Suspension Polymerization of Styrene with Pickering Emulsifiers

Suspension Polymerization Processes

“…The blowing agent vaporises, when the beads are subsequently heated, so that the beads expand and fuse to form a foam. With some particulate stabilisers, small amounts of surfactants may be necessary and the effect of electrolytes can also be important [25,26]. Inorganic stabilizers, such as metal hydroxides, can sometimes be removed from the final polymer particles (by using dilute acids) [24] so that low levels of product contamination are achieved.…”

“…In contrast, those which have a relatively small contact angle (such as carbon black) would tend to be destabilizers. However, contact angles with powdered solids are difficult to measure and values may vary with conditions [26]. Mechanisms of drop stabilization by inorganic solids are still a matter for debate [25,28].…”

Síntese e caracterização de beads acrílicos preparados por polimerização em suspensão visando aplicação como excipiente farmacêutico para compressão direta

“…[44][45][46][47][48][49][50] Partículas como a sílica, a laponita, a montmorilonita, os carbonatos e óxidos nanoparticulados vêm sendo utilizadas como estabilizantes por Pickering. 44,[51][52][53][54][55] Assim, além do desenvolvimento de um novo excipiente, outro objetivo deste trabalho foi investigar a estabilidade de sistemas de polimerização em suspensão empregando diferentes tipos de estabilizantes, nomeadamente, os nanocristais de celulose e a sílica mesoporosa. Apesar de diversos trabalhos que abordam tal tema, não foram encontrados relatos na literatura técnica e científica acerca do emprego dos agentes selecionados.…”

Preparation and characterization of colloidal dispersions of vinyl alcohol–vinyl acetate copolymers: application as stabilizers for vinyl chloride suspension polymerization

“…The main advantage of Pickering stabilizers, with respect to molecular dispersed surface‐active species, is that coarse emulsions (i.e. particle sizes of 10–50 µm) with excellent stability can be obtained 11–13. This is actually also the goal of the suspension polymerization process of VCM and where polymeric stabilizers based on PVAs would be of particular interest.…”

“…A major interest of these colloidal systems is in terms of the possibility of using them to stabilize VCM-water emulsions by adsorption of colloidal particles on an oil-water interface, typical of a Pickering stabilization mechanism. This effect, otherwise well demonstrated in the literature, 10,11 has not been considered so far for VCM-water emulsions.…”