Multiscale structures and rheology of bisurea-loaded resins for anti-sagging applications.

Four representative bisurea molecules (HDI-BA, MDI-BA, TDI-BA, and IPDI-BA) were synthesized and dispersed simultaneously by reacting benzylamine (BA) with various types of diisocyanates in a polyester/-xylene resin medium to produce bisurea-loaded resins (BLRs) for anti-sagging application with paints and coating materials. These bisurea molecules are symmetric and differ only in the central spacer unit, thereby presenting an ideal and simplest model system to delve into the structure-performance relationship. The multiscale structural features arising from self-assembly in each of the BLRs were scrutinized using the combination of multi-angular dynamic light scattering (DLS), small-angle light/X-ray scattering (SALS/SAXS), rheology, and scanning electron/optical microscopy (SEM/OM) characterization.

Multiscale structural and rheological features of colloidal low-methoxyl pectin solutions and calcium-induced sol-gel transition.

The multiscale structural and rheological features of a series of dilute and semidilute low-methoxyl (LM) pectin solutions and a representative pectin/calcium sol-gel sample were systematically explored using a comprehensive combination of dynamic (DLS) and static light/X-ray scattering (SALS/SLS/SAXS), rheology, and microscopy (OM/SEM) characterizations. The study focused on the rarely explored colloidal aspect of LM pectin solutions and sol-gel transition, in contrast to the polymeric features extensively explored in previous studies. A highly uniform colloid-like, micron-sized agglomerate species was revealed in dilute solutions, with a progressively increased degree of flocculation in the semidilute regime (≥1.