Synthesis and characterization of polyurethaneurea–vinyl polymer (PUU–VP) uniform hybrid microspheres by SPG emulsification technique and subsequent suspension polymerization

Abstract

Uniform polyurethaneurea-vinyl polymer (PUU-VP) hybrid microspheres of about 20 m were prepared by a Shirasu porous glass (SPG) membrane emulsification technique and a subsequent radical suspension polymerization process, that is, a mixture of a 40 wt % urethane prepolymer (UP) solution of xylene and a vinyl monomer (VP) containing an initiator was permeated through the uniform pores of the SPG membrane into a continuous phase containing a stabilizer to form uniform droplets. Then, the droplets were allowed to stand for chain extension at room temperature with di-or triamines for 2 h in the absence or presence of ethyl acetate (EA), followed by suspension polymerization at 70°C for 24 h. The effect of the type and the amount of the monomer composition, crosslinker, and chain extender on the monomer conversion, particle morphology, and stability of the dispersion was investigated. A strong relationship was found between the compatibility of PUU with VP and the stability of the dispersion. The monomer conversion increased and the stability of the dispersion was improved as the amount of the crosslinker was increased. Solid and spherical PUU-VA hybrid particles with a smooth surface and a higher destructive strength were obtained when a trifunctional crosslinker and a chain extender were used together.

Production of molecularly imprinted polymer particles with amide-decorated cavities for CO 2 capture using membrane emulsification/suspension polymerisation

“…Acrylamide-based molecularly imprinted 32 polymer (MIP) particles for CO 2 capture with a separation factor of up to 340 at a CO 2 partial 33 pressure of 15 kPa have been fabricated using bulk polymerisation [23]. MIPs contain 34 inherently functionalised nanocavities, which are complementary in shape to the target 35 molecule, and can act as active sites for capturing the target molecules (Fig. 1).…”

Preparation of highly monodisperse W/O emulsions with hydrophobically modified SPG membranes

“…The SPG membrane is inherently hydrophilic owning to the presence of silanol groups on the surface [14], which means it is more adequate to produce O/W emulsions. In the last decade, SPG membranes have been widely applied to fabricate monodisperse O/W emulsions, and resultant microcapsules and microspheres [15][16][17][18][19][20][21][22][23][24][25][26][27].…”

Formation and Modification of Dispersions Using Shirasu Porous Glass Membranes

“…Suspension polymerisation can be carried out in O/W (Ma et al, 2003), W/O (Hu et al, 2011) or W/O/W emulsion (Ma et al, 2004) and can be combined with droplet swelling technique (which is known as "two-stage" suspension polymerisation) to produce microspheres from hydrophilic monomers (Omi et al, 1997). Hollow particles were produced by combining SPG membrane emulsification with interfacial polymerisation (Chu et al, 2003), internal phase separation (Liu et al, 2010), molecular imprinting (Kou et al, 2012), and coating a shell around polymer particles by a sol-gel process (Kong et al, 2013) or interfacial crosslinking (Akamatsu et al, 2010) followed by core disintegration by chemical dissolution or calcination.…”