PEG-4000 Plays A Role in Rubber:

In general, PEG-4000 is used in rubber. If the molecular weight is too low, the compatibility is poor and it is easy to precipitate. Moreover, it is a liquid, which is not easy to add. If the molecular weight is too high, the number of alcohol groups per unit mass is less (low hydroxyl value), and the neutralizing effect of acid is slightly worse. Because PEG-4000 has a solid flake-like molecular weight, it is easy to process and add, and it is less prone to precipitation. The medium molecular weight polymer has better compatibility with rubber, so PEG-4000 is usually chosen.

The effects of PEG can be summarized as follows:

1. Processing aids can improve the extrusion speed of rubber compounds, improve demoulding properties, and make the finished product surface bright. They also help to expel water during vulcanization. When used in tires and rubber molded products, PEG-4000 has good lubricating properties, making the finished product surface smoother. In the production process of natural rubber and synthetic rubber, it can also be used as an internal demoulding agent. The advantage is that it is non-volatile, does not produce ash change, and the mold remains clean after demoulding. Moreover, the surface of the molded product is also made smoother and cleaner by its addition.

2. Sulfur activators play a role in regulating the bonding performance between the rubber and fillers (especially white ones), as well as lowering the Mooney viscosity and increasing the sulfation rate. They have a better activating effect on thiazole-type accelerators, which can improve the sulfation speed and degree of crosslinking, especially for EPDM white CB-reinforced extrusion microwave continuous sulfation formulations. PEG should not be used for products bonded with metals.

3. Acidic fillers' activators, especially for silica, can be used as silica treatments to activate the vulcanization system and wet the surface of acidic fillers such as silica. One reaction is neutralization, and the other is similar to coating. Because acidic fillers will adsorb, please note that the adsorbent promoter is also being used. The amount used is proportional to the acidic surface area of the filler, etc. We can basically understand that the acidic surface has been neutralized. Of course, other vulcanization reactions may also occur with acidic substances such as HS, and those will be taken care of by zinc oxide.

4. Activated dispersing agents are used as activated dispersing agents in rubber compounds containing various fillers and pigments. They can reduce or eliminate the influence of fillers on vulcanization, make various additives disperse evenly and prolong the scorch time, and improve the physical and mechanical properties of rubber products. In various colored rubber products, they can make the products have vivid colors. Due to their polar characteristics, they can also enhance the absorption of non-polar rubber (such as EPDM) to microwaves.