The role of polyethylene glycol in rubber

Polyethylene glycol this thing is very commonly used, all walks of life are useful, in the rubber is mainly to neutralize the acidic filler, accelerate the curing speed and crosslinking density, has good water solubility, and has good compatibility with many organic components, has excellent lubricity, moisture, dispersion, but also can do antistatic agent and softening agent.

In general, PEG-4000 is used in rubber, if the molecular weight is too low, the compatibility is not good, it is easy to precipitate, and it is a liquid, it is not good to add, the molecular weight is too high, the alcohol group per unit mass is less (low hydroxylation value), and the acidic effect is almost almost, because the molecular weight of 4000 is a solid sheet, easy to process, convenient to add, not easy to precipitate, and the polymer of medium molecular weight, Good compatibility with rubber, so generally choose PEG-4000

The role of polyethylene glycol can be summarized as follows:

1. Processing aid

It can improve the extrusion speed of the compound, improve the release property, and make the surface of the product bright, but also help to discharge water during vulcanization. When applied to tires and rubber moulded products

PEG-4000 has a good lubrication effect, making the surface of the product smoother. In the production process of natural rubber and synthetic rubber, it can also be used as an internal release agent. The advantage is that it is not volatile, does not produce gray change, and keeps the mold clean after demoulding. Moreover, the surface of molded products is also smoother and cleaner due to its addition.

2. Sulfide active agent

Play a role in regulating the binding properties of raw rubber and fillers (especially white), and reduce the role of Mooney, improve the vulcanization rate, especially for thiazole accelerators have a better activation effect, can improve the vulcanization rate and crosslinking degree. Especially in EPDM white CB reinforced extrusion microwave continuous vulcanization formula. It is best not to use PEG for products bonded with metal.

3. Active agent for acid fillers

In particular, white carbon black can be used as a treatment agent for white carbon black to activate the vulcanization system. Wet the surface of acidic filler such as white carbon black. One reaction is neutralization, and one is similar to covering. Because the acid filler will adsorb, please note that it is an adsorptive accelerator. The amount of use is proportional to the amount of acidic surface area of the acid filler and so on. We can basically understand that the acidic surface has been neutralized. Of course, other vulcanization reactions will also appear acidic, such as HS and so on. The zinc oxide will take care of that.

4. Activating dispersant

When using a variety of fillers and colors as an activation dispersant in the rubber compound, it can reduce or eliminate the effect of the filler on vulcanization, make the various additives dispersed evenly and extend the scorch time, and improve the physical and mechanical properties of rubber products. In all kinds of colored rubber products, it can make the products bright in color.

Due to its polarity characteristics, it can also enhance the absorption of microwave on non-polar rubber (such as EPDM).

With the increase of molecular weight of polyethylene glycol, the activity decreased moderately, and the modification effect of hydroxyl groups on the surface of the filler was slightly weakened, but when used, the coke activation of the accelerator was weakened, that is, with the increase of molecules, it helps to stabilize the sulfur coke, and the reinforcement effect of the material and rubber was slightly unfavorable.