Master the Basics of Chemical Industry Classification Firsthand

The chemical industry, chemical engineering, and chemical processes are all commonly referred to as "chemicals." The chemical industry encompasses sectors such as petrochemicals, agrochemicals, pharmaceutical chemistry, polymers, coatings, and specialty oils. Emerging in different historical periods, these fields each carry distinct meanings yet remain closely interconnected—deeply intertwined, mutually influential, and characterized by continuity. Over time, they have evolved to incorporate new ideas and applications. Broadly speaking, any process that employs chemical methods to alter the composition or structure of materials—or to synthesize entirely new substances—falls under the umbrella of chemical production technology, or simply chemical processes. The products generated through these processes are known as chemicals or chemical products.

2022-01-10

Preparation of Polyether-Modified Polysiloxane Defoamers

Ordinary polysiloxane defoamers, due to their low surface energy and strong hydrophobicity, exhibit poor miscibility with other organic substances, leading to particularly ineffective performance in aqueous systems. For instance, under high-shear and high-temperature conditions—such as those encountered in jet dyeing processes—conventional polysiloxane defoamers tend to form film-like precipitates, which can cause spotting on dyed fabrics. In contrast, polyether-modified polysiloxanes, thanks to the incorporation of hydrophilic polyether segments, can disperse and emulsify effectively in water while maintaining excellent emulsion stability. Additionally, these polymers possess inverse solubility properties, making them ideal for high-temperature, high-pressure liquid-flow dyeing processes. As a result, polyether-modified polysiloxanes have increasingly gained attention in recent years for their applications in defoaming agents. In this experiment, we used highly hydrogenated silicone oil as the raw material and synthesized low-hydrogenated silicone oil via a controlled polymerization method. Meanwhile, propargyl alcohol was employed as the initiator, and NaOH served as the catalyst to carry out ring-opening copolymerization of ethylene oxide and propylene oxide, yielding an allyl-terminated polyoxyalkylene ether. Finally, this allyl-terminated polyoxyalkylene ether was grafted onto the low-hydrogenated silicone oil, resulting in the production of the desired polyether-modified polysiloxane, which was then formulated into a defoaming agent.

2021-11-12