Effects and measurements of polyoxyethylene block length in polyoxyethylene‐polyoxybutylene copolymers

Abstract

Block copolymer surfactants, made from 1,2-butylene oxide (BO), propylene oxide (PO) and ethylene oxide (EO), exhibit wide ranges of properties and performance. In particular, BO/EO block copolymers exhibit improved surfactant performance with respect to PO/EO analogs. One interesting difference between these two classes of surfactants is the EO capping efficiency of polyoxypropylene {POP) vs. polyoxybutylene (POB) hydrophobe secondary hydroxyl groups. In this regard, nuclear magnetic resonance measurements have shown that POP secondary diols react more readily with EO than POB diols. For the case of ethoxylated POB polymers, the amount of unethoxylated secondary hydroxyl is proportional to the average length of the polyoxyethylene (POE) blocks. Differential scanning calorimetry was used to observe crystallinity of POE blocks. For a given POB hydrophobe molecular weight and weight percentage EO, surfactant performance properties can be augmented by affecting POE block length in the ethoxylation process.

Effect of Surfactants on Association Characteristics of Di- and Triblock Copolymers of Oxyethylene and Oxybutylene in Aqueous Solutions: Dilute Solution Phase Diagrams, SANS, and Viscosity Measurements at Different Temperatures

“…For example, B block is more hydrophobic than P block and EB or EBE copolymers are fairly homogeneous in composition [1]. The surfactantlike properties including gelation behavior of several of laboratory synthesized or commercial E n B n and E n B m E n copolymers in aqueous media have been the subject of many scientific investigations [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In colloidal engineeringbased applications such as detergency, dispersion, stabilization, foaming, emulsification, lubrication, control release of drugs, the block copolymers and low molar mass surfac-tants are often used in combination with each other.…”