116]. 

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