Vinyl polymers prepared via suspension polymerization and methods thereof

A method of producing vinyl polymer particles by suspension polymerization comprising:

• combining an aqueous media and a tricalcium phosphate to a reaction vessel;
• adding a pH stabilizing agent to the reaction vessel;
• adding a vinyl monomer to the reaction vessel;
• adding a peroxide initiator, which also generates CO2 as a result of primary or secondary decomposition, to the reaction vessel;
• adding surfactant or a water soluble free radical initiator to generate surfactant in situ to the reaction vessel;
• maintaining the reactor contents at greater than or equal to 90° C. until a density of a dispersed phase becomes substantially equal to that of a continuous phase, thereby forming a suspension having an initial pH;
• optionally adding a second quantity of tricalcium phosphate and optionally a second quantity of surfactant or optionally a second quantity of water soluble free radical initiator to generate surfactant in situ to the reaction vessel;
• adding a blowing agent to the reaction vessel;
• raising the temperature of the reaction vessel to greater than or equal to 100° C. and holding at said temperature for greater than or equal to 1 hour;
• and
• collecting polymer particles.