Structure of vinyl polysiloxane on properties of polyacrylates film and its pigment printing application

Polysiloxane is a promising modified material due to its good hydrophobicity and toughness, but it suffers from serious uneven distribution and migration during film formation process which gradually lead to the destruction of the hydrophobic structure. A novel silicon-modified copolymer with different molecular weight and vinyl content was synthesized to overcome this problem: an appropriate amount of double bonds between the polysiloxane backbone ensures uniform distribution. Moreover, a multicrosslinked network binder was prepared by miniemulsion polymerization of the polyacrylate copolymers and polysiloxane. Unlike the common crosslinked network of an uneven distribution and migration of silicone backbone, the polysiloxane with suitable crosslinking degree and molecular weight could be effectively distributed evenly during the film formation process. As a result, a better hydrophobicity and toughness performance (89.7° ± 0.5°, 2500% elongation at break) was achieved with this novel poly(methylvinylsiloxane) with 11,024 g/mol at 0.804 mmol/g vinyl content. The product was applied to pigment printing with better wet rubbing fastness and soft handle compared with the unmodified polyacrylates binder. The DSC, SAXS, and XPS indicated that high molecular organosilicon chain and moderate vinyl content were prone to phase separation and obviously shifted onto the surface of film, enriching a uniform organosilicon layer, which played a vital role in the surface hydrophobicity and mechanical properties.