8 августа, 2015 
Malyar Fettes and Gannon were the first to report reactions of liquid polysulfide polymers with epoxy resins [16]. In these adhesives, the epoxy resin is the major component. The polymer LP-3 in which n = 8 has been used most extensively. This polymer has a molecular weight of about 1000 with viscosity in the range 7 to 12 P. The epoxy resins most widely used in adhesive formulations have viscosities the range 80 to 200 P with an epoxy equivalent of 175 to 210. Typical resins are Epon 820 and 828 (Shell), ERL-3794 (Union Carbide), and Araldite 6020 (CIBA). The epoxy-polysulfide reaction is prompted by organic amines (e. g. diethylenetriamine and benzyldimethylamine). The general reaction of a polysulfide polymer, epoxy resin, and amine hardner is
These adhesives are used in the construction, electrical, and transportation industries because of flexibility, adhesion to many substrates, and chemical resistance. They find
|
Parts by weight |
Formulation 1 |
Formulation 2 |
|
Part I |
||
|
Thiokol LP-3 |
100 |
100 |
|
Silica (HDS-100) |
80 |
— |
|
Hydrite 121 |
— |
140 |
|
EH 330 |
20 |
20 |
|
Toluene |
— |
65 |
|
Part II |
||
|
Epon 820 |
200 |
200 |
|
Hydrite 121 |
— |
105 |
|
Toluene |
— |
5 |
|
Working and curing properties |
||
|
Brush life (h) |
0.2 |
1.4 |
|
Trowel life (h) |
0.25 |
— |
|
Setting time for 0.25 mm (h) |
0.8 |
3.5 |
|
Tack-free time for 0.25 mm (h) |
5.0 |
— |
|
Cure time for 0.25 mm (h) |
— |
24 |
|
Ratio of part I to part II |
1:1 (wt) |
1:1 (vol) |
application as adhesives for steel, aluminium, ceramics, wood, and glass; for concrete crack repair and patch repair; as a grouting compound; and as an automotive body solder. Fillers (e. g., calcium carbonate, graphite, milled glass fibers, silica, and talc) can be added to polysulfide-epoxy adhesives to extend pot life, reduce exotherm, and increase rigidity and impact strength. Two formulations of liquid polysulfide-epoxy concrete adhesives are shown in Table 3.
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