Tween Polyoxyethylene sorbitan fatty acid ester, scientific name of Tween, is amber viscous liquid to yellow waxy substance, divided into food grade, medical grade and industrial grade, suitable for pharmaceutical industry, food industry, cosmetics industry, etc. Tween (also known as ethoxylated sorbitol ester) is formed by the condensation of residual hydroxyl groups in the Span molecule with ethylene oxide. In the process of polyoxyethylene, a transesterification reaction occurs, and the ester group previously directly attached to sorbitan can be rearranged to the hydroxyl end of the oxyethylene chain. They are suitable as oil-in-water (O/W) emulsifiers, solvents, dispersants, stabilizers, antistatic agents, lubricants and cleaners.

Sorbitan fatty acid ester (SPAN) is a non-ionic surfactant with fatty acid group as hydrophobic part and sorbitol as hydrophilic part.

PEG 400/2000/4000

Crab shells are rich in a natural resource, namely chitosan.