Development of Used Polystyrene Modified Adhesive II

2.2 Effect of butyl acrylate (BA) on the properties of colloidal emulsion

The amount of butyl acrylate was changed, and the effect of the determination amount on shear strength and viscosity was shown in FIG. 2 . From Figure 2, it can be concluded that with the increase in the amount of BA, the viscosity of the adhesive and the shear strength of the wood are also increasing. When the amount of the monomer exceeds 3.5 s, the viscosity and shear strength of the adhesive are drastically decreased. This is due to the introduction of the modifier BA, the introduction of polar groups (hydroxyl and ester groups) in PS large and medium, to improve its polarity to increase the bonding strength of PS adhesive, while enabling cross-linking reaction of PS chain , reduce its brittleness to improve the toughness of Ps rubber. However, when the amount is excessive, the viscosity and shear strength of the adhesive decrease, which may be due to the dramatic increase in the degree of polymerization of the emulsion, resulting in increased local BA homopolymerization of the emulsion and agglomeration, resulting in dispersion in the emulsion, and poor performance. Therefore, the best dosage of BA is 3.5s, which is about 23% of PS.

2.3 Effect of methyl methacrylate (MAA) on the properties of colloidal emulsion

The amount of functional monomer MAA was changed, and the resulting PS adhesive was adhered to wood to study its effect on shear strength. The results are shown in Figure 3. From the figure, it can be seen that as the amount of MAA increases, the shear strength increases rapidly as the amount of MAA increases; however, if the amount of functional monomer exceeds 1.0 g, the amount of functional monomer continues to increase, and the increase in adhesive strength is not obvious. Cross-linking increased and declined. Moreover, the more monomer is used, the higher the cost. Therefore, the suitable amount of MAA is 1.0g

2.4 Crosslinker effects

The cross-linking agent used was toluene diisocyanate, and the amount of cross-linking agent used was changed to study its effect on the modified PS glue. The results are shown in FIG. 4 . From the figure, it can be seen that with the increase of the amount of cross-linking agent, the shear strength of the modified PS adhesive first increases to a certain value, and then it decreases again, and the effect on the viscosity is small. This is due to the fact that the cross-linking agent is a strongly polar substance that can increase the polar groups of the Ps glue to increase the degree of cross-linking of the modified rubber.” The use of the cross-linking agent increases the adhesive properties, but when the amount is too much, the adhesive layer is Excessive bonding leads to hardening and brittleness, which leads to a decrease in adhesive strength. In addition, it has been found that the amount of cross-linking agent is too much, which can easily reduce the emulsion stability and even break the emulsion. Therefore, when the amount of cross-linking agent is o.2gg, Modified effect is better.

(to be continued)